/**
* Copyright 2010 JBoss Inc
*
* 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.drools.repository;
import java.util.Iterator;
import javax.jcr.Node;
import javax.jcr.RepositoryException;
import javax.jcr.version.Version;
import javax.jcr.version.VersionIterator;
/**
* A lazy iterator for walking back through history.
* Wraps the version iterator from JCR and allows skipping.
*
* @author Michael Neale
*
*/
public class AssetHistoryIterator
implements
Iterator<AssetItem> {
private Node head;
private VersionIterator versionIterator;
private RulesRepository repo;
public AssetHistoryIterator(RulesRepository repo, Node head) {
this.head = head;
this.repo = repo;
try {
this.versionIterator = VersionableItem.getVersionManager(head).getVersionHistory(head.getPath()).getAllVersions();
} catch ( RepositoryException e ) {
throw new RulesRepositoryException( e );
}
}
public boolean hasNext() {
return versionIterator.hasNext();
}
public AssetItem next() {
return new AssetItem(this.repo, (Version) versionIterator.next());
}
/**
* You can't do this with this sort of iterator.
* It makes no sense to remove a history item.
* Removing history is a administrative function only (and in
* any case, it may have to be archived for legal reasons).
*
* @throws UnsupportedOperationException when called.
*/
public void remove() {
throw new UnsupportedOperationException();
}
/**
* Skip the specified number of items. As this is a lazy iterator this
* means less work in pulling it from the database etc.
*/
public void skip(int i) {
this.versionIterator.skip( i );
}
}