Java example source code file (CaptureTest.java)

This example Java source code file (CaptureTest.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

capturetest, class, constructor, encloser, exception, expected, innertester, localtester, mandated, methodparameters, parameter, reflection, string, synthetic, tester, util

The CaptureTest.java Java example source code

/*
 * Copyright (c) 2012, 2013, 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
 * @bug 8015701
 * @summary Test method parameter attribute generation with captured locals.
 * @compile -parameters CaptureTest.java
 * @run main CaptureTest
 */
import java.lang.Class;
import java.lang.reflect.Constructor;
import java.lang.reflect.Parameter;
import java.lang.reflect.Modifier;
import java.util.List;
import java.util.ArrayList;

public class CaptureTest {

    private static final int SYNTHETIC = 0x1000;
    private static final int MANDATED = 0x8000;

    public static void main(String... args) throws Exception {
        new CaptureTest().run();
    }


    private void run() throws Exception {
        final Encloser pn = new Encloser();

        /* Cases covered here:
         *
         * - Local class
         * - Inner class
         * - Anonymous class
         * - Anonymous class extending a local
         * - Anonymous class extending an inner
         */
        pn.makeLocal("hello").check();
        pn.makeInner("hello").check();
        pn.makeAnon("hello").check();
        pn.makeAnonExtendsLocal("hello").check();
        pn.makeAnonExtendsInner("hello").check();

        if (0 != errors)
            throw new Exception("MethodParameters test failed with " +
                                errors + " errors");
    }

    private void error(final String msg) {
        System.err.println("Error: " + msg);
        errors++;
    }

    int errors;

    abstract class Tester {

        public Tester(final int param) {}

        protected abstract String[] names();
        protected abstract int[] modifiers();
        protected abstract Class[] types();

        public void check() {
            final Class<?> cls = this.getClass();
            final Constructor<?> ctor = cls.getDeclaredConstructors()[0];
            final Parameter[] params = ctor.getParameters();
            final String[] names = names();
            final int[] modifiers = modifiers();
            final Class[] types = types();

            System.err.println("Testing class " + cls);

            if (params.length == names.length) {
                for (int i = 0; i < names.length; i++) {
                    System.err.println("Testing parameter " + params[i].getName());
                    if (!params[i].getName().equals(names[i]))
                        error("Expected parameter name " + names[i] +
                              " got " + params[i].getName());
                    if (params[i].getModifiers() != modifiers[i])
                        error("Expected parameter modifiers " +
                              modifiers[i] + " got " +
                              params[i].getModifiers());
                    if (!params[i].getType().equals(types[i]))
                        error("Expected parameter type " + types[i] +
                              " got " + params[i].getType());
                }
            } else
                error("Expected " + names.length + " parameters");

        }

    }

    class Encloser {
        private class InnerTester extends Tester {
            public InnerTester(final int innerparam) {
                super(innerparam);
            }

            protected String[] names() {
                return new String[] {
                    "this$1",
                    "innerparam"
                };
            }

            protected int[] modifiers() {
                return new int[] {
                    Modifier.FINAL | SYNTHETIC,
                    Modifier.FINAL
                };
            }

            protected Class[] types() {
                return new Class[] {
                    Encloser.class,
                    int.class
                };
            }
        }

        public Tester makeInner(final String message) {
            return new InnerTester(2);
        }

        public Tester makeLocal(final String message) {
            class LocalTester extends Tester {
                public LocalTester(final int localparam) {
                    super(localparam);
                }

                protected String[] names() {
                    return new String[] {
                        "this$1",
                        "localparam",
                        "val$message"
                    };
                }

                protected int[] modifiers() {
                    return new int[] {
                        Modifier.FINAL | MANDATED,
                        Modifier.FINAL,
                        Modifier.FINAL | SYNTHETIC
                    };
                }

                protected Class[] types() {
                    return new Class[] {
                        Encloser.class,
                        int.class,
                        String.class
                    };
                }

                public String message() {
                    return message;
                }
            }

            return new LocalTester(2);
        }

        public Tester makeAnonExtendsLocal(final String message) {
            abstract class LocalTester extends Tester {
                public LocalTester(final int localparam) {
                    super(localparam);
                }

                protected String[] names() {
                    return new String[] {
                        "this$1",
                        "localparam",
                        "val$message"
                    };
                }

                protected int[] modifiers() {
                    return new int[] {
                        Modifier.FINAL | MANDATED,
                        Modifier.FINAL,
                        Modifier.FINAL | SYNTHETIC
                    };
                }

                protected Class[] types() {
                    return new Class[] {
                        Encloser.class,
                        int.class,
                        String.class
                    };
                }

            }

            return new LocalTester(2) {
                public String message() {
                    return message;
                }
            };
        }

        public Tester makeAnonExtendsInner(final String message) {
            return new InnerTester(2) {
                protected String[] names() {
                    return new String[] {
                        "this$1",
                        "innerparam",
                        "val$message"
                    };
                }

                protected int[] modifiers() {
                    return new int[] {
                        Modifier.FINAL | MANDATED,
                        Modifier.FINAL,
                        Modifier.FINAL | SYNTHETIC
                    };
                }

                protected Class[] types() {
                    return new Class[] {
                        Encloser.class,
                        int.class,
                        String.class
                    };
                }

                public String message() {
                    return message;
                }
            };
        }

        public Tester makeAnon(final String message) {
            return new Tester(2) {
                protected String[] names() {
                    return new String[] {
                        "this$1",
                        "param",
                        "val$message"
                    };
                }

                protected int[] modifiers() {
                    return new int[] {
                        Modifier.FINAL | MANDATED,
                        Modifier.FINAL,
                        Modifier.FINAL | SYNTHETIC
                    };
                }

                protected Class[] types() {
                    return new Class[] {
                        Encloser.class,
                        int.class,
                        String.class
                    };
                }

                public String message() {
                    return message;
                }
            };
        }
    }
}