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Java example source code file (LocationImpl.java)

This example Java source code file (LocationImpl.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

absentinformationexception, jdi, lineinfo, location, locationimpl, methodimpl, mirrorimpl, referencetypeimpl, string, util

The LocationImpl.java Java example source code

/*
 * Copyright (c) 2002, 2011, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

package sun.jvm.hotspot.jdi;

import com.sun.jdi.*;

import java.util.*;

public class LocationImpl extends MirrorImpl implements Location {
    private final ReferenceTypeImpl declaringType;
    private Method method;
    private sun.jvm.hotspot.oops.Method methodRef;
    private long codeIndex;
    private LineInfo baseLineInfo = null;
    private LineInfo otherLineInfo = null;

    LocationImpl(VirtualMachine vm,
                 Method method, long codeIndex) {
        super(vm);

        this.method = method;
        this.codeIndex = method.isNative()? -1 : codeIndex;
        this.declaringType = (ReferenceTypeImpl)method.declaringType();
    }

    /*
     * This constructor allows lazy creation of the method mirror. This
     * can be a performance savings if the method mirror does not yet
     * exist.
     */
    LocationImpl(VirtualMachine vm, ReferenceType declaringType,
                 sun.jvm.hotspot.oops.Method methodRef, long codeIndex) {
        super(vm);

        this.method = null;
        this.codeIndex = codeIndex;
        this.declaringType = (ReferenceTypeImpl)declaringType;
        this.methodRef = methodRef;
    }

    public boolean equals(Object obj) {
        if ((obj != null) && (obj instanceof Location)) {
            Location other = (Location)obj;
            return (method().equals(other.method())) &&
                   (codeIndex() == other.codeIndex()) &&
                   super.equals(obj);
        } else {
            return false;
        }
    }

    public int hashCode() {
        /*
         * TO DO: better hash code?
         */
        return method().hashCode() + (int)codeIndex();
    }

    public int compareTo(Location other) {
        int rc = method().compareTo(other.method());
        if (rc == 0) {
            long diff = codeIndex() - other.codeIndex();
            if (diff < 0)
                return -1;
            else if (diff > 0)
                return 1;
            else
                return 0;
        }
        return rc;
    }

    public ReferenceType declaringType() {
        return declaringType;
    }

    public Method method() {
        if (method == null) {
            method = declaringType.getMethodMirror(methodRef);
            if (method.isNative()) {
                codeIndex = -1;
            }
        }
        return method;
    }

    public long codeIndex() {
        method();  // be sure information is up-to-date
        return codeIndex;
    }

    LineInfo getBaseLineInfo(SDE.Stratum stratum) {
        LineInfo lineInfo;

        /* check if there is cached info to use */
        if (baseLineInfo != null) {
            return baseLineInfo;
        }

        /* compute the line info */
        MethodImpl methodImpl = (MethodImpl)method();
         lineInfo = methodImpl.codeIndexToLineInfo(stratum,
                                                   codeIndex());

        /* cache it */
        addBaseLineInfo(lineInfo);

        return lineInfo;
    }

    LineInfo getLineInfo(SDE.Stratum stratum) {
        LineInfo lineInfo;

        /* base stratum is done slighly differently */
        if (stratum.isJava()) {
            return getBaseLineInfo(stratum);
        }

        /* check if there is cached info to use */
        lineInfo = otherLineInfo; // copy because of concurrency
        if (lineInfo != null &&
                           stratum.id().equals(lineInfo.liStratum())) {
            return lineInfo;
        }
        int baseLineNumber = lineNumber(SDE.BASE_STRATUM_NAME);
        SDE.LineStratum lineStratum =
                  stratum.lineStratum(declaringType, baseLineNumber);

        if (lineStratum != null && lineStratum.lineNumber() != -1) {
            lineInfo = new StratumLineInfo(stratum.id(),
                                           lineStratum.lineNumber(),
                                           lineStratum.sourceName(),
                                           lineStratum.sourcePath());
        } else {
            /* find best match */
            MethodImpl methodImpl = (MethodImpl)method();
            lineInfo = methodImpl.codeIndexToLineInfo(stratum,
                                                      codeIndex());
        }

        /* cache it */
        addStratumLineInfo(lineInfo);

        return lineInfo;
    }

    void addStratumLineInfo(LineInfo lineInfo) {
        otherLineInfo = lineInfo;
    }

    void addBaseLineInfo(LineInfo lineInfo) {
        baseLineInfo = lineInfo;
    }

    public String sourceName() throws AbsentInformationException {
        return sourceName(vm.getDefaultStratum());
    }

    public String sourceName(String stratumID)
                               throws AbsentInformationException {
        return sourceName(declaringType.stratum(stratumID));
    }

    String sourceName(SDE.Stratum stratum)
                               throws AbsentInformationException {
        return getLineInfo(stratum).liSourceName();
    }

    public String sourcePath() throws AbsentInformationException {
        return sourcePath(vm.getDefaultStratum());
    }

    public String sourcePath(String stratumID)
                               throws AbsentInformationException {
        return sourcePath(declaringType.stratum(stratumID));
    }

    String sourcePath(SDE.Stratum stratum)
                               throws AbsentInformationException {
        return getLineInfo(stratum).liSourcePath();
    }

    public int lineNumber() {
        return lineNumber(vm.getDefaultStratum());
    }

    public int lineNumber(String stratumID) {
        return lineNumber(declaringType.stratum(stratumID));
    }

    int lineNumber(SDE.Stratum stratum) {
        return getLineInfo(stratum).liLineNumber();
    }

    public String toString() {
        if (lineNumber() == -1) {
            return method().toString() + "+" + codeIndex();
        } else {
            return declaringType().name() + ":" + lineNumber();
        }
    }
}

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