| /** |
| * 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.metrics2.lib; |
| |
| import java.util.concurrent.atomic.AtomicInteger; |
| |
| import org.apache.hadoop.metrics2.MetricsInfo; |
| import org.apache.hadoop.metrics2.MetricsRecordBuilder; |
| |
| /** |
| * A mutable float gauge. |
| */ |
| public class MutableGaugeFloat extends MutableGauge { |
| |
| private AtomicInteger value = new AtomicInteger(); |
| |
| MutableGaugeFloat(MetricsInfo info, float initValue) { |
| super(info); |
| this.value.set(Float.floatToIntBits(initValue)); |
| } |
| |
| public float value() { |
| return Float.intBitsToFloat(value.get()); |
| } |
| |
| @Override |
| public void incr() { |
| incr(1.0f); |
| } |
| |
| @Override |
| public void decr() { |
| incr(-1.0f); |
| } |
| |
| @Override |
| public void snapshot(MetricsRecordBuilder builder, boolean all) { |
| if (all || changed()) { |
| builder.addGauge(info(), value()); |
| clearChanged(); |
| } |
| } |
| |
| public void set(float value) { |
| this.value.set(Float.floatToIntBits(value)); |
| setChanged(); |
| } |
| |
| private final boolean compareAndSet(float expect, float update) { |
| return value.compareAndSet(Float.floatToIntBits(expect), |
| Float.floatToIntBits(update)); |
| } |
| |
| private void incr(float delta) { |
| while (true) { |
| float current = value.get(); |
| float next = current + delta; |
| if (compareAndSet(current, next)) { |
| setChanged(); |
| return; |
| } |
| } |
| } |
| } |