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Java example source code file (Session.java)

This example Java source code file (Session.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

disconnected, executionmanager, jdi, jdieventsource, outputlistener, session, set, virtualmachine, vmdisconnectedexception

The Session.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.bdi;

import com.sun.jdi.VirtualMachine;
import com.sun.jdi.VMDisconnectedException;

/**
 * Our repository of what we know about the state of one
 * running VM.
 */
class Session {

    final VirtualMachine vm;
    final ExecutionManager runtime;
    final OutputListener diagnostics;

    boolean running = true;  // Set false by JDIEventSource
    boolean interrupted = false;  // Set false by JDIEventSource

    private JDIEventSource eventSourceThread = null;
    private int traceFlags;
    private boolean dead = false;

    public Session(VirtualMachine vm, ExecutionManager runtime,
                   OutputListener diagnostics) {
        this.vm = vm;
        this.runtime = runtime;
        this.diagnostics = diagnostics;
        this.traceFlags = VirtualMachine.TRACE_NONE;
    }

    /**
     * Determine if VM is interrupted, i.e, present and not running.
     */
    public boolean isInterrupted() {
        return interrupted;
    }

    public void setTraceMode(int traceFlags) {
        this.traceFlags = traceFlags;
        if (!dead) {
            vm.setDebugTraceMode(traceFlags);
        }
    }

    public boolean attach() {
        vm.setDebugTraceMode(traceFlags);
        diagnostics.putString("Connected to VM");
        eventSourceThread = new JDIEventSource(this);
        eventSourceThread.start();
        return true;
    }

    public void detach() {
        if (!dead) {
            eventSourceThread.interrupt();
            eventSourceThread = null;
            //### The VM may already be disconnected
            //### if the debuggee did a System.exit().
            //### Exception handler here is a kludge,
            //### Rather, there are many other places
            //### where we need to handle this exception,
            //### and initiate a detach due to an error
            //### condition, e.g., connection failure.
            try {
                vm.dispose();
            } catch (VMDisconnectedException ee) {}
            dead = true;
            diagnostics.putString("Disconnected from VM");
        }
    }
}

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