/*
* This file is part of the Wayback archival access software
* (http://archive-access.sourceforge.net/projects/wayback/).
*
* Licensed to the Internet Archive (IA) by one or more individual
* contributors.
*
* The IA 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.archive.wayback.resourceindex.ziplines;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.logging.Logger;
import org.archive.util.iterator.CloseableIterator;
import org.archive.wayback.exception.ResourceIndexNotAvailableException;
import org.archive.wayback.util.flatfile.FlatFile;
/**
* @author brad
*
*/
public class ZiplinedBlockStringSequence {
private static final Logger LOGGER = Logger.getLogger(
ZiplinedBlockStringSequence.class.getName());
private FlatFile chunkIndex = null;
private HashMap<String,BlockLocation> chunkMap = null;
private int maxBlocks = 10000;
public ZiplinedBlockStringSequence(FlatFile chunkIndex,
HashMap<String,BlockLocation> chunkMap) {
this.chunkIndex = chunkIndex;
this.chunkMap = chunkMap;
}
private ZiplineBlockMatches getBlockMatches(String prefix)
throws IOException, ResourceIndexNotAvailableException {
ArrayList<ZiplinedBlock> blocks = new ArrayList<ZiplinedBlock>();
boolean first = true;
int numBlocks = 0;
boolean truncated = false;
CloseableIterator<String> itr = null;
try {
itr = chunkIndex.getRecordIteratorLT(prefix);
while(itr.hasNext()) {
if(numBlocks >= maxBlocks) {
truncated = true;
break;
}
String blockDescriptor = itr.next();
numBlocks++;
String parts[] = blockDescriptor.split("\t");
if(parts.length != 4) {
LOGGER.severe("Bad Block descriptor Line(" +
blockDescriptor + " in " + chunkIndex.getPath());
throw new ResourceIndexNotAvailableException("Bad line(" +
blockDescriptor + ")");
}
// only compare the correct length:
String prefCmp = prefix;
String blockCmp = parts[0];
if(first) {
// always add first:
first = false;
} else if(!blockCmp.startsWith(prefCmp)) {
// all done;
break;
}
// add this and keep lookin...
BlockLocation bl = chunkMap.get(parts[1]);
long offset = Long.parseLong(parts[2]);
int count = Integer.parseInt(parts[3]);
blocks.add(new ZiplinedBlock(bl.getLocations(), offset, count));
}
} finally {
if(itr != null) {
itr.close();
}
}
return new ZiplineBlockMatches(blocks,prefix);
}
public StringPrefixIterator getIterator(String prefix, long skip)
throws ResourceIndexNotAvailableException, IOException {
ZiplineBlockMatches matches = getBlockMatches(prefix);
return matches.getIteratorAt(skip);
}
public StringPrefixIterator getIterator(String prefix)
throws ResourceIndexNotAvailableException, IOException {
ZiplineBlockMatches matches = getBlockMatches(prefix);
return matches.getIterator();
}
}