samoa-api/src/main/java/org/apache/samoa/moa/core/SerializeUtils.java

package org.apache.samoa.moa.core;

/*
 * #%L
 * SAMOA
 * %%
 * Copyright (C) 2014 - 2015 Apache Software Foundation
 * %%
 * Licensed 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.
 * #L%
 */

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.io.Serializable;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

/**
 * Class implementing some serialize utility methods.
 * 
 * @author Richard Kirkby (rkirkby@cs.waikato.ac.nz)
 * @version $Revision: 7 $
 */
public class SerializeUtils {

  public static class ByteCountingOutputStream extends OutputStream {

    protected int numBytesWritten = 0;

    public int getNumBytesWritten() {
      return this.numBytesWritten;
    }

    @Override
    public void write(int b) throws IOException {
      this.numBytesWritten++;
    }

    @Override
    public void write(byte[] b, int off, int len) throws IOException {
      this.numBytesWritten += len;
    }

    @Override
    public void write(byte[] b) throws IOException {
      this.numBytesWritten += b.length;
    }
  }

  public static void writeToFile(File file, Serializable obj)
      throws IOException {
    ObjectOutputStream out = new ObjectOutputStream(new GZIPOutputStream(
        new BufferedOutputStream(new FileOutputStream(file))));
    out.writeObject(obj);
    out.flush();
    out.close();
  }

  public static Object readFromFile(File file) throws IOException,
      ClassNotFoundException {
    ObjectInputStream in = new ObjectInputStream(new GZIPInputStream(
        new BufferedInputStream(new FileInputStream(file))));
    Object obj = in.readObject();
    in.close();
    return obj;
  }

  public static Object copyObject(Serializable obj) throws Exception {
    ByteArrayOutputStream baoStream = new ByteArrayOutputStream();
    ObjectOutputStream out = new ObjectOutputStream(
        new BufferedOutputStream(baoStream));
    out.writeObject(obj);
    out.flush();
    out.close();
    byte[] byteArray = baoStream.toByteArray();
    ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(
        new ByteArrayInputStream(byteArray)));
    Object copy = in.readObject();
    in.close();
    return copy;
  }

  public static int measureObjectByteSize(Serializable obj) throws Exception {
    ByteCountingOutputStream bcoStream = new ByteCountingOutputStream();
    ObjectOutputStream out = new ObjectOutputStream(
        new BufferedOutputStream(bcoStream));
    out.writeObject(obj);
    out.flush();
    out.close();
    return bcoStream.getNumBytesWritten();
  }
}