Java tutorial
/** * 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.hbase.regionserver; import java.util.concurrent.atomic.AtomicBoolean; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.hbase.TableName; import org.apache.hadoop.hbase.classification.InterfaceAudience; import org.apache.hadoop.hbase.metrics.Interns; import org.apache.hadoop.metrics2.MetricsRecordBuilder; import org.apache.hadoop.metrics2.lib.DynamicMetricsRegistry; @InterfaceAudience.Private public class MetricsTableSourceImpl implements MetricsTableSource { private static final Log LOG = LogFactory.getLog(MetricsTableSourceImpl.class); private AtomicBoolean closed = new AtomicBoolean(false); // Non-final so that we can null out the wrapper // This is just paranoia. We really really don't want to // leak a whole table by way of keeping the // tableWrapper around too long. private MetricsTableWrapperAggregate tableWrapperAgg; private final MetricsTableAggregateSourceImpl agg; private final DynamicMetricsRegistry registry; private final String tableNamePrefix; private final TableName tableName; private final int hashCode; public MetricsTableSourceImpl(String tblName, MetricsTableAggregateSourceImpl aggregate, MetricsTableWrapperAggregate tblWrapperAgg) { LOG.debug("Creating new MetricsTableSourceImpl for table "); this.tableName = TableName.valueOf(tblName); this.agg = aggregate; agg.register(tblName, this); this.tableWrapperAgg = tblWrapperAgg; this.registry = agg.getMetricsRegistry(); this.tableNamePrefix = "Namespace_" + this.tableName.getNamespaceAsString() + "_table_" + this.tableName.getQualifierAsString() + "_metric_"; this.hashCode = this.tableName.hashCode(); } @Override public void close() { boolean wasClosed = closed.getAndSet(true); // Has someone else already closed this for us? if (wasClosed) { return; } // Before removing the metrics remove this table from the aggregate table bean. // This should mean that it's unlikely that snapshot and close happen at the same time. agg.deregister(tableName.getNameAsString()); // While it's un-likely that snapshot and close happen at the same time it's still possible. // So grab the lock to ensure that all calls to snapshot are done before we remove the metrics synchronized (this) { if (LOG.isTraceEnabled()) { LOG.trace("Removing table Metrics for table "); } tableWrapperAgg = null; } } @Override public MetricsTableAggregateSource getAggregateSource() { return agg; } @Override public int compareTo(MetricsTableSource source) { if (!(source instanceof MetricsTableSourceImpl)) { return -1; } MetricsTableSourceImpl impl = (MetricsTableSourceImpl) source; if (impl == null) { return -1; } return Long.compare(hashCode, impl.hashCode); } void snapshot(MetricsRecordBuilder mrb, boolean ignored) { // If there is a close that started be double extra sure // that we're not getting any locks and not putting data // into the metrics that should be removed. So early out // before even getting the lock. if (closed.get()) { return; } // Grab the read // This ensures that removes of the metrics // can't happen while we are putting them back in. synchronized (this) { // It's possible that a close happened between checking // the closed variable and getting the lock. if (closed.get()) { return; } if (this.tableWrapperAgg != null) { mrb.addCounter( Interns.info(tableNamePrefix + MetricsTableSource.READ_REQUEST_COUNT, MetricsTableSource.READ_REQUEST_COUNT_DESC), tableWrapperAgg.getReadRequestsCount(tableName.getNameAsString())); mrb.addCounter( Interns.info(tableNamePrefix + MetricsTableSource.WRITE_REQUEST_COUNT, MetricsTableSource.WRITE_REQUEST_COUNT_DESC), tableWrapperAgg.getWriteRequestsCount(tableName.getNameAsString())); mrb.addCounter( Interns.info(tableNamePrefix + MetricsTableSource.TOTAL_REQUEST_COUNT, MetricsTableSource.TOTAL_REQUEST_COUNT_DESC), tableWrapperAgg.getTotalRequestsCount(tableName.getNameAsString())); mrb.addGauge( Interns.info(tableNamePrefix + MetricsTableSource.MEMSTORE_SIZE, MetricsTableSource.MEMSTORE_SIZE_DESC), tableWrapperAgg.getMemstoresSize(tableName.getNameAsString())); mrb.addGauge( Interns.info(tableNamePrefix + MetricsTableSource.STORE_FILE_SIZE, MetricsTableSource.STORE_FILE_SIZE_DESC), tableWrapperAgg.getStoreFilesSize(tableName.getNameAsString())); mrb.addGauge( Interns.info(tableNamePrefix + MetricsTableSource.TABLE_SIZE, MetricsTableSource.TABLE_SIZE_DESC), tableWrapperAgg.getTableSize(tableName.getNameAsString())); } } } @Override public String getTableName() { return tableName.getNameAsString(); } @Override public int hashCode() { return hashCode; } @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; return (o instanceof MetricsTableSourceImpl && compareTo((MetricsTableSourceImpl) o) == 0); } public MetricsTableWrapperAggregate getTableWrapper() { return tableWrapperAgg; } public String getTableNamePrefix() { return tableNamePrefix; } }