001 /*
002 $Id: BuilderSupport.java,v 1.8 2005/02/05 16:02:22 mcspanky 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
049 import groovy.lang.Closure;
050 import groovy.lang.GroovyObjectSupport;
051 import groovy.lang.MissingMethodException;
052
053 import java.util.List;
054 import java.util.Map;
055
056 import org.codehaus.groovy.runtime.InvokerHelper;
057
058 /**
059 * An abstract base class for creating arbitrary nested trees of objects
060 * or events
061 *
062 * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
063 * @version $Revision: 1.8 $
064 */
065 public abstract class BuilderSupport extends GroovyObjectSupport {
066
067 private Object current;
068 private Closure nameMappingClosure;
069 private BuilderSupport proxyBuilder;
070
071 public BuilderSupport() {
072 this.proxyBuilder = this;
073 }
074
075 public BuilderSupport(BuilderSupport proxyBuilder) {
076 this(null, proxyBuilder);
077 }
078
079 public BuilderSupport(Closure nameMappingClosure, BuilderSupport proxyBuilder) {
080 this.nameMappingClosure = nameMappingClosure;
081 this.proxyBuilder = proxyBuilder;
082 }
083
084 public Object invokeMethod(String methodName, Object args) {
085 Object name = getName(methodName);
086 return doInvokeMethod(methodName, name, args);
087 }
088
089 protected Object doInvokeMethod(String methodName, Object name, Object args) {
090 Object node = null;
091 Closure closure = null;
092 List list = InvokerHelper.asList(args);
093
094 //System.out.println("Called invokeMethod with name: " + name + " arguments: " + list);
095
096 switch (list.size()) {
097 case 0:
098 node = proxyBuilder.createNode(name);
099 break;
100 case 1:
101 {
102 Object object = list.get(0);
103 if (object instanceof Map) {
104 node = proxyBuilder.createNode(name, (Map) object);
105 } else if (object instanceof Closure) {
106 closure = (Closure) object;
107 node = proxyBuilder.createNode(name);
108 } else {
109 node = proxyBuilder.createNode(name, object);
110 }
111 }
112 break;
113 case 2:
114 {
115 Object object1 = list.get(0);
116 Object object2 = list.get(1);
117 if (object1 instanceof Map) {
118 if (object2 instanceof Closure) {
119 closure = (Closure) object2;
120 node = proxyBuilder.createNode(name, (Map) object1);
121 } else {
122 node = proxyBuilder.createNode(name, (Map) object1, object2);
123 }
124 } else {
125 if (object2 instanceof Closure) {
126 closure = (Closure) object2;
127 node = proxyBuilder.createNode(name, object1);
128 } else if (object2 instanceof Map) {
129 node = proxyBuilder.createNode(name, (Map) object2, object1);
130 } else {
131 throw new MissingMethodException(name.toString(), getClass(), list.toArray());
132 }
133 }
134 }
135 break;
136 case 3:
137 {
138 Object arg0 = list.get(0);
139 Object arg1 = list.get(1);
140 Object arg2 = list.get(2);
141 if (arg0 instanceof Map && arg2 instanceof Closure) {
142 closure = (Closure) arg2;
143 node = proxyBuilder.createNode(name, (Map) arg0, arg1);
144 } else if (arg1 instanceof Map && arg2 instanceof Closure) {
145 closure = (Closure) arg2;
146 node = proxyBuilder.createNode(name, (Map) arg1, arg0);
147 } else {
148 throw new MissingMethodException(name.toString(), getClass(), list.toArray());
149 }
150 }
151 break;
152 default:
153 {
154 throw new MissingMethodException(name.toString(), getClass(), list.toArray());
155 }
156
157 }
158
159 if (current != null) {
160 proxyBuilder.setParent(current, node);
161 }
162
163 if (closure != null) {
164 // push new node on stack
165 Object oldCurrent = current;
166 current = node;
167
168 // lets register the builder as the delegate
169 setClosureDelegate(closure, node);
170 closure.call();
171
172 current = oldCurrent;
173 }
174
175 proxyBuilder.nodeCompleted(current, node);
176 return node;
177 }
178
179 /**
180 * A strategy method to allow derived builders to use
181 * builder-trees and switch in different kinds of builders.
182 * This method should call the setDelegate() method on the closure
183 * which by default passes in this but if node is-a builder
184 * we could pass that in instead (or do something wacky too)
185 *
186 * @param closure the closure on which to call setDelegate()
187 * @param node the node value that we've just created, which could be
188 * a builder
189 */
190 protected void setClosureDelegate(Closure closure, Object node) {
191 closure.setDelegate(this);
192 }
193
194 protected abstract void setParent(Object parent, Object child);
195 protected abstract Object createNode(Object name);
196 protected abstract Object createNode(Object name, Object value);
197 protected abstract Object createNode(Object name, Map attributes);
198 protected abstract Object createNode(Object name, Map attributes, Object value);
199
200 /**
201 * A hook to allow names to be converted into some other object
202 * such as a QName in XML or ObjectName in JMX
203 * @param methodName
204 * @return
205 */
206 protected Object getName(String methodName) {
207 if (nameMappingClosure != null) {
208 return nameMappingClosure.call(methodName);
209 }
210 return methodName;
211 }
212
213
214 /**
215 * A hook to allow nodes to be processed once they have had all of their
216 * children applied
217 */
218 protected void nodeCompleted(Object parent, Object node) {
219 }
220
221 protected Object getCurrent() {
222 return current;
223 }
224
225 protected void setCurrent(Object current) {
226 this.current = current;
227 }
228 }