stringrepresentation.java

该开源工具主要用于class文件的操作

package org.apache.bcel.verifier.statics;

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache BCEL" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
 *    written permission, please contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Apache",
 *    "Apache BCEL", nor may "Apache" appear in their name, without
 *    prior written permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

import org.apache.bcel.classfile.*;

/**
 * BCEL's Node classes (those from the classfile API that <B>accept()</B> Visitor
 * instances) have <B>toString()</B> methods that were not designed to be robust,
 * this gap is closed by this class.
 * When performing class file verification, it may be useful to output which
 * entity (e.g. a <B>Code</B> instance) is not satisfying the verifier's
 * constraints, but in this case it could be possible for the <B>toString()</B>
 * method to throw a RuntimeException.
 * A (new StringRepresentation(Node n)).toString() never throws any exception.
 * Note that this class also serves as a placeholder for more sophisticated message
 * handling in future versions of JustIce.
 * 
 * @version $Id: StringRepresentation.java,v 1.1.1.1 2001/10/29 20:00:37 jvanzyl Exp $
 * @author <A HREF="http://www.inf.fu-berlin.de/~ehaase"/>Enver Haase</A>
 */
public class StringRepresentation extends org.apache.bcel.classfile.EmptyVisitor implements Visitor{
	/** The string representation, created by a visitXXX() method, output by toString(). */
	private String tostring;
	/**
	 * Creates a new StringRepresentation object which is the representation of n.
	 *
	 * @see #toString()
	 */
	public StringRepresentation(Node n){
		n.accept(this);
	}
	/**
	 * Returns the String representation.
	 */
	public String toString(){
		return tostring;
	}
	/**
	 * Returns the String representation of the Node object obj;
	 * this is obj.toString() if it does not throw any RuntimeException,
	 * or else it is a string derived only from obj's class name.
	 */
	private String toString(Node obj){
		String ret;
		try{
			ret = obj.toString();
		}
		catch(RuntimeException e){
			String s = obj.getClass().getName();
			s = s.substring(s.lastIndexOf(".")+1);
			ret = "<<"+s+">>";
		}
		return ret;
	}
	////////////////////////////////
	// Visitor methods start here //
	////////////////////////////////
	// We don't of course need to call some default implementation:
	// e.g. we could also simply output "Code" instead of a possibly
	// lengthy Code attribute's toString().
	public void visitCode(Code obj){
		//tostring = toString(obj);
		tostring = "<CODE>"; // We don't need real code outputs.
	}
	public void visitCodeException(CodeException obj){
		tostring = toString(obj);
	}
	public void visitConstantClass(ConstantClass obj){
		tostring = toString(obj);
	}
	public void visitConstantDouble(ConstantDouble obj){
		tostring = toString(obj);
	}
	public void visitConstantFieldref(ConstantFieldref obj){
		tostring = toString(obj);
	}
	public void visitConstantFloat(ConstantFloat obj){
		tostring = toString(obj);
	}
	public void visitConstantInteger(ConstantInteger obj){
		tostring = toString(obj);
	}
	public void visitConstantInterfaceMethodref(ConstantInterfaceMethodref obj){
		tostring = toString(obj);
	}
	public void visitConstantLong(ConstantLong obj){
		tostring = toString(obj);
	}
	public void visitConstantMethodref(ConstantMethodref obj){
		tostring = toString(obj);
	}
	public void visitConstantNameAndType(ConstantNameAndType obj){
		tostring = toString(obj);
	}
 	public void visitConstantPool(ConstantPool obj){
		tostring = toString(obj);
 	}
	public void visitConstantString(ConstantString obj){
		tostring = toString(obj);
	}
	public void visitConstantUtf8(ConstantUtf8 obj){
		tostring = toString(obj);
	}
	public void visitConstantValue(ConstantValue obj){
		tostring = toString(obj);
	}
	public void visitDeprecated(Deprecated obj){
		tostring = toString(obj);
	}
	public void visitExceptionTable(ExceptionTable obj){
		tostring = toString(obj);
	}
	public void visitField(Field obj){
		tostring = toString(obj);
	}
	public void visitInnerClass(InnerClass obj){
		tostring = toString(obj);
	}
	public void visitInnerClasses(InnerClasses obj){
		tostring = toString(obj);
	}
	public void visitJavaClass(JavaClass obj){
		tostring = toString(obj);
	}
	public void visitLineNumber(LineNumber obj){
		tostring = toString(obj);
	}
	public void visitLineNumberTable(LineNumberTable obj){
		tostring = "<LineNumberTable: "+toString(obj)+">";
	}
	public void visitLocalVariable(LocalVariable obj){
		tostring = toString(obj);
	}
	public void visitLocalVariableTable(LocalVariableTable obj){
		tostring = "<LocalVariableTable: "+toString(obj)+">";
	}
	public void visitMethod(Method obj){
		tostring = toString(obj);
	}
	public void visitSourceFile(SourceFile obj){
		tostring = toString(obj);
	} 
	public void visitSynthetic(Synthetic obj){
		tostring = toString(obj);
	} 
	public void visitUnknown(Unknown obj){
		tostring = toString(obj);
	}
}