Add meaningful descriptions to ConstantDerivedException (fixes #63)

bp-alex · bp-alex · commit e7916e04fe29 · 2017-08-15T10:06:08.000+10:00
diff --git a/src/main/java/org/lmdbjava/ResultCodeMapper.java b/src/main/java/org/lmdbjava/ResultCodeMapper.java
@@ -110,7 +110,8 @@ static void checkRc(final int rc) throws LmdbNativeException {
     if (constant == null) {
       throw new IllegalArgumentException("Unknown result code " + rc);
     }
-    throw new LmdbNativeException.ConstantDerviedException(rc, constant.name());
+    final String msg = constant.name() + " " + constant.toString();
+    throw new LmdbNativeException.ConstantDerviedException(rc, msg);
   }
 
 }
diff --git a/src/test/java/org/lmdbjava/ResultCodeMapperTest.java b/src/test/java/org/lmdbjava/ResultCodeMapperTest.java
@@ -23,6 +23,7 @@
 import static java.lang.Integer.MAX_VALUE;
 import java.util.HashSet;
 import java.util.Set;
+import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.CoreMatchers.notNullValue;
 import static org.hamcrest.MatcherAssert.assertThat;
@@ -107,6 +108,16 @@ public void checkErrConstantDerived() {
     checkRc(20);
   }
 
+  @Test
+  public void checkErrConstantDerivedMessage() {
+    try {
+      checkRc(2);
+      fail("Should have raised exception");
+    } catch (final ConstantDerviedException ex) {
+      assertThat(ex.getMessage(), containsString("No such file or directory"));
+    }
+  }
+
   @Test(expected = FullException.class)
   public void checkErrCursorFull() {
     checkRc(MDB_CURSOR_FULL);

Original file line number	Diff line number	Diff line change
`@@ -110,7 +110,8 @@ static void checkRc(final int rc) throws LmdbNativeException {`
`110`	`110`	`if (constant == null) {`
`111`	`111`	`throw new IllegalArgumentException("Unknown result code " + rc);`
`112`	`112`	`}`
`113`		`- throw new LmdbNativeException.ConstantDerviedException(rc, constant.name());`
	`113`	`+ final String msg = constant.name() + " " + constant.toString();`
	`114`	`+ throw new LmdbNativeException.ConstantDerviedException(rc, msg);`
`114`	`115`	`}`
`115`	`116`
`116`	`117`	`}`