MultimapDiffer.java

package fr.openwide.core.jpa.more.business.difference.differ;

import java.util.Map.Entry;

import com.google.common.base.Equivalence;
import com.google.common.base.Predicate;
import com.google.common.collect.Multimap;

import de.danielbechler.diff.access.Accessor;
import de.danielbechler.diff.access.Instances;
import de.danielbechler.diff.comparison.ComparisonStrategyResolver;
import de.danielbechler.diff.differ.DifferDispatcher;
import de.danielbechler.diff.filtering.IsReturnableResolver;
import de.danielbechler.diff.node.DiffNode;
import fr.openwide.core.jpa.more.business.difference.differ.strategy.ItemContentComparisonStrategy;
import fr.openwide.core.jpa.more.business.difference.differ.strategy.MultimapDifferAsMapStrategy;
import fr.openwide.core.jpa.more.business.difference.differ.strategy.MultimapDifferEntriesStrategy;

/**
 * A Multimap differ that compares {@link Multimap#entries()} by default, and allows comparing {@link Multimap#asMap()}
 * for some nodes.
 */
public class MultimapDiffer extends AbstractContainerDiffer {

	public MultimapDiffer(DifferDispatcher differDispatcher,
			ComparisonStrategyResolver comparisonStrategyResolver, IsReturnableResolver isReturnableResolver) {
		super(
				differDispatcher, comparisonStrategyResolver, isReturnableResolver,
				new MultimapDifferEntriesStrategy<>(Equivalence.equals())
		);
	}

	@Override
	public boolean accepts(Class<?> type) {
		return Multimap.class.isAssignableFrom(type);
	}
	
	public <K, V> MultimapDiffer addEntriesStrategy(Predicate<? super DiffNode> predicate, Equivalence<? super Entry<K, V>> entryEquivalence) {
		addStrategy(predicate, new MultimapDifferEntriesStrategy<>(entryEquivalence));
		return this;
	}
	
	public MultimapDiffer addAsMapStrategy(Predicate<? super DiffNode> predicate) {
		return addAsMapStrategy(predicate, ItemContentComparisonStrategy.deep());
	}
	
	public MultimapDiffer addAsMapStrategy(Predicate<? super DiffNode> predicate, ItemContentComparisonStrategy itemContentComparisonStrategy) {
		addStrategy(predicate, new MultimapDifferAsMapStrategy<>(itemContentComparisonStrategy));
		return this;
	}

	protected static DiffNode newNode(final DiffNode parentNode, final Instances instances) {
		final Accessor accessor = instances.getSourceAccessor();
		final Class<?> type = instances.getType();
		return new DiffNode(parentNode, accessor, type);
	}
}