org.aspectj/weaver/src/main/java/org/aspectj/weaver/bcel/ExceptionRange.java

/* *******************************************************************
 * Copyright (c) 2002 Palo Alto Research Center, Incorporated (PARC).
 * All rights reserved. 
 * This program and the accompanying materials are made available 
 * under the terms of the Eclipse Public License v1.0 
 * which accompanies this distribution and is available at 
 * http://www.eclipse.org/legal/epl-v10.html 
 *  
 * Contributors: 
 *     PARC     initial implementation 
 * ******************************************************************/

package org.aspectj.weaver.bcel;

import org.aspectj.apache.bcel.generic.InstructionHandle;
import org.aspectj.apache.bcel.generic.InstructionList;
import org.aspectj.weaver.UnresolvedType;

/**
 * exceptionRanges are set initially to be low priority. The various setPriority methods should be used accordingly. The priority is
 * used when we pack the exception table into a method... the exception table should be sorted from high to low priority. Exceptions
 * we generate for advice is either high priority (higher than anything coming from the original method... most kinds of
 * non-execution advice) or low priority (lower than anything coming from the original method, for execution advice).
 * 
 * <p>
 * ??? This does not account for handler, or any other "statement-level" advice. When such statement level advice happens, we may
 * want to go to a float level, so we can set the priority of advice to be lower than anything it encloses, and higher than anything
 * enclosing it.
 */

/*
 * we're actually using the fact that we're an instruction targeter, for the handler
 */
public final class ExceptionRange extends Range {

	private InstructionHandle handler;
	private final UnresolvedType exceptionType;
	private final int priority;

	// ---- initialization

	/**
	 * After this constructor is called, this range is not well situated unless {@link #associateWithTargets} is called
	 * 
	 * XXX priority should be fixed
	 */
	public ExceptionRange(InstructionList body, UnresolvedType exceptionType, int priority) {
		super(body);
		this.exceptionType = exceptionType;
		this.priority = priority;
	}

	/**
	 * @param insideExisting
	 */
	public ExceptionRange(InstructionList body, UnresolvedType exceptionType, boolean insideExisting) {
		this(body, exceptionType, insideExisting ? Integer.MAX_VALUE : -1);
	}

	public void associateWithTargets(InstructionHandle start, InstructionHandle end, InstructionHandle handler) {
		// assert body.contains(start) && body.contains(end) && body.contains(handler)
		this.start = start;
		this.end = end;
		this.handler = handler;
		start.addTargeter(this);
		end.addTargeter(this);
		handler.addTargeter(this);
	}

	// ----

	public InstructionHandle getHandler() {
		return handler;
	}

	public UnresolvedType getCatchType() {
		return exceptionType;
	}

	public int getPriority() {
		return priority;
	}

	// ---- from object

	public String toString() {
		String str;
		if (exceptionType == null) {
			str = "finally";
		} else {
			str = "catch " + exceptionType;
		}
		// if (priority >= 0 && priority < Integer.MAX_VALUE) {
		// str += " (priority " + priority + ")";
		// }
		return str;
	}

	public boolean equals(Object other) {
		if (!(other instanceof ExceptionRange))
			return false;
		ExceptionRange o = (ExceptionRange) other;
		return o.getStart() == getStart() && o.getEnd() == getEnd() && o.handler == handler
				&& ((o.exceptionType == null) ? (exceptionType == null) : o.exceptionType.equals(exceptionType))
				&& o.priority == priority;
	}

	private volatile int hashCode = 0;

	public int hashCode() {
		if (hashCode == 0) {
			int ret = 17;
			ret = 37 * ret + getStart().hashCode();
			ret = 37 * ret + getEnd().hashCode();
			ret = 37 * ret + handler.hashCode();
			ret = 37 * ret + ((exceptionType == null) ? 0 : exceptionType.hashCode());
			ret = 37 * ret + priority;
			hashCode = ret;
		}
		return hashCode;
	}

	public void updateTarget(InstructionHandle oldIh, InstructionHandle newIh, InstructionList newBody) {
		super.updateTarget(oldIh, newIh, newBody);
		// we're guaranteed that start, end, and handler are distinct instruction handles.
		if (oldIh == handler) {
			handler = newIh;
		}
	}

	public static boolean isExceptionStart(InstructionHandle ih) {
		if (!isRangeHandle(ih))
			return false;
		Range r = getRange(ih);
		if (!(r instanceof ExceptionRange))
			return false;
		ExceptionRange er = (ExceptionRange) r;
		return er.getStart() == ih;
	}

	public static boolean isExceptionEnd(InstructionHandle ih) {
		if (!isRangeHandle(ih))
			return false;
		Range r = getRange(ih);
		if (!(r instanceof ExceptionRange))
			return false;
		ExceptionRange er = (ExceptionRange) r;
		return er.getEnd() == ih;
	}

}