java/fury-core/src/main/java/org/apache/fury/io/MockOutputStream.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.fury.io;

import java.io.OutputStream;
import java.nio.ByteBuffer;

/**
 * A helper class to track the size of allocations. Writes to this stream do not copy or retain any
 * data, they just bump a size counter that can be later used to know exactly which data size needs
 * to be allocated for actual writing.
 *
 * <p>Note that {@link OutputStream} doesn't support {@link ByteBuffer}, which may incur extra copy.
 * See also {@link MockWritableChannel}.
 */
public class MockOutputStream extends OutputStream {
  private int totalBytes;

  // Writes the specified byte to this output stream.
  public void write(int b) {
    totalBytes += 1;
  }

  public void write(byte[] bytes, int offset, int length) {
    totalBytes += length;
  }

  public void write(ByteBuffer byteBuffer, int numBytes) {
    totalBytes += numBytes;
  }

  public int totalBytes() {
    return totalBytes;
  }
}