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Java example source code file (SourceManager.java)

This example Java source code file (SourceManager.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, arraylist, environment, file, hashmap, jdi, linkedlist, override, referencetype, searchpath, smclasslistener, sourcemanager, sourcemodel, sourcepathchangedevent, string, util

The SourceManager.java Java example source code

/*
 * Copyright (c) 1998, 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.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * 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.
 */

/*
 * This source code is provided to illustrate the usage of a given feature
 * or technique and has been deliberately simplified. Additional steps
 * required for a production-quality application, such as security checks,
 * input validation and proper error handling, might not be present in
 * this sample code.
 */


package com.sun.tools.example.debug.gui;

import java.io.*;
import java.util.*;

import com.sun.jdi.*;

import com.sun.tools.example.debug.event.*;

/**
 * Manage the list of source files.
 * Origin of SourceListener events.
 */
public class SourceManager {

    //### TODO: The source cache should be aged, and some cap
    //### put on memory consumption by source files loaded into core.

    private List<SourceModel> sourceList;
    private SearchPath sourcePath;

    private ArrayList<SourceListener> sourceListeners = new ArrayList();

    private Map<ReferenceType, SourceModel> classToSource = new HashMap();

    private Environment env;

    /**
     * Hold on to it so it can be removed.
     */
    private SMClassListener classListener = new SMClassListener();

    public SourceManager(Environment env) {
        this(env, new SearchPath(""));
    }

    public SourceManager(Environment env, SearchPath sourcePath) {
        this.env = env;
        this.sourceList = new LinkedList<SourceModel>();
        this.sourcePath = sourcePath;
        env.getExecutionManager().addJDIListener(classListener);
    }

    /**
     * Set path for access to source code.
     */
    public void setSourcePath(SearchPath sp) {
        sourcePath = sp;
        // Old cached sources are now invalid.
        sourceList = new LinkedList<SourceModel>();
        notifySourcepathChanged();
        classToSource = new HashMap<ReferenceType, SourceModel>();
    }

    public void addSourceListener(SourceListener l) {
        sourceListeners.add(l);
    }

    public void removeSourceListener(SourceListener l) {
        sourceListeners.remove(l);
    }

    private void notifySourcepathChanged() {
        ArrayList<SourceListener> l = new ArrayList(sourceListeners);
        SourcepathChangedEvent evt = new SourcepathChangedEvent(this);
        for (int i = 0; i < l.size(); i++) {
            l.get(i).sourcepathChanged(evt);
        }
    }

    /**
     * Get path for access to source code.
     */
    public SearchPath getSourcePath() {
        return sourcePath;
    }

    /**
     * Get source object associated with a Location.
     */
    public SourceModel sourceForLocation(Location loc) {
        return sourceForClass(loc.declaringType());
    }

    /**
     * Get source object associated with a class or interface.
     * Returns null if not available.
     */
    public SourceModel sourceForClass(ReferenceType refType) {
        SourceModel sm = classToSource.get(refType);
        if (sm != null) {
            return sm;
        }
        try {
            String filename = refType.sourceName();
            String refName = refType.name();
            int iDot = refName.lastIndexOf('.');
            String pkgName = (iDot >= 0)? refName.substring(0, iDot+1) : "";
            String full = pkgName.replace('.', File.separatorChar) + filename;
            File path = sourcePath.resolve(full);
            if (path != null) {
                sm = sourceForFile(path);
                classToSource.put(refType, sm);
                return sm;
            }
            return null;
        } catch (AbsentInformationException e) {
            return null;
        }
    }

    /**
     * Get source object associated with an absolute file path.
     */
    //### Use hash table for this?
    public SourceModel sourceForFile(File path) {
        Iterator<SourceModel> iter = sourceList.iterator();
        SourceModel sm = null;
        while (iter.hasNext()) {
            SourceModel candidate = iter.next();
            if (candidate.fileName().equals(path)) {
                sm = candidate;
                iter.remove();    // Will move to start of list.
                break;
            }
        }
        if (sm == null && path.exists()) {
            sm = new SourceModel(env, path);
        }
        if (sm != null) {
            // At start of list for faster access
            sourceList.add(0, sm);
        }
        return sm;
    }

    private class SMClassListener extends JDIAdapter
                                   implements JDIListener {

        @Override
        public void classPrepare(ClassPrepareEventSet e) {
            ReferenceType refType = e.getReferenceType();
            SourceModel sm = sourceForClass(refType);
            if (sm != null) {
                sm.addClass(refType);
            }
        }

        @Override
        public void classUnload(ClassUnloadEventSet e) {
            //### iterate through looking for (e.getTypeName()).
            //### then remove it.
        }
    }
}

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