com.metamx.common.guava.FilteringYieldingAccumulator Maven / Gradle / Ivy
/*
* Copyright 2011,2012 Metamarkets Group Inc.
*
* Licensed 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 com.metamx.common.guava;
import com.google.common.base.Predicate;
/**
*/
public class FilteringYieldingAccumulator extends YieldingAccumulator
{
private final Predicate pred;
private final YieldingAccumulator accumulator;
private volatile boolean didSomething = false;
public FilteringYieldingAccumulator(
Predicate pred,
YieldingAccumulator accumulator
) {
this.pred = pred;
this.accumulator = accumulator;
}
@Override
public void yield()
{
accumulator.yield();
}
@Override
public boolean yielded()
{
return accumulator.yielded();
}
@Override
public void reset()
{
didSomething = false;
accumulator.reset();
}
public boolean didSomething()
{
return didSomething;
}
@Override
public OutType accumulate(OutType accumulated, T in)
{
if (pred.apply(in)) {
if (!didSomething) {
didSomething = true;
}
return accumulator.accumulate(accumulated, in);
}
return accumulated;
}
}