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    • de.danielbechler.diff.accessor.CollectionItemAccessor Maven / Gradle / Ivy

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    /*
 * 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.accessor;

import de.danielbechler.diff.path.*;

import java.util.*;

/** @author Daniel Bechler */
public class CollectionItemAccessor extends AbstractAccessor implements TypeAwareAccessor
{
	private final Object referenceItem;

	public CollectionItemAccessor(final Object referenceItem)
	{
		this.referenceItem = referenceItem;
	}

	public Element getPathElement()
	{
		return new CollectionElement(referenceItem);
	}

	public void set(final Object target, final Object value)
	{
		final Collection 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.equals(referenceItem))
			{
				return item;
			}
		}
		return null;
	}

	@Override
	public Class getType()
	{
		return referenceItem != null ? referenceItem.getClass() : null;
	}

	private static Collection objectAsCollection(final Object object)
	{
		if (object == null)
		{
			return null;
		}
		else if (object instanceof Collection)
		{
			//noinspection unchecked
			return (Collection) object;
		}
		throw new IllegalArgumentException(object.getClass().toString());
	}

	public void unset(final Object target)
	{
		final Collection targetCollection = objectAsCollection(target);
		if (targetCollection != null)
		{
			targetCollection.remove(referenceItem);
		}
	}

	@Override
	public String toString()
	{
		return "collection item " + getPathElement();
	}
}
    
    
    
    

    




    
    
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