tapestry/tapestry-framework/src/java/org/apache/tapestry/form/BeanPropertySelectionModel.java

// Copyright 2004, 2005 The Apache Software Foundation
//
// 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.apache.tapestry.form;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;

import org.apache.commons.beanutils.BeanUtils;

/**
 * This class is a property selection model for an object list. This is used in PropertySelection,
 * MultiplePropertySelection or Palette tapestry components. For example, to use for a Hospital
 * class, and have the labels be the hospital names. <code>
 * List&lt;Hospital&gt; list = ...;
 * return new BeanPropertySelectionModel(hospitals, "name");
 * </code>
 * This will use getName() on the Hospital object, as its display.
 * 
 * @author Gabriel Handford
 */
public class BeanPropertySelectionModel implements IPropertySelectionModel, Serializable
{

    /** Comment for <code>serialVersionUID</code>. */
    private static final long serialVersionUID = 3763091973006766644L;
    private List _list;
    private String _labelField;

    /**
     * Build an empty property selection model.
     */
    public BeanPropertySelectionModel()
    {
        this(Arrays.asList(new Object[0]), null);
    }

    /**
     * Build a bean property selection model.
     * 
     * @param list
     *            The list
     * @param labelField
     *            The label field
     */
    public BeanPropertySelectionModel(List list, String labelField)
    {
        _list = list;
        _labelField = labelField;
    }

    /**
     * Build a bean property selection model.
     * 
     * @param c
     *            Collection
     * @param labelField
     *            The label field
     */
    public BeanPropertySelectionModel(Collection c, String labelField)
    {
        _list = new ArrayList(c);
        _labelField = labelField;
    }

    /**
     * Get the number of options.
     * 
     * @return option count
     */
    public int getOptionCount()
    {
        return _list.size();
    }

    /**
     * Get the option at index.
     * 
     * @param index
     *            Index
     * @return object Object at index
     */
    public Object getOption(int index)
    {
        return _list.get(index);
    }

    /**
     * Get the label at index.
     * 
     * @param index
     *            Index
     * @return label Label at index
     */
    public String getLabel(int index)
    {
        Object obj = _list.get(index);
        try {

            return BeanUtils.getProperty(obj, _labelField);
        } catch (Exception e) {
            throw new RuntimeException("Error getting property", e);
        }
    }

    /**
     * Get the value at index.
     * 
     * @param index
     *            Index
     * @return value Value at index
     */
    public String getValue(int index)
    {
        return String.valueOf(index);
    }

    public boolean isDisabled(int index)
    {
        return false;
    }
    
    /**
     * Translate value to object.
     * 
     * @param value
     *            Value
     * @return object Object from value
     */
    public Object translateValue(String value)
    {
        return getOption(Integer.parseInt(value));
    }
}