MultiValueField


1   /*
2    * Copyright 1999-2005 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.formmodel;
17  
18  import java.lang.reflect.Array  ;
19  import java.util.Locale  ;
20  
21  import org.apache.cocoon.forms.FormsConstants;
22  import org.apache.cocoon.forms.FormContext;
23  import org.apache.cocoon.forms.datatype.Datatype;
24  import org.apache.cocoon.forms.datatype.SelectionList;
25  import org.apache.cocoon.forms.datatype.convertor.ConversionResult;
26  import org.apache.cocoon.forms.datatype.convertor.Convertor;
27  import org.apache.cocoon.forms.event.ValueChangedEvent;
28  import org.apache.cocoon.forms.event.WidgetEvent;
29  import org.apache.cocoon.forms.util.I18nMessage;
30  import org.apache.cocoon.forms.validation.ValidationError;
31  import org.apache.cocoon.forms.validation.ValidationErrorAware;
32  import org.apache.cocoon.xml.XMLUtils;
33  import org.xml.sax.ContentHandler  ;
34  import org.xml.sax.SAXException  ;
35  
36  /**
37   * A MultiValueField is mostly the same as a normal {@link Field}, but can
38   * hold multiple values. A MultiValueField should have a Datatype which
39   * has a SelectionList, because the user will always select the values
40   * from a list. A MultiValueField has no concept of "required", you should
41   * instead use the ValueCountValidationRule to check how many items the user
42   * has selected.
43   *
44   * <p>A MultiValueField also has a {@link Datatype} associated with it. In
45   * case of MultiValueFields, this Datatype will always be an array
46   * type, thus {@link Datatype#isArrayType()} will always return true, and
47   * this in return has an influence on the kind of validation rules that
48   * can be used with the Datatype (see {@link Datatype} description for more
49   * information).</p>
50   *
51   * @version $Id: MultiValueField.java 328365 2005-10-25 13:57:30Z bruno $
52   */
53  public class MultiValueField extends AbstractWidget
54                               implements ValidationErrorAware, SelectableWidget, DataWidget {
55  
56      private static final String   MULTIVALUEFIELD_EL = "multivaluefield";
57      private static final String   VALUES_EL = "values";
58      private static final String   VALUE_EL = "value";
59      private static final String   VALIDATION_MSG_EL = "validation-message";
60  
61      private final MultiValueFieldDefinition definition;
62  
63      private SelectionList selectionList;
64      private String  [] enteredValues;
65      private String   invalidEnteredValue;
66      private Object  [] values;
67      private ValidationError validationError;
68  
69      public MultiValueField(MultiValueFieldDefinition definition) {
70          super(definition);
71          this.definition = definition;
72      }
73  
74      public void initialize() {
75          this.selectionList = this.definition.getSelectionList();
76          super.initialize();
77      }
78  
79      public WidgetDefinition getDefinition() {
80          return definition;
81      }
82  
83      public void readFromRequest(FormContext formContext) {
84          if (!getCombinedState().isAcceptingInputs())
85              return;
86  
87          enteredValues = formContext.getRequest().getParameterValues(getRequestParameterName());
88          invalidEnteredValue = null;
89          validationError = null;
90          values = null;
91  
92          boolean conversionFailed = false;
93          if (enteredValues != null) {
94              Object  [] tempValues = (Object  [])Array.newInstance(getDatatype().getTypeClass(), enteredValues.length);
95              for (int i = 0; i < enteredValues.length; i++) {
96                  String   param = enteredValues[i];
97                  ConversionResult conversionResult = definition.getDatatype().convertFromString(param, formContext.getLocale());
98                  if (conversionResult.isSuccessful()) {
99                      tempValues[i] = conversionResult.getResult();
100                 } else {
101                     conversionFailed = true;
102                     invalidEnteredValue = param;
103                     break;
104                 }
105             }
106 
107             if (!conversionFailed)
108                 values = tempValues;
109             else
110                 values = null;
111         } else {
112             values = new Object  [0];
113         }
114     }
115 
116     public boolean validate() {
117         if (!getCombinedState().isValidatingValues()) {
118             this.wasValid = true;
119             return true;
120         }
121 
122         if (values != null) {
123             validationError = definition.getDatatype().validate(values, new ExpressionContextImpl(this));
124         } else if (invalidEnteredValue != null) {
125             validationError = new ValidationError(new I18nMessage("multivaluefield.conversionfailed", new String  [] {invalidEnteredValue}, FormsConstants.I18N_CATALOGUE));
126         }
127 
128         this.wasValid = validationError == null ? super.validate() : false;
129         return this.wasValid;
130     }
131 
132     /**
133      * @return "multivaluefield"
134      */
135     public String   getXMLElementName() {
136         return MULTIVALUEFIELD_EL;
137     }
138 
139     public void generateItemSaxFragment(ContentHandler   contentHandler, Locale   locale) throws SAXException   {
140         contentHandler.startElement(FormsConstants.INSTANCE_NS, VALUES_EL, FormsConstants.INSTANCE_PREFIX_COLON + VALUES_EL, XMLUtils.EMPTY_ATTRIBUTES);
141         Convertor convertor = definition.getDatatype().getConvertor();
142         if (values != null) {
143             for (int i = 0; i < values.length; i++) {
144                 contentHandler.startElement(FormsConstants.INSTANCE_NS, VALUE_EL, FormsConstants.INSTANCE_PREFIX_COLON + VALUE_EL, XMLUtils.EMPTY_ATTRIBUTES);
145                 String   value = convertor.convertToString(values[i], locale, null);
146                 contentHandler.characters(value.toCharArray(), 0, value.length());
147                 contentHandler.endElement(FormsConstants.INSTANCE_NS, VALUE_EL, FormsConstants.INSTANCE_PREFIX_COLON + VALUE_EL);
148             }
149         } else if (enteredValues != null) {
150             for (int i = 0; i < enteredValues.length; i++) {
151                 contentHandler.startElement(FormsConstants.INSTANCE_NS, VALUE_EL, FormsConstants.INSTANCE_PREFIX_COLON + VALUE_EL, XMLUtils.EMPTY_ATTRIBUTES);
152                 String   value = enteredValues[i];
153                 contentHandler.characters(value.toCharArray(), 0, value.length());
154                 contentHandler.endElement(FormsConstants.INSTANCE_NS, VALUE_EL, FormsConstants.INSTANCE_PREFIX_COLON + VALUE_EL);
155             }
156         }
157         contentHandler.endElement(FormsConstants.INSTANCE_NS, VALUES_EL, FormsConstants.INSTANCE_PREFIX_COLON + VALUES_EL);
158 
159         // the selection list
160         if (this.selectionList != null)
161             this.selectionList.generateSaxFragment(contentHandler, locale);
162 
163         // validation message element
164         if (validationError != null) {
165             contentHandler.startElement(FormsConstants.INSTANCE_NS, VALIDATION_MSG_EL, FormsConstants.INSTANCE_PREFIX_COLON + VALIDATION_MSG_EL, XMLUtils.EMPTY_ATTRIBUTES);
166             validationError.generateSaxFragment(contentHandler);
167             contentHandler.endElement(FormsConstants.INSTANCE_NS, VALIDATION_MSG_EL, FormsConstants.INSTANCE_PREFIX_COLON + VALIDATION_MSG_EL);
168         }
169     }
170 
171 
172     public Object   getValue() {
173         return values;
174     }
175 
176     public void setValue(Object   value) {
177         if (value == null) {
178             setValues(new Object  [0]);
179         } else if (value.getClass().isArray()) {
180             setValues((Object  [])value);
181         } else {
182             throw new RuntimeException  ("Cannot set value of field \"" + getRequestParameterName() + "\" with an object of type " + value.getClass().getName());
183         }
184         getForm().addWidgetUpdate(this);
185     }
186 
187     public void setValues(Object  [] values) {
188         // check that all the objects in the array correspond to the datatype
189         for (int i = 0; i < values.length; i++) {
190             if (!definition.getDatatype().getTypeClass().isAssignableFrom(values[i].getClass()))
191                 throw new RuntimeException  ("Cannot set value of field \"" + getRequestParameterName() + "\" with an object of type " + values[i].getClass().getName());
192         }
193         this.values = values;
194         getForm().addWidgetUpdate(this);
195     }
196 
197     /**
198      * Set this field's selection list.
199      * @param selectionList The new selection list.
200      */
201     public void setSelectionList(SelectionList selectionList) {
202         if (selectionList == null) {
203             throw new IllegalArgumentException  ("An MultiValueField's selection list cannot be null.");
204         }
205 
206         if (selectionList.getDatatype() != null &&
207             selectionList.getDatatype() != definition.getDatatype()) {
208 
209             throw new RuntimeException  ("Tried to assign a SelectionList that is not associated with this widget's datatype.");
210         }
211         this.selectionList = selectionList;
212         getForm().addWidgetUpdate(this);
213     }
214 
215     /**
216      * Read this field's selection list from an external source.
217      * All Cocoon-supported protocols can be used.
218      * The format of the XML produced by the source should be the
219      * same as in case of inline specification of the selection list,
220      * thus the root element should be a <code>fd:selection-list</code>
221      * element.
222      * @param uri The URI of the source.
223      */
224     public void setSelectionList(String   uri) {
225         setSelectionList(this.definition.buildSelectionList(uri));
226     }
227 
228     /**
229      * Set this field's selection list using values from an in-memory
230      * object. The <code>object</code> parameter should point to a collection
231      * (Java collection or array, or Javascript array) of objects. Each object
232      * belonging to the collection should have a <em>value</em> property and a
233      * <em>label</em> property, whose values are used to specify the <code>value</code>
234      * attribute and the contents of the <code>fd:label</code> child element
235      * of every <code>fd:item</code> in the list.
236      * <p>Access to the values of the above mentioned properties is done
237      * via <a HREF="http://jakarta.apache.org/commons/jxpath/users-guide.html">XPath</a> expressions.
238      * @param model The collection used as a model for the selection list.
239      * @param valuePath An XPath expression referring to the attribute used
240      * to populate the values of the list's items.
241      * @param labelPath An XPath expression referring to the attribute used
242      * to populate the labels of the list's items.
243      */
244     public void setSelectionList(Object   model, String   valuePath, String   labelPath) {
245         setSelectionList(this.definition.buildSelectionListFromModel(model, valuePath, labelPath));
246     }
247 
248     public void broadcastEvent(WidgetEvent event) {
249         if (event instanceof ValueChangedEvent) {
250             this.definition.fireValueChangedEvent((ValueChangedEvent)event);
251         } else {
252             // Other kinds of events
253             super.broadcastEvent(event);
254         }
255     }
256 
257     public ValidationError getValidationError() {
258         return this.validationError;
259     }
260 
261     public void setValidationError(ValidationError error) {
262         this.validationError = error;
263         getForm().addWidgetUpdate(this);
264     }
265 
266     public Datatype getDatatype() {
267         return definition.getDatatype();
268     }
269 }
270
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags