exceptionrangefilter.java

ProGuard 是一个免费的 Java类文件的压缩

/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification
 *             of Java bytecode.
 *
 * Copyright (c) 2002-2007 Eric Lafortune ([e-mail])
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.classfile.visitor;

import proguard.classfile.*;
import proguard.classfile.attribute.visitor.ExceptionInfoVisitor;
import proguard.classfile.attribute.*;

/**
 * This <code>ExceptionInfoVisitor</code> delegates its visits to another given
 * <code>ExceptionInfoVisitor</code>, but only when the visited exception
 * overlaps with the given instruction range.
 *
 * @author Eric Lafortune
 */
public class ExceptionRangeFilter
implements   ExceptionInfoVisitor
{
    private int                  startOffset;
    private int                  endOffset;
    private ExceptionInfoVisitor exceptionInfoVisitor;


    /**
     * Creates a new ExceptionRangeFilter.
     * @param startOffset          the start offset of the instruction range.
     * @param endOffset            the end offset of the instruction range.
     * @param exceptionInfoVisitor the ExceptionInfoVisitor to which visits
     *                             will be delegated.
     */
    public ExceptionRangeFilter(int                  startOffset,
                                int                  endOffset,
                                ExceptionInfoVisitor exceptionInfoVisitor)
    {
        this.startOffset          = startOffset;
        this.endOffset            = endOffset;
        this.exceptionInfoVisitor = exceptionInfoVisitor;
    }


    // Implementations for ExceptionInfoVisitor.

    public void visitExceptionInfo(Clazz clazz, Method method, CodeAttribute codeAttribute, ExceptionInfo exceptionInfo)
    {
        if (exceptionInfo.isApplicable(startOffset, endOffset))
        {
            exceptionInfoVisitor.visitExceptionInfo(clazz, method, codeAttribute, exceptionInfo);
        }
    }
}