tapestry/tapestry-framework/src/java/org/apache/tapestry/record/PropertyChangeImpl.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.record;

import org.apache.hivemind.util.Defense;
import org.apache.hivemind.util.ToStringBuilder;

/**
 * Represents a change to a component on a page.
 * 
 * @author Howard Lewis Ship
 */

public class PropertyChangeImpl implements PropertyChange
{

    private String _componentPath;

    private String _propertyName;

    private Object _newValue;

    public PropertyChangeImpl(String componentPath, String propertyName,
            Object newValue)
    {
        Defense.notNull(propertyName, "propertyName");

        // TODO: This breaks some tests, but those tests are wrong.
        // Defense.notNull(newValue, "newValue");

        _componentPath = componentPath;
        _propertyName = propertyName;
        _newValue = newValue;
    }

    /**
     * The path to the component on the page, or null if the property is a
     * property of the page.
     */

    public String getComponentPath()
    {
        return _componentPath;
    }

    /**
     * The new value for the property, which may be null.
     */

    public Object getNewValue()
    {
        return _newValue;
    }

    /**
     * The name of the property that changed.
     */

    public String getPropertyName()
    {
        return _propertyName;
    }

    public String toString()
    {
        ToStringBuilder builder = new ToStringBuilder(this);

        builder.append("componentPath", _componentPath);
        builder.append("propertyName", _propertyName);
        builder.append("newValue", _newValue);

        return builder.toString();
    }

    public boolean equals(Object object)
    {
        if (this == object) return true;

        if (object == null || object.getClass() != this.getClass())
            return false;

        PropertyChangeImpl other = (PropertyChangeImpl) object;

        return same(_componentPath, other._componentPath)
                && same(_propertyName, other._propertyName)
                && same(_newValue, other._newValue);
    }

    private boolean same(Object o1, Object o2)
    {
        return o1 == o2 || (o1 != null && o1.equals(o2));
    }
}