| /** |
| * 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); |
| } |
| } |
| } |