MetricsLongValue.java
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上传日期:2018-01-08
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文件大小:3k
- /**
- * 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.util;
- import org.apache.hadoop.metrics.MetricsRecord;
- /**
- * The MetricsLongValue class is for a metric that is not time varied
- * but changes only when it is set.
- * Each time its value is set, it is published only *once* at the next update
- * call.
- *
- */
- public class MetricsLongValue extends MetricsBase{
- private long value;
- private boolean changed;
-
- /**
- * Constructor - create a new metric
- * @param nam the name of the metrics to be used to publish the metric
- * @param registry - where the metrics object will be registered
- */
- public MetricsLongValue(final String nam, final MetricsRegistry registry, final String description) {
- super(nam, description);
- value = 0;
- changed = false;
- registry.add(nam, this);
- }
-
- /**
- * Constructor - create a new metric
- * @param nam the name of the metrics to be used to publish the metric
- * @param registry - where the metrics object will be registered
- * A description of {@link #NO_DESCRIPTION} is used
- */
- public MetricsLongValue(final String nam, MetricsRegistry registry) {
- this(nam, registry, NO_DESCRIPTION);
- }
-
- /**
- * Set the value
- * @param newValue
- */
- public synchronized void set(final long newValue) {
- value = newValue;
- changed = true;
- }
-
- /**
- * Get value
- * @return the value last set
- */
- public synchronized long get() {
- return value;
- }
-
- /**
- * Push the metric to the mr.
- * The metric is pushed only if it was updated since last push
- *
- * Note this does NOT push to JMX
- * (JMX gets the info via {@link #get()}
- *
- * @param mr
- */
- public synchronized void pushMetric(final MetricsRecord mr) {
- if (changed)
- mr.setMetric(getName(), value);
- changed = false;
- }
- }