001 /* ========================================================================
002 * JCommon : a free general purpose class library for the Java(tm) platform
003 * ========================================================================
004 *
005 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
006 *
007 * Project Info: http://www.jfree.org/jcommon/index.html
008 *
009 * This library is free software; you can redistribute it and/or modify it
010 * under the terms of the GNU Lesser General Public License as published by
011 * the Free Software Foundation; either version 2.1 of the License, or
012 * (at your option) any later version.
013 *
014 * This library is distributed in the hope that it will be useful, but
015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
017 * License for more details.
018 *
019 * You should have received a copy of the GNU Lesser General Public
020 * License along with this library; if not, write to the Free Software
021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
022 * USA.
023 *
024 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
025 * in the United States and other countries.]
026 *
027 * ------------------
028 * AttributeList.java
029 * ------------------
030 * (C)opyright 2003-2005, by Thomas Morgner and Contributors.
031 *
032 * Original Author: Thomas Morgner;
033 * Contributor(s): David Gilbert (for Object Refinery Limited);
034 *
035 * $Id: AttributeList.java,v 1.3 2005/10/18 13:35:06 mungady Exp $
036 *
037 * Changes
038 * -------
039 * 25-Sep-2003 : Initial version (TM);
040 * 26-Nov-2003 : Javadoc updates (DG);
041 *
042 */
043
044 package org.jfree.xml.writer;
045
046 import java.util.Iterator;
047 import java.util.List;
048
049 /**
050 * The attribute list is used by a writer to specify the attributes
051 * of an XML element in a certain order.
052 *
053 * @author Thomas Morgner
054 */
055 public class AttributeList {
056
057 /**
058 * A name/value pair of the attribute list.
059 */
060 private static class AttributeEntry {
061
062 /** The name of the attribute entry. */
063 private String name;
064
065 /** The value of the attribute entry. */
066 private String value;
067
068 /**
069 * Creates a new attribute entry for the given name and value.
070 *
071 * @param name the attribute name (<code>null</code> not permitted).
072 * @param value the attribute value (<code>null</code> not permitted).
073 */
074 public AttributeEntry(final String name, final String value) {
075 if (name == null) {
076 throw new NullPointerException("Name must not be null. ["
077 + name + ", " + value + "]");
078 }
079 if (value == null) {
080 throw new NullPointerException("Value must not be null. ["
081 + name + ", " + value + "]");
082 }
083 this.name = name;
084 this.value = value;
085 }
086
087 /**
088 * Returns the attribute name.
089 *
090 * @return the name.
091 */
092 public String getName() {
093 return this.name;
094 }
095
096 /**
097 * Returns the value of this attribute entry.
098 *
099 * @return the value of the entry.
100 */
101 public String getValue() {
102 return this.value;
103 }
104
105 /**
106 * Checks whether the given object is an attribute entry with the same name.
107 *
108 * @param o the suspected other attribute entry.
109 *
110 * @return <code>true</code> if the given object is equal, <code>false</code> otherwise.
111 */
112 public boolean equals(final Object o) {
113 if (this == o) {
114 return true;
115 }
116 if (!(o instanceof AttributeEntry)) {
117 return false;
118 }
119
120 final AttributeEntry attributeEntry = (AttributeEntry) o;
121 if (!this.name.equals(attributeEntry.name)) {
122 return false;
123 }
124 return true;
125 }
126
127 /**
128 * Computes an hashcode for this entry.
129 *
130 * @return the hashcode.
131 */
132 public int hashCode() {
133 return this.name.hashCode();
134 }
135 }
136
137 /**
138 * An iterator over the attribute names of this list.
139 */
140 private static class AttributeIterator implements Iterator {
141
142 /** The backend is an iterator over the attribute entries. */
143 private Iterator backend;
144
145 /**
146 * Creates a new attribute iterator using the given iterator as backend.
147 *
148 * @param backend an iterator over the attribute entries (<code>null</code> not permitted).
149 */
150 public AttributeIterator(final Iterator backend) {
151 if (backend == null) {
152 throw new NullPointerException();
153 }
154 this.backend = backend;
155 }
156
157 /**
158 * Returns <tt>true</tt> if the iteration has more elements. (In other
159 * words, returns <tt>true</tt> if <tt>next</tt> would return an element
160 * rather than throwing an exception.)
161 *
162 * @return <tt>true</tt> if the iterator has more elements.
163 */
164 public boolean hasNext() {
165 return this.backend.hasNext();
166 }
167
168 /**
169 * Returns the next element in the iteration.
170 *
171 * @return the next element in the iteration.
172 */
173 public Object next() {
174 final AttributeEntry entry = (AttributeEntry) this.backend.next();
175 if (entry != null) {
176 return entry.getName();
177 }
178 return entry;
179 }
180
181 /**
182 *
183 * Removes from the underlying collection the last element returned by the
184 * iterator (optional operation). This method can be called only once per
185 * call to <tt>next</tt>. The behavior of an iterator is unspecified if
186 * the underlying collection is modified while the iteration is in
187 * progress in any way other than by calling this method.
188 */
189 public void remove() {
190 this.backend.remove();
191 }
192 }
193
194 /** The storage for all entries of this list. */
195 private List entryList;
196
197 /**
198 * Creates an empty attribute list with no default values.
199 */
200 public AttributeList() {
201 this.entryList = new java.util.ArrayList();
202 }
203
204 /**
205 * Returns an iterator over all attribute names. The names are returned
206 * in their oder of addition to the list. The iterator contains strings.
207 *
208 * @return the iterator over all attribute names.
209 */
210 public Iterator keys() {
211 return new AttributeIterator(this.entryList.iterator());
212 }
213
214 /**
215 * Defines an attribute.
216 *
217 * @param name the name of the attribute to be defined
218 * @param value the value of the attribute.
219 */
220 public synchronized void setAttribute(final String name, final String value) {
221 final AttributeEntry entry = new AttributeEntry(name, value);
222 final int pos = this.entryList.indexOf(entry);
223 if (pos != -1) {
224 this.entryList.remove(pos);
225 }
226 this.entryList.add(entry);
227 }
228
229 /**
230 * Returns the attribute value for the given attribute name or null,
231 * if the attribute is not defined in this list.
232 *
233 * @param name the name of the attribute
234 * @return the attribute value or null.
235 */
236 public synchronized String getAttribute(final String name) {
237 return getAttribute(name, null);
238 }
239
240 /**
241 * Returns the attribute value for the given attribute name or the given
242 * defaultvalue, if the attribute is not defined in this list.
243 *
244 * @param name the name of the attribute.
245 * @param defaultValue the default value.
246 *
247 * @return the attribute value or the defaultValue.
248 */
249 public synchronized String getAttribute(final String name, final String defaultValue) {
250 for (int i = 0; i < this.entryList.size(); i++) {
251 final AttributeEntry ae = (AttributeEntry) this.entryList.get(i);
252 if (ae.getName().equals(name)) {
253 return ae.getValue();
254 }
255 }
256 return defaultValue;
257 }
258
259 /**
260 * Removes the attribute with the given name from the list.
261 *
262 * @param name the name of the attribute which should be removed..
263 */
264 public synchronized void removeAttribute(final String name) {
265 for (int i = 0; i < this.entryList.size(); i++) {
266 final AttributeEntry ae = (AttributeEntry) this.entryList.get(i);
267 if (ae.getName().equals(name)) {
268 this.entryList.remove(ae);
269 return;
270 }
271 }
272 }
273 }