001 /*
002 $Id: Node.java,v 1.10 2005/08/10 09:53:58 hmeling Exp $
003
004 Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved.
005
006 Redistribution and use of this software and associated documentation
007 ("Software"), with or without modification, are permitted provided
008 that the following conditions are met:
009
010 1. Redistributions of source code must retain copyright
011 statements and notices. Redistributions must also contain a
012 copy of this document.
013
014 2. Redistributions in binary form must reproduce the
015 above copyright notice, this list of conditions and the
016 following disclaimer in the documentation and/or other
017 materials provided with the distribution.
018
019 3. The name "groovy" must not be used to endorse or promote
020 products derived from this Software without prior written
021 permission of The Codehaus. For written permission,
022 please contact info@codehaus.org.
023
024 4. Products derived from this Software may not be called "groovy"
025 nor may "groovy" appear in their names without prior written
026 permission of The Codehaus. "groovy" is a registered
027 trademark of The Codehaus.
028
029 5. Due credit should be given to The Codehaus -
030 http://groovy.codehaus.org/
031
032 THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS
033 ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
034 NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
035 FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
036 THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
037 INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
038 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
039 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
040 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
041 STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
042 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
043 OF THE POSSIBILITY OF SUCH DAMAGE.
044
045 */
046 package groovy.util;
047
048 import java.io.PrintWriter;
049 import java.util.ArrayList;
050 import java.util.Collection;
051 import java.util.Collections;
052 import java.util.Iterator;
053 import java.util.List;
054 import java.util.Map;
055
056 import org.codehaus.groovy.runtime.InvokerHelper;
057
058 /**
059 * Represents an arbitrary tree node which can be used for structured metadata which can be any arbitrary XML-like tree.
060 * A node can have a name, a value and an optional Map of attributes.
061 * Typically the name is a String and a value is either a String or a List of other Nodes.
062 * Though the types are extensible to provide a flexible structure.
063 * e.g. you could use a QName as the name which includes a namespace URI and a local name. Or a JMX ObjectName etc.
064 * So this class can represent metadata like {foo a=1 b="abc"} or nested metadata like {foo a=1 b="123" { bar x=12 text="hello" }}
065 *
066 * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
067 * @version $Revision: 1.10 $
068 */
069 public class Node implements java.io.Serializable {
070
071 private Node parent;
072 private Object name;
073 private Map attributes;
074 private Object value;
075
076 public Node(Node parent, Object name) {
077 this(parent, name, Collections.EMPTY_MAP, Collections.EMPTY_LIST);
078 }
079
080 public Node(Node parent, Object name, Object value) {
081 this(parent, name, Collections.EMPTY_MAP, value);
082 }
083
084 public Node(Node parent, Object name, Map attributes) {
085 this(parent, name, attributes, Collections.EMPTY_LIST);
086 }
087
088 public Node(Node parent, Object name, Map attributes, Object value) {
089 this.parent = parent;
090 this.name = name;
091 this.attributes = attributes;
092 this.value = value;
093
094 if (parent != null) {
095 Object parentValue = parent.value();
096 List parentList = null;
097 if (parentValue instanceof List) {
098 parentList = (List) parentValue;
099 }
100 else {
101 parentList = new ArrayList();
102 parentList.add(parentValue);
103 parent.setValue(parentList);
104 }
105 parentList.add(this);
106 }
107 }
108
109 public String text() {
110 if (value instanceof String) {
111 return (String) value;
112 }
113 else if (value instanceof Collection) {
114 Collection coll = (Collection) value;
115 String previousText = null;
116 StringBuffer buffer = null;
117 for (Iterator iter = coll.iterator(); iter.hasNext();) {
118 Object child = iter.next();
119 if (child instanceof String) {
120 String childText = (String) child;
121 if (previousText == null) {
122 previousText = childText;
123 }
124 else {
125 if (buffer == null) {
126 buffer = new StringBuffer();
127 buffer.append(previousText);
128 }
129 buffer.append(childText);
130 }
131 }
132 }
133 if (buffer != null) {
134 return buffer.toString();
135 }
136 else {
137 if (previousText != null) {
138 return previousText;
139 }
140 }
141 }
142 return "";
143 }
144
145 public Iterator iterator() {
146 return children().iterator();
147 }
148
149 public List children() {
150 if (value == null) {
151 return Collections.EMPTY_LIST;
152 }
153 else if (value instanceof List) {
154 return (List) value;
155 }
156 else {
157 // we're probably just a String
158 return Collections.singletonList(value);
159 }
160 }
161
162 public Map attributes() {
163 return attributes;
164 }
165
166 public Object attribute(Object key) {
167 return (attributes != null) ? attributes.get(key) : null;
168 }
169
170 public Object name() {
171 return name;
172 }
173
174 public Object value() {
175 return value;
176 }
177
178 public void setValue(Object value) {
179 this.value = value;
180 }
181
182 public Node parent() {
183 return parent;
184 }
185
186 public Object get(String key) {
187 if (key.charAt(0) == '@') {
188 String attributeName = key.substring(1);
189 return attributes().get(attributeName);
190 }
191 else {
192 // iterate through list looking for node with name 'key'
193 List answer = new ArrayList();
194 for (Iterator iter = children().iterator(); iter.hasNext();) {
195 Object child = iter.next();
196 if (child instanceof Node) {
197 Node childNode = (Node) child;
198 Object childNodeName = childNode.name();
199 if (childNodeName != null && childNodeName.equals(key)) {
200 answer.add(childNode);
201 }
202 }
203 }
204 return answer;
205 }
206 }
207
208 // public Object get(int idx) {
209 // return children().get(idx);
210 // }
211
212
213
214 /**
215 * Provide a collection of all the nodes in the tree
216 * using a depth first traversal
217 */
218 public List depthFirst() {
219 List answer = new ArrayList();
220 answer.add(this);
221 answer.addAll(depthFirstRest());
222 return answer;
223 }
224
225 private List depthFirstRest() {
226 List answer = new ArrayList();
227 for (Iterator iter = InvokerHelper.asIterator(value); iter.hasNext(); ) {
228 Object child = iter.next();
229 if (child instanceof Node) {
230 Node childNode = (Node) child;
231 List children = childNode.depthFirstRest();
232 answer.add(childNode);
233 answer.addAll(children);
234 }
235 }
236 return answer;
237 }
238
239 /**
240 * Provide a collection of all the nodes in the tree
241 * using a bredth first traversal
242 */
243 public List breadthFirst() {
244 List answer = new ArrayList();
245 answer.add(this);
246 answer.addAll(breadthFirstRest());
247 return answer;
248 }
249
250 private List breadthFirstRest() {
251 List answer = new ArrayList();
252 for (Iterator iter = InvokerHelper.asIterator(value); iter.hasNext(); ) {
253 Object child = iter.next();
254 if (child instanceof Node) {
255 Node childNode = (Node) child;
256 answer.add(childNode);
257 }
258 }
259 List copy = new ArrayList(answer);
260 for (Iterator iter = copy.iterator(); iter.hasNext(); ) {
261 Node childNode = (Node) iter.next();
262 List children = childNode.breadthFirstRest();
263 answer.addAll(children);
264 }
265 return answer;
266 }
267
268 public String toString() {
269 return name + "[attributes=" + attributes + "; value=" + value + "]";
270 }
271
272 public void print(PrintWriter out) {
273 new NodePrinter(out).print(this);
274 }
275 }