dcevm/dcevm/src/test/java7/com/github/dcevm/test/structural/TypeNarrowingHeapTest.java

/*
 * Copyright (c) 2010, 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 com.github.dcevm.test.structural;

import com.github.dcevm.test.TestUtil;
import org.junit.Before;
import org.junit.Test;

import static com.github.dcevm.test.util.HotSwapTestHelper.__toVersion__;
import static com.github.dcevm.test.util.HotSwapTestHelper.__version__;
import static org.junit.Assert.assertEquals;

/**
 * Test case for type narrowing.
 *
 * @author Thomas Wuerthinger
 */
public class TypeNarrowingHeapTest {

    // Version 0
    public static class A {

        int x = 1;
        int y = 2;
        int z = 3;

        public int value() {
            return x;
        }
    }

    public static class C {
        private A a;

        public C(A a) {
            this.a = a;
        }
    }

    public static class B extends A {

    }


    // Version 1
    public static class B___1 {
    }


    @Before
    public void setUp() throws Exception {
        __toVersion__(0);
        A a = new A();
        B b = new B();
    }

    @Test
    public void testSimpleTypeNarrowing() {

        assert __version__() == 0;

        A a = convertBtoA(new B());

        assertEquals(1, a.value());

        // Cannot do conversion if A object is on the stack!
        a = null;

        __toVersion__(1);

        TestUtil.assertException(NoSuchMethodError.class, new Runnable() {
          @Override
          public void run() {
            B b = new B();
            b.value();
          }
        });

        __toVersion__(0);
        assert __version__() == 0;
    }

    @Test
    public void testTypeNarrowingWithField() {
        C c = new C(new A());

        __toVersion__(1);

        __toVersion__(0);

        c = new C(convertBtoA(new B()));

        TestUtil.assertException(UnsupportedOperationException.class, new Runnable() {
            @Override
            public void run() {
                __toVersion__(1);
            }
        });

        assert __version__() == 0;

        c.a = null;

        __toVersion__(1);

        __toVersion__(0);
    }

    // Method to enforce cast (otherwise bytecodes become invalid in version 2)
    public static A convertBtoA(Object b) {
        return (A)b;
    }

    @Test
    public void testTypeNarrowingWithArray() {
        final B b = new B();
        final A[] arr = new A[3];
        arr[0] = new A();

        assert b instanceof A;

        __toVersion__(1);

        assert !(b instanceof A);

        TestUtil.assertException(ArrayStoreException.class, new Runnable() {
            @Override
            public void run() {
                arr[1] = b;
            }
        });

        __toVersion__(0);

        arr[1] = new B();

        TestUtil.assertException(UnsupportedOperationException.class, new Runnable() {
            @Override
            public void run() {
                __toVersion__(1);
            }
        });

        assert __version__() == 0;

        assert b instanceof A;

        arr[1] = new A();

        __toVersion__(1);

        assert !(b instanceof A);

        __toVersion__(0);

        assert b instanceof A;
    }
}