Added SimplifyBooleanExpressionCheck to find code like "if (b == true)".

Also fixed SimplyfyBooleanReturnCheck and introduced tests.

src/checkstyle/com/puppycrawl/tools/checkstyle/checks/SimplifyBooleanExpressionCheck.java

@@ -0,0 +1,54 @@
+package com.puppycrawl.tools.checkstyle.checks;
+
+import com.puppycrawl.tools.checkstyle.api.Check;
+import com.puppycrawl.tools.checkstyle.api.TokenTypes;
+import com.puppycrawl.tools.checkstyle.api.DetailAST;
+
+////////////////////////////////////////////////////////////////////////////////
+// checkstyle: Checks Java source code for adherence to a set of rules.
+// Copyright (C) 2001-2002  Oliver Burn
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+////////////////////////////////////////////////////////////////////////////////
+
+
+public class SimplifyBooleanExpressionCheck
+        extends Check
+{
+    /** @see Check */
+    public int[] getDefaultTokens()
+    {
+        return new int[] {TokenTypes.LITERAL_TRUE, TokenTypes.LITERAL_FALSE};
+    }
+
+    /** @see Check */
+    public void visitToken(DetailAST aAST)
+    {
+        final DetailAST parent = aAST.getParent();
+        switch (parent.getType()) {
+            case TokenTypes.NOT_EQUAL:
+            case TokenTypes.EQUAL:
+            case TokenTypes.LNOT:
+            case TokenTypes.LOR:
+            case TokenTypes.LAND:
+                log(parent.getLineNo(), parent.getColumnNo(),
+                        // TODO: i18n
+                        "Expression can be simplified.");
+                break;
+            default:
+                break;
+        }
+    }
+}

src/checkstyle/com/puppycrawl/tools/checkstyle/checks/SimplifyBooleanReturnCheck.java

@@ -49,19 +49,29 @@ public class SimplifyBooleanReturnCheck
             throw new IllegalArgumentException("not an if");
         }
 
+        // LITERAL_IF has the following four or five children:
+        // '('
+        // condition
+        // ')'
+        // thenstatement
+        // [ LITERAL_ELSE (with the elseStatement as a child) ]
+
         // don't bother if this is not if then else
-        if (aAST.getChildCount() != 3) {
+        if (aAST.getChildCount() != 5) {
             return;
         }
 
-        AST condition = aAST.getFirstChild();
-        AST thenStatement = condition.getNextSibling();
-        AST elseStatement = thenStatement.getNextSibling();
+        // skip '(' and ')'
+        // TODO: Introduce helpers in DetailAST
+        AST condition = aAST.getFirstChild().getNextSibling();
+        AST thenStatement = condition.getNextSibling().getNextSibling();
+        AST elseStatement = thenStatement.getNextSibling().getFirstChild();
 
         if (returnsOnlyBooleanLiteral(thenStatement)
                 && returnsOnlyBooleanLiteral(elseStatement))
         {
-            log(aAST.getLineNo(), "Remove conditional logic.");
+            // TODO: i18n
+            log(aAST.getLineNo(), aAST.getColumnNo(), "Remove conditional logic.");
         }
     }
 

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

@@ -0,0 +1,31 @@
+package com.puppycrawl.tools.checkstyle;
+
+import com.puppycrawl.tools.checkstyle.checks.SimplifyBooleanExpressionCheck;
+
+public class SimplifyBooleanExpressionCheckTest
+extends BaseCheckTestCase
+{
+    public SimplifyBooleanExpressionCheckTest(String aName)
+    {
+        super(aName);
+    }
+
+    public void testIt()
+            throws Exception
+    {
+        final CheckConfiguration checkConfig = new CheckConfiguration();
+        checkConfig.setClassname(SimplifyBooleanExpressionCheck.class.getName());
+        final Checker c = createChecker(checkConfig);
+        final String fname = getPath("InputSimplifyBoolean.java");
+        final String[] expected = {
+            "20:18: Expression can be simplified.",
+            "41:36: Expression can be simplified.",
+            "42:36: Expression can be simplified.",
+            "43:16: Expression can be simplified.",
+            "43:32: Expression can be simplified.",
+            // TODO: Change Check.log to avoid duplicate messages
+            "43:32: Expression can be simplified.",
+        };
+        verify(c, fname, expected);
+    }
+}

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

@@ -0,0 +1,33 @@
+package com.puppycrawl.tools.checkstyle;
+
+import com.puppycrawl.tools.checkstyle.checks.SimplifyBooleanReturnCheck;
+
+/*
+ * Created by IntelliJ IDEA.
+ * User: lk
+ * Date: Oct 21, 2002
+ * Time: 8:59:11 AM
+ * To change this template use Options | File Templates.
+ */
+public class SimplifyBooleanReturnCheckTest
+    extends BaseCheckTestCase
+{
+    public SimplifyBooleanReturnCheckTest(String aName)
+    {
+        super(aName);
+    }
+
+    public void testIt()
+            throws Exception
+    {
+        final CheckConfiguration checkConfig = new CheckConfiguration();
+        checkConfig.setClassname(SimplifyBooleanReturnCheck.class.getName());
+        final Checker c = createChecker(checkConfig);
+        final String fname = getPath("InputSimplifyBoolean.java");
+        final String[] expected = {
+            "20:9: Remove conditional logic.",
+            "33:9: Remove conditional logic.",
+        };
+        verify(c, fname, expected);
+    }
+}