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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).
 *
 * 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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 *
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package javax.swing.text.html;

import javax.swing.text.*;
import java.io.Serializable;
import java.util.*;


An implementation of AttributeSet that can multiplex
across a set of AttributeSets.

/**
 * An implementation of <code>AttributeSet</code> that can multiplex
 * across a set of <code>AttributeSet</code>s.
 *
 */
class MuxingAttributeSet implements AttributeSet, Serializable {
    
Creates a MuxingAttributeSet with the passed in
attributes.

/**
     * Creates a <code>MuxingAttributeSet</code> with the passed in
     * attributes.
     */
    public MuxingAttributeSet(AttributeSet[] attrs) {
        this.attrs = attrs;
    }

    
Creates an empty MuxingAttributeSet. This is intended for
use by subclasses only, and it is also intended that subclasses will
set the constituent AttributeSets before invoking any
of the AttributeSet methods.

/**
     * Creates an empty <code>MuxingAttributeSet</code>. This is intended for
     * use by subclasses only, and it is also intended that subclasses will
     * set the constituent <code>AttributeSet</code>s before invoking any
     * of the <code>AttributeSet</code> methods.
     */
    protected MuxingAttributeSet() {
    }

    
Directly sets the AttributeSets that comprise this
MuxingAttributeSet.

/**
     * Directly sets the <code>AttributeSet</code>s that comprise this
     * <code>MuxingAttributeSet</code>.
     */
    protected synchronized void setAttributes(AttributeSet[] attrs) {
        this.attrs = attrs;
    }

    
Returns the AttributeSets multiplexing too. When the
AttributeSets need to be referenced, this should be called.

/**
     * Returns the <code>AttributeSet</code>s multiplexing too. When the
     * <code>AttributeSet</code>s need to be referenced, this should be called.
     */
    protected synchronized AttributeSet[] getAttributes() {
        return attrs;
    }

    
Inserts as at index. This assumes
the value of index is between 0 and attrs.length,
inclusive.

/**
     * Inserts <code>as</code> at <code>index</code>. This assumes
     * the value of <code>index</code> is between 0 and attrs.length,
     * inclusive.
     */
    protected synchronized void insertAttributeSetAt(AttributeSet as,
                                                     int index) {
        int numAttrs = attrs.length;
        AttributeSet newAttrs[] = new AttributeSet[numAttrs + 1];
        if (index < numAttrs) {
            if (index > 0) {
                System.arraycopy(attrs, 0, newAttrs, 0, index);
                System.arraycopy(attrs, index, newAttrs, index + 1,
                                 numAttrs - index);
            }
            else {
                System.arraycopy(attrs, 0, newAttrs, 1, numAttrs);
            }
        }
        else {
            System.arraycopy(attrs, 0, newAttrs, 0, numAttrs);
        }
        newAttrs[index] = as;
        attrs = newAttrs;
    }

    
Removes the AttributeSet at index. This assumes
the value of index is greater than or equal to 0,
and less than attrs.length.

/**
     * Removes the AttributeSet at <code>index</code>. This assumes
     * the value of <code>index</code> is greater than or equal to 0,
     * and less than attrs.length.
     */
    protected synchronized void removeAttributeSetAt(int index) {
        int numAttrs = attrs.length;
        AttributeSet[] newAttrs = new AttributeSet[numAttrs - 1];
        if (numAttrs > 0) {
            if (index == 0) {
                // FIRST
                System.arraycopy(attrs, 1, newAttrs, 0, numAttrs - 1);
            }
            else if (index < (numAttrs - 1)) {
                // MIDDLE
                System.arraycopy(attrs, 0, newAttrs, 0, index);
                System.arraycopy(attrs, index + 1, newAttrs, index,
                                 numAttrs - index - 1);
            }
            else {
                // END
                System.arraycopy(attrs, 0, newAttrs, 0, numAttrs - 1);
            }
        }
        attrs = newAttrs;
    }

    //  --- AttributeSet methods ----------------------------

    
Gets the number of attributes that are defined.

See Also:
Returns:the number of attributes
/**
     * Gets the number of attributes that are defined.
     *
     * @return the number of attributes
     * @see AttributeSet#getAttributeCount
     */
    public int getAttributeCount() {
        AttributeSet[] as = getAttributes();
        int n = 0;
        for (int i = 0; i < as.length; i++) {
            n += as[i].getAttributeCount();
        }
        return n;
    }

    
Checks whether a given attribute is defined.
This will convert the key over to CSS if the
key is a StyleConstants key that has a CSS
mapping.

Params:
  • key – the attribute key
See Also:
Returns:true if the attribute is defined
/**
     * Checks whether a given attribute is defined.
     * This will convert the key over to CSS if the
     * key is a StyleConstants key that has a CSS
     * mapping.
     *
     * @param key the attribute key
     * @return true if the attribute is defined
     * @see AttributeSet#isDefined
     */
    public boolean isDefined(Object key) {
        AttributeSet[] as = getAttributes();
        for (int i = 0; i < as.length; i++) {
            if (as[i].isDefined(key)) {
                return true;
            }
        }
        return false;
    }

    
Checks whether two attribute sets are equal.

Params:
  • attr – the attribute set to check against
See Also:
Returns:true if the same
/**
     * Checks whether two attribute sets are equal.
     *
     * @param attr the attribute set to check against
     * @return true if the same
     * @see AttributeSet#isEqual
     */
    public boolean isEqual(AttributeSet attr) {
        return ((getAttributeCount() == attr.getAttributeCount()) &&
                containsAttributes(attr));
    }

    
Copies a set of attributes.

See Also:
Returns:the copy
/**
     * Copies a set of attributes.
     *
     * @return the copy
     * @see AttributeSet#copyAttributes
     */
    public AttributeSet copyAttributes() {
        AttributeSet[] as = getAttributes();
        MutableAttributeSet a = new SimpleAttributeSet();
        int n = 0;
        for (int i = as.length - 1; i >= 0; i--) {
            a.addAttributes(as[i]);
        }
        return a;
    }

    
Gets the value of an attribute.  If the requested
attribute is a StyleConstants attribute that has
a CSS mapping, the request will be converted.

Params:
  • key – the attribute name
See Also:
Returns:the attribute value
/**
     * Gets the value of an attribute.  If the requested
     * attribute is a StyleConstants attribute that has
     * a CSS mapping, the request will be converted.
     *
     * @param key the attribute name
     * @return the attribute value
     * @see AttributeSet#getAttribute
     */
    public Object getAttribute(Object key) {
        AttributeSet[] as = getAttributes();
        int n = as.length;
        for (int i = 0; i < n; i++) {
            Object o = as[i].getAttribute(key);
            if (o != null) {
                return o;
            }
        }
        return null;
    }

    
Gets the names of all attributes.

See Also:
Returns:the attribute names
/**
     * Gets the names of all attributes.
     *
     * @return the attribute names
     * @see AttributeSet#getAttributeNames
     */
    public Enumeration getAttributeNames() {
        return new MuxingAttributeNameEnumeration();
    }

    
Checks whether a given attribute name/value is defined.

Params:
  • name – the attribute name
  • value – the attribute value
See Also:
Returns:true if the name/value is defined
/**
     * Checks whether a given attribute name/value is defined.
     *
     * @param name the attribute name
     * @param value the attribute value
     * @return true if the name/value is defined
     * @see AttributeSet#containsAttribute
     */
    public boolean containsAttribute(Object name, Object value) {
        return value.equals(getAttribute(name));
    }

    
Checks whether the attribute set contains all of
the given attributes.

Params:
  • attrs – the attributes to check
See Also:
Returns:true if the element contains all the attributes
/**
     * Checks whether the attribute set contains all of
     * the given attributes.
     *
     * @param attrs the attributes to check
     * @return true if the element contains all the attributes
     * @see AttributeSet#containsAttributes
     */
    public boolean containsAttributes(AttributeSet attrs) {
        boolean result = true;

        Enumeration names = attrs.getAttributeNames();
        while (result && names.hasMoreElements()) {
            Object name = names.nextElement();
            result = attrs.getAttribute(name).equals(getAttribute(name));
        }

        return result;
    }

    
Returns null, subclasses may wish to do something more
intelligent with this.

/**
     * Returns null, subclasses may wish to do something more
     * intelligent with this.
     */
    public AttributeSet getResolveParent() {
        return null;
    }

    
The AttributeSets that make up the resulting
AttributeSet.

/**
     * The <code>AttributeSet</code>s that make up the resulting
     * <code>AttributeSet</code>.
     */
    private AttributeSet[] attrs;


    
An Enumeration of the Attribute names in a MuxingAttributeSet.
This may return the same name more than once.

/**
     * An Enumeration of the Attribute names in a MuxingAttributeSet.
     * This may return the same name more than once.
     */
    private class MuxingAttributeNameEnumeration implements Enumeration {

        MuxingAttributeNameEnumeration() {
            updateEnum();
        }

        public boolean hasMoreElements() {
            if (currentEnum == null) {
                return false;
            }
            return currentEnum.hasMoreElements();
        }

        public Object nextElement() {
            if (currentEnum == null) {
                throw new NoSuchElementException("No more names");
            }
            Object retObject = currentEnum.nextElement();
            if (!currentEnum.hasMoreElements()) {
                updateEnum();
            }
            return retObject;
        }

        void updateEnum() {
            AttributeSet[] as = getAttributes();
            currentEnum = null;
            while (currentEnum == null && attrIndex < as.length) {
                currentEnum = as[attrIndex++].getAttributeNames();
                if (!currentEnum.hasMoreElements()) {
                    currentEnum = null;
                }
            }
        }


        
Index into attrs the current Enumeration came from. 
/** Index into attrs the current Enumeration came from. */
        private int attrIndex;
        
Enumeration from attrs. 
/** Enumeration from attrs. */
        private Enumeration currentEnum;
    }
}