org.apache.hadoop.hdfs.tools.offlineEditsViewer.OfflineEditsVisitorFactory 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.hadoop.hdfs.tools.offlineEditsViewer;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.Paths;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.util.StringUtils;
/**
* EditsVisitorFactory for different implementations of EditsVisitor
*
*/
@InterfaceAudience.Private
@InterfaceStability.Unstable
public class OfflineEditsVisitorFactory {
/**
* Factory function that creates an EditsVisitor object
*
* @param filename output filename
* @param processor type of visitor to create
* @param printToScreen parameter passed to visitor constructor
*
* @return EditsVisitor for appropriate output format (binary, xml, etc.)
*/
static public OfflineEditsVisitor getEditsVisitor(String filename,
String processor, boolean printToScreen) throws IOException {
if(StringUtils.equalsIgnoreCase("binary", processor)) {
return new BinaryEditsVisitor(filename);
}
OfflineEditsVisitor vis;
OutputStream fout = Files.newOutputStream(Paths.get(filename));
OutputStream out = null;
try {
if (!printToScreen) {
out = fout;
}
else {
OutputStream outs[] = new OutputStream[2];
outs[0] = fout;
outs[1] = System.out;
out = new TeeOutputStream(outs);
}
if(StringUtils.equalsIgnoreCase("xml", processor)) {
vis = new XmlEditsVisitor(out);
} else if(StringUtils.equalsIgnoreCase("stats", processor)) {
vis = new StatisticsEditsVisitor(out);
} else {
throw new IOException("Unknown processor " + processor +
" (valid processors: xml, binary, stats)");
}
out = fout = null;
return vis;
} finally {
IOUtils.closeStream(fout);
IOUtils.closeStream(out);
}
}
}