/*

  * Copyright 2004-2008 the Seasar Foundation and the Others.

  *

  * Licensed under the Apache License, Version 2.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

  *

  *     http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, 

  * either express or implied. See the License for the specific language

  * governing permissions and limitations under the License.

  */

 package org.seasar.uruma.viewer;

 import java.lang.reflect.Field;

 import org.eclipse.jface.viewers.ILabelProvider;

 import org.eclipse.jface.viewers.ILabelProviderListener;

 import org.eclipse.swt.graphics.Image;

 import org.seasar.framework.beans.BeanDesc;

 import org.seasar.framework.beans.factory.BeanDescFactory;

 import org.seasar.framework.util.FieldUtil;

 import org.seasar.uruma.annotation.BindingLabel;

 /**

  * 汎用的な {@link ILabelProvider} の実装クラスです。<br />

  * <p>

  * {@link GenericLabelProvider#setTargetClass(Class) setTargetClass()}

  * メソッドで設定されたクラスの中から {@link BindingLabel} アノテーションが付加されたフィールドをテーブルのカラムとして表示します。

  * </p>

  * <p>

  * {@link BindingLabel} アノテーションが付加されたフィールドが存在しない場合、<code>toString()</code>

  * メソッドの戻り値をラベルに設定します。

  * </p>

  * <p>

  * {@link BindingLabel} アノテーションが付加されたフィールドが複数存在する場合、一番最初のフィールドが有効となります。

  * </p>

  * 

  * @author y-komori

  */

 public class GenericLabelProvider implements ILabelProvider,

         TargetClassHoldingProvider {

     protected Field labelField;

     /*

      * @see org.eclipse.jface.viewers.ILabelProvider#getImage(java.lang.Object)

      */

     public Image getImage(final Object element) {

         return null;

     }

     /*

      * @see org.eclipse.jface.viewers.ILabelProvider#getText(java.lang.Object)

      */

     public String getText(final Object element) {

         if (labelField != null) {

             Object value = FieldUtil.get(labelField, element);

             return (value != null) ? value.toString() : "";

         } else {

             return element.toString();

         }

     }

     /*

      * @see org.eclipse.jface.viewers.IBaseLabelProvider#addListener(org.eclipse.jface.viewers.ILabelProviderListener)

      */

     public void addListener(final ILabelProviderListener listener) {

         // Do nothing.

     }

     /*

      * @see org.eclipse.jface.viewers.IBaseLabelProvider#dispose()

      */

     public void dispose() {

         // Do nothing.

     }

     /*

      * @see org.eclipse.jface.viewers.IBaseLabelProvider#isLabelProperty(java.lang.Object,

      *      java.lang.String)

      */

     public boolean isLabelProperty(final Object element, final String property) {

         // Do nothing.

         return false;

     }

     /*

      * @see org.eclipse.jface.viewers.IBaseLabelProvider#removeListener(org.eclipse.jface.viewers.ILabelProviderListener)

      */

     public void removeListener(final ILabelProviderListener listener) {

         // Do nothing.

     }

     /*

      * @see org.seasar.uruma.viewer.TargetClassHoldingProvider#setTargetClass(java.lang.Class)

      */

     public void setTargetClass(final Class<?> clazz) {

         BeanDesc desc = BeanDescFactory.getBeanDesc(clazz);

         int fieldSize = desc.getFieldSize();

         for (int i = 0; i < fieldSize; i++) {

             Field field = desc.getField(i);

             BindingLabel annotation = field.getAnnotation(BindingLabel.class);

             if (annotation != null) {

                 labelField = field;

                 break;

             }

         }

     }

 }