| /* |
| * 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.tephra.hbase.txprune; |
| |
| |
| import com.google.common.base.Supplier; |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.hadoop.hbase.TableName; |
| |
| /** |
| * Supplies instances of {@link PruneUpperBoundWriter} implementations. |
| */ |
| public class PruneUpperBoundWriterSupplier implements Supplier<PruneUpperBoundWriter> { |
| private static final Log LOG = LogFactory.getLog(PruneUpperBoundWriterSupplier.class); |
| |
| private static volatile PruneUpperBoundWriter instance; |
| private static volatile int refCount = 0; |
| private static final Object lock = new Object(); |
| |
| private final TableName tableName; |
| private final DataJanitorState dataJanitorState; |
| private final long pruneFlushInterval; |
| |
| public PruneUpperBoundWriterSupplier(TableName tableName, DataJanitorState dataJanitorState, |
| long pruneFlushInterval) { |
| this.tableName = tableName; |
| this.dataJanitorState = dataJanitorState; |
| this.pruneFlushInterval = pruneFlushInterval; |
| } |
| |
| @Override |
| public PruneUpperBoundWriter get() { |
| synchronized (lock) { |
| if (instance == null) { |
| instance = new PruneUpperBoundWriter(tableName, dataJanitorState, pruneFlushInterval); |
| instance.startAndWait(); |
| } |
| refCount++; |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("Incrementing Reference Count for PruneUpperBoundWriter " + refCount); |
| } |
| return instance; |
| } |
| } |
| |
| public void release() { |
| synchronized (lock) { |
| refCount--; |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("Decrementing Reference Count for PruneUpperBoundWriter " + refCount); |
| } |
| |
| if (refCount == 0) { |
| try { |
| instance.stopAndWait(); |
| } catch (Exception ex) { |
| LOG.warn("Exception while trying to shutdown PruneUpperBoundWriter thread. ", ex); |
| } finally { |
| // If the thread is still alive (might happen if the thread was blocked on HBase PUT call), interrupt it again |
| if (instance.isAlive()) { |
| try { |
| instance.shutDown(); |
| } catch (Exception e) { |
| LOG.warn("Exception while trying to shutdown PruneUpperBoundWriter thread. ", e); |
| } |
| } |
| instance = null; |
| } |
| } |
| } |
| } |
| } |