001    /* AttributeSet.java --
002       Copyright (C) 2002, 2005 Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
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009    any later version.
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013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
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019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
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031    independent module, the terms and conditions of the license of that
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037    
038    package javax.print.attribute;
039    
040    /**
041     * <code>AttributeSet</code> is the top-level interface for sets of printing
042     * attributes in the Java Print Service API.
043     * <p>
044     * There are no duplicate values allowed in an attribute set and there is
045     * at most one attribute object contained per category type. Based on the
046     * {@link java.util.Map} interface the values of attribute sets are objects
047     * of type {@link javax.print.attribute.Attribute} and the entries are the
048     * categories as {@link java.lang.Class} instances.
049     * </p>
050     * <p>
051     * The following specialized types of <code>AttributeSet</code> are available:
052     * <ul>
053     *  <li>{@link javax.print.attribute.DocAttributeSet}</li>
054     *  <li>{@link javax.print.attribute.PrintRequestAttributeSet}</li>
055     *  <li>{@link javax.print.attribute.PrintJobAttributeSet}</li>
056     *  <li>{@link javax.print.attribute.PrintServiceAttributeSet}</li>
057     * </ul>
058     * </p>
059     * <p>
060     * Attribute sets may be unmodifiable depending on the context of usage. If
061     * used as read-only attribute set modifying operations throw an
062     * {@link javax.print.attribute.UnmodifiableSetException}.
063     * </p>
064     * <p>
065     * The Java Print Service API provides implementation classes for the existing
066     * attribute set interfaces but applications may use their own implementations.
067     * </p>
068     *
069     * @author Michael Koch (konqueror@gmx.de)
070     */
071    public interface AttributeSet
072    {
073      /**
074       * Adds the specified attribute value to this attribute set
075       * if it is not already present.
076       *
077       * This operation removes any existing attribute of the same category
078       * before adding the given attribute to the set.
079       *
080       * @param attribute the attribute to add.
081       * @return <code>true</code> if the set is changed, false otherwise.
082       * @throws NullPointerException if the attribute is <code>null</code>.
083       * @throws UnmodifiableSetException if the set does not support modification.
084       */
085      boolean add (Attribute attribute);
086    
087      /**
088       * Adds all of the elements in the specified set to this attribute set.
089       *
090       * @param attributes the set of attributes to add.
091       * @return <code>true</code> if the set is changed, false otherwise.
092       * @throws UnmodifiableSetException if the set does not support modification.
093       *
094       * @see #add(Attribute)
095       */
096      boolean addAll (AttributeSet attributes);
097    
098      /**
099       * Removes all attributes from this attribute set.
100       *
101       * @throws UnmodifiableSetException if the set does not support modification.
102       */
103      void clear ();
104    
105      /**
106       * Checks if this attributes set contains an attribute with the given
107       * category.
108       *
109       * @param category the category to test for.
110       * @return <code>true</code> if an attribute of the category is contained
111       * in the set, <code>false</code> otherwise.
112       */
113      boolean containsKey (Class<?> category);
114    
115      /**
116       * Checks if this attribute set contains the given attribute.
117       *
118       * @param attribute the attribute to test for.
119       * @return <code>true</code> if the attribute is contained in the set,
120       * <code>false</code> otherwise.
121       */
122      boolean containsValue (Attribute attribute);
123    
124      /**
125       * Tests this set for equality with the given object. <code>true</code> is
126       * returned, if the given object is also of type <code>AttributeSet</code>
127       * and the contained attributes are the same as in this set.
128       *
129       * @param obj the Object to test.
130       * @return <code>true</code> if equal, false otherwise.
131       */
132      boolean equals (Object obj);
133    
134      /**
135       * Returns the attribute object contained in this set for the given attribute
136       * category.
137       *
138       * @param category the category of the attribute. A <code>Class</code>
139       * instance of a class implementing the <code>Attribute</code> interface.
140       * @return The attribute for this category or <code>null</code> if no
141       * attribute is contained for the given category.
142       * @throws NullPointerException if category is null.
143       * @throws ClassCastException if category is not implementing
144       * <code>Attribute</code>.
145       */
146      Attribute get (Class<?> category);
147    
148      /**
149       * Returns the hashcode value. The hashcode value is the sum of all hashcodes
150       * of the attributes contained in this set.
151       *
152       * @return The hashcode for this attribute set.
153       */
154      int hashCode ();
155    
156      /**
157       * Checks if the attribute set is empty.
158       *
159       * @return <code>true</code> if the attribute set is empty, false otherwise.
160       */
161      boolean isEmpty ();
162    
163      /**
164       * Removes the given attribute from the set. If the given attribute is <code>null</code>
165       * nothing is done and <code>false</code> is returned.
166       *
167       * @param attribute the attribute to remove.
168       * @return <code>true</code> if removed, false in all other cases.
169       * @throws UnmodifiableSetException if the set does not support modification.
170       */
171      boolean remove (Attribute attribute);
172    
173      /**
174       * Removes the attribute entry of the given category from the set. If the given
175       * category is <code>null</code> nothing is done and <code>false</code> is returned.
176       *
177       * @param category the category of the entry to be removed.
178       * @return <code>true</code> if an attribute is removed, false in all other cases.
179       * @throws UnmodifiableSetException if the set does not support modification.
180       */
181      boolean remove (Class<?> category);
182    
183      /**
184       * Returns the number of elements in this attribute set.
185       *
186       * @return The number of elements.
187       */
188      int size ();
189    
190      /**
191       * Returns the content of the attribute set as an array
192       *
193       * @return An array of attributes.
194       */
195      Attribute[] toArray ();
196    }