Author: ggregory
Date: Thu Jan 5 09:35:43 2006
New Revision: 366225
URL: http://svn.apache.org/viewcvs?rev=366225&view=rev
Log:
http://issues.apache.org/bugzilla/show_bug.cgi?id=37574
[lang] [PATCH] new ExceptionUtils.setCause() method
Modified:
jakarta/commons/proper/lang/trunk/src/java/org/apache/commons/lang/exception/ExceptionUtils.java
jakarta/commons/proper/lang/trunk/src/test/org/apache/commons/lang/exception/ExceptionUtilsTestCase.java
Modified:
jakarta/commons/proper/lang/trunk/src/java/org/apache/commons/lang/exception/ExceptionUtils.java
URL:
http://svn.apache.org/viewcvs/jakarta/commons/proper/lang/trunk/src/java/org/apache/commons/lang/exception/ExceptionUtils.java?rev=366225&r1=366224&r2=366225&view=diff
==============================================================================
---
jakarta/commons/proper/lang/trunk/src/java/org/apache/commons/lang/exception/ExceptionUtils.java
(original)
+++
jakarta/commons/proper/lang/trunk/src/java/org/apache/commons/lang/exception/ExceptionUtils.java
Thu Jan 5 09:35:43 2006
@@ -31,10 +31,11 @@
import org.apache.commons.lang.ArrayUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.lang.SystemUtils;
+import org.apache.commons.lang.NullArgumentException;
/**
* <p>Provides utilities for manipulating and examining
- * <code>Throwable</code> objects.</p>
+<code>Throwable</code> objects.</p>
*
* @author <a href="mailto:dlr@finemaltcoding.com";>Daniel Rall</a>
* @author Dmitri Plotnikov
@@ -73,22 +74,40 @@
};
/**
- * <p>The Method object for JDK1.4 getCause.</p>
+ * <p>
+ * The Method object for Java 1.4 getCause.
+ * </p>
*/
private static final Method THROWABLE_CAUSE_METHOD;
+
+ /**
+ * <p>
+ * The Method object for Java 1.4 initCause.
+ * </p>
+ */
+ private static final Method THROWABLE_INITCAUSE_METHOD;
+
static {
- Method getCauseMethod;
+ Method causeMethod;
try {
- getCauseMethod = Throwable.class.getMethod("getCause", null);
+ causeMethod = Throwable.class.getMethod("getCause", null);
} catch (Exception e) {
- getCauseMethod = null;
+ causeMethod = null;
}
- THROWABLE_CAUSE_METHOD = getCauseMethod;
+ THROWABLE_CAUSE_METHOD = causeMethod;
+ try {
+ causeMethod = Throwable.class.getMethod("initCause", new
Class[]{Throwable.class});
+ } catch (Exception e) {
+ causeMethod = null;
+ }
+ THROWABLE_INITCAUSE_METHOD = causeMethod;
}
/**
- * <p>Public constructor allows an instance of <code>ExceptionUtils</code>
- * to be created, although that is not normally necessary.</p>
+ * <p>
+ * Public constructor allows an instance of <code>ExceptionUtils</code> to
be created, although that is not
+ * normally necessary.
+ * </p>
*/
public ExceptionUtils() {
super();
@@ -130,6 +149,72 @@
}
/**
+ * <p>
+ * Sets the cause of a <code>Throwable</code> using introspection,
allowing source code compatibility between
+ * pre-1.4 and post-1.4 Java releases.
+ * </p>
+ *
+ * <p>
+ * The typical use of this method is inside a constructor as in the
following example:
+ * </p>
+ *
+ * <p>
+ * <pre>
+ * import org.apache.commons.lang.exception.ExceptionUtils;
+ *
+ * public class MyException extends Exception {
+ *
+ * public MyException(String msg) {
+ * super(msg);
+ * }
+ *
+ * public MyException(String msg, Throwable cause) {
+ * super(msg);
+ * ExceptionUtils.setCause(this, cause);
+ * }
+ *
+ * }
+ * </pre>
+ * </p>
+ *
+ * @param target
+ * the target <code>Throwable</code>
+ * @param cause
+ * the <code>Throwable</code> to set in the target
+ * @return a <code>true</code> if the target has been modified
+ * @since 2.2
+ */
+ public static boolean setCause(Throwable target, Throwable cause) {
+ if (target == null) {
+ throw new NullArgumentException("target");
+ }
+ Object[] causeArgs = new Object[]{cause};
+ boolean modifiedTarget = false;
+ if (THROWABLE_INITCAUSE_METHOD != null) {
+ try {
+ THROWABLE_INITCAUSE_METHOD.invoke(target, causeArgs);
+ modifiedTarget = true;
+ } catch (IllegalAccessException ignored) {
+ // Exception ignored.
+ } catch (InvocationTargetException ignored) {
+ // Exception ignored.
+ }
+ }
+ try {
+ Method setCauseMethod = target.getClass().getMethod("setCause",
new Class[]{Throwable.class});
+ setCauseMethod.invoke(target, causeArgs);
+ modifiedTarget = true;
+ } catch (NoSuchMethodException ignored) {
+ // Exception ignored.
+ } catch (IllegalAccessException ignored) {
+ // Exception ignored.
+ } catch (InvocationTargetException ignored) {
+ // Exception ignored.
+ }
+ return modifiedTarget;
+ }
+
+ /**
* Returns the given list as a <code>String[]</code>.
* @param list a list to transform.
* @return the given list as a <code>String[]</code>.
@@ -768,14 +853,20 @@
}
/**
- * <p>Returns an array where each element is a line from the argument.</p>
- * <p>The end of line is determined by the value of [EMAIL PROTECTED]
SystemUtils#LINE_SEPARATOR}.</p>
- *
- * <p>Functionality shared between the
- * <code>getStackFrames(Throwable)</code> methods of this and the
- * [EMAIL PROTECTED] org.apache.commons.lang.exception.NestableDelegate}
- * classes.</p>
- * @param stackTrace A stack trace String.
+ * <p>
+ * Returns an array where each element is a line from the argument.
+ * </p>
+ * <p>
+ * The end of line is determined by the value of [EMAIL PROTECTED]
SystemUtils#LINE_SEPARATOR}.
+ * </p>
+ *
+ * <p>
+ * Functionality shared between the <code>getStackFrames(Throwable)</code>
methods of this and the
+ * [EMAIL PROTECTED] org.apache.commons.lang.exception.NestableDelegate}
classes.
+ * </p>
+ *
+ * @param stackTrace
+ * A stack trace String.
* @return an array where each element is a line from the argument.
*/
static String[] getStackFrames(String stackTrace) {
Modified:
jakarta/commons/proper/lang/trunk/src/test/org/apache/commons/lang/exception/ExceptionUtilsTestCase.java
URL:
http://svn.apache.org/viewcvs/jakarta/commons/proper/lang/trunk/src/test/org/apache/commons/lang/exception/ExceptionUtilsTestCase.java?rev=366225&r1=366224&r2=366225&view=diff
==============================================================================
---
jakarta/commons/proper/lang/trunk/src/test/org/apache/commons/lang/exception/ExceptionUtilsTestCase.java
(original)
+++
jakarta/commons/proper/lang/trunk/src/test/org/apache/commons/lang/exception/ExceptionUtilsTestCase.java
Thu Jan 5 09:35:43 2006
@@ -16,6 +16,7 @@
package org.apache.commons.lang.exception;
import java.io.ByteArrayOutputStream;
+import java.io.IOException;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.io.StringWriter;
@@ -25,6 +26,7 @@
import junit.framework.Assert;
import junit.framework.Test;
import junit.framework.TestSuite;
+
import org.apache.commons.lang.SystemUtils;
/**
@@ -139,6 +141,25 @@
assertSame(withoutCause, ExceptionUtils.getRootCause(withCause));
}
+ public void testSetCause() {
+ Exception cause = new ExceptionWithoutCause();
+ assertEquals(true, ExceptionUtils.setCause(new
ExceptionWithCause(null), cause));
+ if (SystemUtils.isJavaVersionAtLeast(140)) {
+ assertEquals(true, ExceptionUtils.setCause(new
ExceptionWithoutCause(), cause));
+ }
+ }
+
+ /**
+ * Tests overriding a cause to <code>null</code>.
+ */
+ public void testSetCauseToNull() {
+ Exception ex = new ExceptionWithCause(new IOException());
+ assertEquals(true, ExceptionUtils.setCause(ex, new
IllegalStateException()));
+ assertNotNull(ExceptionUtils.getCause(ex));
+ assertEquals(true, ExceptionUtils.setCause(ex, null));
+ assertNull(ExceptionUtils.getCause(ex));
+ }
+
//-----------------------------------------------------------------------
public void testIsThrowableNested() {
if (SystemUtils.isJavaVersionAtLeast(140)) {
@@ -387,11 +408,15 @@
private Throwable cause;
public ExceptionWithCause(Throwable cause) {
- this.cause = cause;
+ setCause(cause);
}
public Throwable getCause() {
return cause;
+ }
+
+ public void setCause(Throwable cause) {
+ this.cause = cause;
}
}
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