////////////////////////////////////////////////////////////////////////////////
// checkstyle: Checks Java source code for adherence to a set of rules.
// Copyright (C) 2001-2017 the original author or authors.
//
// 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 java.util.ArrayList;
import java.util.List;
import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
import com.puppycrawl.tools.checkstyle.api.DetailAST;
import com.puppycrawl.tools.checkstyle.api.FullIdent;
import com.puppycrawl.tools.checkstyle.api.TokenTypes;
/**
* <p>
* Check that finds import statements that use the * notation.
* </p>
* <p>
* Rationale: Importing all classes from a package or static
* members from a class leads to tight coupling between packages
* or classes and might lead to problems when a new version of a
* library introduces name clashes.
* </p>
* <p>
* An example of how to configure the check is:
* </p>
* <pre>
* <module name="AvoidStarImport">
* <property name="excludes" value="java.io,java.net,java.lang.Math"/>
* <property name="allowClassImports" value="false"/>
* <property name="allowStaticMemberImports" value="false"/>
* </module>
* </pre>
* The optional "excludes" property allows for certain packages like
* java.io or java.net to be exempted from the rule. It also is used to
* allow certain classes like java.lang.Math or java.io.File to be
* excluded in order to support static member imports.
*
* <p>The optional "allowClassImports" when set to true, will allow starred
* class imports but will not affect static member imports.
*
* <p>The optional "allowStaticMemberImports" when set to true will allow
* starred static member imports but will not affect class imports.
*
* @author Oliver Burn
* @author <a href="bschneider@vecna.com">Bill Schneider</a>
* @author Travis Schneeberger
*/
public class AvoidStarImportCheck
extends AbstractCheck {
/**
* A key is pointing to the warning message text in "messages.properties"
* file.
*/
public static final String MSG_KEY = "import.avoidStar";
/** Suffix for the star import. */
private static final String STAR_IMPORT_SUFFIX = ".*";
/** The packages/classes to exempt from this check. */
private final List<String> excludes = new ArrayList<>();
/** Whether to allow all class imports. */
private boolean allowClassImports;
/** Whether to allow all static member imports. */
private boolean allowStaticMemberImports;
@Override
public int[] getDefaultTokens() {
return new int[] {TokenTypes.IMPORT, TokenTypes.STATIC_IMPORT};
}
@Override
public int[] getAcceptableTokens() {
return new int[] {TokenTypes.IMPORT, TokenTypes.STATIC_IMPORT};
}
@Override
public int[] getRequiredTokens() {
// original implementation checks both IMPORT and STATIC_IMPORT tokens to avoid ".*" imports
// however user can allow using "import" or "import static"
// by configuring allowClassImports and allowStaticMemberImports
// To avoid potential confusion when user specifies conflicting options on configuration
// (see example below) we are adding both tokens to Required list
// <module name="AvoidStarImport">
// <property name="tokens" value="IMPORT"/>
// <property name="allowStaticMemberImports" value="false"/>
// </module>
return new int[] {TokenTypes.IMPORT, TokenTypes.STATIC_IMPORT};
}
/**
* Sets the list of packages or classes to be exempt from the check.
* The excludes can contain a .* or not.
* @param excludesParam a list of package names/fully-qualifies class names
* where star imports are ok.
*/
public void setExcludes(String... excludesParam) {
excludes.clear();
for (final String exclude : excludesParam) {
if (exclude.endsWith(STAR_IMPORT_SUFFIX)) {
excludes.add(exclude);
}
else {
excludes.add(exclude + STAR_IMPORT_SUFFIX);
}
}
}
/**
* Sets whether or not to allow all non-static class imports.
* @param allow true to allow false to disallow
*/
public void setAllowClassImports(boolean allow) {
allowClassImports = allow;
}
/**
* Sets whether or not to allow all static member imports.
* @param allow true to allow false to disallow
*/
public void setAllowStaticMemberImports(boolean allow) {
allowStaticMemberImports = allow;
}
@Override
public void visitToken(final DetailAST ast) {
if (!allowClassImports && ast.getType() == TokenTypes.IMPORT) {
final DetailAST startingDot = ast.getFirstChild();
logsStarredImportViolation(startingDot);
}
else if (!allowStaticMemberImports
&& ast.getType() == TokenTypes.STATIC_IMPORT) {
// must navigate past the static keyword
final DetailAST startingDot = ast.getFirstChild().getNextSibling();
logsStarredImportViolation(startingDot);
}
}
/**
* Gets the full import identifier. If the import is a starred import and
* it's not excluded then a violation is logged.
* @param startingDot the starting dot for the import statement
*/
private void logsStarredImportViolation(DetailAST startingDot) {
final FullIdent name = FullIdent.createFullIdent(startingDot);
final String importText = name.getText();
if (importText.endsWith(STAR_IMPORT_SUFFIX) && !excludes.contains(importText)) {
log(startingDot.getLineNo(), MSG_KEY, importText);
}
}
}