a sample code to explain how to use FileBackedOutputStream

FileBackedOutputStreamSample.java

package guava.io;

import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;

import com.google.common.base.Stopwatch;
import com.google.common.io.FileBackedOutputStream;

public class FileBackedOutputStreamSample {
	private static final int KB = 1024;
	private static final int MB = 1024 * KB;

	private static final int THRESHOLD = 32 * KB;
	private static final int[] TEST_SIZE = new int[]{ 16 * KB, 32 * KB, 128 * KB, 1 * MB, 32 * MB};

	public static void main(String[] args) throws IOException {
		for (int writeSize : TEST_SIZE) {
			testFileBackedOutputStream(writeSize);
			testByteArrayOutputStream(writeSize);
			System.out.println();
		}
	}

	private static void testFileBackedOutputStream(int writeSize) throws IOException {
		test(new FileBackedOutputStream(THRESHOLD), writeSize);
	}

	private static void testByteArrayOutputStream(int writeSize) throws IOException {
		test(new ByteArrayOutputStream(), writeSize);
	}

	private static void test(OutputStream oStream, int writeSize) throws IOException {
		BufferedOutputStream buffer = new BufferedOutputStream(oStream);
		byte[] bytes = new byte[KB];

		Stopwatch watch = new Stopwatch().start();
		try {
			for (int i = 0; i < writeSize / KB; ++i) {
				buffer.write(bytes);
			}
			watch.stop();
		} finally {
			buffer.close();
		}

		System.out.printf(
				"I\'ve finished to write %,12d bytes in %,6d msec via %s%n",
				writeSize,
				watch.elapsedMillis(),
				oStream.getClass().getName());
	}

}