// Copyright 2009 Google 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 com.google.enterprise.connector.util.diffing; import com.google.enterprise.connector.spi.Document; import com.google.enterprise.connector.spi.DocumentList; import com.google.enterprise.connector.spi.RepositoryException; import java.io.IOException; import java.util.Iterator; import java.util.List; /** * An implementation of {@link DocumentList} for the {@link DiffingConnector}. * * @since 2.8 */ public class DiffingConnectorDocumentList implements DocumentList { private final Iterator<CheckpointAndChange> checkpointAndChangeIterator; private String checkpoint; /** * Creates a document list that returns a batch of documents from the provided * {@link CheckpointAndChangeQueue}. * * @param queue a CheckpointAndChangeQueue containing document changes * @param checkpoint point into the change queue after which to start * returning documents * @throws IOException if persisting fails */ public DiffingConnectorDocumentList(CheckpointAndChangeQueue queue, String checkpoint) throws IOException { List<CheckpointAndChange> guaranteedChanges = queue.resume(checkpoint); checkpointAndChangeIterator = guaranteedChanges.iterator(); this.checkpoint = checkpoint; } @Override public String checkpoint() { return checkpoint; } @Override public Document nextDocument() throws RepositoryException { if (checkpointAndChangeIterator.hasNext()) { CheckpointAndChange checkpointAndChange = checkpointAndChangeIterator.next(); checkpoint = checkpointAndChange.getCheckpoint().toString(); return checkpointAndChange.getChange().getDocumentHandle().getDocument(); } else { return null; } } }