org.apache.hadoop.hdfs.protocol.OpenFilesIterator 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.protocol;
import java.io.IOException;
import java.util.EnumSet;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.fs.BatchedRemoteIterator;
import org.apache.htrace.core.TraceScope;
import org.apache.htrace.core.Tracer;
/**
* OpenFilesIterator is a remote iterator that iterates over the open files list
* managed by the NameNode. Since the list is retrieved in batches, it does not
* represent a consistent view of all open files.
*/
@InterfaceAudience.Private
@InterfaceStability.Evolving
public class OpenFilesIterator extends
BatchedRemoteIterator {
/** No path to be filtered by default. */
public static final String FILTER_PATH_DEFAULT = "/";
/**
* Open file types to filter the results.
*/
public enum OpenFilesType {
ALL_OPEN_FILES((short) 0x01),
BLOCKING_DECOMMISSION((short) 0x02);
private final short mode;
OpenFilesType(short mode) {
this.mode = mode;
}
public short getMode() {
return mode;
}
public static OpenFilesType valueOf(short num) {
for (OpenFilesType type : OpenFilesType.values()) {
if (type.getMode() == num) {
return type;
}
}
return null;
}
}
private final ClientProtocol namenode;
private final Tracer tracer;
private final EnumSet types;
/** List files filtered by given path. */
private String path;
public OpenFilesIterator(ClientProtocol namenode, Tracer tracer,
EnumSet types, String path) {
super(HdfsConstants.GRANDFATHER_INODE_ID);
this.namenode = namenode;
this.tracer = tracer;
this.types = types;
this.path = path;
}
@Override
public BatchedEntries makeRequest(Long prevId)
throws IOException {
try (TraceScope ignored = tracer.newScope("listOpenFiles")) {
return namenode.listOpenFiles(prevId, types, path);
}
}
@Override
public Long elementToPrevKey(OpenFileEntry entry) {
return entry.getId();
}
}