I tired from these horrable long stack traces, so I've added iterative

implementation of tree processing, now we can activate it by setting
checkstyle.use.recursive.algorithm to false (by default checkstyle
still uses recursive algorithm).

Also I've chenged build.xml so it will be possible to use it from any
location and user will be able to specify filter for tests.

build.xml

@@ -32,6 +32,8 @@
   <property name="checkstyle.minimum.javaversion" value="1.4" />
   <property name="checkstyle.testinputs.minimum.javaversion" value="1.5" />
   <property name="version" value="4.0-beta5" />
+  <property name="testcases" value="**/*Test.java"/>
+
 
   <path id="build.classpath">
     <pathelement location="${antlr.jar}" />
@@ -405,8 +407,7 @@ For users of JDK 1.5 at least version 1.6.2 of Ant is required.
 
     <mkdir dir="${testreport.dir}"/>
     <property name="testinputs.dir"
-              location="src/testinputs/com/puppycrawl/tools/checkstyle"/>
-    <property name="testcases" value="**/*Test.java"/>
+              location="${basedir}/src/testinputs/com/puppycrawl/tools/checkstyle"/>
 
     <junit printsummary="yes"
            fork="yes"
@@ -416,6 +417,9 @@ For users of JDK 1.5 at least version 1.6.2 of Ant is required.
            failureProperty="tests.have.failed">
 
       <sysproperty key="testinputs.dir" value="${testinputs.dir}"/>
+      <sysproperty key="checkstyle.use.recursive.algorithm"
+                   value="${checkstyle.use.recursive.algorithm}"/>
+      <sysproperty key="checkstyle.root" value="${basedir}" />
 
       <sysproperty key="emma.coverage.out.file"
                    file="${emma.coverage.out.file}"

src/checkstyle/com/puppycrawl/tools/checkstyle/TreeWalker.java

@@ -125,12 +125,31 @@ public final class TreeWalker
     /** a factory for creating submodules (i.e. the Checks) */
     private ModuleFactory mModuleFactory;
 
+    /** contrals whether we should use recursive or iterative
+     * algorithm for tree processing.
+     */
+    private final boolean mRecursive;
+
     /**
      * Creates a new <code>TreeWalker</code> instance.
      */
     public TreeWalker()
     {
         setFileExtensions(new String[]{"java"});
+        // Tree walker can use two possible algorithms for
+        // tree processing (iterative and recursive.
+        // Recursive is default for now.
+        String recursive =
+            System.getProperty("checkstyle.use.recursive.algorithm", "true");
+        mRecursive = "true".equals(recursive);
+        if (mRecursive) {
+            Utils.getExceptionLogger()
+                .debug("TreeWalker uses recursive algorithm");
+        }
+        else {
+            Utils.getExceptionLogger()
+                .debug("TreeWalker uses iterative algorithm");
+        }
     }
 
     /** @param aTabWidth the distance between tab stops */
@@ -389,7 +408,12 @@ public final class TreeWalker
 
          // empty files are not flagged by javac, will yield aAST == null
         if (aAST != null) {
-            process(aAST);
+            if (useRecursiveAlgorithm()) {
+                processRec(aAST);
+            }
+            else {
+                processIter(aAST);
+            }
         }
 
         notifyEnd(aAST);
@@ -426,9 +450,10 @@ public final class TreeWalker
 
     /**
      * Recursively processes a node calling interested checks at each node.
+     * Uses recursive algorithm.
      * @param aAST the node to start from
      */
-    private void process(DetailAST aAST)
+    private void processRec(DetailAST aAST)
     {
         if (aAST == null) {
             return;
@@ -438,16 +463,15 @@ public final class TreeWalker
 
         final DetailAST child = (DetailAST) aAST.getFirstChild();
         if (child != null) {
-            process(child);
+            processRec(child);
         }
 
         notifyLeave(aAST);
 
         final DetailAST sibling = (DetailAST) aAST.getNextSibling();
         if (sibling != null) {
-            process(sibling);
+            processRec(sibling);
         }
-
     }
 
     /**
@@ -570,4 +594,34 @@ public final class TreeWalker
         super.destroy();
     }
 
+    /**
+     * @return true if we should use recursive algorithm
+     *         for tree processing, false for iterative one.
+     */
+    private boolean useRecursiveAlgorithm()
+    {
+        return mRecursive;
+    }
+
+    /**
+     * Processes a node calling interested checks at each node.
+     * Uses iterative algorithm.
+     * @param aRoot the root of tree for process
+     */
+    private void processIter(DetailAST aRoot)
+    {
+        DetailAST curNode = aRoot;
+        while (curNode != null) {
+            notifyVisit(curNode);
+            DetailAST toVisit = (DetailAST) curNode.getFirstChild();
+            while (curNode != null && toVisit == null) {
+                notifyLeave(curNode);
+                toVisit = (DetailAST) curNode.getNextSibling();
+                if (toVisit == null) {
+                    curNode = curNode.getParent();
+                }
+            }
+            curNode = toVisit;
+        }
+    }
 }

src/tests/com/puppycrawl/tools/checkstyle/PackageNamesLoaderTest.java

@@ -42,7 +42,8 @@ public class PackageNamesLoaderTest extends TestCase
     {
         final ModuleFactory moduleFactory =
             PackageNamesLoader.loadModuleFactory(
-                "src/checkstyle/com/puppycrawl/tools/checkstyle/checkstyle_packages.xml");
+                System.getProperty("checkstyle.root")
+                + "/src/checkstyle/com/puppycrawl/tools/checkstyle/checkstyle_packages.xml");
         validateFactory(moduleFactory);
     }
 

src/tests/com/puppycrawl/tools/checkstyle/filters/SuppressionsLoaderTest.java

@@ -17,7 +17,8 @@ public class SuppressionsLoaderTest extends TestCase
     {
         final FilterSet fc =
             SuppressionsLoader.loadSuppressions(
-                "src/testinputs/com/puppycrawl/tools/checkstyle/suppressions_none.xml");
+                System.getProperty("testinputs.dir")
+                + "/suppressions_none.xml");
         final FilterSet fc2 = new FilterSet();
         assertEquals(fc, fc2);
     }
@@ -27,7 +28,8 @@ public class SuppressionsLoaderTest extends TestCase
     {
         final FilterSet fc =
             SuppressionsLoader.loadSuppressions(
-                "src/testinputs/com/puppycrawl/tools/checkstyle/suppressions_multiple.xml");
+                System.getProperty("testinputs.dir")
+                + "/suppressions_multiple.xml");
         final FilterSet fc2 = new FilterSet();
         SuppressElement se0 = new SuppressElement("file0", "check0");
         fc2.addFilter(se0);
@@ -47,13 +49,14 @@ public class SuppressionsLoaderTest extends TestCase
     public void testNoFile()
         throws CheckstyleException
     {
+        final String fn = System.getProperty("testinputs.dir")
+            + "/suppressions_no_file.xml";
         try {
-            SuppressionsLoader.loadSuppressions(
-                "src/testinputs/com/puppycrawl/tools/checkstyle/suppressions_no_file.xml");
+            SuppressionsLoader.loadSuppressions(fn);
         }
         catch (CheckstyleException ex) {
             assertEquals(
-                "unable to parse src/testinputs/com/puppycrawl/tools/checkstyle/suppressions_no_file.xml - Attribute \"files\" is required and must be specified for element type \"suppress\".",
+                "unable to parse " + fn + " - Attribute \"files\" is required and must be specified for element type \"suppress\".",
                 ex.getMessage());
         }
     }
@@ -61,13 +64,14 @@ public class SuppressionsLoaderTest extends TestCase
     public void testNoCheck()
         throws CheckstyleException
     {
+        final String fn = System.getProperty("testinputs.dir")
+            + "/suppressions_no_check.xml";
         try {
-            SuppressionsLoader.loadSuppressions(
-                "src/testinputs/com/puppycrawl/tools/checkstyle/suppressions_no_check.xml");
+            SuppressionsLoader.loadSuppressions(fn);
         }
         catch (CheckstyleException ex) {
             assertEquals(
-                "unable to parse src/testinputs/com/puppycrawl/tools/checkstyle/suppressions_no_check.xml - Attribute \"checks\" is required and must be specified for element type \"suppress\".",
+                "unable to parse " + fn + " - Attribute \"checks\" is required and must be specified for element type \"suppress\".",
                 ex.getMessage());
         }
     }
@@ -75,14 +79,15 @@ public class SuppressionsLoaderTest extends TestCase
     public void testBadInt()
         throws CheckstyleException
     {
+        final String fn = System.getProperty("testinputs.dir")
+            + "/suppressions_bad_int.xml";
         try {
-            SuppressionsLoader.loadSuppressions(
-                "src/testinputs/com/puppycrawl/tools/checkstyle/suppressions_bad_int.xml");
+            SuppressionsLoader.loadSuppressions(fn);
         }
         catch (CheckstyleException ex) {
             assertTrue(
                 ex.getMessage(),
-                ex.getMessage().startsWith("number format exception src/testinputs/com/puppycrawl/tools/checkstyle/suppressions_bad_int.xml - "));
+                ex.getMessage().startsWith("number format exception " + fn + " - "));
         }
     }
 }