////////////////////////////////////////////////////////////////////////////////
// checkstyle: Checks Java source code for adherence to a set of rules.
// Copyright (C) 2001-2014 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.FileContents;
import com.puppycrawl.tools.checkstyle.api.FullIdent;
import com.puppycrawl.tools.checkstyle.api.TextBlock;
import com.puppycrawl.tools.checkstyle.api.TokenTypes;
import com.puppycrawl.tools.checkstyle.api.Utils;
import com.puppycrawl.tools.checkstyle.checks.javadoc.JavadocTag;
import com.puppycrawl.tools.checkstyle.checks.javadoc.JavadocUtils;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* <p>
* Checks for unused import statements.
* </p>
* <p>
* An example of how to configure the check is:
* </p>
* <pre>
* <module name="UnusedImports"/>
* </pre>
*
* Compatible with Java 1.5 source.
*
* @author Oliver Burn
*/
public class UnusedImportsCheck extends Check
{
/** regex to match class names. */
private static final Pattern CLASS_NAME = Pattern.compile(
"((:?[\\p{L}_$][\\p{L}\\p{N}_$]*\\.)*[\\p{L}_$][\\p{L}\\p{N}_$]*)");
/** regex to match the first class name. */
private static final Pattern FIRST_CLASS_NAME = Pattern.compile(
"^" + CLASS_NAME);
/** regex to match argument names. */
private static final Pattern ARGUMENT_NAME = Pattern.compile(
"[(,]\\s*" + CLASS_NAME.pattern());
/** flag to indicate when time to start collecting references. */
private boolean mCollect;
/** flag whether to process Javadoc comments. */
private boolean mProcessJavadoc;
/** set of the imports. */
private final Set<FullIdent> mImports = Sets.newHashSet();
/** set of references - possibly to imports or other things. */
private final Set<String> mReferenced = Sets.newHashSet();
/** Default constructor. */
public UnusedImportsCheck()
{
}
public void setProcessJavadoc(boolean aValue)
{
mProcessJavadoc = aValue;
}
@Override
public void beginTree(DetailAST aRootAST)
{
mCollect = false;
mImports.clear();
mReferenced.clear();
}
@Override
public void finishTree(DetailAST aRootAST)
{
// loop over all the imports to see if referenced.
for (final FullIdent imp : mImports) {
if (!mReferenced.contains(Utils.baseClassname(imp.getText()))) {
log(imp.getLineNo(),
imp.getColumnNo(),
"import.unused", imp.getText());
}
}
}
@Override
public int[] getDefaultTokens()
{
return new int[] {
TokenTypes.IDENT,
TokenTypes.IMPORT,
TokenTypes.STATIC_IMPORT,
// Definitions that may contain Javadoc...
TokenTypes.PACKAGE_DEF,
TokenTypes.ANNOTATION_DEF,
TokenTypes.ANNOTATION_FIELD_DEF,
TokenTypes.ENUM_DEF,
TokenTypes.ENUM_CONSTANT_DEF,
TokenTypes.CLASS_DEF,
TokenTypes.INTERFACE_DEF,
TokenTypes.METHOD_DEF,
TokenTypes.CTOR_DEF,
TokenTypes.VARIABLE_DEF,
};
}
@Override
public int[] getRequiredTokens()
{
return getDefaultTokens();
}
@Override
public void visitToken(DetailAST aAST)
{
if (aAST.getType() == TokenTypes.IDENT) {
if (mCollect) {
processIdent(aAST);
}
}
else if (aAST.getType() == TokenTypes.IMPORT) {
processImport(aAST);
}
else if (aAST.getType() == TokenTypes.STATIC_IMPORT) {
processStaticImport(aAST);
}
else {
mCollect = true;
if (mProcessJavadoc) {
processJavadoc(aAST);
}
}
}
/**
* Collects references made by IDENT.
* @param aAST the IDENT node to process
*/
private void processIdent(DetailAST aAST)
{
final DetailAST parent = aAST.getParent();
final int parentType = parent.getType();
if (((parentType != TokenTypes.DOT)
&& (parentType != TokenTypes.METHOD_DEF))
|| ((parentType == TokenTypes.DOT)
&& (aAST.getNextSibling() != null)))
{
mReferenced.add(aAST.getText());
}
}
/**
* Collects the details of imports.
* @param aAST node containing the import details
*/
private void processImport(DetailAST aAST)
{
final FullIdent name = FullIdent.createFullIdentBelow(aAST);
if ((name != null) && !name.getText().endsWith(".*")) {
mImports.add(name);
}
}
/**
* Collects the details of static imports.
* @param aAST node containing the static import details
*/
private void processStaticImport(DetailAST aAST)
{
final FullIdent name =
FullIdent.createFullIdent(
aAST.getFirstChild().getNextSibling());
if ((name != null) && !name.getText().endsWith(".*")) {
mImports.add(name);
}
}
/**
* Collects references made in JavaDoc comments.
* @param aAST node to inspect for JavaDoc
*/
private void processJavadoc(DetailAST aAST)
{
final FileContents contents = getFileContents();
final int lineNo = aAST.getLineNo();
final TextBlock cmt = contents.getJavadocBefore(lineNo);
if (cmt != null) {
mReferenced.addAll(processJavadoc(cmt));
}
}
/**
* Process a javadoc {@link TextBlock} and return the set of classes
* referenced within.
* @param aCmt The javadoc block to parse
* @return a set of classes referenced in the javadoc block
*/
private Set<String> processJavadoc(TextBlock aCmt)
{
final Set<String> references = new HashSet<String>();
// process all the @link type tags
// INLINEs inside BLOCKs get hidden when using ALL
for (final JavadocTag tag
: getValidTags(aCmt, JavadocUtils.JavadocTagType.INLINE))
{
if (tag.canReferenceImports()) {
references.addAll(processJavadocTag(tag));
}
}
// process all the @throws type tags
for (final JavadocTag tag
: getValidTags(aCmt, JavadocUtils.JavadocTagType.BLOCK))
{
if (tag.canReferenceImports()) {
references.addAll(
matchPattern(tag.getArg1(), FIRST_CLASS_NAME));
}
}
return references;
}
/**
* Returns the list of valid tags found in a javadoc {@link TextBlock}
* @param aCmt The javadoc block to parse
* @param aTagType The type of tags we're interested in
* @return the list of tags
*/
private List<JavadocTag> getValidTags(TextBlock aCmt,
JavadocUtils.JavadocTagType aTagType)
{
return JavadocUtils.getJavadocTags(aCmt, aTagType).getValidTags();
}
/**
* Returns a list of references found in a javadoc {@link JavadocTag}
* @param aTag The javadoc tag to parse
* @return A list of references found in this tag
*/
private Set<String> processJavadocTag(JavadocTag aTag)
{
final Set<String> references = new HashSet<String>();
final String identifier = aTag.getArg1().trim();
for (Pattern pattern : new Pattern[]
{FIRST_CLASS_NAME, ARGUMENT_NAME})
{
references.addAll(matchPattern(identifier, pattern));
}
return references;
}
/**
* Extracts a list of texts matching a {@link Pattern} from a
* {@link String}.
* @param aIdentifier The String to match the pattern against
* @param aPattern The Pattern used to extract the texts
* @return A list of texts which matched the pattern
*/
private Set<String> matchPattern(String aIdentifier, Pattern aPattern)
{
final Set<String> references = new HashSet<String>();
final Matcher matcher = aPattern.matcher(aIdentifier);
while (matcher.find()) {
references.add(matcher.group(1));
}
return references;
}
}