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 * 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
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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).
 *
 * 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.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 HashAttributeSet provides an <code>AttributeSet</code>
 * implementation with characteristics of a hash map.
 * <P>
 *
 * @author  Alan Kaminsky
 */
public class HashAttributeSet implements AttributeSet, Serializable {

    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.
     */
    private transient HashMap attrMap = new HashMap();

    
Write the instance to a stream (ie serialize the object)
@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./**
     * Write the instance to a stream (ie serialize the object)
     *
     * @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).
/**
     * Reconstitute an instance from a stream that is, deserialize it).
     */
    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:
NullPointerException – 
    (unchecked exception) Thrown if attribute is null./**
     * Construct a new attribute set,
     * initially populated with the given attribute.
     *
     * @param  attribute  Attribute value to add to the set.
     *
     * @exception  NullPointerException
     *     (unchecked exception) Thrown if <CODE>attribute</CODE> is 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:
NullPointerException – 
    (unchecked exception) Thrown if any element of
    attributes is null./**
     * 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</CODE> 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 null, an empty attribute set is constructed.
     *
     * @exception  NullPointerException
     *     (unchecked exception) Thrown if any element of
     *     <CODE>attributes</CODE> is 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 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:
NullPointerException – if interfaceName is null./**
     * 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.
     * @exception NullPointerException if interfaceName is 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:
NullPointerException – 
    (unchecked exception) Thrown if attribute is null.
NullPointerException – if interfaceName is null.
ClassCastException – 
    (unchecked exception) Thrown if attribute is not an
    instance of 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.
     *
     * @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.
     *
     * @exception  NullPointerException
     *     (unchecked exception) Thrown if <CODE>attribute</CODE> is null.
     * @exception NullPointerException if interfaceName is null.
     * @exception  ClassCastException
     *     (unchecked exception) Thrown if <CODE>attribute</CODE> is not an
     *     instance of <CODE>interfaceName</CODE>.
     */
    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:
NullPointerException – 
    (unchecked exception) Thrown if any element of
attributes is null.
NullPointerException – if interfaceName is null.
ClassCastException – 
    (unchecked exception) Thrown if any element of
attributes is not an instance of
interfaceName./**
     * 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</CODE> 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
     *                    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.
     *
     * @exception  NullPointerException
     *     (unchecked exception) Thrown if any element of
     * <CODE>attributes</CODE> is null.
     * @exception NullPointerException if interfaceName is null.
     * @exception  ClassCastException
     *     (unchecked exception) Thrown if any element of
     * <CODE>attributes</CODE> is not an instance of
     * <CODE>interfaceName</CODE>.
     */
    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:
ClassCastException – 
    (unchecked exception) Thrown if any element of
attributes is not an instance of
interfaceName./**
     * 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
     *                    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.
     *
     * @exception  ClassCastException
     *     (unchecked exception) Thrown if any element of
     * <CODE>attributes</CODE> is not an instance of
     * <CODE>interfaceName</CODE>.
     */
    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:
NullPointerException – 
    (unchecked exception) Thrown if the category is null.
ClassCastException – 
    (unchecked exception) Thrown if the category is not a Class that implements interface Attribute.
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 <tt>null</tt> 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 java.lang.Class Class}
     *                   that implements interface {@link Attribute
     *                   Attribute}.
     *
     * @return  The attribute value in the given attribute category contained
     *          in this attribute set, or <tt>null</tt> if this attribute set
     *          does not contain any attribute value in the given attribute
     *          category.
     *
     * @throws  NullPointerException
     *     (unchecked exception) Thrown if the <CODE>category</CODE> is null.
     * @throws  ClassCastException
     *     (unchecked exception) Thrown if the <CODE>category</CODE> is not a
     *     {@link java.lang.Class Class} that implements interface {@link
     *     Attribute Attribute}.
     */
    public Attribute get(Class<?> category) {
        return (Attribute)
            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:
NullPointerException – 
   (unchecked exception) Thrown if the attribute is null.
UnmodifiableSetException – 
   (unchecked exception) Thrown if this attribute set does not support
    the add() operation.
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  <tt>true</tt> 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
     *    (unchecked exception) Thrown if the <CODE>attribute</CODE> is null.
     * @throws  UnmodifiableSetException
     *    (unchecked exception) Thrown if this attribute set does not support
     *     the <CODE>add()</CODE> 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:
UnmodifiableSetException – 
    (unchecked exception) Thrown if this attribute set does not
    support the remove() operation.
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</CODE> is null, then
     * <CODE>remove()</CODE> does nothing and returns <tt>false</tt>.
     *
     * @param  category Attribute category to be removed from this
     *                  attribute set.
     *
     * @return  <tt>true</tt> 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
     *     (unchecked exception) Thrown if this attribute set does not
     *     support the <CODE>remove()</CODE> 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:
UnmodifiableSetException – 
    (unchecked exception) Thrown if this attribute set does not
    support the remove() operation.
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</CODE> is null, then
     * <CODE>remove()</CODE> does nothing and returns <tt>false</tt>.
     *
     * @param attribute Attribute value to be removed from this attribute set.
     *
     * @return  <tt>true</tt> 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
     *     (unchecked exception) Thrown if this attribute set does not
     *     support the <CODE>remove()</CODE> 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 <tt>true</tt> if this attribute set contains an
     * attribute for the specified category.
     *
     * @param  category whose presence in this attribute set is
     *            to be tested.
     *
     * @return  <tt>true</tt> 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 <tt>true</tt> if this attribute set contains the given
     * attribute.
     *
     * @param  attribute  value whose presence in this attribute set is
     *            to be tested.
     *
     * @return  <tt>true</tt> 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)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:
UnmodifiableSetException – 
   (Unchecked exception) Thrown if this attribute set does not
    support the addAll(AttributeSet) method.
NullPointerException – 
    (Unchecked exception) Thrown if some element in the specified
    set is null, or the set is null.
See Also:
add(Attribute)
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)</CODE>
     * operation is unspecified if the specified set is modified while
     * the operation is in progress.
     * <P>
     * If the <CODE>addAll(AttributeSet)</CODE> 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  <tt>true</tt> if this attribute set changed as a result of the
     *          call.
     *
     * @throws  UnmodifiableSetException
     *    (Unchecked exception) Thrown if this attribute set does not
     *     support the <tt>addAll(AttributeSet)</tt> method.
     * @throws  NullPointerException
     *     (Unchecked exception) Thrown if some element in the specified
     *     set is null, or the set is 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 <tt>Integer.MAX_VALUE</tt> elements,
     * returns  <tt>Integer.MAX_VALUE</tt>.
     *
     * @return  The number of attributes in this attribute set.
     */
    public int size() {
        return attrMap.size();
    }

    
Returns:
the Attributes contained in this set as an array, zero length
if the AttributeSet is empty./**
     *
     * @return the Attributes contained in this set as an array, zero length
     * if the 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 – 
  (unchecked exception) Thrown if this attribute set does not support
    the clear() operation./**
     * Removes all attributes from this attribute set.
     *
     * @throws  UnmodifiableSetException
     *   (unchecked exception) Thrown if this attribute set does not support
     *     the <CODE>clear()</CODE> 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 true if this attribute set contains no attributes.
     *
     * @return 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 <tt>true</tt> 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
     * <tt>equals()</tt> method works properly across different
     * implementations of the AttributeSet interface.
     *
     * @param  object to be compared for equality with this attribute set.
     *
     * @return  <tt>true</tt> 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 AttributeSet.
     * This ensures that <tt>t1.equals(t2)</tt> implies that
     * <tt>t1.hashCode()==t2.hashCode()</tt> for any two attribute sets
     * <tt>t1</tt> and <tt>t2</tt>, as required by the general contract of
     * {@link java.lang.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;
    }

}