NullContextWithUpdateThread.java
上传用户:quxuerui
上传日期:2018-01-08
资源大小:41811k
文件大小:3k
源码类别:
网格计算
开发平台:
Java
- /*
- * 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.metrics.spi;
- import org.apache.hadoop.metrics.ContextFactory;
- import org.apache.hadoop.metrics.MetricsException;
- /**
- * A null context which has a thread calling
- * periodically when monitoring is started. This keeps the data sampled
- * correctly.
- * In all other respects, this is like the NULL context: No data is emitted.
- * This is suitable for Monitoring systems like JMX which reads the metrics
- * when someone reads the data from JMX.
- *
- * The default impl of start and stop monitoring:
- * is the AbstractMetricsContext is good enough.
- *
- */
- public class NullContextWithUpdateThread extends AbstractMetricsContext {
- private static final String PERIOD_PROPERTY = "period";
- /** Creates a new instance of NullContextWithUpdateThread */
- public NullContextWithUpdateThread() {
- }
- public void init(String contextName, ContextFactory factory) {
- super.init(contextName, factory);
- // If period is specified, use it, otherwise the default is good enough
- String periodStr = getAttribute(PERIOD_PROPERTY);
- if (periodStr != null) {
- int period = 0;
- try {
- period = Integer.parseInt(periodStr);
- } catch (NumberFormatException nfe) {
- }
- if (period <= 0) {
- throw new MetricsException("Invalid period: " + periodStr);
- }
- setPeriod(period);
- }
- }
- /**
- * Do-nothing version of emitRecord
- */
- protected void emitRecord(String contextName, String recordName,
- OutputRecord outRec)
- {}
- /**
- * Do-nothing version of update
- */
- protected void update(MetricsRecordImpl record) {
- }
- /**
- * Do-nothing version of remove
- */
- protected void remove(MetricsRecordImpl record) {
- }
- }