RedundantImportCheck.java

////////////////////////////////////////////////////////////////////////////////
// checkstyle: Checks Java source code for adherence to a set of rules.
// Copyright (C) 2001-2020 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.HashSet;
import java.util.Set;

import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
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>
 * Checks for redundant import statements. 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}
 *   package, e.g. importing {@code java.lang.String}.</li>
 *   <li>The class non-statically imported is from the same package as the
 *   current package.</li>
 * </ul>
 * <p>
 * To configure the check:
 * </p>
 * <pre>
 * &lt;module name="RedundantImport"/&gt;
 * </pre>
 *
 * @since 3.0
 */
@FileStatefulCheck
public class RedundantImportCheck
    extends AbstractCheck {

    /**
     * A key is pointing to the warning message text in "messages.properties"
     * file.
     */
    public static final String MSG_LANG = "import.lang";

    /**
     * A key is pointing to the warning message text in "messages.properties"
     * file.
     */
    public static final String MSG_SAME = "import.same";

    /**
     * A key is pointing to the warning message text in "messages.properties"
     * file.
     */
    public static final String MSG_DUPLICATE = "import.duplicate";

    /** Set of the imports. */
    private final Set<FullIdent> imports = new HashSet<>();
    /** Set of static imports. */
    private final Set<FullIdent> staticImports = new HashSet<>();

    /** Name of package in file. */
    private String pkgName;

    @Override
    public void beginTree(DetailAST aRootAST) {
        pkgName = null;
        imports.clear();
        staticImports.clear();
    }

    @Override
    public int[] getDefaultTokens() {
        return getRequiredTokens();
    }

    @Override
    public int[] getAcceptableTokens() {
        return getRequiredTokens();
    }

    @Override
    public int[] getRequiredTokens() {
        return new int[] {
            TokenTypes.IMPORT, TokenTypes.STATIC_IMPORT, TokenTypes.PACKAGE_DEF,
        };
    }

    @Override
    public void visitToken(DetailAST ast) {
        if (ast.getType() == TokenTypes.PACKAGE_DEF) {
            pkgName = FullIdent.createFullIdent(
                    ast.getLastChild().getPreviousSibling()).getText();
        }
        else if (ast.getType() == TokenTypes.IMPORT) {
            final FullIdent imp = FullIdent.createFullIdentBelow(ast);
            if (isFromPackage(imp.getText(), "java.lang")) {
                log(ast, MSG_LANG, imp.getText());
            }
            // imports from unnamed package are not allowed,
            // so we are checking SAME rule only for named packages
            else if (pkgName != null && isFromPackage(imp.getText(), pkgName)) {
                log(ast, MSG_SAME, imp.getText());
            }
            // Check for a duplicate import
            imports.stream().filter(full -> imp.getText().equals(full.getText()))
                .forEach(full -> log(ast, MSG_DUPLICATE, full.getLineNo(), imp.getText()));

            imports.add(imp);
        }
        else {
            // Check for a duplicate static import
            final FullIdent imp =
                FullIdent.createFullIdent(
                    ast.getLastChild().getPreviousSibling());
            staticImports.stream().filter(full -> imp.getText().equals(full.getText()))
                .forEach(full -> log(ast, MSG_DUPLICATE, full.getLineNo(), imp.getText()));

            staticImports.add(imp);
        }
    }

    /**
     * Determines if an import statement is for types from a specified package.
     * @param importName the import name
     * @param pkg the package name
     * @return whether from the package
     */
    private static boolean isFromPackage(String importName, String pkg) {
        // imports from unnamed package are not allowed:
        // https://docs.oracle.com/javase/specs/jls/se7/html/jls-7.html#jls-7.5
        // So '.' must be present in member name and we are not checking for it
        final int index = importName.lastIndexOf('.');
        final String front = importName.substring(0, index);
        return front.equals(pkg);
    }

}




















Active mutators

BOOLEAN_FALSE_RETURN
BOOLEAN_TRUE_RETURN
CONDITIONALS_BOUNDARY_MUTATOR
CONSTRUCTOR_CALL_MUTATOR
INCREMENTS_MUTATOR
INVERT_NEGS_MUTATOR
MATH_MUTATOR
NEGATE_CONDITIONALS_MUTATOR
REMOVE_CONDITIONALS_EQUAL_ELSE_MUTATOR
REMOVE_CONDITIONALS_EQUAL_IF_MUTATOR
REMOVE_CONDITIONALS_ORDER_ELSE_MUTATOR
REMOVE_CONDITIONALS_ORDER_IF_MUTATOR
RETURN_VALS_MUTATOR
VOID_METHOD_CALL_MUTATOR

Tests examined

com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testStateIsClearedOnBeginTree1() (52 ms)
com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() (5 ms)
com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testWithChecker() (6 ms)
com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testGetRequiredTokens() (2 ms)
com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testGetAcceptableTokens() (3 ms)

Report generated by PIT 1.4.9

1		////////////////////////////////////////////////////////////////////////////////
2		// checkstyle: Checks Java source code for adherence to a set of rules.
3		// Copyright (C) 2001-2020 the original author or authors.
4		//
5		// This library is free software; you can redistribute it and/or
6		// modify it under the terms of the GNU Lesser General Public
7		// License as published by the Free Software Foundation; either
8		// version 2.1 of the License, or (at your option) any later version.
9		//
10		// This library is distributed in the hope that it will be useful,
11		// but WITHOUT ANY WARRANTY; without even the implied warranty of
12		// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13		// Lesser General Public License for more details.
14		//
15		// You should have received a copy of the GNU Lesser General Public
16		// License along with this library; if not, write to the Free Software
17		// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18		////////////////////////////////////////////////////////////////////////////////
19
20		package com.puppycrawl.tools.checkstyle.checks.imports;
21
22		import java.util.HashSet;
23		import java.util.Set;
24
25		import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
26		import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
27		import com.puppycrawl.tools.checkstyle.api.DetailAST;
28		import com.puppycrawl.tools.checkstyle.api.FullIdent;
29		import com.puppycrawl.tools.checkstyle.api.TokenTypes;
30
31		/**
32		* <p>
33		* Checks for redundant import statements. An import statement is
34		* considered redundant if:
35		* </p>
36		* <ul>
37		* <li>It is a duplicate of another import. This is, when a class is imported
38		* more than once.</li>
39		* <li>The class non-statically imported is from the {@code java.lang}
40		* package, e.g. importing {@code java.lang.String}.</li>
41		* <li>The class non-statically imported is from the same package as the
42		* current package.</li>
43		* </ul>
44		* <p>
45		* To configure the check:
46		* </p>
47		* <pre>
48		* <module name="RedundantImport"/>
49		* </pre>
50		*
51		* @since 3.0
52		*/
53		@FileStatefulCheck
54		public class RedundantImportCheck
55		extends AbstractCheck {
56
57		/**
58		* A key is pointing to the warning message text in "messages.properties"
59		* file.
60		*/
61		public static final String MSG_LANG = "import.lang";
62
63		/**
64		* A key is pointing to the warning message text in "messages.properties"
65		* file.
66		*/
67		public static final String MSG_SAME = "import.same";
68
69		/**
70		* A key is pointing to the warning message text in "messages.properties"
71		* file.
72		*/
73		public static final String MSG_DUPLICATE = "import.duplicate";
74
75		/** Set of the imports. */
76	1 1. : removed call to java/util/HashSet::<init> → KILLED	private final Set<FullIdent> imports = new HashSet<>();
77		/** Set of static imports. */
78	1 1. : removed call to java/util/HashSet::<init> → KILLED	private final Set<FullIdent> staticImports = new HashSet<>();
79
80		/** Name of package in file. */
81		private String pkgName;
82
83		@Override
84		public void beginTree(DetailAST aRootAST) {
85		pkgName = null;
86	1 1. beginTree : removed call to java/util/Set::clear → KILLED	imports.clear();
87	1 1. beginTree : removed call to java/util/Set::clear → KILLED	staticImports.clear();
88		}
89
90		@Override
91		public int[] getDefaultTokens() {
92	1 1. getDefaultTokens : mutated return of Object value for com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::getDefaultTokens to ( if (x != null) null else throw new RuntimeException ) → KILLED	return getRequiredTokens();
93		}
94
95		@Override
96		public int[] getAcceptableTokens() {
97	1 1. getAcceptableTokens : mutated return of Object value for com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::getAcceptableTokens to ( if (x != null) null else throw new RuntimeException ) → KILLED	return getRequiredTokens();
98		}
99
100		@Override
101		public int[] getRequiredTokens() {
102	1 1. getRequiredTokens : mutated return of Object value for com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::getRequiredTokens to ( if (x != null) null else throw new RuntimeException ) → KILLED	return new int[] {
103		TokenTypes.IMPORT, TokenTypes.STATIC_IMPORT, TokenTypes.PACKAGE_DEF,
104		};
105		}
106
107		@Override
108		public void visitToken(DetailAST ast) {
109	3 1. visitToken : negated conditional → KILLED 2. visitToken : removed conditional - replaced equality check with false → KILLED 3. visitToken : removed conditional - replaced equality check with true → KILLED	if (ast.getType() == TokenTypes.PACKAGE_DEF) {
110		pkgName = FullIdent.createFullIdent(
111		ast.getLastChild().getPreviousSibling()).getText();
112		}
113	3 1. visitToken : negated conditional → KILLED 2. visitToken : removed conditional - replaced equality check with false → KILLED 3. visitToken : removed conditional - replaced equality check with true → KILLED	else if (ast.getType() == TokenTypes.IMPORT) {
114		final FullIdent imp = FullIdent.createFullIdentBelow(ast);
115	3 1. visitToken : negated conditional → KILLED 2. visitToken : removed conditional - replaced equality check with false → KILLED 3. visitToken : removed conditional - replaced equality check with true → KILLED	if (isFromPackage(imp.getText(), "java.lang")) {
116	1 1. visitToken : removed call to com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::log → KILLED	log(ast, MSG_LANG, imp.getText());
117		}
118		// imports from unnamed package are not allowed,
119		// so we are checking SAME rule only for named packages
120	6 1. visitToken : removed conditional - replaced equality check with true → SURVIVED 2. visitToken : negated conditional → KILLED 3. visitToken : negated conditional → KILLED 4. visitToken : removed conditional - replaced equality check with false → KILLED 5. visitToken : removed conditional - replaced equality check with false → KILLED 6. visitToken : removed conditional - replaced equality check with true → KILLED	else if (pkgName != null && isFromPackage(imp.getText(), pkgName)) {
121	1 1. visitToken : removed call to com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::log → KILLED	log(ast, MSG_SAME, imp.getText());
122		}
123		// Check for a duplicate import
124	3 1. lambda$visitToken$0 : replaced boolean return with false for com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::lambda$visitToken$0 → KILLED 2. lambda$visitToken$0 : replaced boolean return with true for com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::lambda$visitToken$0 → KILLED 3. lambda$visitToken$0 : replaced return of integer sized value with (x == 0 ? 1 : 0) → KILLED	imports.stream().filter(full -> imp.getText().equals(full.getText()))
125	2 1. lambda$visitToken$1 : removed call to com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::log → KILLED 2. visitToken : removed call to java/util/stream/Stream::forEach → KILLED	.forEach(full -> log(ast, MSG_DUPLICATE, full.getLineNo(), imp.getText()));
126
127		imports.add(imp);
128		}
129		else {
130		// Check for a duplicate static import
131		final FullIdent imp =
132		FullIdent.createFullIdent(
133		ast.getLastChild().getPreviousSibling());
134	3 1. lambda$visitToken$2 : replaced boolean return with false for com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::lambda$visitToken$2 → KILLED 2. lambda$visitToken$2 : replaced boolean return with true for com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::lambda$visitToken$2 → KILLED 3. lambda$visitToken$2 : replaced return of integer sized value with (x == 0 ? 1 : 0) → KILLED	staticImports.stream().filter(full -> imp.getText().equals(full.getText()))
135	2 1. lambda$visitToken$3 : removed call to com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::log → KILLED 2. visitToken : removed call to java/util/stream/Stream::forEach → KILLED	.forEach(full -> log(ast, MSG_DUPLICATE, full.getLineNo(), imp.getText()));
136
137		staticImports.add(imp);
138		}
139		}
140
141		/**
142		* Determines if an import statement is for types from a specified package.
143		* @param importName the import name
144		* @param pkg the package name
145		* @return whether from the package
146		*/
147		private static boolean isFromPackage(String importName, String pkg) {
148		// imports from unnamed package are not allowed:
149		// https://docs.oracle.com/javase/specs/jls/se7/html/jls-7.html#jls-7.5
150		// So '.' must be present in member name and we are not checking for it
151		final int index = importName.lastIndexOf('.');
152		final String front = importName.substring(0, index);
153	3 1. isFromPackage : replaced boolean return with false for com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::isFromPackage → KILLED 2. isFromPackage : replaced boolean return with true for com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::isFromPackage → KILLED 3. isFromPackage : replaced return of integer sized value with (x == 0 ? 1 : 0) → KILLED	return front.equals(pkg);
154		}
155
156		}
		Mutations
76		1.1 Location : Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() removed call to java/util/HashSet::<init> → KILLED
78		1.1 Location : Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() removed call to java/util/HashSet::<init> → KILLED
86		1.1 Location : beginTree Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testStateIsClearedOnBeginTree1() removed call to java/util/Set::clear → KILLED
87		1.1 Location : beginTree Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testStateIsClearedOnBeginTree1() removed call to java/util/Set::clear → KILLED
92		1.1 Location : getDefaultTokens Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() mutated return of Object value for com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::getDefaultTokens to ( if (x != null) null else throw new RuntimeException ) → KILLED
97		1.1 Location : getAcceptableTokens Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testGetAcceptableTokens() mutated return of Object value for com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::getAcceptableTokens to ( if (x != null) null else throw new RuntimeException ) → KILLED
102		1.1 Location : getRequiredTokens Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testGetRequiredTokens() mutated return of Object value for com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::getRequiredTokens to ( if (x != null) null else throw new RuntimeException ) → KILLED
109		1.1 Location : visitToken Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() negated conditional → KILLED 2.2 Location : visitToken Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testWithChecker() removed conditional - replaced equality check with false → KILLED 3.3 Location : visitToken Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() removed conditional - replaced equality check with true → KILLED
113		1.1 Location : visitToken Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() negated conditional → KILLED 2.2 Location : visitToken Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() removed conditional - replaced equality check with false → KILLED 3.3 Location : visitToken Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() removed conditional - replaced equality check with true → KILLED
115		1.1 Location : visitToken Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() negated conditional → KILLED 2.2 Location : visitToken Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() removed conditional - replaced equality check with false → KILLED 3.3 Location : visitToken Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() removed conditional - replaced equality check with true → KILLED
116		1.1 Location : visitToken Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() removed call to com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::log → KILLED
120		1.1 Location : visitToken Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testWithChecker() negated conditional → KILLED 2.2 Location : visitToken Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testWithChecker() negated conditional → KILLED 3.3 Location : visitToken Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testWithChecker() removed conditional - replaced equality check with false → KILLED 4.4 Location : visitToken Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testWithChecker() removed conditional - replaced equality check with false → KILLED 5.5 Location : visitToken Killed by : none removed conditional - replaced equality check with true → SURVIVED 6.6 Location : visitToken Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testWithChecker() removed conditional - replaced equality check with true → KILLED
121		1.1 Location : visitToken Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testWithChecker() removed call to com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::log → KILLED
124		1.1 Location : lambda$visitToken$0 Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() replaced boolean return with false for com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::lambda$visitToken$0 → KILLED 2.2 Location : lambda$visitToken$0 Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() replaced boolean return with true for com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::lambda$visitToken$0 → KILLED 3.3 Location : lambda$visitToken$0 Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() replaced return of integer sized value with (x == 0 ? 1 : 0) → KILLED
125		1.1 Location : lambda$visitToken$1 Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() removed call to com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::log → KILLED 2.2 Location : visitToken Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() removed call to java/util/stream/Stream::forEach → KILLED
134		1.1 Location : lambda$visitToken$2 Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testWithChecker() replaced boolean return with false for com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::lambda$visitToken$2 → KILLED 2.2 Location : lambda$visitToken$2 Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testWithChecker() replaced boolean return with true for com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::lambda$visitToken$2 → KILLED 3.3 Location : lambda$visitToken$2 Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testWithChecker() replaced return of integer sized value with (x == 0 ? 1 : 0) → KILLED
135		1.1 Location : lambda$visitToken$3 Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testWithChecker() removed call to com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::log → KILLED 2.2 Location : visitToken Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testWithChecker() removed call to java/util/stream/Stream::forEach → KILLED
153		1.1 Location : isFromPackage Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() replaced boolean return with false for com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::isFromPackage → KILLED 2.2 Location : isFromPackage Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() replaced boolean return with true for com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheck::isFromPackage → KILLED 3.3 Location : isFromPackage Killed by : com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheckTest.testUnnamedPackage() replaced return of integer sized value with (x == 0 ? 1 : 0) → KILLED

RedundantImportCheck.java

Mutations

Active mutators

Tests examined