package com.de22.javabytecode;

import java.io.IOException;
import com.common.debug.*;
import com.de22.javabytecode.constant.*;

/**
 * Copyright Wynne Crisman 1999,2006<p>
 */
public abstract class Constant extends Component {
	public static final byte CONSTANT_UTF8 = 0x01;
	public static final byte CONSTANT_INTEGER = 0x03;
	public static final byte CONSTANT_FLOAT = 0x04;
	public static final byte CONSTANT_LONG = 0x05;
	public static final byte CONSTANT_DOUBLE = 0x06;
	public static final byte CONSTANT_CLASS = 0x07;
	public static final byte CONSTANT_STRING = 0x08;
	public static final byte CONSTANT_FIELD_REF = 0x09;
	public static final byte CONSTANT_METHOD_REF = 0x0A;
	public static final byte CONSTANT_INTERFACE_METHOD_REF = 0x0B;
	public static final byte CONSTANT_NAME_AND_TYPE = 0x0C;
/**
 * Constant constructor.
 */
public Constant(Type type) {
	super(type);
}//Constant()//
/**
 * Gets this constant's identifying constant.
 * @return The constant value that identifies this constant object type.
 */
public abstract byte getTag();
/**
 * Gets a display string that shows the resulting value of the constant in a viewer friendly way.
 * @return The viewer friendly constant result.
 */
public abstract String getPrettyValue();
/**
 * Determines whether the constant takes double the constant entries in the class bytes.
 * @return Whether the constant is a double size constant.
 */
public boolean isDoubleSize() {
	return false;
}//isDoubleSize()//
/**
 * Reads a constant from the given stream.
 * @param type The type object that the constant will belong to.
 * @param in The input stream to read the constant from.
 */
protected static Constant readConstant(Type type, java.io.ObjectInput in) throws java.io.IOException, ClassNotFoundException {
	Constant constant = null;
	short tag = in.readByte();
	
	switch(tag) {
		case CONSTANT_CLASS:
			constant = new ConstantType(type);
			break;
		case CONSTANT_DOUBLE:
			constant = new ConstantDouble(type);
			break;
		case CONSTANT_FIELD_REF:
			constant = new ConstantFieldRef(type);
			break;
		case CONSTANT_FLOAT:
			constant = new ConstantFloat(type);
			break;
		case CONSTANT_INTEGER:
			constant = new ConstantInteger(type);
			break;
		case CONSTANT_INTERFACE_METHOD_REF:
			constant = new ConstantInterfaceMethodRef(type);
			break;
		case CONSTANT_LONG:
			constant = new ConstantLong(type);
			break;
		case CONSTANT_METHOD_REF:
			constant = new ConstantMethodRef(type);
			break;
		case CONSTANT_NAME_AND_TYPE:
			constant = new ConstantNameAndType(type);
			break;
		case CONSTANT_STRING:
			constant = new ConstantString(type);
			break;
		case CONSTANT_UTF8:
			constant = new ConstantUtf8(type);
			break;
		default:
			Debug.halt();
			break;
	}//switch//

	constant.readExternal(in);

	return constant;
}//readConstant()//
/**
 * Reads this object from the given stream.
 * @param in The input stream to read this object from.
 */
public void readExternal(java.io.ObjectInput in) throws IOException, ClassNotFoundException {
	//The tag will be read by the readConstant(Type, ObjectInput) method.//
}//readExternal()//
/**
 * Writes this object to the given stream.
 * @param out The output stream to write this object to.
 */
public void writeExternal(java.io.ObjectOutput out) throws IOException {
	out.writeByte(getTag());
}//writeExternal()//
}//Constant//