added new Unnecessary Constructor rule

git-svn-id: https://pmd.svn.sourceforge.net/svnroot/pmd/trunk@1182 51baf565-9d33-0410-a72c-fc3788e3496d

pmd/etc/Java1.4-c.jjt

@@ -576,7 +576,9 @@ void FormalParameter() :
 void ConstructorDeclaration() :
 {}
 {
-  [ "public" | "protected" | "private" ]
+  [ "public" { ((AccessNode) jjtThis).setPublic( true ); }
+  | "protected" { ((AccessNode) jjtThis).setProtected( true ); }
+  | "private" ] { ((AccessNode) jjtThis).setPrivate( true ); }
   <IDENTIFIER> FormalParameters() [ "throws" NameList() ]
   "{"
     [ LOOKAHEAD(ExplicitConstructorInvocation()) ExplicitConstructorInvocation() ]

pmd/etc/build.xml

@@ -60,7 +60,7 @@
         <!--<pmd reportFile="c:\jdk-1.4.html" rulesetfiles="rulesets/tmp.xml" format="html">-->
         <pmd reportFile="c:\jdk-1.4.html" rulesetfiles="rulesets/tmp.xml" format="html">
             <!--<fileset dir="c:\data\pmd\pmd\src\net\sourceforge\pmd\">-->
-            <fileset dir="c:\j2sdk1.4.1_01\src\java\lang">
+            <fileset dir="c:\j2sdk1.4.1_01\src\java\">
                 <include name="**/*.java"/>
                 <!--<exclude name="**/ast**/"/>-->
             </fileset>
@@ -83,6 +83,34 @@
         </junit>
     </target>
 
+
+    <target name="jjtree">
+        <jjtree target="etc/Java1.4-c.jjt" outputdirectory="src/net/sourceforge/pmd/ast" javacchome="c:/javacc2.1"/>
+        <javacc target="src/net/sourceforge/pmd/ast/Java1.4-c.jj" outputdirectory="src/net/sourceforge/pmd/ast" javacchome="c:/javacc2.1"/>
+        <delete file="src/net/sourceforge/pmd/ast/Java1.4-c.jj"/>
+    </target>
+
+	<target name="clean" depends="delete,compile"/>
+
+    <target name="dist" depends="clean,jar"/>
+
+    <target name="cpdjnlp" depends="dist">
+        <signjar jar="${lib}\pmd-${version}.jar" alias="myself" keystore="${jnlp_staging_area}myKeyStore" storepass="password"/>
+        <exec executable="pscp.exe" os="Windows 2000">
+            <arg line=" ${lib}\pmd-${version}.jar tomcopeland@pmd.sourceforge.net:/home/groups/p/pm/pmd/htdocs"/>
+        </exec>
+    </target>
+
+<target name="run-cpd" depends="compile">
+ <java classname="net.sourceforge.pmd.cpd.GUI" fork="yes">
+	<classpath>
+ 	    <path refid="classpath.path"/>
+	</classpath>
+ </java>
+</target>
+
+
+
   <path id="quilt.classpath">
     <pathelement location="${lib.repo}/quilt-0.4.jar" />
     <pathelement location="${lib.repo}/bcel-5.1-dev.jar" />
@@ -107,12 +135,6 @@
         </quilt>
     </target>
 
-    <target name="jjtree">
-        <jjtree target="etc/Java1.4-c.jjt" outputdirectory="src/net/sourceforge/pmd/ast" javacchome="c:/javacc2.1"/>
-        <javacc target="src/net/sourceforge/pmd/ast/Java1.4-c.jj" outputdirectory="src/net/sourceforge/pmd/ast" javacchome="c:/javacc2.1"/>
-        <delete file="src/net/sourceforge/pmd/ast/Java1.4-c.jj"/>
-    </target>
-
     <target name="jjtree-2">
         <mkdir dir="tmp"/>
         <jjtree target="etc/Java1.4-c.jjt" outputdirectory="src/net/sourceforge/pmd/ast" javacchome="/home/dpeugh/software/javacc2.1"/>
@@ -125,25 +147,6 @@
     </target>
 
 
-	<target name="clean" depends="delete,compile"/>
-
-    <target name="dist" depends="clean,jar"/>
-
-    <target name="cpdjnlp" depends="dist">
-        <signjar jar="${lib}\pmd-${version}.jar" alias="myself" keystore="${jnlp_staging_area}myKeyStore" storepass="password"/>
-        <exec executable="pscp.exe" os="Windows 2000">
-            <arg line=" ${lib}\pmd-${version}.jar tomcopeland@pmd.sourceforge.net:/home/groups/p/pm/pmd/htdocs"/>
-        </exec>
-    </target>
-
-<target name="run-cpd" depends="compile">
- <java classname="net.sourceforge.pmd.cpd.GUI" fork="yes">
-	<classpath>
- 	    <path refid="classpath.path"/>
-	</classpath>
- </java>
-</target>
-
 
 </project>
 

pmd/etc/changelog.txt

@@ -1,5 +1,5 @@
 ???? 2002 - ????:
-Added new rules: StringToStringRule, AvoidReassigningParametersRule
+Added new rules: StringToStringRule, AvoidReassigningParametersRule, UnnecessaryConstructorRule
 Fixed bug 631010: AvoidDeeplyNestedIfStmtsRule works correctly with if..else stmts now
 Fixed bug 631605: OnlyOneReturn handles line spillover now.
 

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

@@ -0,0 +1,27 @@
+/*
+ * User: tom
+ * Date: Nov 1, 2002
+ * Time: 9:12:42 AM
+ */
+package test.net.sourceforge.pmd.rules;
+
+import net.sourceforge.pmd.rules.UnnecessaryConstructorRule;
+
+public class UnnecessaryConstructorRuleTest extends RuleTst {
+
+    public void test1() throws Throwable {
+        super.runTest("UnnecessaryConstructor1.java", 1, new UnnecessaryConstructorRule());
+    }
+
+    public void testPrivate() throws Throwable {
+        super.runTest("UnnecessaryConstructor2.java", 0, new UnnecessaryConstructorRule());
+    }
+
+    public void testHasArgs() throws Throwable {
+        super.runTest("UnnecessaryConstructor3.java", 0, new UnnecessaryConstructorRule());
+    }
+
+    public void testHasBody() throws Throwable {
+        super.runTest("UnnecessaryConstructor4.java", 0, new UnnecessaryConstructorRule());
+    }
+}

pmd/rulesets/newrules.xml

@@ -42,6 +42,22 @@ public class Foo {
     </example>
   </rule>
 
+  <rule name="UnnecessaryConstructorRule"
+        message="Avoid unnecessary constructors - the compiler will generate these for you"
+        class="net.sourceforge.pmd.rules.UnnecessaryConstructorRule">
+    <description>
+Unnecessary constructor detects when a constructor is not necessary; i.e., when there's only one constructor,
+it's public, has an empty body, and takes no arguments.
+    </description>
+    <example>
+<![CDATA[
+public class Foo {
+ public Foo() {}
+}
+]]>
+    </example>
+  </rule>
+
   </ruleset>
 
 

pmd/src/net/sourceforge/pmd/PMD.java

@@ -30,6 +30,7 @@ public class PMD {
         try {
             JavaParser parser = new JavaParser(reader);
             ASTCompilationUnit c = parser.CompilationUnit();
+            Thread.yield();
             //c.dump("");
             SymbolFacade stb = new SymbolFacade();
             stb.initializeWith(c);

pmd/src/net/sourceforge/pmd/ast/ASTConstructorDeclaration.java

@@ -2,7 +2,7 @@
 
 package net.sourceforge.pmd.ast;
 
-public class ASTConstructorDeclaration extends SimpleNode {
+public class ASTConstructorDeclaration extends AccessNode {
   public ASTConstructorDeclaration(int id) {
     super(id);
   }

pmd/src/net/sourceforge/pmd/rules/UnnecessaryConstructorRule.java

@@ -0,0 +1,55 @@
+/*
+ * User: tom
+ * Date: Nov 1, 2002
+ * Time: 8:54:28 AM
+ */
+package net.sourceforge.pmd.rules;
+
+import net.sourceforge.pmd.AbstractRule;
+import net.sourceforge.pmd.RuleContext;
+import net.sourceforge.pmd.ast.*;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class UnnecessaryConstructorRule extends AbstractRule {
+
+    private List constructors;
+
+    public Object visit(ASTCompilationUnit node, Object data) {
+        constructors = new ArrayList();
+        node.findChildrenOfType(ASTConstructorDeclaration.class, constructors);
+
+        // there must be be the only constructor
+        // TODO this gets thrown off by inner classes
+        if (constructors.size() > 1) {
+            return data;
+        }
+
+        return super.visit(node, data);
+    }
+
+    public Object visit(ASTConstructorDeclaration node, Object data) {
+        // must be public
+        AccessNode accessNode = (AccessNode)node;
+        if (!accessNode.isPublic()) {
+            return data;
+        }
+
+        // must have no parameters
+        ASTFormalParameters params = (ASTFormalParameters)accessNode.jjtGetChild(0);
+        if (params.jjtGetNumChildren() > 0) {
+            return data;
+        }
+
+        // the constructor must be empty
+        if (node.jjtGetNumChildren() > 1) {
+            return data;
+        }
+
+        RuleContext ctx = (RuleContext)data;
+        ctx.getReport().addRuleViolation(createRuleViolation(ctx, node.getBeginLine()));
+
+        return data;
+    }
+}

pmd/test-data/UnnecessaryConstructor1.java

@@ -0,0 +1,3 @@
+public class UnnecessaryConstructor1 {
+ public UnnecessaryConstructor1() {}
+}

pmd/test-data/UnnecessaryConstructor2.java

@@ -0,0 +1,3 @@
+public class UnnecessaryConstructor2 {
+ private UnnecessaryConstructor2() {}
+}

pmd/test-data/UnnecessaryConstructor3.java

@@ -0,0 +1,3 @@
+public class UnnecessaryConstructor3 {
+ public UnnecessaryConstructor3(int x) {}
+}

pmd/test-data/UnnecessaryConstructor4.java

@@ -0,0 +1,5 @@
+public class UnnecessaryConstructor4 {
+ public UnnecessaryConstructor4() {  
+  int x = 2;
+ }
+}