/*
* Copyright 2014 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.differ;
import de.danielbechler.diff.access.Instances;
import de.danielbechler.diff.access.MapEntryAccessor;
import de.danielbechler.diff.comparison.ComparisonStrategyResolver;
import de.danielbechler.diff.node.DiffNode;
import de.danielbechler.util.Assert;
import de.danielbechler.util.Collections;
import java.util.Collection;
import java.util.Map;
import java.util.Set;
/**
* Used to find differences between {@link Map Maps}
*
* @author Daniel Bechler
*/
public final class MapDiffer implements Differ
{
private final ComparisonStrategyResolver comparisonStrategyResolver;
private final DifferDispatcher differDispatcher;
public MapDiffer(final DifferDispatcher differDispatcher, final ComparisonStrategyResolver comparisonStrategyResolver)
{
Assert.notNull(differDispatcher, "differDispatcher");
this.differDispatcher = differDispatcher;
this.comparisonStrategyResolver = comparisonStrategyResolver;
}
private static Collection<?> findAddedKeys(final Instances instances)
{
final Set<?> source = instances.getWorking(Map.class).keySet();
final Set<?> filter = instances.getBase(Map.class).keySet();
return Collections.filteredCopyOf(source, filter);
}
private static Collection<?> findRemovedKeys(final Instances instances)
{
final Set<?> source = instances.getBase(Map.class).keySet();
final Set<?> filter = instances.getWorking(Map.class).keySet();
return Collections.filteredCopyOf(source, filter);
}
private static Iterable<?> findKnownKeys(final Instances instances)
{
final Set<?> keys = instances.getWorking(Map.class).keySet();
final Collection<?> changed = Collections.setOf(keys);
changed.removeAll(findAddedKeys(instances));
changed.removeAll(findRemovedKeys(instances));
return changed;
}
public boolean accepts(final Class<?> type)
{
if (type != null)
{
return Map.class.isAssignableFrom(type);
}
return false;
}
public final DiffNode compare(final DiffNode parentNode, final Instances instances)
{
final DiffNode mapNode = new DiffNode(parentNode, instances.getSourceAccessor(), instances.getType());
if (instances.hasBeenAdded())
{
compareEntries(mapNode, instances, instances.getWorking(Map.class).keySet());
mapNode.setState(DiffNode.State.ADDED);
}
else if (instances.hasBeenRemoved())
{
compareEntries(mapNode, instances, instances.getBase(Map.class).keySet());
mapNode.setState(DiffNode.State.REMOVED);
}
else if (instances.areSame())
{
mapNode.setState(DiffNode.State.UNTOUCHED);
}
else if (comparisonStrategyResolver.resolveComparisonStrategy(mapNode) != null)
{
comparisonStrategyResolver.resolveComparisonStrategy(mapNode).compare(mapNode, instances.getType(), instances.getWorking(Map.class), instances.getBase(Map.class));
}
else
{
compareEntries(mapNode, instances, findAddedKeys(instances));
compareEntries(mapNode, instances, findRemovedKeys(instances));
compareEntries(mapNode, instances, findKnownKeys(instances));
}
return mapNode;
}
private void compareEntries(final DiffNode mapNode, final Instances mapInstances, final Iterable<?> keys)
{
for (final Object key : keys)
{
differDispatcher.dispatch(mapNode, mapInstances, new MapEntryAccessor(key));
}
}
}