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.event;
021    
022    import org.apache.commons.logging.Log;
023    import org.apache.commons.logging.LogFactory;
024    
025    import javax.faces.component.StateHolder;
026    import javax.faces.component.UIComponentBase;
027    import javax.faces.context.FacesContext;
028    import javax.faces.el.ValueBinding;
029    
030    /*
031     * Date: Jan 9, 2007
032     * Time: 8:08:01 PM
033     */
034    public class TabChangeListenerValueBindingDelegate implements TabChangeListener, StateHolder {
035      private static final Log LOG = LogFactory.getLog(TabChangeListenerValueBindingDelegate.class);
036      private String type;
037      private ValueBinding valueBinding;
038    
039      public TabChangeListenerValueBindingDelegate() {
040      }
041    
042      public TabChangeListenerValueBindingDelegate(String type, ValueBinding valueBinding) {
043        this.type = type;
044        this.valueBinding = valueBinding;
045      }
046    
047      public void processTabChange(TabChangeEvent tabChangeEvent) {
048        TabChangeListener handler = getTabChangeListener();
049        if (handler != null) {
050          handler.processTabChange(tabChangeEvent);
051        } else {
052          LOG.error("Ignoring TabChangeEvent. No TabChangeListener found.");
053        }
054      }
055    
056      public Object saveState(FacesContext context) {
057        Object[] state = new Object[2];
058        state[0] = UIComponentBase.saveAttachedState(context, valueBinding);
059        state[1] = type;
060        return state;
061      }
062    
063      public void restoreState(FacesContext context, Object state) {
064        Object[] values = (Object[]) state;
065        valueBinding = (ValueBinding) UIComponentBase.restoreAttachedState(context, values[0]);
066        type = (String) values[1];
067    
068      }
069    
070      public boolean isTransient() {
071        return false;
072      }
073    
074      public void setTransient(boolean newTransientValue) {
075        // ignore
076      }
077    
078      private TabChangeListener getTabChangeListener() {
079        TabChangeListener handler = null;
080        if (valueBinding != null) {
081          Object obj = valueBinding.getValue(FacesContext.getCurrentInstance());
082          if (obj != null && obj instanceof TabChangeListener) {
083            handler = (TabChangeListener) obj;
084          }
085        }
086        if (handler == null && type != null) {
087          handler = createTabChangeListener(type);
088          if (handler != null && valueBinding != null) {
089            valueBinding.setValue(FacesContext.getCurrentInstance(), handler);
090          }
091        }
092        return handler;
093      }
094    
095      private TabChangeListener createTabChangeListener(String className) {
096        try {
097          Class clazz = getClass().getClassLoader().loadClass(className);
098          return ((TabChangeListener) clazz.newInstance());
099        } catch (Exception e) {
100          LOG.error("", e);
101        }
102        return null;
103      }
104    
105    }