org.brekka.commons.persistence.support.EntityUtils.java Source code

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Here is the source code for org.brekka.commons.persistence.support.EntityUtils.java

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/*
 * Copyright 2012 the original author or authors.
 *
 * 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 org.brekka.commons.persistence.support;

import java.io.Serializable;

import org.brekka.commons.persistence.model.IdentifiableEntity;
import org.hibernate.proxy.HibernateProxy;

/**
 * Utilities for working with entities.
 * 
 * @author Andrew Taylor (andrew@brekka.org)
 */
public final class EntityUtils {

    /**
     * Non-cons
     */
    private EntityUtils() {
    }

    /**
     * Determine whether two entity instances are the same by their primary key.
     * 
     * @param left
     *            entity on the left
     * @param right
     *            entity on the right
     * @return true only if both entities have non-null ID's and they are equal as determined by the equals method of
     *         the id type.
     */
    public static <ID extends Serializable> boolean identityEquals(final IdentifiableEntity<ID> left,
            final IdentifiableEntity<ID> right) {
        if (left != null && right != null) {
            ID leftId = left.getId();
            ID rightId = right.getId();
            if (leftId != null && rightId != null) {
                return leftId.equals(rightId);
            }
        }
        return false;
    }

    public static <T> T narrow(final Object object, final Class<T> expected) {
        if (object instanceof HibernateProxy) {
            HibernateProxy proxy = (HibernateProxy) object;
            return expected.cast(proxy.getHibernateLazyInitializer().getImplementation());
        }
        return expected.cast(object);
    }
}