/*
 * Copyright (c) 2000, 2008, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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,
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 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package javax.management.openmbean;


// java import
//
import java.io.InvalidObjectException;
import java.io.ObjectStreamException;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.Date;
import java.util.Map;
import java.util.HashMap;

// jmx import
//
import javax.management.ObjectName;


The SimpleType class is the open type class whose instances describe
all open data values which are neither arrays, nor CompositeData values, nor TabularData values. It predefines all its possible instances as static fields, and has no public constructor. 

Given a SimpleType instance describing values whose Java class name is className,
the internal fields corresponding to the name and description of this SimpleType instance
are also set to className.
In other words, its methods getClassName, getTypeName and getDescription
all return the same string value className.
Since:
1.5/**
 * The <code>SimpleType</code> class is the <i>open type</i> class whose instances describe
 * all <i>open data</i> values which are neither arrays,
 * nor {@link CompositeData <code>CompositeData</code>} values,
 * nor {@link TabularData <code>TabularData</code>} values.
 * It predefines all its possible instances as static fields, and has no public constructor.
 * <p>
 * Given a <code>SimpleType</code> instance describing values whose Java class name is <i>className</i>,
 * the internal fields corresponding to the name and description of this <code>SimpleType</code> instance
 * are also set to <i>className</i>.
 * In other words, its methods <code>getClassName</code>, <code>getTypeName</code> and <code>getDescription</code>
 * all return the same string value <i>className</i>.
 *
 * @since 1.5
 */
public final class SimpleType<T> extends OpenType<T> {

    /* Serial version */
    static final long serialVersionUID = 2215577471957694503L;

    // SimpleType instances.
    // IF YOU ADD A SimpleType, YOU MUST UPDATE OpenType and typeArray

    
The SimpleType instance describing values whose
Java class name is java.lang.Void.
/**
     * The <code>SimpleType</code> instance describing values whose
     * Java class name is <code>java.lang.Void</code>.
     */
    public static final SimpleType<Void> VOID =
        new SimpleType<Void>(Void.class);

    
The SimpleType instance describing values whose
Java class name is java.lang.Boolean.
/**
     * The <code>SimpleType</code> instance describing values whose
     * Java class name is <code>java.lang.Boolean</code>.
     */
    public static final SimpleType<Boolean> BOOLEAN =
        new SimpleType<Boolean>(Boolean.class);

    
The SimpleType instance describing values whose
Java class name is java.lang.Character.
/**
     * The <code>SimpleType</code> instance describing values whose
     * Java class name is <code>java.lang.Character</code>.
     */
    public static final SimpleType<Character> CHARACTER =
        new SimpleType<Character>(Character.class);

    
The SimpleType instance describing values whose
Java class name is java.lang.Byte.
/**
     * The <code>SimpleType</code> instance describing values whose
     * Java class name is <code>java.lang.Byte</code>.
     */
    public static final SimpleType<Byte> BYTE =
        new SimpleType<Byte>(Byte.class);

    
The SimpleType instance describing values whose
Java class name is java.lang.Short.
/**
     * The <code>SimpleType</code> instance describing values whose
     * Java class name is <code>java.lang.Short</code>.
     */
    public static final SimpleType<Short> SHORT =
        new SimpleType<Short>(Short.class);

    
The SimpleType instance describing values whose
Java class name is java.lang.Integer.
/**
     * The <code>SimpleType</code> instance describing values whose
     * Java class name is <code>java.lang.Integer</code>.
     */
    public static final SimpleType<Integer> INTEGER =
        new SimpleType<Integer>(Integer.class);

    
The SimpleType instance describing values whose
Java class name is java.lang.Long.
/**
     * The <code>SimpleType</code> instance describing values whose
     * Java class name is <code>java.lang.Long</code>.
     */
    public static final SimpleType<Long> LONG =
        new SimpleType<Long>(Long.class);

    
The SimpleType instance describing values whose
Java class name is java.lang.Float.
/**
     * The <code>SimpleType</code> instance describing values whose
     * Java class name is <code>java.lang.Float</code>.
     */
    public static final SimpleType<Float> FLOAT =
        new SimpleType<Float>(Float.class);

    
The SimpleType instance describing values whose
Java class name is java.lang.Double.
/**
     * The <code>SimpleType</code> instance describing values whose
     * Java class name is <code>java.lang.Double</code>.
     */
    public static final SimpleType<Double> DOUBLE =
        new SimpleType<Double>(Double.class);

    
The SimpleType instance describing values whose
Java class name is java.lang.String.
/**
     * The <code>SimpleType</code> instance describing values whose
     * Java class name is <code>java.lang.String</code>.
     */
    public static final SimpleType<String> STRING =
        new SimpleType<String>(String.class);

    
The SimpleType instance describing values whose
Java class name is java.math.BigDecimal.
/**
     * The <code>SimpleType</code> instance describing values whose
     * Java class name is <code>java.math.BigDecimal</code>.
     */
    public static final SimpleType<BigDecimal> BIGDECIMAL =
        new SimpleType<BigDecimal>(BigDecimal.class);

    
The SimpleType instance describing values whose
Java class name is java.math.BigInteger.
/**
     * The <code>SimpleType</code> instance describing values whose
     * Java class name is <code>java.math.BigInteger</code>.
     */
    public static final SimpleType<BigInteger> BIGINTEGER =
        new SimpleType<BigInteger>(BigInteger.class);

    
The SimpleType instance describing values whose
Java class name is java.util.Date.
/**
     * The <code>SimpleType</code> instance describing values whose
     * Java class name is <code>java.util.Date</code>.
     */
    public static final SimpleType<Date> DATE =
        new SimpleType<Date>(Date.class);

    
The SimpleType instance describing values whose
Java class name is javax.management.ObjectName.
/**
     * The <code>SimpleType</code> instance describing values whose
     * Java class name is <code>javax.management.ObjectName</code>.
     */
    public static final SimpleType<ObjectName> OBJECTNAME =
        new SimpleType<ObjectName>(ObjectName.class);

    private static final SimpleType<?>[] typeArray = {
        VOID, BOOLEAN, CHARACTER, BYTE, SHORT, INTEGER, LONG, FLOAT,
        DOUBLE, STRING, BIGDECIMAL, BIGINTEGER, DATE, OBJECTNAME,
    };


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


    /* *** Constructor *** */

    private SimpleType(Class<T> valueClass) {
        super(valueClass.getName(), valueClass.getName(), valueClass.getName(),
              false);
    }


    /* *** SimpleType specific information methods *** */

    
Tests whether obj is a value for this
SimpleType instance.  
 This method returns
true if and only if obj is not null and
obj's class name is the same as the className field
defined for this SimpleType instance (ie the class name returned by the 
getClassName method). 
Params:
obj – the object to be tested.
Returns:
true if obj is a value for this
SimpleType instance./**
     * Tests whether <var>obj</var> is a value for this
     * <code>SimpleType</code> instance.  <p> This method returns
     * <code>true</code> if and only if <var>obj</var> is not null and
     * <var>obj</var>'s class name is the same as the className field
     * defined for this <code>SimpleType</code> instance (ie the class
     * name returned by the {@link OpenType#getClassName()
     * getClassName} method).
     *
     * @param obj the object to be tested.
     *
     * @return <code>true</code> if <var>obj</var> is a value for this
     * <code>SimpleType</code> instance.
     */
    public boolean isValue(Object obj) {

        // if obj is null, return false
        //
        if (obj == null) {
            return false;
        }

        // Test if obj's class name is the same as for this instance
        //
        return this.getClassName().equals(obj.getClass().getName());
    }


    /* *** Methods overriden from class Object *** */

    
Compares the specified obj parameter with this SimpleType instance for equality.

Two SimpleType instances are equal if and only if their getClassName methods return the same value. 
Params:
obj –  the object to be compared for equality with this SimpleType instance;
             if obj is null or is not an instance of the class SimpleType,
             equals returns false.
Returns:
 true if the specified object is equal to this SimpleType instance./**
     * Compares the specified <code>obj</code> parameter with this <code>SimpleType</code> instance for equality.
     * <p>
     * Two <code>SimpleType</code> instances are equal if and only if their
     * {@link OpenType#getClassName() getClassName} methods return the same value.
     *
     * @param  obj  the object to be compared for equality with this <code>SimpleType</code> instance;
     *              if <var>obj</var> is <code>null</code> or is not an instance of the class <code>SimpleType</code>,
     *              <code>equals</code> returns <code>false</code>.
     *
     * @return  <code>true</code> if the specified object is equal to this <code>SimpleType</code> instance.
     */
    public boolean equals(Object obj) {

        /* If it weren't for readReplace(), we could replace this method
           with just:
           return (this == obj);
        */

        if (!(obj instanceof SimpleType<?>))
            return false;

        SimpleType<?> other = (SimpleType<?>) obj;

        // Test if other's className field is the same as for this instance
        //
        return this.getClassName().equals(other.getClassName());
    }

    
Returns the hash code value for this SimpleType instance.
The hash code of a SimpleType instance is the the hash code of the string value returned by the getClassName method. 

As SimpleType 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 SimpleType instance/**
     * Returns the hash code value for this <code>SimpleType</code> instance.
     * The hash code of a <code>SimpleType</code> instance is the the hash code of
     * the string value returned by the {@link OpenType#getClassName() getClassName} method.
     * <p>
     * As <code>SimpleType</code> instances are immutable, the hash code for this instance is calculated once,
     * on the first call to <code>hashCode</code>, and then the same value is returned for subsequent calls.
     *
     * @return  the hash code value for this <code>SimpleType</code> 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 = Integer.valueOf(this.getClassName().hashCode());
        }

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

    
Returns a string representation of this SimpleType instance.

The string representation consists of
the name of this class (ie javax.management.openmbean.SimpleType) and the type name
for this instance (which is the java class name of the values this SimpleType instance represents).

As SimpleType 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 SimpleType instance/**
     * Returns a string representation of this <code>SimpleType</code> instance.
     * <p>
     * The string representation consists of
     * the name of this class (ie <code>javax.management.openmbean.SimpleType</code>) and the type name
     * for this instance (which is the java class name of the values this <code>SimpleType</code> instance represents).
     * <p>
     * As <code>SimpleType</code> instances are immutable, the string representation for this instance is calculated once,
     * on the first call to <code>toString</code>, and then the same value is returned for subsequent calls.
     *
     * @return  a string representation of this <code>SimpleType</code> instance
     */
    public String toString() {

        // Calculate the string representation if it has not yet been done (ie 1st call to toString())
        //
        if (myToString == null) {
            myToString = this.getClass().getName()+ "(name="+ getTypeName() +")";
        }

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

    private static final Map<SimpleType<?>,SimpleType<?>> canonicalTypes =
        new HashMap<SimpleType<?>,SimpleType<?>>();
    static {
        for (int i = 0; i < typeArray.length; i++) {
            final SimpleType<?> type = typeArray[i];
            canonicalTypes.put(type, type);
        }
    }

    
Replace an object read from an ObjectInputStream with the unique instance for that value. 
Throws:
ObjectStreamException – if the read object cannot be
resolved.
Returns:
the replacement object./**
     * Replace an object read from an {@link
     * java.io.ObjectInputStream} with the unique instance for that
     * value.
     *
     * @return the replacement object.
     *
     * @exception ObjectStreamException if the read object cannot be
     * resolved.
     */
    public Object readResolve() throws ObjectStreamException {
        final SimpleType<?> canonical = canonicalTypes.get(this);
        if (canonical == null) {
            // Should not happen
            throw new InvalidObjectException("Invalid SimpleType: " + this);
        }
        return canonical;
    }
}