jdk-24/test/jdk/java/lang/Thread/virtual/ThreadLocals.java

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/**
 * @test
 * @summary Test Virtual threads using thread locals
 * @library /test/lib
 * @compile --enable-preview -source ${jdk.version} ThreadLocals.java
 * @run testng/othervm --enable-preview ThreadLocals
 */

import jdk.test.lib.thread.VThreadRunner;
import org.testng.annotations.Test;
import static org.testng.Assert.*;

public class ThreadLocals {
    static final ThreadLocal<Object> LOCAL = new ThreadLocal<>();
    static final ThreadLocal<Object> INHERITED_LOCAL = new InheritableThreadLocal<>();

    /**
     * Basic test of thread local set/get.
     */
    @Test
    public void testThreadLocal1() throws Exception {
        for (int i = 0; i < 10; i++) {
            VThreadRunner.run(() -> {
                assertTrue(LOCAL.get() == null);
                Object obj = new Object();
                LOCAL.set(obj);
                assertTrue(LOCAL.get() == obj);
            });
        }
    }

    /**
     * Test setting thread local before blocking operation.
     */
    @Test
    public void testThreadLocal2() throws Exception {
        VThreadRunner.run(() -> {
            assertTrue(LOCAL.get() == null);
            Object obj = new Object();
            LOCAL.set(obj);
            try { Thread.sleep(100); } catch (InterruptedException e) { }
            assertTrue(LOCAL.get() == obj);
        });
    }

    /**
     * Test Thread that cannot set values for its copy of thread-locals.
     */
    @Test
    public void testThreadLocal3() throws Exception {
        Object INITIAL_VALUE = new Object();
        ThreadLocal<Object> LOCAL2 = new ThreadLocal<>() {
            @Override
            protected Object initialValue() {
                return INITIAL_VALUE;
            }
        };
        ThreadLocal<Object> INHERITED_LOCAL2 = new InheritableThreadLocal<>()  {
            @Override
            protected Object initialValue() {
                return INITIAL_VALUE;
            }
        };

        VThreadRunner.run(VThreadRunner.NO_THREAD_LOCALS, () -> {
            assertThrows(UnsupportedOperationException.class, () -> LOCAL.set(null));
            assertThrows(UnsupportedOperationException.class, () -> LOCAL.set(new Object()));
            assertTrue(LOCAL.get() == null);
            LOCAL.remove();  // should not throw

            assertThrows(UnsupportedOperationException.class, () -> LOCAL2.set(null));
            assertThrows(UnsupportedOperationException.class, () -> LOCAL2.set(new Object()));
            assertTrue(LOCAL2.get() == INITIAL_VALUE);
            LOCAL2.remove();  // should not throw

            assertThrows(UnsupportedOperationException.class, () -> INHERITED_LOCAL.set(null));
            assertThrows(UnsupportedOperationException.class, () -> INHERITED_LOCAL.set(new Object()));
            assertTrue(INHERITED_LOCAL.get() == null);
            INHERITED_LOCAL.remove();  // should not throw

            assertThrows(UnsupportedOperationException.class, () -> INHERITED_LOCAL2.set(null));
            assertThrows(UnsupportedOperationException.class, () -> INHERITED_LOCAL2.set(new Object()));
            assertTrue(INHERITED_LOCAL2.get() == INITIAL_VALUE);
            INHERITED_LOCAL2.remove();  // should not throw
        });
    }

    /**
     * Basic test of inheritable thread local set/get, no initial value inherited.
     */
    @Test
    public void testInheritedThreadLocal1() throws Exception {
        assertTrue(INHERITED_LOCAL.get() == null);
        for (int i = 0; i < 10; i++) {
            VThreadRunner.run(() -> {
                assertTrue(INHERITED_LOCAL.get() == null);
                Object obj = new Object();
                INHERITED_LOCAL.set(obj);
                assertTrue(INHERITED_LOCAL.get() == obj);
            });
        }
        assertTrue(INHERITED_LOCAL.get() == null);
    }

    /**
     * Test inheriting initial value of InheritableThreadLocal from platform thread.
     */
    @Test
    public void testInheritedThreadLocal2() throws Exception {
        assertTrue(INHERITED_LOCAL.get() == null);
        var obj = new Object();
        INHERITED_LOCAL.set(obj);
        try {
            VThreadRunner.run(() -> {
                assertTrue(INHERITED_LOCAL.get() == obj);
            });
        } finally {
            INHERITED_LOCAL.remove();
        }
    }

    /**
     * Test inheriting initial value of InheritableThreadLocal from virtual thread.
     */
    @Test
    public void testInheritedThreadLocal3() throws Exception {
        assertTrue(INHERITED_LOCAL.get() == null);
        VThreadRunner.run(() -> {
            var obj = new Object();
            INHERITED_LOCAL.set(obj);
            VThreadRunner.run(() -> {
                assertTrue(INHERITED_LOCAL.get() == obj);
            });
            assertTrue(INHERITED_LOCAL.get() == obj);

        });
        assertTrue(INHERITED_LOCAL.get() == null);
    }

    /**
     * Test Thread that does not inherit initial value of InheritableThreadLocals
     * from platform thread.
     */
    @Test
    public void testInheritedThreadLocal4() throws Exception {
        assertTrue(INHERITED_LOCAL.get() == null);
        var obj = new Object();
        INHERITED_LOCAL.set(obj);
        try {
            int characteristics = VThreadRunner.NO_INHERIT_THREAD_LOCALS;
            VThreadRunner.run(characteristics, () -> {
                assertTrue(INHERITED_LOCAL.get() == null);
            });
        } finally {
            INHERITED_LOCAL.remove();
        }
    }

    /**
     * Test Thread that does not inherit initial value of InheritableThreadLocals
     * from virtual thread.
     */
    @Test
    public void testInheritedThreadLocal5() throws Exception {
        assertTrue(INHERITED_LOCAL.get() == null);
        VThreadRunner.run(() -> {
            var obj = new Object();
            INHERITED_LOCAL.set(obj);
            int characteristics = VThreadRunner.NO_INHERIT_THREAD_LOCALS;
            VThreadRunner.run(characteristics, () -> {
                assertTrue(INHERITED_LOCAL.get() == null);
            });
            assertTrue(INHERITED_LOCAL.get() == obj);

        });
        assertTrue(INHERITED_LOCAL.get() == null);
    }
}