package org.apache.lucene.facet.search;
import java.util.Arrays;
/*
* 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.
*/
/**
* An IntArrayAllocator is an object which manages counter array objects
* of a certain length. These counter arrays are needed temporarily during
* faceted search (see {@link FacetsAccumulator} and can be reused across searches
* instead of being allocated afresh on every search.
* <P>
* An IntArrayAllocator is thread-safe.
*
* @lucene.experimental
*/
public final class IntArrayAllocator extends TemporaryObjectAllocator<int[]> {
// An IntArrayAllocater deals with integer arrays of a fixed length.
private int length;
/**
* Construct an allocator for counter arrays of length <CODE>length</CODE>,
* keeping around a pool of up to <CODE>maxArrays</CODE> old arrays.
* <P>
* Note that the pool size only restricts the number of arrays that hang
* around when not needed, but <I>not</I> the maximum number of arrays
* that are allocated when actually is use: If a number of concurrent
* threads ask for an allocation, all of them will get a counter array,
* even if their number is greater than maxArrays. If an application wants
* to limit the number of concurrent threads making allocations, it needs
* to do so on its own - for example by blocking new threads until the
* existing ones have finished.
* <P>
* In particular, when maxArrays=0, this object behaves as a trivial
* allocator, always allocating a new array and never reusing an old one.
*/
public IntArrayAllocator(int length, int maxArrays) {
super(maxArrays);
this.length = length;
}
@Override
public int[] create() {
return new int[length];
}
@Override
public void clear(int[] array) {
Arrays.fill(array, 0);
}
}