001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License. You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied. See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019
020 package org.apache.myfaces.tobago.taglib.component;
021
022 import org.apache.myfaces.tobago.apt.annotation.BodyContent;
023 import org.apache.myfaces.tobago.apt.annotation.Tag;
024 import org.apache.myfaces.tobago.apt.annotation.TagAttribute;
025 import org.apache.myfaces.tobago.component.ComponentUtil;
026 import org.apache.myfaces.tobago.event.TabChangeListener;
027 import org.apache.myfaces.tobago.event.TabChangeSource;
028 import org.apache.myfaces.tobago.event.TabChangeListenerValueBindingDelegate;
029 import org.apache.myfaces.tobago.event.TabChangeEvent;
030
031 import org.apache.commons.logging.Log;
032 import org.apache.commons.logging.LogFactory;
033
034 import javax.faces.component.UIComponent;
035 import javax.faces.context.FacesContext;
036 import javax.faces.el.ValueBinding;
037 import javax.faces.el.MethodBinding;
038 import javax.faces.webapp.UIComponentTag;
039 import javax.faces.application.Application;
040 import javax.servlet.jsp.JspException;
041 import javax.servlet.jsp.tagext.TagSupport;
042
043 /**
044 * Register an TabChangedListener instance on the UIComponent
045 * associated with the closest parent UIComponent custom action.
046 */
047 @Tag(name = "tabChangeListener", bodyContent = BodyContent.EMPTY)
048 public class TabChangeListenerTag extends TagSupport {
049
050 private static final long serialVersionUID = -419199086962377873L;
051
052 private static final Class[] TAB_CHANGE_LISTENER_ARGS = new Class[] {TabChangeEvent.class};
053
054 private static final Log LOG = LogFactory.getLog(TabChangeListenerTag.class);
055
056 /**
057 * <p>The fully qualified class name of the {@link TabChangeListener}
058 * instance to be created.</p>
059 */
060 private String type;
061 private String binding;
062 private String listener;
063
064 /**
065 * Fully qualified Java class name of a TabChangeListener to be
066 * created and registered.
067 */
068 @TagAttribute(required = true)
069 public void setType(String type) {
070 this.type = type;
071 }
072
073 /**
074 * The value binding expression to a TabChangeListener.
075 */
076 @TagAttribute
077 public void setBinding(String binding) {
078 this.binding = binding;
079 }
080
081
082 /**
083 * A method binding expression to a processTabChange(TabChangeEvent tabChangeEvent) method.
084 */
085 @TagAttribute
086 public void setListener(String listener) {
087 this.listener = listener;
088 }
089
090 /**
091 * <p>Create a new instance of the specified {@link TabChangeListener}
092 * class, and register it with the {@link javax.faces.component.UIComponent} instance associated
093 * with our most immediately surrounding {@link javax.faces.webapp.UIComponentTag} instance, if
094 * the {@link javax.faces.component.UIComponent} instance was created by this execution of the
095 * containing JSP page.</p>
096 *
097 * @throws JspException if a JSP error occurs
098 */
099 public int doStartTag() throws JspException {
100
101 // Locate our parent UIComponentTag
102 UIComponentTag tag =
103 UIComponentTag.getParentUIComponentTag(pageContext);
104 if (tag == null) {
105 // TODO Message resource i18n
106 throw new JspException("Not nested in faces tag");
107 }
108
109 if (!tag.getCreated()) {
110 return (SKIP_BODY);
111 }
112
113 UIComponent component = tag.getComponentInstance();
114 if (component == null) {
115 // TODO Message resource i18n
116 throw new JspException("Component Instance is null");
117 }
118 if (!(component instanceof TabChangeSource)) {
119 // TODO Message resource i18n
120 throw new JspException("Component " + component.getClass().getName() + " is not instanceof TabChangeSource");
121 }
122 TabChangeSource changeSource = (TabChangeSource) component;
123
124 TabChangeListener handler = null;
125 ValueBinding valueBinding = null;
126 if (binding != null && UIComponentTag.isValueReference(binding)) {
127 valueBinding = ComponentUtil.createValueBinding(binding);
128 if (valueBinding != null) {
129 Object obj = valueBinding.getValue(FacesContext.getCurrentInstance());
130 if (obj != null && obj instanceof TabChangeListener) {
131 handler = (TabChangeListener) obj;
132 }
133 }
134 }
135
136 if (handler == null && type != null) {
137 handler = createTabChangeListener(type);
138 if (handler != null && valueBinding != null) {
139 valueBinding.setValue(FacesContext.getCurrentInstance(), handler);
140 }
141 }
142 if (handler != null) {
143 if (valueBinding != null) {
144 changeSource.addTabChangeListener(new TabChangeListenerValueBindingDelegate(type, valueBinding));
145 } else {
146 changeSource.addTabChangeListener(handler);
147 }
148 }
149
150 if (listener != null && UIComponentTag.isValueReference(listener)) {
151 Application application = FacesContext.getCurrentInstance().getApplication();
152 MethodBinding methodBinding = application.createMethodBinding(listener, TAB_CHANGE_LISTENER_ARGS);
153 changeSource.setTabChangeListener(methodBinding);
154 }
155 // TODO else LOG.warn?
156 return (SKIP_BODY);
157 }
158
159
160 /**
161 * <p>Release references to any acquired resources.
162 */
163 public void release() {
164 this.type = null;
165 this.binding = null;
166 }
167
168 /**
169 * <p>Create and return a new {@link TabChangeListener} to be registered
170 * on our surrounding {@link javax.faces.component.UIComponent}.</p>
171 *
172 * @throws javax.servlet.jsp.JspException if a new instance cannot be created
173 */
174 protected TabChangeListener createTabChangeListener(String className) throws JspException {
175 try {
176 Class clazz = getClass().getClassLoader().loadClass(className);
177 return ((TabChangeListener) clazz.newInstance());
178 } catch (Exception e) {
179 throw new JspException(e);
180 }
181 }
182 }