/*
* Copyright 2012 Daniel Bechler
*
* 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 de.danielbechler.diff.access;
import de.danielbechler.diff.selector.CollectionItemElementSelector;
import de.danielbechler.diff.selector.ElementSelector;
import java.util.Collection;
/**
* @author Daniel Bechler
*/
public class CollectionItemAccessor implements TypeAwareAccessor, Accessor
{
private final Object referenceItem;
public CollectionItemAccessor(final Object referenceItem)
{
this.referenceItem = referenceItem;
}
@SuppressWarnings("unchecked")
private static Collection<Object> objectAsCollection(final Object object)
{
if (object == null)
{
return null;
}
else if (object instanceof Collection)
{
return (Collection<Object>) object;
}
throw new IllegalArgumentException(object.getClass().toString());
}
public ElementSelector getElementSelector()
{
return new CollectionItemElementSelector(referenceItem);
}
public void set(final Object target, final Object value)
{
final Collection<Object> targetCollection = objectAsCollection(target);
if (targetCollection == null)
{
return;
}
final Object previous = get(target);
if (previous != null)
{
targetCollection.remove(previous);
}
targetCollection.add(value);
}
public Object get(final Object target)
{
final Collection targetCollection = objectAsCollection(target);
if (targetCollection == null)
{
return null;
}
for (final Object item : targetCollection)
{
if (item != null && item.equals(referenceItem))
{
return item;
}
}
return null;
}
public Class<?> getType()
{
return referenceItem != null ? referenceItem.getClass() : null;
}
public void unset(final Object target)
{
final Collection targetCollection = objectAsCollection(target);
if (targetCollection != null)
{
targetCollection.remove(referenceItem);
}
}
@Override
public String toString()
{
return "collection item " + getElementSelector();
}
}