Issue #85 Exception Unwrapping Example

Author: bytefish

PgBulkInsert/pgbulkinsert-core/src/main/java/de/bytefish/pgbulkinsert/util/ExceptionUtils.java

@@ -0,0 +1,28 @@
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+package de.bytefish.pgbulkinsert.util;
+
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+public class ExceptionUtils {
+
+    private ExceptionUtils() {}
+
+    @Nullable
+    public static Throwable getRootCause(@Nullable Throwable t) {
+        if (t == null) {
+            return null;
+        }
+
+        Throwable rootCause = null;
+        Throwable cause = t.getCause();
+
+        // Now get to the Inner-Most Cause:
+        while (cause != null && cause != rootCause) {
+            rootCause = cause;
+            cause = cause.getCause();
+        }
+
+        return rootCause;
+    }
+}

PgBulkInsert/pgbulkinsert-core/src/test/java/de/bytefish/pgbulkinsert/test/util/ExceptionUtilsTest.java

@@ -0,0 +1,29 @@
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+package de.bytefish.pgbulkinsert.test.util;
+
+import de.bytefish.pgbulkinsert.exceptions.BinaryWriteFailedException;
+import de.bytefish.pgbulkinsert.util.ExceptionUtils;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.sql.SQLException;
+
+public class ExceptionUtilsTest {
+
+    @Test
+    public void testExceptionUtils() {
+
+        // Exception Hierarchy:
+        SQLException sqlException = new SQLException("My SQLException");
+        IOException ioException = new IOException("My IOException with a SQLException cause", sqlException);
+        BinaryWriteFailedException binaryWriteFailedException = new BinaryWriteFailedException(ioException);
+
+        // Get the root cause:
+        Throwable innerMostException = ExceptionUtils.getRootCause(binaryWriteFailedException);
+
+        Assert.assertNotNull(innerMostException);
+        Assert.assertEquals("My SQLException", innerMostException.getMessage());
+    }
+}