org.apache.jackrabbit.oak.plugins.document.BlobReferenceIterator Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.jackrabbit.oak.plugins.document;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;
import org.apache.jackrabbit.oak.plugins.blob.ReferencedBlob;
/**
* An iterator over all referenced binaries.
*
* Only top-level referenced are returned (indirection, if any, is not resolved).
* The items are returned in no particular order.
* An item might be returned multiple times.
*/
public class BlobReferenceIterator implements Iterator {
private static final int BATCH_SIZE = 1000;
private final DocumentStore docStore;
private final BlobCollector blobCollector;
private HashSet batch = new HashSet();
private Iterator batchIterator;
private boolean done;
private String fromKey = NodeDocument.MIN_ID_VALUE;
public BlobReferenceIterator(DocumentNodeStore nodeStore) {
this.docStore = nodeStore.getDocumentStore();
batchIterator = batch.iterator();
this.blobCollector = new BlobCollector(nodeStore);
}
@Override
public boolean hasNext() {
if (!batchIterator.hasNext()) {
loadBatch();
}
return batchIterator.hasNext() || !done;
}
@Override
public ReferencedBlob next() {
// this will load the next batch if required
if (!hasNext()) {
throw new NoSuchElementException();
}
return batchIterator.next();
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
private void loadBatch() {
if (done) {
return;
}
batch.clear();
// read until at least BATCH_SIZE references are available
while (true) {
boolean hasMore = loadBatchQuery();
if (!hasMore) {
done = true;
break;
}
if (batch.size() > BATCH_SIZE) {
break;
}
}
batchIterator = batch.iterator();
}
private boolean loadBatchQuery() {
// read about BATCH_SIZE documents
List list =
docStore.query(Collection.NODES, fromKey, NodeDocument.MAX_ID_VALUE, NodeDocument.HAS_BINARY_FLAG,
NodeDocument.HAS_BINARY_VAL,
BATCH_SIZE);
boolean hasMore = false;
for (NodeDocument doc : list) {
if (doc.getId().equals(fromKey)) {
// already read
continue;
}
hasMore = true;
fromKey = doc.getId();
blobCollector.collect(doc, batch);
}
return hasMore;
}
}