lucene/core/src/test/org/apache/lucene/util/TestByteBlockPool.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.lucene.util;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class TestByteBlockPool extends LuceneTestCase {

  public void testReadAndWrite() throws IOException {
    Counter bytesUsed = Counter.newCounter();
    ByteBlockPool pool = new ByteBlockPool(new ByteBlockPool.DirectTrackingAllocator(bytesUsed));
    pool.nextBuffer();
    boolean reuseFirst = random().nextBoolean();
    for (int j = 0; j < 2; j++) {
        
      List<BytesRef> list = new ArrayList<>();
      int maxLength = atLeast(500);
      final int numValues = atLeast(100);
      BytesRefBuilder ref = new BytesRefBuilder();
      for (int i = 0; i < numValues; i++) {
        final String value = TestUtil.randomRealisticUnicodeString(random(),
            maxLength);
        list.add(new BytesRef(value));
        ref.copyChars(value);
        pool.append(ref.get());
      }
      // verify
      long position = 0;
      for (BytesRef expected : list) {
        ref.grow(expected.length);
        ref.setLength(expected.length);
        if (random().nextBoolean()) {
          pool.readBytes(position, ref.bytes(), 0, ref.length());
        } else {
          for (int i = 0; i < ref.length(); ++i) {
            ref.setByteAt(i, pool.readByte(position + i));
          }
        }
        assertEquals(expected, ref.get());
        position += ref.length();
      }
      pool.reset(random().nextBoolean(), reuseFirst);
      if (reuseFirst) {
        assertEquals(ByteBlockPool.BYTE_BLOCK_SIZE, bytesUsed.get());
      } else {
        assertEquals(0, bytesUsed.get());
        pool.nextBuffer(); // prepare for next iter
      }
    }
  } 
}