Op.java

package com.github.zangxiaoqiang.dfc.protocol;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;

/** Operation */
public enum Op {
	WRITE_BLOCK((byte) 80), 
	READ_BLOCK((byte) 81), 
	WRITE_FILE((byte) 82), 
	READ_FILE((byte) 83);
	// READ_METADATA((byte)82),
	// REPLACE_BLOCK((byte)83),
	// COPY_BLOCK((byte)84),
	// BLOCK_CHECKSUM((byte)85);

	/** The code for this operation. */
	public final byte code;

	private Op(byte code) {
		this.code = code;
	}

	private static final int FIRST_CODE = values()[0].code;

	/** Return the object represented by the code. */
	public static Op valueOf(byte code) {
		final int i = (code & 0xff) - FIRST_CODE;
		return i < 0 || i >= values().length ? null : values()[i];
	}

	/** Read from in */
	public static Op read(DataInput in) throws IOException {
		return valueOf(in.readByte());
	}

	/** Write to out */
	public void write(DataOutput out) throws IOException {
		out.writeByte(code);
	}
}