/**
* 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.yarn.server.utils;
import java.io.Closeable;
import java.io.IOException;
import java.util.Iterator;
import java.util.Map;
import org.apache.hadoop.classification.InterfaceAudience.Public;
import org.apache.hadoop.classification.InterfaceStability.Evolving;
import org.iq80.leveldb.DB;
import org.iq80.leveldb.DBException;
import org.iq80.leveldb.DBIterator;
import org.iq80.leveldb.ReadOptions;
/**
* A wrapper for a DBIterator to translate the raw RuntimeExceptions that
* can be thrown into DBExceptions.
*/
@Public
@Evolving
public class LeveldbIterator implements Iterator<Map.Entry<byte[], byte[]>>,
Closeable {
private DBIterator iter;
/**
* Create an iterator for the specified database
*/
public LeveldbIterator(DB db) {
iter = db.iterator();
}
/**
* Create an iterator for the specified database
*/
public LeveldbIterator(DB db, ReadOptions options) {
iter = db.iterator(options);
}
/**
* Create an iterator using the specified underlying DBIterator
*/
public LeveldbIterator(DBIterator iter) {
this.iter = iter;
}
/**
* Repositions the iterator so the key of the next BlockElement
* returned greater than or equal to the specified targetKey.
*/
public void seek(byte[] key) throws DBException {
try {
iter.seek(key);
} catch (DBException e) {
throw e;
} catch (RuntimeException e) {
throw new DBException(e.getMessage(), e);
}
}
/**
* Repositions the iterator so is is at the beginning of the Database.
*/
public void seekToFirst() throws DBException {
try {
iter.seekToFirst();
} catch (DBException e) {
throw e;
} catch (RuntimeException e) {
throw new DBException(e.getMessage(), e);
}
}
/**
* Repositions the iterator so it is at the end of of the Database.
*/
public void seekToLast() throws DBException {
try {
iter.seekToLast();
} catch (DBException e) {
throw e;
} catch (RuntimeException e) {
throw new DBException(e.getMessage(), e);
}
}
/**
* Returns <tt>true</tt> if the iteration has more elements.
*/
public boolean hasNext() throws DBException {
try {
return iter.hasNext();
} catch (DBException e) {
throw e;
} catch (RuntimeException e) {
throw new DBException(e.getMessage(), e);
}
}
/**
* Returns the next element in the iteration.
*/
@Override
public Map.Entry<byte[], byte[]> next() throws DBException {
try {
return iter.next();
} catch (DBException e) {
throw e;
} catch (RuntimeException e) {
throw new DBException(e.getMessage(), e);
}
}
/**
* Returns the next element in the iteration, without advancing the
* iteration.
*/
public Map.Entry<byte[], byte[]> peekNext() throws DBException {
try {
return iter.peekNext();
} catch (DBException e) {
throw e;
} catch (RuntimeException e) {
throw new DBException(e.getMessage(), e);
}
}
/**
* @return true if there is a previous entry in the iteration.
*/
public boolean hasPrev() throws DBException {
try {
return iter.hasPrev();
} catch (DBException e) {
throw e;
} catch (RuntimeException e) {
throw new DBException(e.getMessage(), e);
}
}
/**
* @return the previous element in the iteration and rewinds the iteration.
*/
public Map.Entry<byte[], byte[]> prev() throws DBException {
try {
return iter.prev();
} catch (DBException e) {
throw e;
} catch (RuntimeException e) {
throw new DBException(e.getMessage(), e);
}
}
/**
* @return the previous element in the iteration, without rewinding the
* iteration.
*/
public Map.Entry<byte[], byte[]> peekPrev() throws DBException {
try {
return iter.peekPrev();
} catch (DBException e) {
throw e;
} catch (RuntimeException e) {
throw new DBException(e.getMessage(), e);
}
}
/**
* Removes from the database the last element returned by the iterator.
*/
@Override
public void remove() throws DBException {
try {
iter.remove();
} catch (DBException e) {
throw e;
} catch (RuntimeException e) {
throw new DBException(e.getMessage(), e);
}
}
/**
* Closes the iterator.
*/
@Override
public void close() throws IOException {
try {
iter.close();
} catch (RuntimeException e) {
throw new IOException(e.getMessage(), e);
}
}
}