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 }