pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / contrib / facet / src / java / org / apache / lucene / facet / search / FloatArrayAllocator.java

diff --git a/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/facet/search/FloatArrayAllocator.java b/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/facet/search/FloatArrayAllocator.java
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+++ b/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/facet/search/FloatArrayAllocator.java
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+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 FloatArrayAllocator is an object which manages float array objects
+ * of a certain size. These float 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 FloatArrayAllocator is thread-safe.
+ * 
+ * @lucene.experimental
+ */
+public final class FloatArrayAllocator extends TemporaryObjectAllocator<float[]> {
+
+  // An FloatArrayAllocater deals with integer arrays of a fixed size, size.
+  private int size;
+
+  /**
+   * Construct an allocator for float arrays of size <CODE>size</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 FloatArrayAllocator(int size, int maxArrays) {
+    super(maxArrays);
+    this.size = size;
+  }
+
+  @Override
+  public float[] create() {
+    return new float[size];
+  }
+
+  @Override
+  public void clear(float[] array) {
+    Arrays.fill(array, 0);
+  }
+
+}