foundation/org.eclipse.persistence.core/src/main/java/org/eclipse/persistence/internal/identitymaps/IdentityMapEnumeration.java

/*
 * Copyright (c) 1998, 2020 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0,
 * or the Eclipse Distribution License v. 1.0 which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
 */

// Contributors:
//     Oracle - initial API and implementation from Oracle TopLink
//     12/14/2017-3.0 Tomas Kraus
//       - 522635: ConcurrentModificationException when triggering lazy load from conforming query
package org.eclipse.persistence.internal.identitymaps;

import java.util.Collection;
import java.util.NoSuchElementException;

/**
 * Allows to iterate over {@code Object} instances stored in {@link CacheKey} instances
 * in the {@link IdentityMap}.
 */
public class IdentityMapEnumeration extends AbstractIdentityMapEnumeration<Object>{

    /**
     * Creates an instance of {@link CacheKey} instances enumeration.
     * Checking of read lock on the {@link CacheKey} instances is turned on.
     *
     * @param keys {@link Collection} of {@link CacheKey} instances to be iterated
     */
    public IdentityMapEnumeration(Collection<CacheKey> keys) {
        super(keys, true);
    }

    /**
     * Get next {@link CacheKey#getObject()} element of {@link CacheKey} enumeration
     * if this enumeration object has at least one more element to provide.
     *
     * @return the next {@link CacheKey#getObject()} element of this enumeration
     * @exception  NoSuchElementException  if no more elements exist
     */
    @Override
    public Object nextElement() {
        return getNextElement().getObject();
    }
}