////////////////////////////////////////////////////////////////////////////////
// checkstyle: Checks Java source code for adherence to a set of rules.
// Copyright (C) 2001-2008 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
////////////////////////////////////////////////////////////////////////////////
package com.puppycrawl.tools.checkstyle.checks.imports;
import com.google.common.collect.Sets;
import com.puppycrawl.tools.checkstyle.api.Check;
import com.puppycrawl.tools.checkstyle.api.DetailAST;
import com.puppycrawl.tools.checkstyle.api.FullIdent;
import com.puppycrawl.tools.checkstyle.api.TokenTypes;
import java.util.Set;
/**
* <p>
* Checks for imports that are redundant. An import statement is
* considered redundant if:
* </p>
*<ul>
* <li>It is a duplicate of another import. This is, when a class is imported
* more than once.</li>
* <li>The class non-statically imported is from the <code>java.lang</code>
* package. For example importing <code>java.lang.String</code>.</li>
* <li>The class non-statically imported is from the same package as the
* current package.</li>
*</ul>
* <p>
* An example of how to configure the check is:
* </p>
* <pre>
* <module name="RedundantImport"/>
* </pre>
*
* Compatible with Java 1.5 source.
*
* @author Oliver Burn
* @version 1.0
*/
public class RedundantImportCheck
extends Check
{
/** name of package in file */
private String mPkgName;
/** set of the imports */
private final Set<FullIdent> mImports = Sets.newHashSet();
/** set of static imports */
private final Set<FullIdent> mStaticImports = Sets.newHashSet();
@Override
public void beginTree(DetailAST aRootAST)
{
mPkgName = null;
mImports.clear();
mStaticImports.clear();
}
@Override
public int[] getDefaultTokens()
{
return new int[]
{TokenTypes.IMPORT,
TokenTypes.STATIC_IMPORT,
TokenTypes.PACKAGE_DEF, };
}
@Override
public void visitToken(DetailAST aAST)
{
if (aAST.getType() == TokenTypes.PACKAGE_DEF) {
mPkgName = FullIdent.createFullIdent(
aAST.getLastChild().getPreviousSibling()).getText();
}
else if (aAST.getType() == TokenTypes.IMPORT) {
final FullIdent imp = FullIdent.createFullIdentBelow(aAST);
if (fromPackage(imp.getText(), "java.lang")) {
log(aAST.getLineNo(), aAST.getColumnNo(), "import.lang",
imp.getText());
}
else if (fromPackage(imp.getText(), mPkgName)) {
log(aAST.getLineNo(), aAST.getColumnNo(), "import.same",
imp.getText());
}
// Check for a duplicate import
for (FullIdent full : mImports) {
if (imp.getText().equals(full.getText())) {
log(aAST.getLineNo(), aAST.getColumnNo(),
"import.duplicate", full.getLineNo(),
imp.getText());
}
}
mImports.add(imp);
}
else {
// Check for a duplicate static import
final FullIdent imp =
FullIdent.createFullIdent(
aAST.getLastChild().getPreviousSibling());
for (FullIdent full : mStaticImports) {
if (imp.getText().equals(full.getText())) {
log(aAST.getLineNo(), aAST.getColumnNo(),
"import.duplicate", full.getLineNo(), imp.getText());
}
}
mStaticImports.add(imp);
}
}
/**
* Determines if an import statement is for types from a specified package.
* @param aImport the import name
* @param aPkg the package name
* @return whether from the package
*/
private static boolean fromPackage(String aImport, String aPkg)
{
boolean retVal = false;
if (aPkg == null) {
// If not package, then check for no package in the import.
retVal = (aImport.indexOf('.') == -1);
}
else {
final int index = aImport.lastIndexOf('.');
if (index != -1) {
final String front = aImport.substring(0, index);
retVal = front.equals(aPkg);
}
}
return retVal;
}
}