Java example source code file (Vars.java)

This example Java source code file (Vars.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, abstracttestvars, arguments, byname, exception, internalexception, iterator, jdi, jdiscaffold, list, localvariable, method, string, stringbuffer, util, variables

The Vars.java Java example source code

/*
 * Copyright (c) 2000, 2002, 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.
 */

/**
 *  @test
 *  @summary Test Method.variables() and the like.
 *
 *  @author Robert Field
 *
 *  @library scaffold
 *  @run build JDIScaffold VMConnection
 *  @run compile -g Vars.java
 *  @run main/othervm Vars
 */

import com.sun.jdi.*;
import com.sun.jdi.event.*;
import java.util.*;

/*
 * This class is internal
 */
abstract class AbstractTestVars {
    abstract float test1(String blah, int i);
    native int test2(double k, boolean b);
    String test3(short sh, long lo) {
        String st = "roses";
        return st;
    }
}

/*
 * This class is internal
 */
class TestVars extends AbstractTestVars {
    float test1(String blah, int i) {
        return (float)1.1;
    }

    void hi() {
        return;
    }

    public static void main(String[] args) throws Exception {
        new TestVars().hi();
        return;
    }
}

/*
 * "Vars" test runs TestVars and makes LocalVariable queries
 */
public class Vars extends JDIScaffold {
    final String[] args;

    boolean failed = false;

    Vars(String args[]) {
        super();
        this.args = args;
    }

    public static void main(String[] args) throws Exception {
        new Vars(args).runTests();
    }

    static final int VARIABLES = 1;
    static final int BYNAME = 2;
    static final int ARGUMENTS = 3;

    String testCase(Method method, int which) {
        try {
            List vars;
            switch (which) {
                case VARIABLES:
                    vars = method.variables();
                    break;
                case BYNAME:
                    vars = method.variablesByName("st");
                    break;
                case ARGUMENTS:
                    vars = method.arguments();
                    break;
                default:
                    throw new InternalException("should not happen");
            }
            StringBuffer sb = new StringBuffer();
            for (Iterator it = vars.iterator(); it.hasNext(); ) {
                LocalVariable lv = (LocalVariable)it.next();
                if (sb.length() > 0) {
                    sb.append(",");
                }
                sb.append(lv.name());
            }
            return sb.toString();
        } catch (Exception exc) {
            String st = exc.getClass().getName();
            int inx = st.lastIndexOf('.');
            return st.substring(inx+1);
        }
    }

    /**
     * Sets failed if fails.
     */
    void test(Method method, int which, String name, String expected) {
        String got = testCase(method, which);
        if (got.equals(expected)) {
            System.out.println(name + ": got expected: " + got);
        } else {
            failed = true;
            System.out.println(name + ": ERROR expected: " + expected);
            System.out.println("      got: " + got);
        }
    }

    void test2(Method method, int which, String name, String expected, String expected2) {
        String got = testCase(method, which);
        if (got.equals(expected) || got.equals(expected2)) {
            System.out.println(name + ": got expected: " + got);
        } else {
            failed = true;
            System.out.println(name + ": ERROR expected: " + expected);
            System.out.println("      got: " + got);
        }
    }

    protected void runTests() throws Exception {
        List argList = new ArrayList(Arrays.asList(args));
        argList.add("TestVars");
        System.out.println("run args: " + argList);
        connect((String[])argList.toArray(args));
        waitForVMStart();

        /*
         * Get to a point where the classes are loaded.
         */
        BreakpointEvent bp = resumeTo("TestVars", "hi", "()V");

        /*
         * These classes should have no line numbers, except for
         * one in the implicit constructor.
         */
        ReferenceType rt = findReferenceType("AbstractTestVars");
        if (rt == null) {
            throw new Exception("AbstractTestVars: not loaded");
        }
        Method method = findMethod(rt, "test1", "(Ljava/lang/String;I)F");
        if (method == null) {
            throw new Exception("Method not found");
        }
        test(method, VARIABLES, "abstract/variables",
             "AbsentInformationException");
        test(method, BYNAME, "abstract/variablesByName",
             "AbsentInformationException");
        test(method, ARGUMENTS, "abstract/arguments",
             "AbsentInformationException");

        method = findMethod(rt, "test2", "(DZ)I");
        if (method == null) {
            throw new Exception("Method not found");
        }
        test(method, VARIABLES, "native/variables",
             "AbsentInformationException");
        test(method, BYNAME, "native/variablesByName",
             "AbsentInformationException");
        test(method, ARGUMENTS, "native/arguments",
             "AbsentInformationException");

        method = findMethod(rt, "test3", "(SJ)Ljava/lang/String;");
        if (method == null) {
            throw new Exception("Method not found");
        }
        // javac can put these in whatever order it desires.  hopper
        // does it one way and mantis another.
        test2(method, VARIABLES, "normal/variables", "sh,lo,st", "st,sh,lo");
        test(method, BYNAME, "normal/variablesByName", "st");
        test(method, ARGUMENTS, "normal/arguments", "sh,lo");

        // Allow application to complete
        resumeToVMDeath();

        if (failed) {
            throw new Exception("Vars: failed");
        } else {
            System.out.println("Vars: passed");
        }
    }
}