JavaScriptJXPathBindingBuilder


1   /*
2    * Copyright 1999-2004 The Apache Software Foundation.
3    * 
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    * 
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    * 
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.apache.cocoon.forms.binding;
17  
18  import java.util.Collections  ;
19  import java.util.HashMap  ;
20  import java.util.Iterator  ;
21  import java.util.Map  ;
22  
23  import org.apache.avalon.framework.context.Context;
24  import org.apache.avalon.framework.context.ContextException;
25  import org.apache.avalon.framework.context.Contextualizable;
26  import org.apache.cocoon.forms.binding.JXPathBindingManager.Assistant;
27  import org.apache.cocoon.forms.util.DomHelper;
28  import org.apache.cocoon.forms.util.JavaScriptHelper;
29  import org.mozilla.javascript.Function;
30  import org.w3c.dom.Element  ;
31  
32  /**
33   * Builds a {@link Binding} based on two JavaScript snippets, respectively for loading and saving the form.
34   * This binding also optionally accepts named child bindings, which are useful when the bound widget is a container.
35   * <p>
36   * The syntax for this binding is as follows:
37   * <pre>
38   *   &lt;fb:javascript id="foo" path="@foo"&gt;
39   *     &lt;fb:load-form&gt;
40   *       var appValue = jxpathPointer.getValue();
41   *       var formValue = doLoadConversion(appValue);
42   *       widget.setValue(formValue);
43   *       childBindings["foo"].loadFormFromModel(widget, jxpathContext);
44   *     &lt;/fb:load-form&gt;
45   *     &lt;fb:save-form&gt;
46   *       var formValue = widget.getValue();
47   *       var appValue = doSaveConversion(formValue);
48   *       jxpathPointer.setValue(appValue);
49   *       childBindings["foo"].saveFormToModel(widget, jxpathContext);
50   *     &lt;/fb:save-form&gt;
51   *     &lt;fb:child-binding name="foo"&gt;
52   *       &lt;fb:value id="bar" path="baz"/&gt;
53   *     &lt;/fb:child-binding&gt;
54   *   &lt;/fb:javascript&gt;
55   * </pre>
56   * This example is rather trivial and could be replaced by a simple &lt;fb:value&gt;, but
57   * it shows the available variables in the script:
58   * <ul>
59   * <li><code>widget</code>: the widget identified by the "id" attribute,
60   * <li><code>jxpathPointer</code>: the JXPath pointer corresponding to the "path" attribute,
61   * <li><code>jxpathContext</code> (not shown): the JXPath context corresponding to the "path" attribute
62   * </ul>
63   * <b>Notes:</b><ul>
64   * <li>The &lt;fb:save-form&gt; snippet should be ommitted if the "direction" attribute is set to "load".</li>
65   * <li>The &lt;fb:load-form&gt; snippet should be ommitted if the "direction" attribute is set to "save".</li>
66   * </ul>
67   *
68   * @author <a HREF="http://www.apache.org/~sylvain/">Sylvain Wallez</a>
69   * @version $Id: JavaScriptJXPathBindingBuilder.java 289538 2005-09-16 13:46:22Z sylvain $
70   */
71  public class JavaScriptJXPathBindingBuilder extends JXPathBindingBuilderBase implements Contextualizable {
72  
73      private Context avalonContext;
74  
75      public void contextualize(Context context) throws ContextException {
76          this.avalonContext = context;
77      }
78  
79      public JXPathBindingBase buildBinding(Element   element, Assistant assistant) throws BindingException {
80          try {
81              CommonAttributes commonAtts = JXPathBindingBuilderBase.getCommonAttributes(element);
82  
83              String   id = DomHelper.getAttribute(element, "id", null);
84              String   path = DomHelper.getAttribute(element, "path", null);
85  
86              JavaScriptJXPathBinding otherBinding = (JavaScriptJXPathBinding)assistant.getContext().getSuperBinding();
87              
88              if(otherBinding!=null) {
89                  commonAtts = JXPathBindingBuilderBase.mergeCommonAttributes(otherBinding.getCommonAtts(),commonAtts);
90                  
91                  if(id==null)
92                      id=otherBinding.getId();
93                  if(path==null)
94                      path=otherBinding.getPath();
95              }
96              
97              // Build load script
98              Function loadScript = null;
99              if (commonAtts.loadEnabled) {
100                 if (otherBinding != null)
101                     loadScript = otherBinding.getLoadScript();
102                 
103                 Element   loadElem = DomHelper.getChildElement(element, BindingManager.NAMESPACE, "load-form");
104                 if (loadElem != null) {
105                     loadScript = JavaScriptHelper.buildFunction(loadElem, "loadForm", JavaScriptJXPathBinding.LOAD_PARAMS);
106                 }
107             }
108 
109             // Build save script
110             Function saveScript = null;
111             if (commonAtts.saveEnabled) {
112                 if (otherBinding != null)
113                     saveScript = otherBinding.getSaveScript();
114                 
115                 Element   saveElem = DomHelper.getChildElement(element, BindingManager.NAMESPACE, "save-form");
116                 if (saveElem != null) {
117                     saveScript = JavaScriptHelper.buildFunction(saveElem, "saveForm", JavaScriptJXPathBinding.SAVE_PARAMS);
118                 }
119             }
120 
121             // Build child bindings
122             Map   childBindings = new HashMap  ();
123             
124             if (otherBinding != null) {
125                 Map   otherChildren = otherBinding.getChildBindingsMap();
126                 Iterator   it = otherChildren.entrySet().iterator();
127                 while(it.hasNext()) {
128                     Map.Entry   entry = (Map.Entry  )it.next();
129                     childBindings.put(entry.getKey(),entry.getValue());
130                 }
131             }
132             
133             Element  [] children = DomHelper.getChildElements(element, BindingManager.NAMESPACE, "child-binding");
134             if (children.length != 0) {
135                 for (int i = 0; i < children.length; i++) {
136                     Element   child = children[i];
137 
138                     // Get the binding name and check its uniqueness
139                     String   name = DomHelper.getAttribute(child, "name");
140                     
141                     JXPathBindingBase[] otherBindings = null;
142                     if (childBindings.containsKey(name)) {
143                         //throw new BindingException("Duplicate name '" + name + "' at " + DomHelper.getLocation(child));
144                         otherBindings = ((ComposedJXPathBindingBase)childBindings.get(name)).getChildBindings();
145                     }
146                     
147                     // Build the child binding
148                     JXPathBindingBase[] bindings = assistant.makeChildBindings(child,otherBindings);
149                     if (bindings == null) {
150                         bindings = new JXPathBindingBase[0];
151                     }
152 
153                     ComposedJXPathBindingBase composedBinding = new ComposedJXPathBindingBase(commonAtts, bindings);
154                     composedBinding.enableLogging(getLogger());
155                     childBindings.put(name, composedBinding);
156                 }
157             }
158 
159             JXPathBindingBase result = new JavaScriptJXPathBinding(this.avalonContext, commonAtts, id, path, loadScript, saveScript,
160                 Collections.unmodifiableMap(childBindings));
161             result.enableLogging(getLogger());
162             return result;
163 
164         } catch(BindingException be) {
165             throw be;
166         } catch(Exception   e) {
167             throw new BindingException("Cannot build binding at " + DomHelper.getLocation(element), e);
168         }
169     }
170 }
171
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