EmptyBlockInStream.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 tachyon.client;

import java.io.IOException;

/**
 * <code> EmptyBlockInStream </code> is a <code> InStream </code> can not read anything.
 */
public class EmptyBlockInStream extends InStream {
  /**
   * @param file
   *          the file the block belongs to
   * @param readType
   *          the InStream's read type
   */
  EmptyBlockInStream(TachyonFile file, ReadType readType) {
    super(file, readType);
  }

  @Override
  public void close() throws IOException {
  }

  @Override
  public int read() throws IOException {
    return -1;
  }

  @Override
  public int read(byte[] b) throws IOException {
    return read(b, 0, b.length);
  }

  @Override
  public int read(byte[] b, int off, int len) throws IOException {
    return b.length == 0 ? 0 : -1;
  }

  @Override
  public void seek(long pos) throws IOException {
    if (pos < 0) {
      throw new IOException("pos is negative: " + pos);
    }
  }

  @Override
  public long skip(long n) throws IOException {
    return 0;
  }
}