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    1   /**
    2    * Copyright (c) 2004-2013 QOS.ch, Copyright (C) 2015 Google Inc.
    3    * All rights reserved.
    4    *
    5    * Permission is hereby granted, free  of charge, to any person obtaining
    6    * a  copy  of this  software  and  associated  documentation files  (the
    7    * "Software"), to  deal in  the Software without  restriction, including
    8    * without limitation  the rights to  use, copy, modify,  merge, publish,
    9    * distribute,  sublicense, and/or sell  copies of  the Software,  and to
    10   * permit persons to whom the Software  is furnished to do so, subject to
    11   * the following conditions:
    12   *
    13   * The  above  copyright  notice  and  this permission  notice  shall  be
    14   * included in all copies or substantial portions of the Software.
    15   *
    16   * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
    17   * EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
    18   * MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
    19   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
    20   * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
    21   * OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
    22   * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
    23   */
    24
    25  package org.slf4j.helpers;
    26
    27  import static org.junit.Assert.assertEquals;
    28  import static org.junit.Assert.assertFalse;
    29  import static org.junit.Assert.assertNull;
    30  import static org.junit.Assert.fail;
    31
    32  import java.lang.Thread.UncaughtExceptionHandler;
    33  import java.util.Map;
    34
    35  import org.junit.After;
    36  import org.junit.Test;
    37  import org.slf4j.spi.MDCAdapter;
    38
    39  /**
    40   * Tests for {@link BasicMDCAdapter}
    41   *
    42   * @author Lukasz Cwik
    43   */
    44  public class BasicMDCAdapterTest {
    45      MDCAdapter mdc = new BasicMDCAdapter();
    46
    47      @After
    48      public void tearDown() throws Exception {
    49          mdc.clear();
    50      }
    51
    52      @Test
    53      public void testSettingAndGettingWithMDC() {
    54          assertNull(mdc.get("testKey"));
    55          mdc.put("testKey", "testValue");
    56          assertEquals(mdc.get("testKey"), "testValue");
    57      }
    58
    59      @Test
    60      public void testOverwritingAKeyInMDC() {
    61          assertNull(mdc.get("testKey"));
    62          mdc.put("testKey", "testValue");
    63          mdc.put("testKey", "differentTestValue");
    64          assertEquals(mdc.get("testKey"), "differentTestValue");
    65      }
    66
    67      @Test
    68      public void testClearingMDC() {
    69          mdc.put("testKey", "testValue");
    70          assertFalse(mdc.getCopyOfContextMap().isEmpty());
    71          mdc.clear();
    72          assertNull(mdc.getCopyOfContextMap());
    73      }
    74
    75      @Test
    76      public void testGetCopyOfContextMapFromMDC() {
    77          mdc.put("testKey", "testValue");
    78          Map<String, String> copy = mdc.getCopyOfContextMap();
    79          mdc.put("anotherTestKey", "anotherTestValue");
    80          assertFalse(copy.size() == mdc.getCopyOfContextMap().size());
    81      }
    82
    83      @Test
    84      public void testMDCInheritsValuesFromParentThread() throws Exception {
    85          mdc.put("parentKey", "parentValue");
    86          runAndWait(new Runnable() {
    87              public void run() {
    88                  mdc.put("childKey", "childValue");
    89                  assertEquals("parentValue", mdc.get("parentKey"));
    90              }
    91          });
    92      }
    93
    94      @Test
    95      public void testMDCDoesntGetValuesFromChildThread() throws Exception {
    96          mdc.put("parentKey", "parentValue");
    97          runAndWait(new Runnable() {
    98              public void run() {
    99                  mdc.put("childKey", "childValue");
    100             }
    101         });
    102         assertEquals("parentValue", mdc.get("parentKey"));
    103         assertNull(mdc.get("childKey"));
    104     }
    105
    106     @Test
    107     public void testMDCChildThreadCanOverwriteParentThread() throws Exception {
    108         mdc.put("sharedKey", "parentValue");
    109         runAndWait(new Runnable() {
    110             public void run() {
    111                 assertEquals("parentValue", mdc.get("sharedKey"));
    112                 mdc.put("sharedKey", "childValue");
    113                 assertEquals("childValue", mdc.get("sharedKey"));
    114             }
    115         });
    116         assertEquals("parentValue", mdc.get("sharedKey"));
    117     }
    118
    119     private void runAndWait(Runnable runnable) throws Exception {
    120         RecordingExceptionHandler handler = new RecordingExceptionHandler();
    121         Thread thread = new Thread(runnable);
    122         thread.setUncaughtExceptionHandler(handler);
    123         thread.start();
    124         try {
    125             thread.join();
    126         } catch (Throwable t) {
    127             fail("Unexpected failure in child thread:" + t.getMessage());
    128         }
    129         assertFalse(handler.getMessage(), handler.hadException());
    130     }
    131
    132     /** A {@link UncaughtExceptionHandler} that records whether the thread threw an exception. */
    133     private static class RecordingExceptionHandler implements UncaughtExceptionHandler {
    134         private Throwable exception;
    135
    136         public void uncaughtException(Thread t, Throwable e) {
    137             exception = e;
    138         }
    139
    140         boolean hadException() {
    141             return exception != null;
    142         }
    143
    144         String getMessage() {
    145             return exception != null ? exception.getMessage() : "";
    146         }
    147     }
    148 }