package org.apache.lucene.util.encoding;
import java.io.IOException;
import java.io.OutputStream;
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 {@link IntEncoderFilter} which sorts the values to encode in ascending
* order before encoding them. Encoding therefore happens upon calling
* {@link #close()}. Since this encoder is usually chained with another encoder
* that relies on sorted values, it does not offer a default constructor.
*
* @lucene.experimental
*/
public class SortingIntEncoder extends IntEncoderFilter {
private float grow = 2.0f;
private int index = 0;
private int[] set = new int[1024];
/** Initializes with the given encoder. */
public SortingIntEncoder(IntEncoder encoder) {
super(encoder);
}
@Override
public void close() throws IOException {
if (index == 0) {
return;
}
Arrays.sort(set, 0, index);
for (int i = 0; i < index; i++) {
encoder.encode(set[i]);
}
encoder.close();
index = 0;
super.close();
}
@Override
public void encode(int value) throws IOException {
if (index == set.length) {
int[] newSet = new int[(int) (set.length * grow)];
System.arraycopy(set, 0, newSet, 0, set.length);
set = newSet;
}
set[index++] = value;
}
@Override
public IntDecoder createMatchingDecoder() {
return encoder.createMatchingDecoder();
}
@Override
public void reInit(OutputStream out) {
super.reInit(out);
index = 0;
}
@Override
public String toString() {
return "Sorting (" + encoder.toString() + ")";
}
}