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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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
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 *
 * 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).
 *
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 * 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.print.attribute;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.HashMap;


Class HashAttributeSet provides an AttributeSet implementation with characteristics of a hash map. 
Author:Alan Kaminsky
/**
 * Class {@code HashAttributeSet} provides an {@code AttributeSet}
 * implementation with characteristics of a hash map.
 *
 * @author Alan Kaminsky
 */
public class HashAttributeSet implements AttributeSet, Serializable {

    
Use serialVersionUID from JDK 1.4 for interoperability.

/**
     * Use serialVersionUID from JDK 1.4 for interoperability.
     */
    private static final long serialVersionUID = 5311560590283707917L;

    
The interface of which all members of this attribute set must be an instance. It is assumed to be interface Attribute or a subinterface thereof. 
@serial
/**
     * The interface of which all members of this attribute set must be an
     * instance. It is assumed to be interface {@link Attribute Attribute} or a
     * subinterface thereof.
     *
     * @serial
     */
    private Class<?> myInterface;

    
A HashMap used by the implementation. The serialised form doesn't include this instance variable. 
/**
     * A {@code HashMap} used by the implementation. The serialised form doesn't
     * include this instance variable.
     */
    private transient HashMap<Class<?>, Attribute> attrMap = new HashMap<>();

    
Write the instance to a stream (ie serialize the object).

Params:
  • s – the output stream
Throws:
@serialDataThe serialized form of an attribute set explicitly writes the
            number of attributes in the set, and each of the attributes.
            This does not guarantee equality of serialized forms since
            the order in which the attributes are written is not defined.
/**
     * Write the instance to a stream (ie serialize the object).
     *
     * @param  s the output stream
     * @throws IOException if an I/O exception has occurred
     * @serialData The serialized form of an attribute set explicitly writes the
     *             number of attributes in the set, and each of the attributes.
     *             This does not guarantee equality of serialized forms since
     *             the order in which the attributes are written is not defined.
     */
    private void writeObject(ObjectOutputStream s) throws IOException {

        s.defaultWriteObject();
        Attribute [] attrs = toArray();
        s.writeInt(attrs.length);
        for (int i = 0; i < attrs.length; i++) {
            s.writeObject(attrs[i]);
        }
    }

    
Reconstitute an instance from a stream that is, deserialize it).

Params:
  • s – the input stream
Throws:
/**
     * Reconstitute an instance from a stream that is, deserialize it).
     *
     * @param  s the input stream
     * @throws ClassNotFoundException if the class is not found
     * @throws IOException if an I/O exception has occurred
     */
    private void readObject(ObjectInputStream s)
        throws ClassNotFoundException, IOException {

        s.defaultReadObject();
        attrMap = new HashMap<>();
        int count = s.readInt();
        Attribute attr;
        for (int i = 0; i < count; i++) {
            attr = (Attribute)s.readObject();
            add(attr);
        }
    }

    
Construct a new, empty attribute set.

/**
     * Construct a new, empty attribute set.
     */
    public HashAttributeSet() {
        this(Attribute.class);
    }

    
Construct a new attribute set, initially populated with the given
attribute.

Params:
  • attribute – attribute value to add to the set
Throws:
/**
     * Construct a new attribute set, initially populated with the given
     * attribute.
     *
     * @param  attribute attribute value to add to the set
     * @throws NullPointerException if {@code attribute} is {@code null}
     */
    public HashAttributeSet(Attribute attribute) {
        this (attribute, Attribute.class);
    }

    
Construct a new attribute set, initially populated with the values from the given array. The new attribute set is populated by adding the elements of attributes array to the set in sequence, starting at index 0. Thus, later array elements may replace earlier array elements if the array contains duplicate attribute values or attribute categories. 
Params:
  • attributes – array of attribute values to add to the set. If null, an empty attribute set is constructed.
Throws:
/**
     * Construct a new attribute set, initially populated with the values from
     * the given array. The new attribute set is populated by adding the
     * elements of {@code attributes} array to the set in sequence, starting at
     * index 0. Thus, later array elements may replace earlier array elements if
     * the array contains duplicate attribute values or attribute categories.
     *
     * @param  attributes array of attribute values to add to the set. If
     *         {@code null}, an empty attribute set is constructed.
     * @throws NullPointerException if any element of {@code attributes} is
     *         {@code null}
     */
    public HashAttributeSet(Attribute[] attributes) {
        this (attributes, Attribute.class);
    }

    
Construct a new attribute set, initially populated with the values from
the given set.

Params:
  • attributes – set of attributes from which to initialise this set. If null, an empty attribute set is constructed.
/**
     * Construct a new attribute set, initially populated with the values from
     * the given set.
     *
     * @param  attributes set of attributes from which to initialise this set.
     *         If {@code null}, an empty attribute set is constructed.
     */
    public HashAttributeSet(AttributeSet attributes) {
        this (attributes, Attribute.class);
    }

    
Construct a new, empty attribute set, where the members of the attribute
set are restricted to the given interface.

Params:
  • interfaceName – the interface of which all members of this attribute set must be an instance. It is assumed to be interface Attribute or a subinterface thereof.
Throws:
/**
     * Construct a new, empty attribute set, where the members of the attribute
     * set are restricted to the given interface.
     *
     * @param  interfaceName the interface of which all members of this
     *         attribute set must be an instance. It is assumed to be interface
     *         {@link Attribute Attribute} or a subinterface thereof.
     * @throws NullPointerException if {@code interfaceName} is {@code null}
     */
    protected HashAttributeSet(Class<?> interfaceName) {
        if (interfaceName == null) {
            throw new NullPointerException("null interface");
        }
        myInterface = interfaceName;
    }

    
Construct a new attribute set, initially populated with the given
attribute, where the members of the attribute set are restricted to the
given interface.

Params:
  • attribute – attribute value to add to the set
  • interfaceName – the interface of which all members of this attribute set must be an instance. It is assumed to be interface Attribute or a subinterface thereof.
Throws:
/**
     * Construct a new attribute set, initially populated with the given
     * attribute, where the members of the attribute set are restricted to the
     * given interface.
     *
     * @param  attribute attribute value to add to the set
     * @param  interfaceName the interface of which all members of this
     *         attribute set must be an instance. It is assumed to be interface
     *         {@link Attribute Attribute} or a subinterface thereof.
     * @throws NullPointerException if {@code attribute} or
     *         {@code interfaceName} are {@code null}
     * @throws ClassCastException if {@code attribute} is not an instance of
     *         {@code interfaceName}
     */
    protected HashAttributeSet(Attribute attribute, Class<?> interfaceName) {
        if (interfaceName == null) {
            throw new NullPointerException("null interface");
        }
        myInterface = interfaceName;
        add (attribute);
    }

    
Construct a new attribute set, where the members of the attribute set are restricted to the given interface. The new attribute set is populated by adding the elements of attributes array to the set in sequence, starting at index 0. Thus, later array elements may replace earlier array elements if the array contains duplicate attribute values or attribute categories. 
Params:
  • attributes – array of attribute values to add to the set. If null, an empty attribute set is constructed.
  • interfaceName – the interface of which all members of this attribute set must be an instance. It is assumed to be interface Attribute or a subinterface thereof.
Throws:
/**
     * Construct a new attribute set, where the members of the attribute set are
     * restricted to the given interface. The new attribute set is populated by
     * adding the elements of {@code attributes} array to the set in sequence,
     * starting at index 0. Thus, later array elements may replace earlier array
     * elements if the array contains duplicate attribute values or attribute
     * categories.
     *
     * @param  attributes array of attribute values to add to the set. If
     *         {@code null}, an empty attribute set is constructed.
     * @param  interfaceName the interface of which all members of this
     *         attribute set must be an instance. It is assumed to be interface
     *         {@link Attribute Attribute} or a subinterface thereof.
     * @throws NullPointerException if {@code interfaceName} is {@code null}, or
     *         if any element of {@code attributes} is {@code null}
     * @throws ClassCastException if any element of {@code attributes} is not an
     *         instance of {@code interfaceName}
     */
    protected HashAttributeSet(Attribute[] attributes, Class<?> interfaceName) {
        if (interfaceName == null) {
            throw new NullPointerException("null interface");
        }
        myInterface = interfaceName;
        int n = attributes == null ? 0 : attributes.length;
        for (int i = 0; i < n; ++ i) {
            add (attributes[i]);
        }
    }

    
Construct a new attribute set, initially populated with the values from
the given set where the members of the attribute set are restricted to
the given interface.

Params:
  • attributes – set of attribute values to initialise the set. If null, an empty attribute set is constructed.
  • interfaceName – The interface of which all members of this attribute set must be an instance. It is assumed to be interface Attribute or a subinterface thereof.
Throws:
/**
     * Construct a new attribute set, initially populated with the values from
     * the given set where the members of the attribute set are restricted to
     * the given interface.
     *
     * @param  attributes set of attribute values to initialise the set. If
     *         {@code null}, an empty attribute set is constructed.
     * @param  interfaceName The interface of which all members of this
     *         attribute set must be an instance. It is assumed to be interface
     *         {@link Attribute Attribute} or a subinterface thereof.
     * @throws ClassCastException if any element of {@code attributes} is not an
     *         instance of {@code interfaceName}
     */
    protected HashAttributeSet(AttributeSet attributes, Class<?> interfaceName) {
      myInterface = interfaceName;
      if (attributes != null) {
        Attribute[] attribArray = attributes.toArray();
        int n = attribArray == null ? 0 : attribArray.length;
        for (int i = 0; i < n; ++ i) {
          add (attribArray[i]);
        }
      }
    }

    
Returns the attribute value which this attribute set contains in the given attribute category. Returns null if this attribute set does not contain any attribute value in the given attribute category. 
Params:
  • category – attribute category whose associated attribute value is to be returned. It must be a Class that implements interface Attribute.
Throws:
Returns:the attribute value in the given attribute category contained in this attribute set, or null if this attribute set does not contain any attribute value in the given attribute category
/**
     * Returns the attribute value which this attribute set contains in the
     * given attribute category. Returns {@code null} if this attribute set does
     * not contain any attribute value in the given attribute category.
     *
     * @param  category attribute category whose associated attribute value is
     *         to be returned. It must be a {@link Class Class} that implements
     *         interface {@link Attribute Attribute}.
     * @return the attribute value in the given attribute category contained in
     *         this attribute set, or {@code null} if this attribute set does
     *         not contain any attribute value in the given attribute category
     * @throws NullPointerException if the {@code category} is {@code null}
     * @throws ClassCastException if the {@code category} is not a
     *         {@link Class Class} that implements interface
     *         {@link Attribute Attribute}
     */
    public Attribute get(Class<?> category) {
        return attrMap.get(AttributeSetUtilities.
                           verifyAttributeCategory(category,
                                                   Attribute.class));
    }

    
Adds the specified attribute to this attribute set if it is not already
present, first removing any existing in the same attribute category as
the specified attribute value.

Params:
  • attribute – attribute value to be added to this attribute set
Throws:
Returns:true if this attribute set changed as a result of the call, i.e., the given attribute value was not already a member of this attribute set
/**
     * Adds the specified attribute to this attribute set if it is not already
     * present, first removing any existing in the same attribute category as
     * the specified attribute value.
     *
     * @param  attribute attribute value to be added to this attribute set
     * @return {@code true} if this attribute set changed as a result of the
     *         call, i.e., the given attribute value was not already a member of
     *         this attribute set
     * @throws NullPointerException if the {@code attribute} is {@code null}
     * @throws UnmodifiableSetException if this attribute set does not support
     *         the {@code add()} operation
     */
    public boolean add(Attribute attribute) {
        Object oldAttribute =
            attrMap.put(attribute.getCategory(),
                        AttributeSetUtilities.
                        verifyAttributeValue(attribute, myInterface));
        return (!attribute.equals(oldAttribute));
    }

    
Removes any attribute for this category from this attribute set if present. If category is null, then remove() does nothing and returns false. 
Params:
  • category – attribute category to be removed from this attribute set
Throws:
Returns:true if this attribute set changed as a result of the call, i.e., the given attribute category had been a member of this attribute set
/**
     * Removes any attribute for this category from this attribute set if
     * present. If {@code category} is {@code null}, then {@code remove()} does
     * nothing and returns {@code false}.
     *
     * @param  category attribute category to be removed from this attribute set
     * @return {@code true} if this attribute set changed as a result of the
     *         call, i.e., the given attribute category had been a member of
     *         this attribute set
     * @throws UnmodifiableSetException if this attribute set does not support
     *         the {@code remove()} operation
     */
    public boolean remove(Class<?> category) {
        return
            category != null &&
            AttributeSetUtilities.
            verifyAttributeCategory(category, Attribute.class) != null &&
            attrMap.remove(category) != null;
    }

    
Removes the specified attribute from this attribute set if present. If attribute is null, then remove() does nothing and returns false. 
Params:
  • attribute – attribute value to be removed from this attribute set
Throws:
Returns:true if this attribute set changed as a result of the call, i.e., the given attribute value had been a member of this attribute set
/**
     * Removes the specified attribute from this attribute set if present. If
     * {@code attribute} is {@code null}, then {@code remove()} does nothing and
     * returns {@code false}.
     *
     * @param  attribute attribute value to be removed from this attribute set
     * @return {@code true} if this attribute set changed as a result of the
     *         call, i.e., the given attribute value had been a member of this
     *         attribute set
     * @throws UnmodifiableSetException if this attribute set does not support
     *         the {@code remove()} operation
     */
    public boolean remove(Attribute attribute) {
        return
            attribute != null &&
            attrMap.remove(attribute.getCategory()) != null;
    }

    
Returns true if this attribute set contains an attribute for the specified category. 
Params:
  • category – whose presence in this attribute set is to be tested
Returns:true if this attribute set contains an attribute value for the specified category
/**
     * Returns {@code true} if this attribute set contains an attribute for the
     * specified category.
     *
     * @param  category whose presence in this attribute set is to be tested
     * @return {@code true} if this attribute set contains an attribute value
     *         for the specified category
     */
    public boolean containsKey(Class<?> category) {
        return
            category != null &&
            AttributeSetUtilities.
            verifyAttributeCategory(category, Attribute.class) != null &&
            attrMap.get(category) != null;
    }

    
Returns true if this attribute set contains the given attribute. 
Params:
  • attribute – value whose presence in this attribute set is to be
        tested
Returns:true if this attribute set contains the given attribute value
/**
     * Returns {@code true} if this attribute set contains the given attribute.
     *
     * @param  attribute value whose presence in this attribute set is to be
     *         tested
     * @return {@code true} if this attribute set contains the given attribute
     *         value
     */
    public boolean containsValue(Attribute attribute) {
        return
           attribute != null &&
           attribute instanceof Attribute &&
           attribute.equals(attrMap.get(attribute.getCategory()));
    }

    
Adds all of the elements in the specified set to this attribute. The outcome is the same as if the add(Attribute) operation had been applied to this attribute set successively with each element from the specified set. The behavior of the addAll(AttributeSet) operation is unspecified if the specified set is modified while the operation is in progress. 
 If the addAll(AttributeSet) operation throws an exception, the effect on this attribute set's state is implementation dependent; elements from the specified set before the point of the exception may or may not have been added to this attribute set. 
Params:
  • attributes – whose elements are to be added to this attribute set
Throws:
See Also:
Returns:true if this attribute set changed as a result of the call
/**
     * Adds all of the elements in the specified set to this attribute. The
     * outcome is the same as if the {@link #add(Attribute) add(Attribute)}
     * operation had been applied to this attribute set successively with each
     * element from the specified set. The behavior of the
     * {@code addAll(AttributeSet)} operation is unspecified if the specified
     * set is modified while the operation is in progress.
     * <p>
     * If the {@code addAll(AttributeSet)} operation throws an exception, the
     * effect on this attribute set's state is implementation dependent;
     * elements from the specified set before the point of the exception may or
     * may not have been added to this attribute set.
     *
     * @param  attributes whose elements are to be added to this attribute set
     * @return {@code true} if this attribute set changed as a result of the
     *         call
     * @throws UnmodifiableSetException if this attribute set does not support
     *         the {@code addAll(AttributeSet)} method
     * @throws NullPointerException if some element in the specified set is
     *         {@code null}, or the set is {@code null}
     * @see #add(Attribute)
     */
    public boolean addAll(AttributeSet attributes) {

        Attribute []attrs = attributes.toArray();
        boolean result = false;
        for (int i=0; i<attrs.length; i++) {
            Attribute newValue =
                AttributeSetUtilities.verifyAttributeValue(attrs[i],
                                                           myInterface);
            Object oldValue = attrMap.put(newValue.getCategory(), newValue);
            result = (! newValue.equals(oldValue)) || result;
        }
        return result;
    }

    
Returns the number of attributes in this attribute set. If this attribute set contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE. 
Returns:the number of attributes in this attribute set
/**
     * Returns the number of attributes in this attribute set. If this attribute
     * set contains more than {@code Integer.MAX_VALUE} elements, returns
     * {@code Integer.MAX_VALUE}.
     *
     * @return the number of attributes in this attribute set
     */
    public int size() {
        return attrMap.size();
    }

    
Returns an array of the attributes contained in this set.

Returns:the attributes contained in this set as an array, zero length if the AttributeSet is empty
/**
     * Returns an array of the attributes contained in this set.
     *
     * @return the attributes contained in this set as an array, zero length if
     *         the {@code AttributeSet} is empty
     */
    public Attribute[] toArray() {
        Attribute []attrs = new Attribute[size()];
        attrMap.values().toArray(attrs);
        return attrs;
    }

    
Removes all attributes from this attribute set.

Throws:
  • UnmodifiableSetException – if this attribute set does not support the clear() operation
/**
     * Removes all attributes from this attribute set.
     *
     * @throws UnmodifiableSetException if this attribute set does not support
     *         the {@code clear()} operation
     */
    public void clear() {
        attrMap.clear();
    }

    
Returns true if this attribute set contains no attributes. 
Returns:true if this attribute set contains no attributes
/**
     * Returns {@code true} if this attribute set contains no attributes.
     *
     * @return {@code true} if this attribute set contains no attributes
     */
    public boolean isEmpty() {
        return attrMap.isEmpty();
    }

    
Compares the specified object with this attribute set for equality. Returns true if the given object is also an attribute set and the two attribute sets contain the same attribute category-attribute value mappings. This ensures that the equals() method works properly across different implementations of the AttributeSet interface. 
Params:
  • object – to be compared for equality with this attribute set
Returns:true if the specified object is equal to this attribute set
/**
     * Compares the specified object with this attribute set for equality.
     * Returns {@code true} if the given object is also an attribute set and the
     * two attribute sets contain the same attribute category-attribute value
     * mappings. This ensures that the {@code equals()} method works properly
     * across different implementations of the {@code AttributeSet} interface.
     *
     * @param  object to be compared for equality with this attribute set
     * @return {@code true} if the specified object is equal to this attribute
     *         set
     */
    public boolean equals(Object object) {
        if (object == null || !(object instanceof AttributeSet)) {
            return false;
        }

        AttributeSet aset = (AttributeSet)object;
        if (aset.size() != size()) {
            return false;
        }

        Attribute[] attrs = toArray();
        for (int i=0;i<attrs.length; i++) {
            if (!aset.containsValue(attrs[i])) {
                return false;
            }
        }
        return true;
    }

    
Returns the hash code value for this attribute set. The hash code of an attribute set is defined to be the sum of the hash codes of each entry in the AttributeSet. This ensures that t1.equals(t2) implies that t1.hashCode()==t2.hashCode() for any two attribute sets t1 and t2, as required by the general contract of Object.hashCode(). 
Returns:the hash code value for this attribute set
/**
     * Returns the hash code value for this attribute set. The hash code of an
     * attribute set is defined to be the sum of the hash codes of each entry in
     * the {@code AttributeSet}. This ensures that {@code t1.equals(t2)} implies
     * that {@code t1.hashCode()==t2.hashCode()} for any two attribute sets
     * {@code t1} and {@code t2}, as required by the general contract of
     * {@link Object#hashCode() Object.hashCode()}.
     *
     * @return the hash code value for this attribute set
     */
    public int hashCode() {
        int hcode = 0;
        Attribute[] attrs = toArray();
        for (int i=0;i<attrs.length; i++) {
            hcode += attrs[i].hashCode();
        }
        return hcode;
    }
}