CollectionItemByKeySelector.java

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

import org.apache.commons.lang3.builder.HashCodeBuilder;

import com.google.common.base.Equivalence;
import com.google.common.base.Function;

import de.danielbechler.diff.selector.ElementSelector;
import de.danielbechler.util.Strings;

public class CollectionItemByKeySelector<T, K> extends ElementSelector implements IKeyAwareSelector<K> {
	
	private final Function<? super T, ? extends K> keyFunction;
	
	private final Equivalence<? super K> equivalence;
	
	private final K key;
	
	private final String humanReadableString;

	public CollectionItemByKeySelector(Function<? super T, ? extends K> keyFunction, Equivalence<? super K> equivalence,
			K key, String humanReadableString) {
		this.keyFunction = keyFunction;
		this.equivalence = equivalence;
		this.key = key;
		this.humanReadableString = Strings.toSingleLineString(humanReadableString);
	}

	@Override
	@SuppressWarnings("unchecked")
	public boolean equals(final Object o) {
		if (this == o) {
			return true;
		}
		if (o instanceof CollectionItemByKeySelector) {
			CollectionItemByKeySelector<?, ?> other = (CollectionItemByKeySelector<?, ?>)o;
			return keyFunction.equals(other.keyFunction)
					&& equivalence.equals(other.equivalence)
					&& equivalence.equivalent(key, (K) other.key);
		}

		return false;
	}

	@Override
	public int hashCode() {
		return new HashCodeBuilder()
				.append(keyFunction)
				.append(equivalence)
				.append(equivalence.hash(key))
				.build();
	}

	@Override
	public String toHumanReadableString() {
		return humanReadableString;
	}
	
	@Override
	public K getKey() {
		return key;
	}
}