001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2016 the original author or authors.
004//
005// This library is free software; you can redistribute it and/or
006// modify it under the terms of the GNU Lesser General Public
007// License as published by the Free Software Foundation; either
008// version 2.1 of the License, or (at your option) any later version.
009//
010// This library is distributed in the hope that it will be useful,
011// but WITHOUT ANY WARRANTY; without even the implied warranty of
012// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
013// Lesser General Public License for more details.
014//
015// You should have received a copy of the GNU Lesser General Public
016// License along with this library; if not, write to the Free Software
017// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
018////////////////////////////////////////////////////////////////////////////////
019
020package com.puppycrawl.tools.checkstyle.checks;
021
022import java.util.Set;
023
024import com.google.common.collect.ImmutableSet;
025import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
026import com.puppycrawl.tools.checkstyle.api.DetailAST;
027import com.puppycrawl.tools.checkstyle.api.TokenTypes;
028import com.puppycrawl.tools.checkstyle.utils.CheckUtils;
029import com.puppycrawl.tools.checkstyle.utils.CommonUtils;
030
031/**
032 * Check that method/constructor/catch/foreach parameters are final.
033 * The user can set the token set to METHOD_DEF, CONSTRUCTOR_DEF,
034 * LITERAL_CATCH, FOR_EACH_CLAUSE or any combination of these token
035 * types, to control the scope of this check.
036 * Default scope is both METHOD_DEF and CONSTRUCTOR_DEF.
037 * <p>
038 * Check has an option <b>ignorePrimitiveTypes</b> which allows ignoring lack of
039 * final modifier at
040 * <a href="http://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html">
041 *  primitive data type</a> parameter. Default value <b>false</b>.
042 * </p>
043 * E.g.:
044 * <p>
045 * {@code
046 * private void foo(int x) { ... } //parameter is of primitive type
047 * }
048 * </p>
049 *
050 * @author lkuehne
051 * @author o_sukhodolsky
052 * @author Michael Studman
053 * @author <a href="mailto:nesterenko-aleksey@list.ru">Aleksey Nesterenko</a>
054 */
055public class FinalParametersCheck extends AbstractCheck {
056
057    /**
058     * A key is pointing to the warning message text in "messages.properties"
059     * file.
060     */
061    public static final String MSG_KEY = "final.parameter";
062
063    /**
064     * Contains
065     * <a href="http://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html">
066     * primitive datatypes</a>.
067     */
068    private final Set<Integer> primitiveDataTypes = ImmutableSet.of(
069            TokenTypes.LITERAL_BYTE,
070            TokenTypes.LITERAL_SHORT,
071            TokenTypes.LITERAL_INT,
072            TokenTypes.LITERAL_LONG,
073            TokenTypes.LITERAL_FLOAT,
074            TokenTypes.LITERAL_DOUBLE,
075            TokenTypes.LITERAL_BOOLEAN,
076            TokenTypes.LITERAL_CHAR);
077
078    /**
079     * Option to ignore primitive types as params.
080     */
081    private boolean ignorePrimitiveTypes;
082
083    /**
084     * Sets ignoring primitive types as params.
085     * @param ignorePrimitiveTypes true or false.
086     */
087    public void setIgnorePrimitiveTypes(boolean ignorePrimitiveTypes) {
088        this.ignorePrimitiveTypes = ignorePrimitiveTypes;
089    }
090
091    @Override
092    public int[] getDefaultTokens() {
093        return new int[] {
094            TokenTypes.METHOD_DEF,
095            TokenTypes.CTOR_DEF,
096        };
097    }
098
099    @Override
100    public int[] getAcceptableTokens() {
101        return new int[] {
102            TokenTypes.METHOD_DEF,
103            TokenTypes.CTOR_DEF,
104            TokenTypes.LITERAL_CATCH,
105            TokenTypes.FOR_EACH_CLAUSE,
106        };
107    }
108
109    @Override
110    public int[] getRequiredTokens() {
111        return CommonUtils.EMPTY_INT_ARRAY;
112    }
113
114    @Override
115    public void visitToken(DetailAST ast) {
116        // don't flag interfaces
117        final DetailAST container = ast.getParent().getParent();
118        if (container.getType() != TokenTypes.INTERFACE_DEF) {
119            if (ast.getType() == TokenTypes.LITERAL_CATCH) {
120                visitCatch(ast);
121            }
122            else if (ast.getType() == TokenTypes.FOR_EACH_CLAUSE) {
123                visitForEachClause(ast);
124            }
125            else {
126                visitMethod(ast);
127            }
128        }
129    }
130
131    /**
132     * Checks parameters of the method or ctor.
133     * @param method method or ctor to check.
134     */
135    private void visitMethod(final DetailAST method) {
136        final DetailAST modifiers =
137            method.findFirstToken(TokenTypes.MODIFIERS);
138        // exit on fast lane if there is nothing to check here
139
140        if (method.branchContains(TokenTypes.PARAMETER_DEF)
141                // ignore abstract and native methods
142                && !modifiers.branchContains(TokenTypes.ABSTRACT)
143                && !modifiers.branchContains(TokenTypes.LITERAL_NATIVE)) {
144            // we can now be sure that there is at least one parameter
145            final DetailAST parameters =
146                method.findFirstToken(TokenTypes.PARAMETERS);
147            DetailAST child = parameters.getFirstChild();
148            while (child != null) {
149                // children are PARAMETER_DEF and COMMA
150                if (child.getType() == TokenTypes.PARAMETER_DEF) {
151                    checkParam(child);
152                }
153                child = child.getNextSibling();
154            }
155        }
156    }
157
158    /**
159     * Checks parameter of the catch block.
160     * @param catchClause catch block to check.
161     */
162    private void visitCatch(final DetailAST catchClause) {
163        checkParam(catchClause.findFirstToken(TokenTypes.PARAMETER_DEF));
164    }
165
166    /**
167     * Checks parameter of the for each clause.
168     * @param forEachClause for each clause to check.
169     */
170    private void visitForEachClause(final DetailAST forEachClause) {
171        checkParam(forEachClause.findFirstToken(TokenTypes.VARIABLE_DEF));
172    }
173
174    /**
175     * Checks if the given parameter is final.
176     * @param param parameter to check.
177     */
178    private void checkParam(final DetailAST param) {
179        if (!param.branchContains(TokenTypes.FINAL) && !isIgnoredParam(param)
180                && !CheckUtils.isReceiverParameter(param)) {
181            final DetailAST paramName = param.findFirstToken(TokenTypes.IDENT);
182            final DetailAST firstNode = CheckUtils.getFirstNode(param);
183            log(firstNode.getLineNo(), firstNode.getColumnNo(),
184                MSG_KEY, paramName.getText());
185        }
186    }
187
188    /**
189     * Checks for skip current param due to <b>ignorePrimitiveTypes</b> option.
190     * @param paramDef {@link TokenTypes#PARAMETER_DEF PARAMETER_DEF}
191     * @return true if param has to be skipped.
192     */
193    private boolean isIgnoredParam(DetailAST paramDef) {
194        boolean result = false;
195        if (ignorePrimitiveTypes) {
196            final DetailAST parameterType = paramDef
197                .findFirstToken(TokenTypes.TYPE).getFirstChild();
198            if (primitiveDataTypes.contains(parameterType.getType())) {
199                result = true;
200            }
201        }
202        return result;
203    }
204}