storm-client/src/jvm/org/apache/storm/metric/api/ReducedMetric.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.storm.metric.api;

public class ReducedMetric implements IMetric {
    private final IReducer reducer;
    private Object accumulator;

    public ReducedMetric(IReducer reducer) {
        this.reducer = reducer;
        accumulator = this.reducer.init();
    }

    public void update(Object value) {
        accumulator = reducer.reduce(accumulator, value);
    }

    @Override
    public Object getValueAndReset() {
        Object ret = reducer.extractResult(accumulator);
        accumulator = reducer.init();
        return ret;
    }
}