java/11 : java.management/javax/management/openmbean/OpenMBeanAttributeInfoSupport.java

OpenMBeanAttributeInfoSupport
https://openjdk.java.net/
GPLv2 + Classpath Exception
/*
 * Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */


package javax.management.openmbean;


// java import
//
import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import javax.management.Descriptor;
import javax.management.DescriptorRead;
import javax.management.ImmutableDescriptor;
import javax.management.MBeanAttributeInfo;
import com.sun.jmx.remote.util.EnvHelp;
import sun.reflect.misc.MethodUtil;
import sun.reflect.misc.ReflectUtil;

Describes an attribute of an open MBean.
Since: 1.5/**
 * Describes an attribute of an open MBean.
 *
 *
 * @since 1.5
 */
public class OpenMBeanAttributeInfoSupport
    extends MBeanAttributeInfo
    implements OpenMBeanAttributeInfo {

    /* Serial version */
    static final long serialVersionUID = -4867215622149721849L;

    @serial The open mbean attribute's open type/**
     * @serial The open mbean attribute's <i>open type</i>
     */
    private OpenType<?> openType;

    @serial The open mbean attribute's default value/**
     * @serial The open mbean attribute's default value
     */
    private final Object defaultValue;

    @serial The open mbean attribute's legal values. This Set is unmodifiable/**
     * @serial The open mbean attribute's legal values. This {@link
     * Set} is unmodifiable
     */
    private final Set<?> legalValues;  // to be constructed unmodifiable

    @serial The open mbean attribute's min value/**
     * @serial The open mbean attribute's min value
     */
    private final Comparable<?> minValue;

    @serial The open mbean attribute's max value/**
     * @serial The open mbean attribute's max value
     */
    private final Comparable<?> maxValue;


    // As this instance is immutable, these two values need only
    // be calculated once.
    private transient Integer myHashCode = null;
    private transient String  myToString = null;


    Constructs an OpenMBeanAttributeInfoSupport instance, which describes the attribute of an open MBean with the specified name, openType and 
description, and the specified read/write access properties. 
Params: name –  cannot be a null or empty string.
description –  cannot be a null or empty string.
openType –  cannot be null.
isReadable – true if the attribute has a getter exposed for management.
isWritable – true if the attribute has a setter exposed for management.
isIs – true if the attribute's getter is of the form isXXX.
Throws: IllegalArgumentException – if name or 
description are null or empty string, or openType is null./**
     * Constructs an {@code OpenMBeanAttributeInfoSupport} instance,
     * which describes the attribute of an open MBean with the
     * specified {@code name}, {@code openType} and {@code
     * description}, and the specified read/write access properties.
     *
     * @param name  cannot be a null or empty string.
     *
     * @param description  cannot be a null or empty string.
     *
     * @param openType  cannot be null.
     *
     * @param isReadable {@code true} if the attribute has a getter
     * exposed for management.
     *
     * @param isWritable {@code true} if the attribute has a setter
     * exposed for management.
     *
     * @param isIs {@code true} if the attribute's getter is of the
     * form <code>is<i>XXX</i></code>.
     *
     * @throws IllegalArgumentException if {@code name} or {@code
     * description} are null or empty string, or {@code openType} is
     * null.
     */
    public OpenMBeanAttributeInfoSupport(String name,
                                         String description,
                                         OpenType<?> openType,
                                         boolean isReadable,
                                         boolean isWritable,
                                         boolean isIs) {
        this(name, description, openType, isReadable, isWritable, isIs,
             (Descriptor) null);
    }

    Constructs an OpenMBeanAttributeInfoSupport instance, which describes the attribute of an open MBean with the specified name, openType, 
description, read/write access properties, and Descriptor.
The descriptor can contain entries that will define the values returned by certain methods of this class, as explained in the 
package description.
Params: name –  cannot be a null or empty string.
description –  cannot be a null or empty string.
openType –  cannot be null.
isReadable – true if the attribute has a getter exposed for management.
isWritable – true if the attribute has a setter exposed for management.
isIs – true if the attribute's getter is of the form isXXX.
descriptor – The descriptor for the attribute.  This may be null
which is equivalent to an empty descriptor.
Throws: IllegalArgumentException – if name or 
description are null or empty string, or openType is null, or the descriptor entries are invalid as described in the package description.
Since: 1.6/**
     * <p>Constructs an {@code OpenMBeanAttributeInfoSupport} instance,
     * which describes the attribute of an open MBean with the
     * specified {@code name}, {@code openType}, {@code
     * description}, read/write access properties, and {@code Descriptor}.</p>
     *
     * <p>The {@code descriptor} can contain entries that will define
     * the values returned by certain methods of this class, as
     * explained in the <a href="package-summary.html#constraints">
     * package description</a>.
     *
     * @param name  cannot be a null or empty string.
     *
     * @param description  cannot be a null or empty string.
     *
     * @param openType  cannot be null.
     *
     * @param isReadable {@code true} if the attribute has a getter
     * exposed for management.
     *
     * @param isWritable {@code true} if the attribute has a setter
     * exposed for management.
     *
     * @param isIs {@code true} if the attribute's getter is of the
     * form <code>is<i>XXX</i></code>.
     *
     * @param descriptor The descriptor for the attribute.  This may be null
     * which is equivalent to an empty descriptor.
     *
     * @throws IllegalArgumentException if {@code name} or {@code
     * description} are null or empty string, or {@code openType} is
     * null, or the descriptor entries are invalid as described in the
     * <a href="package-summary.html#constraints">package description</a>.
     *
     * @since 1.6
     */
    public OpenMBeanAttributeInfoSupport(String name,
                                         String description,
                                         OpenType<?> openType,
                                         boolean isReadable,
                                         boolean isWritable,
                                         boolean isIs,
                                         Descriptor descriptor) {
        // Construct parent's state
        //
        super(name,
              (openType==null) ? null : openType.getClassName(),
              description,
              isReadable,
              isWritable,
              isIs,
              ImmutableDescriptor.union(descriptor, (openType==null)?null:
                openType.getDescriptor()));

        // Initialize this instance's specific state
        //
        this.openType = openType;

        descriptor = getDescriptor();  // replace null by empty
        this.defaultValue = valueFrom(descriptor, "defaultValue", openType);
        this.legalValues = valuesFrom(descriptor, "legalValues", openType);
        this.minValue = comparableValueFrom(descriptor, "minValue", openType);
        this.maxValue = comparableValueFrom(descriptor, "maxValue", openType);

        try {
            check(this);
        } catch (OpenDataException e) {
            throw new IllegalArgumentException(e.getMessage(), e);
        }
    }

    Constructs an OpenMBeanAttributeInfoSupport instance, which describes the attribute of an open MBean with the specified name, openType, description and defaultValue, and the specified read/write access properties. 
Params: name –  cannot be a null or empty string.
description –  cannot be a null or empty string.
openType –  cannot be null.
isReadable – true if the attribute has a getter exposed for management.
isWritable – true if the attribute has a setter exposed for management.
isIs – true if the attribute's getter is of the form isXXX.
defaultValue – must be a valid value for the 
openType specified for this attribute; default value not supported for ArrayType and TabularType; can be null, in which case it means that no default value is set.
Type parameters: <T> – allows the compiler to check that the defaultValue, if non-null, has the correct Java type for the given openType.
Throws: IllegalArgumentException – if name or 
description are null or empty string, or openType is null.
OpenDataException – if defaultValue is not a valid value for the specified openType, or 
defaultValue is non null and openType is an 
ArrayType or a TabularType./**
     * Constructs an {@code OpenMBeanAttributeInfoSupport} instance,
     * which describes the attribute of an open MBean with the
     * specified {@code name}, {@code openType}, {@code description}
     * and {@code defaultValue}, and the specified read/write access
     * properties.
     *
     * @param name  cannot be a null or empty string.
     *
     * @param description  cannot be a null or empty string.
     *
     * @param openType  cannot be null.
     *
     * @param isReadable {@code true} if the attribute has a getter
     * exposed for management.
     *
     * @param isWritable {@code true} if the attribute has a setter
     * exposed for management.
     *
     * @param isIs {@code true} if the attribute's getter is of the
     * form <code>is<i>XXX</i></code>.
     *
     * @param defaultValue must be a valid value for the {@code
     * openType} specified for this attribute; default value not
     * supported for {@code ArrayType} and {@code TabularType}; can
     * be null, in which case it means that no default value is set.
     *
     * @param <T> allows the compiler to check that the {@code defaultValue},
     * if non-null, has the correct Java type for the given {@code openType}.
     *
     * @throws IllegalArgumentException if {@code name} or {@code
     * description} are null or empty string, or {@code openType} is
     * null.
     *
     * @throws OpenDataException if {@code defaultValue} is not a
     * valid value for the specified {@code openType}, or {@code
     * defaultValue} is non null and {@code openType} is an {@code
     * ArrayType} or a {@code TabularType}.
     */
    public <T> OpenMBeanAttributeInfoSupport(String   name,
                                             String   description,
                                             OpenType<T> openType,
                                             boolean  isReadable,
                                             boolean  isWritable,
                                             boolean  isIs,
                                             T        defaultValue)
            throws OpenDataException {
        this(name, description, openType, isReadable, isWritable, isIs,
             defaultValue, (T[]) null);
    }


    Constructs an OpenMBeanAttributeInfoSupport instance, which describes the attribute of an open MBean with the specified name, openType, description, defaultValue and legalValues, and the specified read/write access properties.
The contents of legalValues are copied, so subsequent modifications of the array referenced by legalValues have no impact on this OpenMBeanAttributeInfoSupport instance.
Params: name –  cannot be a null or empty string.
description –  cannot be a null or empty string.
openType –  cannot be null.
isReadable – true if the attribute has a getter exposed for management.
isWritable – true if the attribute has a setter exposed for management.
isIs – true if the attribute's getter is of the form isXXX.
defaultValue – must be a valid value for the 
openType specified for this attribute; default value not supported for ArrayType and TabularType; can be null, in which case it means that no default value is set.
legalValues – each contained value must be valid for the openType specified for this attribute; legal values not supported for ArrayType and TabularType; can be null or empty.
Type parameters: <T> – allows the compiler to check that the 
defaultValue and legalValues, if non-null, have the correct Java type for the given openType.
Throws: IllegalArgumentException – if name or 
description are null or empty string, or openType is null.
OpenDataException – if defaultValue is not a valid value for the specified openType, or one value in legalValues is not valid for the specified 
openType, or defaultValue is non null and 
openType is an ArrayType or a TabularType, or legalValues is non null and non empty and 
openType is an ArrayType or a TabularType, or legalValues is non null and non empty and 
defaultValue is not contained in legalValues./**
     * <p>Constructs an {@code OpenMBeanAttributeInfoSupport} instance,
     * which describes the attribute of an open MBean with the
     * specified {@code name}, {@code openType}, {@code description},
     * {@code defaultValue} and {@code legalValues}, and the specified
     * read/write access properties.</p>
     *
     * <p>The contents of {@code legalValues} are copied, so subsequent
     * modifications of the array referenced by {@code legalValues}
     * have no impact on this {@code OpenMBeanAttributeInfoSupport}
     * instance.</p>
     *
     * @param name  cannot be a null or empty string.
     *
     * @param description  cannot be a null or empty string.
     *
     * @param openType  cannot be null.
     *
     * @param isReadable {@code true} if the attribute has a getter
     * exposed for management.
     *
     * @param isWritable {@code true} if the attribute has a setter
     * exposed for management.
     *
     * @param isIs {@code true} if the attribute's getter is of the
     * form <code>is<i>XXX</i></code>.
     *
     * @param defaultValue must be a valid value
     * for the {@code
     * openType} specified for this attribute; default value not
     * supported for {@code ArrayType} and {@code TabularType}; can
     * be null, in which case it means that no default value is set.
     *
     * @param legalValues each contained value must be valid for the
     * {@code openType} specified for this attribute; legal values
     * not supported for {@code ArrayType} and {@code TabularType};
     * can be null or empty.
     *
     * @param <T> allows the compiler to check that the {@code
     * defaultValue} and {@code legalValues}, if non-null, have the
     * correct Java type for the given {@code openType}.
     *
     * @throws IllegalArgumentException if {@code name} or {@code
     * description} are null or empty string, or {@code openType} is
     * null.
     *
     * @throws OpenDataException if {@code defaultValue} is not a
     * valid value for the specified {@code openType}, or one value in
     * {@code legalValues} is not valid for the specified {@code
     * openType}, or {@code defaultValue} is non null and {@code
     * openType} is an {@code ArrayType} or a {@code TabularType}, or
     * {@code legalValues} is non null and non empty and {@code
     * openType} is an {@code ArrayType} or a {@code TabularType}, or
     * {@code legalValues} is non null and non empty and {@code
     * defaultValue} is not contained in {@code legalValues}.
     */
    public <T> OpenMBeanAttributeInfoSupport(String   name,
                                             String   description,
                                             OpenType<T> openType,
                                             boolean  isReadable,
                                             boolean  isWritable,
                                             boolean  isIs,
                                             T        defaultValue,
                                             T[]      legalValues)
            throws OpenDataException {
        this(name, description, openType, isReadable, isWritable, isIs,
             defaultValue, legalValues, null, null);
    }


    Constructs an OpenMBeanAttributeInfoSupport instance, which describes the attribute of an open MBean, with the specified name, openType, description, defaultValue, minValue and maxValue. It is possible to specify minimal and maximal values only for an open type whose values are Comparable. 
Params: name –  cannot be a null or empty string.
description –  cannot be a null or empty string.
openType –  cannot be null.
isReadable – true if the attribute has a getter exposed for management.
isWritable – true if the attribute has a setter exposed for management.
isIs – true if the attribute's getter is of the form isXXX.
defaultValue – must be a valid value for the 
openType specified for this attribute; default value not supported for ArrayType and TabularType; can be null, in which case it means that no default value is set.
minValue – must be valid for the openType specified for this attribute; can be null, in which case it means that no minimal value is set.
maxValue – must be valid for the openType specified for this attribute; can be null, in which case it means that no maximal value is set.
Type parameters: <T> – allows the compiler to check that the 
defaultValue, minValue, and maxValue, if non-null, have the correct Java type for the given 
openType.
Throws: IllegalArgumentException – if name or 
description are null or empty string, or openType is null.
OpenDataException – if defaultValue, 
minValue or maxValue is not a valid value for the specified openType, or defaultValue is non null and openType is an ArrayType or a 
TabularType, or both minValue and maxValue are non-null and minValue.compareTo(maxValue) > 0 is 
true, or both defaultValue and minValue are non-null and minValue.compareTo(defaultValue) > 0 is true, or both defaultValue and maxValue are non-null and defaultValue.compareTo(maxValue) > 0 is true./**
     * Constructs an {@code OpenMBeanAttributeInfoSupport} instance,
     * which describes the attribute of an open MBean, with the
     * specified {@code name}, {@code openType}, {@code description},
     * {@code defaultValue}, {@code minValue} and {@code maxValue}.
     *
     * It is possible to specify minimal and maximal values only for
     * an open type whose values are {@code Comparable}.
     *
     * @param name  cannot be a null or empty string.
     *
     * @param description  cannot be a null or empty string.
     *
     * @param openType  cannot be null.
     *
     * @param isReadable {@code true} if the attribute has a getter
     * exposed for management.
     *
     * @param isWritable {@code true} if the attribute has a setter
     * exposed for management.
     *
     * @param isIs {@code true} if the attribute's getter is of the
     * form <code>is<i>XXX</i></code>.
     *
     * @param defaultValue must be a valid value for the {@code
     * openType} specified for this attribute; default value not
     * supported for {@code ArrayType} and {@code TabularType}; can be
     * null, in which case it means that no default value is set.
     *
     * @param minValue must be valid for the {@code openType}
     * specified for this attribute; can be null, in which case it
     * means that no minimal value is set.
     *
     * @param maxValue must be valid for the {@code openType}
     * specified for this attribute; can be null, in which case it
     * means that no maximal value is set.
     *
     * @param <T> allows the compiler to check that the {@code
     * defaultValue}, {@code minValue}, and {@code maxValue}, if
     * non-null, have the correct Java type for the given {@code
     * openType}.
     *
     * @throws IllegalArgumentException if {@code name} or {@code
     * description} are null or empty string, or {@code openType} is
     * null.
     *
     * @throws OpenDataException if {@code defaultValue}, {@code
     * minValue} or {@code maxValue} is not a valid value for the
     * specified {@code openType}, or {@code defaultValue} is non null
     * and {@code openType} is an {@code ArrayType} or a {@code
     * TabularType}, or both {@code minValue} and {@code maxValue} are
     * non-null and {@code minValue.compareTo(maxValue) > 0} is {@code
     * true}, or both {@code defaultValue} and {@code minValue} are
     * non-null and {@code minValue.compareTo(defaultValue) > 0} is
     * {@code true}, or both {@code defaultValue} and {@code maxValue}
     * are non-null and {@code defaultValue.compareTo(maxValue) > 0}
     * is {@code true}.
     */
    public <T> OpenMBeanAttributeInfoSupport(String     name,
                                             String     description,
                                             OpenType<T>   openType,
                                             boolean    isReadable,
                                             boolean    isWritable,
                                             boolean    isIs,
                                             T          defaultValue,
                                             Comparable<T> minValue,
                                             Comparable<T> maxValue)
            throws OpenDataException {
        this(name, description, openType, isReadable, isWritable, isIs,
             defaultValue, null, minValue, maxValue);
    }

    private <T> OpenMBeanAttributeInfoSupport(String name,
                                              String description,
                                              OpenType<T> openType,
                                              boolean isReadable,
                                              boolean isWritable,
                                              boolean isIs,
                                              T defaultValue,
                                              T[] legalValues,
                                              Comparable<T> minValue,
                                              Comparable<T> maxValue)
            throws OpenDataException {
        super(name,
              (openType==null) ? null : openType.getClassName(),
              description,
              isReadable,
              isWritable,
              isIs,
              makeDescriptor(openType,
                             defaultValue, legalValues, minValue, maxValue));

        this.openType = openType;

        Descriptor d = getDescriptor();
        this.defaultValue = defaultValue;
        this.minValue = minValue;
        this.maxValue = maxValue;
        // We already converted the array into an unmodifiable Set
        // in the descriptor.
        this.legalValues = (Set<?>) d.getFieldValue("legalValues");

        check(this);
    }

    An object serialized in a version of the API before Descriptors were
added to this class will have an empty or null Descriptor.
For consistency with our
behavior in this version, we must replace the object with one
where the Descriptors reflect the same values of openType, defaultValue,
etc.
/**
     * An object serialized in a version of the API before Descriptors were
     * added to this class will have an empty or null Descriptor.
     * For consistency with our
     * behavior in this version, we must replace the object with one
     * where the Descriptors reflect the same values of openType, defaultValue,
     * etc.
     **/
    private Object readResolve() {
        if (getDescriptor().getFieldNames().length == 0) {
            OpenType<Object> xopenType = cast(openType);
            Set<Object> xlegalValues = cast(legalValues);
            Comparable<Object> xminValue = cast(minValue);
            Comparable<Object> xmaxValue = cast(maxValue);
            return new OpenMBeanAttributeInfoSupport(
                    name, description, openType,
                    isReadable(), isWritable(), isIs(),
                    makeDescriptor(xopenType, defaultValue, xlegalValues,
                                   xminValue, xmaxValue));
        } else
            return this;
    }

    static void check(OpenMBeanParameterInfo info) throws OpenDataException {
        OpenType<?> openType = info.getOpenType();
        if (openType == null)
            throw new IllegalArgumentException("OpenType cannot be null");

        if (info.getName() == null ||
                info.getName().trim().equals(""))
            throw new IllegalArgumentException("Name cannot be null or empty");

        if (info.getDescription() == null ||
                info.getDescription().trim().equals(""))
            throw new IllegalArgumentException("Description cannot be null or empty");

        // Check and initialize defaultValue
        //
        if (info.hasDefaultValue()) {
            // Default value not supported for ArrayType and TabularType
            // Cast to Object because "OpenType<T> instanceof" is illegal
            if (openType.isArray() || (Object)openType instanceof TabularType) {
                throw new OpenDataException("Default value not supported " +
                                            "for ArrayType and TabularType");
            }
            // Check defaultValue's class
            if (!openType.isValue(info.getDefaultValue())) {
                final String msg =
                    "Argument defaultValue's class [\"" +
                    info.getDefaultValue().getClass().getName() +
                    "\"] does not match the one defined in openType[\"" +
                    openType.getClassName() +"\"]";
                throw new OpenDataException(msg);
            }
        }

        // Check that we don't have both legalValues and min or max
        //
        if (info.hasLegalValues() &&
                (info.hasMinValue() || info.hasMaxValue())) {
            throw new OpenDataException("cannot have both legalValue and " +
                                        "minValue or maxValue");
        }

        // Check minValue and maxValue
        if (info.hasMinValue() && !openType.isValue(info.getMinValue())) {
            final String msg =
                "Type of minValue [" + info.getMinValue().getClass().getName() +
                "] does not match OpenType [" + openType.getClassName() + "]";
            throw new OpenDataException(msg);
        }
        if (info.hasMaxValue() && !openType.isValue(info.getMaxValue())) {
            final String msg =
                "Type of maxValue [" + info.getMaxValue().getClass().getName() +
                "] does not match OpenType [" + openType.getClassName() + "]";
            throw new OpenDataException(msg);
        }

        // Check that defaultValue is a legal value
        //
        if (info.hasDefaultValue()) {
            Object defaultValue = info.getDefaultValue();
            if (info.hasLegalValues() &&
                    !info.getLegalValues().contains(defaultValue)) {
                throw new OpenDataException("defaultValue is not contained " +
                                            "in legalValues");
            }

            // Check that minValue <= defaultValue <= maxValue
            //
            if (info.hasMinValue()) {
                if (compare(info.getMinValue(), defaultValue) > 0) {
                    throw new OpenDataException("minValue cannot be greater " +
                                                "than defaultValue");
                }
            }
            if (info.hasMaxValue()) {
                if (compare(info.getMaxValue(), defaultValue) < 0) {
                    throw new OpenDataException("maxValue cannot be less " +
                                                "than defaultValue");
                }
            }
        }

        // Check legalValues
        //
        if (info.hasLegalValues()) {
            // legalValues not supported for TabularType and arrays
            if ((Object)openType instanceof TabularType || openType.isArray()) {
                throw new OpenDataException("Legal values not supported " +
                                            "for TabularType and arrays");
            }
            // Check legalValues are valid with openType
            for (Object v : info.getLegalValues()) {
                if (!openType.isValue(v)) {
                    final String msg =
                        "Element of legalValues [" + v +
                        "] is not a valid value for the specified openType [" +
                        openType.toString() +"]";
                    throw new OpenDataException(msg);
                }
            }
        }


        // Check that, if both specified, minValue <= maxValue
        //
        if (info.hasMinValue() && info.hasMaxValue()) {
            if (compare(info.getMinValue(), info.getMaxValue()) > 0) {
                throw new OpenDataException("minValue cannot be greater " +
                                            "than maxValue");
            }
        }

    }

    @SuppressWarnings({"unchecked", "rawtypes"})
    static int compare(Object x, Object y) {
        return ((Comparable) x).compareTo(y);
    }

    static <T> Descriptor makeDescriptor(OpenType<T> openType,
                                         T defaultValue,
                                         T[] legalValues,
                                         Comparable<T> minValue,
                                         Comparable<T> maxValue) {
        Map<String, Object> map = new HashMap<String, Object>();
        if (defaultValue != null)
            map.put("defaultValue", defaultValue);
        if (legalValues != null) {
            Set<T> set = new HashSet<T>();
            for (T v : legalValues)
                set.add(v);
            set = Collections.unmodifiableSet(set);
            map.put("legalValues", set);
        }
        if (minValue != null)
            map.put("minValue", minValue);
        if (maxValue != null)
            map.put("maxValue", maxValue);
        if (map.isEmpty()) {
            return openType.getDescriptor();
        } else {
            map.put("openType", openType);
            return new ImmutableDescriptor(map);
        }
    }

    static <T> Descriptor makeDescriptor(OpenType<T> openType,
                                         T defaultValue,
                                         Set<T> legalValues,
                                         Comparable<T> minValue,
                                         Comparable<T> maxValue) {
        T[] legals;
        if (legalValues == null)
            legals = null;
        else {
            legals = cast(new Object[legalValues.size()]);
            legalValues.toArray(legals);
        }
        return makeDescriptor(openType, defaultValue, legals, minValue, maxValue);
    }


    static <T> T valueFrom(Descriptor d, String name, OpenType<T> openType) {
        Object x = d.getFieldValue(name);
        if (x == null)
            return null;
        try {
            return convertFrom(x, openType);
        } catch (Exception e) {
            final String msg =
                "Cannot convert descriptor field " + name + "  to " +
                openType.getTypeName();
            throw EnvHelp.initCause(new IllegalArgumentException(msg), e);
        }
    }

    static <T> Set<T> valuesFrom(Descriptor d, String name,
                                 OpenType<T> openType) {
        Object x = d.getFieldValue(name);
        if (x == null)
            return null;
        Collection<?> coll;
        if (x instanceof Set<?>) {
            Set<?> set = (Set<?>) x;
            boolean asis = true;
            for (Object element : set) {
                if (!openType.isValue(element)) {
                    asis = false;
                    break;
                }
            }
            if (asis)
                return cast(set);
            coll = set;
        } else if (x instanceof Object[]) {
            coll = Arrays.asList((Object[]) x);
        } else {
            final String msg =
                "Descriptor value for " + name + " must be a Set or " +
                "an array: " + x.getClass().getName();
            throw new IllegalArgumentException(msg);
        }

        Set<T> result = new HashSet<T>();
        for (Object element : coll)
            result.add(convertFrom(element, openType));
        return result;
    }

    static <T> Comparable<?> comparableValueFrom(Descriptor d, String name,
                                                 OpenType<T> openType) {
        T t = valueFrom(d, name, openType);
        if (t == null || t instanceof Comparable<?>)
            return (Comparable<?>) t;
        final String msg =
            "Descriptor field " + name + " with value " + t +
            " is not Comparable";
        throw new IllegalArgumentException(msg);
    }

    private static <T> T convertFrom(Object x, OpenType<T> openType) {
        if (openType.isValue(x)) {
            T t = OpenMBeanAttributeInfoSupport.<T>cast(x);
            return t;
        }
        return convertFromStrings(x, openType);
    }

    private static <T> T convertFromStrings(Object x, OpenType<T> openType) {
        if (openType instanceof ArrayType<?>)
            return convertFromStringArray(x, openType);
        else if (x instanceof String)
            return convertFromString((String) x, openType);
        final String msg =
            "Cannot convert value " + x + " of type " +
            x.getClass().getName() + " to type " + openType.getTypeName();
        throw new IllegalArgumentException(msg);
    }

    private static <T> T convertFromString(String s, OpenType<T> openType) {
        Class<T> c;
        try {
            String className = openType.safeGetClassName();
            ReflectUtil.checkPackageAccess(className);
            c = cast(Class.forName(className));
        } catch (ClassNotFoundException e) {
            throw new NoClassDefFoundError(e.toString());  // can't happen
        }

        // Look for: public static T valueOf(String)
        Method valueOf;
        try {
            // It is safe to call this plain Class.getMethod because the class "c"
            // was checked before by ReflectUtil.checkPackageAccess(openType.safeGetClassName());
            valueOf = c.getMethod("valueOf", String.class);
            if (!Modifier.isStatic(valueOf.getModifiers()) ||
                    valueOf.getReturnType() != c)
                valueOf = null;
        } catch (NoSuchMethodException e) {
            valueOf = null;
        }
        if (valueOf != null) {
            try {
                return c.cast(MethodUtil.invoke(valueOf, null, new Object[] {s}));
            } catch (Exception e) {
                final String msg =
                    "Could not convert \"" + s + "\" using method: " + valueOf;
                throw new IllegalArgumentException(msg, e);
            }
        }

        // Look for: public T(String)
        Constructor<T> con;
        try {
            // It is safe to call this plain Class.getConstructor because the class "c"
            // was checked before by ReflectUtil.checkPackageAccess(openType.safeGetClassName());
            con = c.getConstructor(String.class);
        } catch (NoSuchMethodException e) {
            con = null;
        }
        if (con != null) {
            try {
                return con.newInstance(s);
            } catch (Exception e) {
                final String msg =
                    "Could not convert \"" + s + "\" using constructor: " + con;
                throw new IllegalArgumentException(msg, e);
            }
        }

        throw new IllegalArgumentException("Don't know how to convert " +
                                           "string to " +
                                           openType.getTypeName());
    }


    /* A Descriptor contained an array value encoded as Strings.  The
       Strings must be organized in an array corresponding to the desired
       array.  If the desired array has n dimensions, so must the String
       array.  We will convert element by element from String to desired
       component type. */
    private static <T> T convertFromStringArray(Object x,
                                                OpenType<T> openType) {
        ArrayType<?> arrayType = (ArrayType<?>) openType;
        OpenType<?> baseType = arrayType.getElementOpenType();
        int dim = arrayType.getDimension();
        String squareBrackets = "[";
        for (int i = 1; i < dim; i++)
            squareBrackets += "[";
        Class<?> stringArrayClass;
        Class<?> targetArrayClass;
        try {
            String baseClassName = baseType.safeGetClassName();

            // check access to the provided base type class name and bail out early
            ReflectUtil.checkPackageAccess(baseClassName);

            stringArrayClass =
                Class.forName(squareBrackets + "Ljava.lang.String;");
            targetArrayClass =
                Class.forName(squareBrackets + "L" + baseClassName + ";");
        } catch (ClassNotFoundException e) {
            throw new NoClassDefFoundError(e.toString());  // can't happen
        }
        if (!stringArrayClass.isInstance(x)) {
            final String msg =
                "Value for " + dim + "-dimensional array of " +
                baseType.getTypeName() + " must be same type or a String " +
                "array with same dimensions";
            throw new IllegalArgumentException(msg);
        }
        OpenType<?> componentOpenType;
        if (dim == 1)
            componentOpenType = baseType;
        else {
            try {
                componentOpenType = new ArrayType<T>(dim - 1, baseType);
            } catch (OpenDataException e) {
                throw new IllegalArgumentException(e.getMessage(), e);
                // can't happen
            }
        }
        int n = Array.getLength(x);
        Object[] targetArray = (Object[])
            Array.newInstance(targetArrayClass.getComponentType(), n);
        for (int i = 0; i < n; i++) {
            Object stringish = Array.get(x, i);  // String or String[] etc
            Object converted =
                convertFromStrings(stringish, componentOpenType);
            Array.set(targetArray, i, converted);
        }
        return OpenMBeanAttributeInfoSupport.<T>cast(targetArray);
    }

    @SuppressWarnings("unchecked")
    static <T> T cast(Object x) {
        return (T) x;
    }

    Returns the open type for the values of the attribute described by this OpenMBeanAttributeInfoSupport instance. /**
     * Returns the open type for the values of the attribute described
     * by this {@code OpenMBeanAttributeInfoSupport} instance.
     */
    public OpenType<?> getOpenType() {
        return openType;
    }

    Returns the default value for the attribute described by this OpenMBeanAttributeInfoSupport instance, if specified, or null otherwise. /**
     * Returns the default value for the attribute described by this
     * {@code OpenMBeanAttributeInfoSupport} instance, if specified,
     * or {@code null} otherwise.
     */
    public Object getDefaultValue() {

        // Special case for ArrayType and TabularType
        // [JF] TODO: clone it so that it cannot be altered,
        // [JF] TODO: if we decide to support defaultValue as an array itself.
        // [JF] As of today (oct 2000) it is not supported so
        // defaultValue is null for arrays. Nothing to do.

        return defaultValue;
    }

    Returns an unmodifiable Set of legal values for the attribute described by this OpenMBeanAttributeInfoSupport instance, if specified, or null otherwise. /**
     * Returns an unmodifiable Set of legal values for the attribute
     * described by this {@code OpenMBeanAttributeInfoSupport}
     * instance, if specified, or {@code null} otherwise.
     */
    public Set<?> getLegalValues() {

        // Special case for ArrayType and TabularType
        // [JF] TODO: clone values so that they cannot be altered,
        // [JF] TODO: if we decide to support LegalValues as an array itself.
        // [JF] As of today (oct 2000) it is not supported so
        // legalValues is null for arrays. Nothing to do.

        // Returns our legalValues Set (set was constructed unmodifiable)
        return (legalValues);
    }

    Returns the minimal value for the attribute described by this OpenMBeanAttributeInfoSupport instance, if specified, or null otherwise. /**
     * Returns the minimal value for the attribute described by this
     * {@code OpenMBeanAttributeInfoSupport} instance, if specified,
     * or {@code null} otherwise.
     */
    public Comparable<?> getMinValue() {

        // Note: only comparable values have a minValue,
        // so that's not the case of arrays and tabulars (always null).

        return minValue;
    }

    Returns the maximal value for the attribute described by this OpenMBeanAttributeInfoSupport instance, if specified, or null otherwise. /**
     * Returns the maximal value for the attribute described by this
     * {@code OpenMBeanAttributeInfoSupport} instance, if specified,
     * or {@code null} otherwise.
     */
    public Comparable<?> getMaxValue() {

        // Note: only comparable values have a maxValue,
        // so that's not the case of arrays and tabulars (always null).

        return maxValue;
    }

    Returns true if this 
OpenMBeanAttributeInfoSupport instance specifies a non-null default value for the described attribute, false otherwise. /**
     * Returns {@code true} if this {@code
     * OpenMBeanAttributeInfoSupport} instance specifies a non-null
     * default value for the described attribute, {@code false}
     * otherwise.
     */
    public boolean hasDefaultValue() {

        return (defaultValue != null);
    }

    Returns true if this 
OpenMBeanAttributeInfoSupport instance specifies a non-null set of legal values for the described attribute, false otherwise. /**
     * Returns {@code true} if this {@code
     * OpenMBeanAttributeInfoSupport} instance specifies a non-null
     * set of legal values for the described attribute, {@code false}
     * otherwise.
     */
    public boolean hasLegalValues() {

        return (legalValues != null);
    }

    Returns true if this 
OpenMBeanAttributeInfoSupport instance specifies a non-null minimal value for the described attribute, false otherwise. /**
     * Returns {@code true} if this {@code
     * OpenMBeanAttributeInfoSupport} instance specifies a non-null
     * minimal value for the described attribute, {@code false}
     * otherwise.
     */
    public boolean hasMinValue() {

        return (minValue != null);
    }

    Returns true if this 
OpenMBeanAttributeInfoSupport instance specifies a non-null maximal value for the described attribute, false otherwise. /**
     * Returns {@code true} if this {@code
     * OpenMBeanAttributeInfoSupport} instance specifies a non-null
     * maximal value for the described attribute, {@code false}
     * otherwise.
     */
    public boolean hasMaxValue() {

        return (maxValue != null);
    }


    Tests whether obj is a valid value for the attribute described by this OpenMBeanAttributeInfoSupport instance. 
Params: obj – the object to be tested.
Returns: true if obj is a valid value for the parameter described by this 
OpenMBeanAttributeInfoSupport instance, false otherwise./**
     * Tests whether {@code obj} is a valid value for the attribute
     * described by this {@code OpenMBeanAttributeInfoSupport}
     * instance.
     *
     * @param obj the object to be tested.
     *
     * @return {@code true} if {@code obj} is a valid value for
     * the parameter described by this {@code
     * OpenMBeanAttributeInfoSupport} instance, {@code false}
     * otherwise.
     */
    public boolean isValue(Object obj) {
        return isValue(this, obj);
    }

    @SuppressWarnings({"unchecked", "rawtypes"})  // cast to Comparable
    static boolean isValue(OpenMBeanParameterInfo info, Object obj) {
        if (info.hasDefaultValue() && obj == null)
            return true;
        return
            info.getOpenType().isValue(obj) &&
            (!info.hasLegalValues() || info.getLegalValues().contains(obj)) &&
            (!info.hasMinValue() ||
            ((Comparable) info.getMinValue()).compareTo(obj) <= 0) &&
            (!info.hasMaxValue() ||
            ((Comparable) info.getMaxValue()).compareTo(obj) >= 0);
    }

    /* ***  Commodity methods from java.lang.Object  *** */


    Compares the specified obj parameter with this 
OpenMBeanAttributeInfoSupport instance for equality.  Returns true if and only if all of the following statements are true: 

obj is non null,
obj also implements the OpenMBeanAttributeInfo interface,
their names are equal
their open types are equal
their access properties (isReadable, isWritable and isIs) are equal
their default, min, max and legal values are equal.
 This ensures that this equals method works properly for obj parameters which are different implementations of the OpenMBeanAttributeInfo interface. If obj also implements DescriptorRead, then its getDescriptor() method must also return the same value as for this object.
Params: obj – the object to be compared for equality with this OpenMBeanAttributeInfoSupport instance.
Returns: true if the specified object is equal to this OpenMBeanAttributeInfoSupport instance./**
     * Compares the specified {@code obj} parameter with this {@code
     * OpenMBeanAttributeInfoSupport} instance for equality.
     * <p>
     * Returns {@code true} if and only if all of the following statements are true:
     * <ul>
     * <li>{@code obj} is non null,</li>
     * <li>{@code obj} also implements the {@code OpenMBeanAttributeInfo} interface,</li>
     * <li>their names are equal</li>
     * <li>their open types are equal</li>
     * <li>their access properties (isReadable, isWritable and isIs) are equal</li>
     * <li>their default, min, max and legal values are equal.</li>
     * </ul>
     * This ensures that this {@code equals} method works properly for
     * {@code obj} parameters which are different implementations of
     * the {@code OpenMBeanAttributeInfo} interface.
     *
     * <p>If {@code obj} also implements {@link DescriptorRead}, then its
     * {@link DescriptorRead#getDescriptor() getDescriptor()} method must
     * also return the same value as for this object.</p>
     *
     * @param obj the object to be compared for equality with this
     * {@code OpenMBeanAttributeInfoSupport} instance.
     *
     * @return {@code true} if the specified object is equal to this
     * {@code OpenMBeanAttributeInfoSupport} instance.
     */
    public boolean equals(Object obj) {
        if (!(obj instanceof OpenMBeanAttributeInfo))
            return false;

        OpenMBeanAttributeInfo other = (OpenMBeanAttributeInfo) obj;

        return
            this.isReadable() == other.isReadable() &&
            this.isWritable() == other.isWritable() &&
            this.isIs() == other.isIs() &&
            equal(this, other);
    }

    static boolean equal(OpenMBeanParameterInfo x1, OpenMBeanParameterInfo x2) {
        if (x1 instanceof DescriptorRead) {
            if (!(x2 instanceof DescriptorRead))
                return false;
            Descriptor d1 = ((DescriptorRead) x1).getDescriptor();
            Descriptor d2 = ((DescriptorRead) x2).getDescriptor();
            if (!d1.equals(d2))
                return false;
        } else if (x2 instanceof DescriptorRead)
            return false;

        return
            x1.getName().equals(x2.getName()) &&
            x1.getOpenType().equals(x2.getOpenType()) &&
            (x1.hasDefaultValue() ?
                x1.getDefaultValue().equals(x2.getDefaultValue()) :
                !x2.hasDefaultValue()) &&
            (x1.hasMinValue() ?
                x1.getMinValue().equals(x2.getMinValue()) :
                !x2.hasMinValue()) &&
            (x1.hasMaxValue() ?
                x1.getMaxValue().equals(x2.getMaxValue()) :
                !x2.hasMaxValue()) &&
            (x1.hasLegalValues() ?
                x1.getLegalValues().equals(x2.getLegalValues()) :
                !x2.hasLegalValues());
    }

    Returns the hash code value for this 
OpenMBeanAttributeInfoSupport instance.
The hash code of an OpenMBeanAttributeInfoSupport instance is the sum of the hash codes of all elements of information used in equals comparisons (ie: its name, its open type, its default, min, max and legal
values, and its Descriptor).
This ensures that t1.equals(t2) implies that 
t1.hashCode()==t2.hashCode() for any two 
OpenMBeanAttributeInfoSupport instances t1 and 
t2, as required by the general contract of the method Object.hashCode(). 
However, note that another instance of a class implementing the OpenMBeanAttributeInfo interface may be equal to this OpenMBeanAttributeInfoSupport instance as defined by equals(Object), but may have a different hash code if it is calculated differently. 
As OpenMBeanAttributeInfoSupport instances are immutable, the hash code for this instance is calculated once, on the first call to hashCode, and then the same value is returned for subsequent calls. 
Returns: the hash code value for this 
OpenMBeanAttributeInfoSupport instance/**
     * <p>Returns the hash code value for this {@code
     * OpenMBeanAttributeInfoSupport} instance.</p>
     *
     * <p>The hash code of an {@code OpenMBeanAttributeInfoSupport}
     * instance is the sum of the hash codes of all elements of
     * information used in {@code equals} comparisons (ie: its name,
     * its <i>open type</i>, its default, min, max and legal
     * values, and its Descriptor).
     *
     * <p>This ensures that {@code t1.equals(t2)} implies that {@code
     * t1.hashCode()==t2.hashCode()} for any two {@code
     * OpenMBeanAttributeInfoSupport} instances {@code t1} and {@code
     * t2}, as required by the general contract of the method {@link
     * Object#hashCode() Object.hashCode()}.
     *
     * <p>However, note that another instance of a class implementing
     * the {@code OpenMBeanAttributeInfo} interface may be equal to
     * this {@code OpenMBeanAttributeInfoSupport} instance as defined
     * by {@link #equals(java.lang.Object)}, but may have a different
     * hash code if it is calculated differently.
     *
     * <p>As {@code OpenMBeanAttributeInfoSupport} instances are
     * immutable, the hash code for this instance is calculated once,
     * on the first call to {@code hashCode}, and then the same value
     * is returned for subsequent calls.
     *
     * @return the hash code value for this {@code
     * OpenMBeanAttributeInfoSupport} instance
     */
    public int hashCode() {

        // Calculate the hash code value if it has not yet been done
        // (ie 1st call to hashCode())
        //
        if (myHashCode == null)
            myHashCode = hashCode(this);

        // return always the same hash code for this instance (immutable)
        //
        return myHashCode.intValue();
    }

    static int hashCode(OpenMBeanParameterInfo info) {
        int value = 0;
        value += info.getName().hashCode();
        value += info.getOpenType().hashCode();
        if (info.hasDefaultValue())
            value += info.getDefaultValue().hashCode();
        if (info.hasMinValue())
            value += info.getMinValue().hashCode();
        if (info.hasMaxValue())
            value += info.getMaxValue().hashCode();
        if (info.hasLegalValues())
            value += info.getLegalValues().hashCode();
        if (info instanceof DescriptorRead)
            value += ((DescriptorRead) info).getDescriptor().hashCode();
        return value;
    }

    Returns a string representation of this OpenMBeanAttributeInfoSupport instance.  The string representation consists of the name of this class (i.e. javax.management.openmbean.OpenMBeanAttributeInfoSupport), the string representation of the name and open type of the described parameter, the string representation of its default, min, max and legal values and the string representation of its descriptor. 
As OpenMBeanAttributeInfoSupport instances are immutable, the string representation for this instance is calculated once, on the first call to toString, and then the same value is returned for subsequent calls. 
Returns: a string representation of this OpenMBeanAttributeInfoSupport instance./**
     * Returns a string representation of this
     * {@code OpenMBeanAttributeInfoSupport} instance.
     * <p>
     * The string representation consists of the name of this class (i.e.
     * {@code javax.management.openmbean.OpenMBeanAttributeInfoSupport}),
     * the string representation of the name and open type of the
     * described parameter, the string representation of its
     * default, min, max and legal values and the string
     * representation of its descriptor.
     *
     * <p>As {@code OpenMBeanAttributeInfoSupport} instances are
     * immutable, the string representation for this instance is
     * calculated once, on the first call to {@code toString}, and
     * then the same value is returned for subsequent calls.
     *
     * @return a string representation of this
     * {@code OpenMBeanAttributeInfoSupport} instance.
     */
    public String toString() {

        // Calculate the string value if it has not yet been done
        // (ie 1st call to toString())
        //
        if (myToString == null)
            myToString = toString(this);

        // return always the same string representation for this
        // instance (immutable)
        //
        return myToString;
    }

    static String toString(OpenMBeanParameterInfo info) {
        Descriptor d = (info instanceof DescriptorRead) ?
            ((DescriptorRead) info).getDescriptor() : null;
        return
            info.getClass().getName() +
            "(name=" + info.getName() +
            ",openType=" + info.getOpenType() +
            ",default=" + info.getDefaultValue() +
            ",minValue=" + info.getMinValue() +
            ",maxValue=" + info.getMaxValue() +
            ",legalValues=" + info.getLegalValues() +
            ((d == null) ? "" : ",descriptor=" + d) +
            ")";
    }
}
Params:	name – cannot be a null or empty string. description – cannot be a null or empty string. openType – cannot be null. isReadable – `true` if the attribute has a getter exposed for management. isWritable – `true` if the attribute has a setter exposed for management. isIs – `true` if the attribute's getter is of the form `isXXX`.
Throws:	IllegalArgumentException – if `name` or `description` are null or empty string, or `openType` is null.
Params:	name – cannot be a null or empty string. description – cannot be a null or empty string. openType – cannot be null. isReadable – `true` if the attribute has a getter exposed for management. isWritable – `true` if the attribute has a setter exposed for management. isIs – `true` if the attribute's getter is of the form `isXXX`. defaultValue – must be a valid value for the `openType` specified for this attribute; default value not supported for `ArrayType` and `TabularType`; can be null, in which case it means that no default value is set.
Type parameters:	<T> – allows the compiler to check that the `defaultValue`, if non-null, has the correct Java type for the given `openType`.
Throws:	IllegalArgumentException – if `name` or `description` are null or empty string, or `openType` is null. OpenDataException – if `defaultValue` is not a valid value for the specified `openType`, or `defaultValue` is non null and `openType` is an `ArrayType` or a `TabularType`.
Params:	obj – the object to be tested.
Returns:	`true` if `obj` is a valid value for the parameter described by this `OpenMBeanAttributeInfoSupport` instance, `false` otherwise.
Params:	obj – the object to be compared for equality with this `OpenMBeanAttributeInfoSupport` instance.
Returns:	`true` if the specified object is equal to this `OpenMBeanAttributeInfoSupport` instance.
/

java/ 11/ java.management/javax/management/openmbean/OpenMBeanAttributeInfoSupport.java
