ExceptionUtils.getThrowables(Throwable): Switched from concrete

ArrayList local reference to List.

ExceptionUtils.getStackTrace(Throwable): New method for extracting the
text of a stack trace.

ExceptionUtils.getStackFrames(Throwable): Splits an exception's stace
trace into frames.

ExceptionUtils.getStackFrames(String): Splits a stace trace into frames.

NestableDelegate printStackTrace(): Delegate to
printStackTrace(PrintStream) using System.err rather than duplicating
its impl.

NestableDelegate printStackTrace(PrintWriter): Used new name
getStackFrames() method name.

NestableDelegate getStackFrames(Throwable): Renamed decompose() to
this and delegated to ExceptionUtils.getStackFrames(String) for half
of impl.


git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/lang/trunk@136985 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/commons/lang/exception/ExceptionUtils.java

@@ -57,14 +57,13 @@ package org.apache.commons.lang.exception;
 import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
+import java.io.PrintWriter;
+import java.io.StringWriter;
 import java.sql.SQLException;
 import java.util.ArrayList;
-
+import java.util.LinkedList;
-/*
+import java.util.List;
-TODO: Refactor code from NestableDelegate to ExceptionUtils.
+import java.util.StringTokenizer;
-
-printStackTrace(Throwable, PrintWriter)
-*/
 
 /**
  * Utility routines for manipulating <code>Throwable</code> objects.
@@ -308,7 +307,7 @@ public class ExceptionUtils
      */
     public static Throwable[] getThrowables(Throwable t)
     {
-        ArrayList list = new ArrayList();
+        List list = new ArrayList();
         while (t != null)
         {
             list.add(t);
@@ -367,4 +366,52 @@ public class ExceptionUtils
         }
         return -1;
     }
+
+    /**
+     * A convenient way of extracting the stack trace from an
+     * exception.
+     *
+     * @param t The <code>Throwable</code>.
+     * @return The stack trace as generated by the exception's
+     * <code>printStackTrace(PrintWriter)</code> method.
+     */
+    public static String getStackTrace(Throwable t)
+    {
+        StringWriter sw = new StringWriter();
+        PrintWriter pw = new PrintWriter(sw, true);
+        t.printStackTrace(pw);
+        return sw.getBuffer().toString();
+    }
+
+    /**
+     * Captures the stack trace associated with the specified
+     * <code>Throwable</code> object, decomposing it into a list of
+     * stack frames.
+     *
+     * @param t The <code>Throwable</code>.
+     * @return  An array of strings describing each stack frame.
+     */
+    public static String[] getStackFrames(Throwable t)
+    {
+        return getStackFrames(getStackTrace(t));
+    }
+
+    /**
+     * Functionality shared between the
+     * <code>getStackFrames(Throwable)</code> methods of this and the
+     * {@link org.apache.commons.lang.exception.NestableDelegate}
+     * classes.
+     */
+    static String[] getStackFrames(String stackTrace)
+    {
+        // TODO: Use constant from org.apache.commons.lang.SystemUtils.
+        String linebreak = System.getProperty("line.separator");
+        StringTokenizer frames = new StringTokenizer(stackTrace, linebreak);
+        List list = new LinkedList();
+        while (frames.hasMoreTokens())
+        {
+            list.add(frames.nextToken());
+        }
+        return (String []) list.toArray(new String[] {});
+    }
 }

src/java/org/apache/commons/lang/exception/NestableDelegate.java

@@ -59,15 +59,13 @@ import java.io.PrintStream;
 import java.io.PrintWriter;
 import java.io.StringWriter;
 import java.io.Writer;
-import java.util.LinkedList;
-import java.util.StringTokenizer;
 
 /**
  * @author <a href="mailto:Rafal.Krzewski@e-point.pl">Rafal Krzewski</a>
  * @author <a href="mailto:dlr@collab.net">Daniel Rall</a>
  * @author <a href="mailto:knielsen@apache.org">Kasper Nielsen</a>
  * @author <a href="mailto:steven@caswell.name">Steven Caswell</a>
- * @version $Id: NestableDelegate.java,v 1.5 2002/08/21 23:52:02 dlr Exp $
+ * @version $Id: NestableDelegate.java,v 1.6 2002/08/24 19:18:50 dlr Exp $
  */
 public class NestableDelegate
 {
@@ -257,17 +255,16 @@ public class NestableDelegate
      * stream.
      */
     public void printStackTrace()
-    {
-        synchronized (System.err)
     {
         printStackTrace(System.err);
     }
-    }
 
     /**
-     * Prints the stack trace of this exception to the specified print stream.
+     * Prints the stack trace of this exception to the specified
+     * stream.
      *
      * @param out <code>PrintStream</code> to use for output.
+     * @see #printStackTrace(PrintWriter)
      */
     public void printStackTrace(PrintStream out)
     {
@@ -281,7 +278,8 @@ public class NestableDelegate
     }
 
     /**
-     * Prints the stack trace of this exception to the specified print writer.
+     * Prints the stack trace of this exception to the specified
+     * writer.
      *
      * @param out <code>PrintWriter</code> to use for output.
      */
@@ -289,7 +287,7 @@ public class NestableDelegate
     {
         synchronized (out)
         {
-            String[] st = decompose(this.cause);
+            String[] st = getStackFrames(this.cause);
             Throwable nestedCause = ExceptionUtils.getCause(this.cause);
             if (nestedCause != null)
             {
@@ -300,7 +298,7 @@ public class NestableDelegate
                 }
                 else
                 {
-                    String[] nst = decompose(nestedCause);
+                    String[] nst = getStackFrames(nestedCause);
                     for (int i = 0; i < nst.length; i++)
                     {
                         out.println(nst[i]);
@@ -318,13 +316,14 @@ public class NestableDelegate
     }
 
     /**
-     * Captures the stack trace associated with a <code>Throwable</code>
+     * Captures the stack trace associated with the specified
-     * object, decomposing it into a list of stack frames.
+     * <code>Throwable</code> object, decomposing it into a list of
+     * stack frames.
      *
      * @param t The <code>Throwable</code>.
      * @return  An array of strings describing each stack frame.
      */
-    private String[] decompose(Throwable t)
+    private String[] getStackFrames(Throwable t)
     {
         StringWriter sw = new StringWriter();
         PrintWriter pw = new PrintWriter(sw, true);
@@ -338,15 +337,6 @@ public class NestableDelegate
         {
             t.printStackTrace(pw);
         }
-
+        return ExceptionUtils.getStackFrames(sw.getBuffer().toString());
-        String linebreak = System.getProperty("line.separator");
-        StringTokenizer st = new StringTokenizer(sw.getBuffer().toString(),
-                                                 linebreak);
-        LinkedList list = new LinkedList();
-        while (st.hasMoreTokens())
-        {
-            list.add(st.nextToken());
-        }
-        return (String []) list.toArray(new String[] {});
     }
 }