Implemented OptimizableToArrayCallRule

git-svn-id: https://pmd.svn.sourceforge.net/svnroot/pmd/trunk@2687 51baf565-9d33-0410-a72c-fc3788e3496d

pmd/etc/changelog.txt

@@ -1,5 +1,5 @@
 ????, 2004 - 1.8:
-New rules: ExceptionAsFlowControlRule, BadComparisonRule, AvoidThrowingCertainExceptionTypesRule, AvoidCatchingNPERule
+New rules: ExceptionAsFlowControlRule, BadComparisonRule, AvoidThrowingCertainExceptionTypesRule, AvoidCatchingNPERule, OptimizableToArrayCallRule
 Major grammar changes - lots of new node types added, many superfluous nodes removed from the runtime AST.  Bug 786611 - http://sourceforge.net/tracker/index.php?func=detail&aid=786611&group_id=56262&atid=479921 - explains it a bit more.
 Fixed bug 786611 - Expressions are no longer over-expanded in the AST
 Fixed bug 874284 - The AST now contains tokens for bitwise or expressions - i.e., "|"

pmd/regress/test/net/sourceforge/pmd/rules/OptimizableToArrayCallRuleTest.java

@@ -0,0 +1,39 @@
+package test.net.sourceforge.pmd.rules;
+
+import net.sourceforge.pmd.Rule;
+import net.sourceforge.pmd.RuleSetNotFoundException;
+import net.sourceforge.pmd.PMD;
+import test.net.sourceforge.pmd.testframework.TestDescriptor;
+import test.net.sourceforge.pmd.testframework.SimpleAggregatorTst;
+
+public class OptimizableToArrayCallRuleTest extends SimpleAggregatorTst {
+
+    private Rule rule;
+
+    public void setUp() throws RuleSetNotFoundException {
+        rule = findRule("rulesets/newrules.xml", "OptimizableToArrayCallRule");
+    }
+
+    public void testAll() {
+       runTests(new TestDescriptor[] {
+           new TestDescriptor(TEST1, "failure case", 1, rule),
+           new TestDescriptor(TEST2, "Array dimensioner uses method call, ok", 0, rule),
+           new TestDescriptor(TEST3, "Array dimensioner uses variable, ok", 0, rule),
+       });
+    }
+
+    private static final String TEST1 =
+    "public class Foo {" + PMD.EOL +
+    " {x.toArray(new Foo[0]);}" + PMD.EOL +
+    "}";
+
+    private static final String TEST2 =
+    "public class Foo {" + PMD.EOL +
+    " {x.toArray(new Foo[x.size()]);}" + PMD.EOL +
+    "}";
+
+    private static final String TEST3 =
+    "public class Foo {" + PMD.EOL +
+    " {x.toArray(new Foo[y]);}" + PMD.EOL +
+    "}";
+}

pmd/rulesets/newrules.xml

@@ -6,6 +6,45 @@ These are new rules for the next release
   </description>
 
 
+    <rule name="OptimizableToArrayCallRule"
+          message="This call to Collection.toArray() may be optimizable"
+          class="net.sourceforge.pmd.rules.XPathRule">
+      <description>
+  A call to Collection.toArray can use the Collection's size vs an empty Array of the desired type.
+      </description>
+      <properties>
+          <property name="xpath">
+              <value>
+                  <![CDATA[
+//PrimaryExpression
+[PrimaryPrefix/Name[ends-with(@Image, 'toArray')]]
+[
+PrimarySuffix/Arguments/ArgumentList/Expression
+ /PrimaryExpression/PrimaryPrefix/AllocationExpression
+ /ArrayDimsAndInits/Expression/PrimaryExpression/PrimaryPrefix/Literal[@Image='0']
+]
+
+                  ]]>
+              </value>
+          </property>
+      </properties>
+        <priority>3</priority>
+
+      <example>
+  <![CDATA[
+class Example {
+ void bar() {
+   // A bit inefficient, unlike...
+   x.toArray(new Foo[0]);
+
+   // ..this one, which sizes the destination array, avoiding
+   // a reflection call in some Collection implementations
+   x.toArray(new Foo[x.size()]);
+}
+}  ]]>
+      </example>
+    </rule>
+
     <rule name="BadComparisonRule"
           message="Avoid equality comparisons with Double.NaN"
           class="net.sourceforge.pmd.rules.XPathRule">

pmd/xdocs/credits.xml

@@ -39,6 +39,7 @@
         </subsection>
         <subsection name="Contributors">
         <ul>
+            <li>Radim Kubacki - OptimizableToArrayCallRule suggestion, bug reports, pmd-netbeans feedback</li>
             <li>Will Sargent - AvoidThrowingCertainExceptionTypesRule, AvoidCatchingNPERule, ExceptionAsFlowControlRule, URL updates for 'Similar projects' page</li>
             <li>Mike Thome - BadComparisonRule suggestion</li>
             <li>Bertrand Mollinier Toublet - Bug report which led to platform character set encoding enhancement</li>
@@ -131,7 +132,6 @@
             <li>J.D. Fagan - feature suggestions</li>
             <li>William McArthur - ForLoopShouldBeWhileLoop rule</li>
             <li>Ales Bukovsky - pmd-netbeans feedback</li>
-            <li>Radim Kubacki - bug reports, pmd-netbeans feedback</li>
             <li>Stefan Bodewig - bug report</li>
             <li>Paul Kendall - enhanced EmptyCatchBlock rule</li>
             <li>Sean Sullivan - rule suggestions</li>