fixed false alarm about unused imports for class array objects (e.g. Vector[].class), reported by Michael Rumpf

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

@@ -797,6 +797,18 @@ class Verifier
     void reportReference(String aType)
     {
         mReferenced.add(aType);
+
+        // we might have multiple levels of inner classes,
+        // all of them have to be marked as referenced
+
+        // as an unwanted side effect we also add package names like
+        // "com", "java", etc., but that probably doesn't hurt
+        // and could be fixed by getting more info using the classloader
+        int lastDot = aType.lastIndexOf('.');
+        while (lastDot != -1) {
+            mReferenced.add(aType.substring(0, lastDot));
+            lastDot = aType.lastIndexOf('.', lastDot - 1);
+        }
     }
 
 
@@ -1434,9 +1446,7 @@ class Verifier
             else if (fromPackage(imp.getText(), mPkgName)) {
                 log(imp.getLineNo(), "Redundant import from the same package.");
             }
-            else if (!imp.getText().endsWith(".*")
-                     && !mReferenced.contains(basename(imp.getText())))
-            {
+            else if (!isReferencedImport(imp)) {
                 log(imp.getLineNo(), "Unused import - " + imp.getText());
             }
             else if (isIllegalImport(imp.getText())) {
@@ -1446,6 +1456,24 @@ class Verifier
         }
     }
 
+    /**
+     * Checks is an import statement is referenced.
+     * @param aImp the import parameter, e.g. "javax.swing.JButton".
+     * @return if aImp is used by one of the entries in mReferenced.
+     */
+    private boolean isReferencedImport(LineText aImp)
+    {
+        if (aImp.getText().endsWith(".*")) {
+            // we should try to figure out the used classes via classloader
+            return true;
+        }
+        String impText = aImp.getText();
+
+        return
+            mReferenced.contains(basename(impText))
+            || mReferenced.contains(impText);
+    }
+
     /**
      * Checks if an import is from a package that must not be used.
      * @param aImportText the argument of the import keyword

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

@@ -181,10 +181,12 @@ builtInType
 identifier
 	:	i1:IDENT
         {
-            ver.reportReference(i1.getText());
             sLastIdentifier = new LineText(i1.getLine(), i1.getColumn(), i1.getText());
         }
         ( DOT^ i2:IDENT {ver.verifyDot(#DOT); sLastIdentifier.appendText("." + i2.getText());} )*
+        {
+            ver.reportReference(sLastIdentifier.getText());
+        }
 	;
 
 identifierStar
@@ -956,9 +958,9 @@ postfixExpression
 	:	primaryExpression // start with a primary
 
 		(	// qualified id (id.id.id.id...) -- build the name
-			DOT^ {ver.verifyDot(#DOT);} ( IDENT {ver.reportReference(sFirstIdent);}
+			DOT^ {ver.verifyDot(#DOT);} ( i1:IDENT {sLastIdentifier.appendText("." + i1.getText()); ver.reportReference(sLastIdentifier.getText());}
 				| "this"
-				| "class" {ver.reportReference(sFirstIdent);}
+				| "class" {ver.reportReference(sLastIdentifier.getText());}
 				| newExpression
 				| "super" // ClassName.super.field
 				)
@@ -966,7 +968,7 @@ postfixExpression
 			// is the _last_ qualifier.
 
 			// allow ClassName[].class
-		|	( lbc:LBRACK^ {#lbc.setType(ARRAY_DECLARATOR);} RBRACK! )+
+		|	( lbc:LBRACK^ {#lbc.setType(ARRAY_DECLARATOR); ver.reportReference(sLastIdentifier.getText());} RBRACK! )+
 			DOT^ "class" {ver.verifyDot(#DOT);}
 
 			// an array indexing operation
@@ -995,7 +997,11 @@ postfixExpression
 
 // the basic element of an expression
 primaryExpression
-	:	i1:IDENT {sFirstIdent = i1.getText();}
+	:	i1:IDENT
+        {
+            sFirstIdent = i1.getText();
+            sLastIdentifier = new LineText(i1.getLine(), i1.getColumn(), i1.getText());
+        }
 	|	constant
 	|	"true"
 	|	"false"

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

@@ -13,10 +13,18 @@ import java.sql.Connection;
 import java.util.List;
 import java.util.List;
 import sun.net.ftpclient.FtpClient;
+import java.util.Iterator;
+import java.util.Enumeration;
+import java.util.Arrays;
+import javax.swing.JToolBar;
+import javax.swing.JToggleButton;
+import javax.swing.ScrollPaneLayout;
+import javax.swing.BorderFactory;
 
 /**
  * Test case for imports
  * @author Oliver Burn
+ * @author lkuehne
  **/
 class InputImport
 {
@@ -25,5 +33,25 @@ class InputImport
     /** ignore **/
     private Class mUse2 = java.io.File.class;
     /** ignore **/
+    private Class mUse3 = Iterator[].class;
+    /** ignore **/
+    private Class mUse4 = java.util.Enumeration[].class;
+    /** usage of illegal import **/
     private FtpClient ftpClient = null;
+
+    /** usage via static method, both normal and fully qualified */
+    {
+        int[] x = {};
+        Arrays.sort(x);
+        Object obj = javax.swing.BorderFactory.createEmptyBorder();
+    }
+
+    /** usage of inner class as type */
+    private JToolBar.Separator mSep = null;
+
+    /** usage of inner class in Constructor */
+    private Object mUse5 = new ScrollPaneLayout.UIRessource();
+
+    /** usage of inner class in constructor, fully qualified */
+    private Object mUse6 = new javax.swing.JToggleButton.ToggleButtonModel();
 }