Source code

001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2018 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.blocks;
021
022import java.util.Locale;
023
024import com.puppycrawl.tools.checkstyle.StatelessCheck;
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.CommonUtils;
029
030/**
031 * <p>
032 * Checks the placement of left curly braces on types, methods and
033 * other blocks:
034 *  {@link TokenTypes#LITERAL_CATCH LITERAL_CATCH},  {@link
035 * TokenTypes#LITERAL_DO LITERAL_DO},  {@link TokenTypes#LITERAL_ELSE
036 * LITERAL_ELSE},  {@link TokenTypes#LITERAL_FINALLY LITERAL_FINALLY},  {@link
037 * TokenTypes#LITERAL_FOR LITERAL_FOR},  {@link TokenTypes#LITERAL_IF
038 * LITERAL_IF},  {@link TokenTypes#LITERAL_SWITCH LITERAL_SWITCH},  {@link
039 * TokenTypes#LITERAL_SYNCHRONIZED LITERAL_SYNCHRONIZED},  {@link
040 * TokenTypes#LITERAL_TRY LITERAL_TRY},  {@link TokenTypes#LITERAL_WHILE
041 * LITERAL_WHILE},  {@link TokenTypes#STATIC_INIT STATIC_INIT},
042 * {@link TokenTypes#LAMBDA LAMBDA}.
043 * </p>
044 *
045 * <p>
046 * The policy to verify is specified using the {@link LeftCurlyOption} class and
047 * defaults to {@link LeftCurlyOption#EOL}.
048 * </p>
049 * <p>
050 * An example of how to configure the check is:
051 * </p>
052 * <pre>
053 * &lt;module name="LeftCurly"/&gt;
054 * </pre>
055 * <p>
056 * An example of how to configure the check with policy
057 * {@link LeftCurlyOption#NLOW} is:
058 * </p>
059 * <pre>
060 * &lt;module name="LeftCurly"&gt;
061 *      &lt;property name="option" value="nlow"/&gt;
062 * &lt;/module&gt;
063 * </pre>
064 * <p>
065 * An example of how to configure the check to validate enum definitions:
066 * </p>
067 * <pre>
068 * &lt;module name="LeftCurly"&gt;
069 *      &lt;property name="ignoreEnums" value="false"/&gt;
070 * &lt;/module&gt;
071 * </pre>
072 *
073 * @author Oliver Burn
074 * @author lkuehne
075 * @author maxvetrenko
076 */
077@StatelessCheck
078public class LeftCurlyCheck
079    extends AbstractCheck {
080
081    /**
082     * A key is pointing to the warning message text in "messages.properties"
083     * file.
084     */
085    public static final String MSG_KEY_LINE_NEW = "line.new";
086
087    /**
088     * A key is pointing to the warning message text in "messages.properties"
089     * file.
090     */
091    public static final String MSG_KEY_LINE_PREVIOUS = "line.previous";
092
093    /**
094     * A key is pointing to the warning message text in "messages.properties"
095     * file.
096     */
097    public static final String MSG_KEY_LINE_BREAK_AFTER = "line.break.after";
098
099    /** Open curly brace literal. */
100    private static final String OPEN_CURLY_BRACE = "{";
101
102    /** If true, Check will ignore enums. */
103    private boolean ignoreEnums = true;
104
105    /** The policy to enforce. */
106    private LeftCurlyOption option = LeftCurlyOption.EOL;
107
108    /**
109     * Set the option to enforce.
110     * @param optionStr string to decode option from
111     * @throws IllegalArgumentException if unable to decode
112     */
113    public void setOption(String optionStr) {
114        try {
115            option = LeftCurlyOption.valueOf(optionStr.trim().toUpperCase(Locale.ENGLISH));
116        }
117        catch (IllegalArgumentException iae) {
118            throw new IllegalArgumentException("unable to parse " + optionStr, iae);
119        }
120    }
121
122    /**
123     * Sets whether check should ignore enums when left curly brace policy is EOL.
124     * @param ignoreEnums check's option for ignoring enums.
125     */
126    public void setIgnoreEnums(boolean ignoreEnums) {
127        this.ignoreEnums = ignoreEnums;
128    }
129
130    @Override
131    public int[] getDefaultTokens() {
132        return getAcceptableTokens();
133    }
134
135    @Override
136    public int[] getAcceptableTokens() {
137        return new int[] {
138            TokenTypes.INTERFACE_DEF,
139            TokenTypes.CLASS_DEF,
140            TokenTypes.ANNOTATION_DEF,
141            TokenTypes.ENUM_DEF,
142            TokenTypes.CTOR_DEF,
143            TokenTypes.METHOD_DEF,
144            TokenTypes.ENUM_CONSTANT_DEF,
145            TokenTypes.LITERAL_WHILE,
146            TokenTypes.LITERAL_TRY,
147            TokenTypes.LITERAL_CATCH,
148            TokenTypes.LITERAL_FINALLY,
149            TokenTypes.LITERAL_SYNCHRONIZED,
150            TokenTypes.LITERAL_SWITCH,
151            TokenTypes.LITERAL_DO,
152            TokenTypes.LITERAL_IF,
153            TokenTypes.LITERAL_ELSE,
154            TokenTypes.LITERAL_FOR,
155            TokenTypes.STATIC_INIT,
156            TokenTypes.OBJBLOCK,
157            TokenTypes.LAMBDA,
158        };
159    }
160
161    @Override
162    public int[] getRequiredTokens() {
163        return CommonUtils.EMPTY_INT_ARRAY;
164    }
165
166    @Override
167    public void visitToken(DetailAST ast) {
168        final DetailAST startToken;
169        DetailAST brace;
170
171        switch (ast.getType()) {
172            case TokenTypes.CTOR_DEF:
173            case TokenTypes.METHOD_DEF:
174                startToken = skipAnnotationOnlyLines(ast);
175                brace = ast.findFirstToken(TokenTypes.SLIST);
176                break;
177            case TokenTypes.INTERFACE_DEF:
178            case TokenTypes.CLASS_DEF:
179            case TokenTypes.ANNOTATION_DEF:
180            case TokenTypes.ENUM_DEF:
181            case TokenTypes.ENUM_CONSTANT_DEF:
182                startToken = skipAnnotationOnlyLines(ast);
183                final DetailAST objBlock = ast.findFirstToken(TokenTypes.OBJBLOCK);
184                brace = objBlock;
185
186                if (objBlock != null) {
187                    brace = objBlock.getFirstChild();
188                }
189                break;
190            case TokenTypes.LITERAL_WHILE:
191            case TokenTypes.LITERAL_CATCH:
192            case TokenTypes.LITERAL_SYNCHRONIZED:
193            case TokenTypes.LITERAL_FOR:
194            case TokenTypes.LITERAL_TRY:
195            case TokenTypes.LITERAL_FINALLY:
196            case TokenTypes.LITERAL_DO:
197            case TokenTypes.LITERAL_IF:
198            case TokenTypes.STATIC_INIT:
199            case TokenTypes.LAMBDA:
200                startToken = ast;
201                brace = ast.findFirstToken(TokenTypes.SLIST);
202                break;
203            case TokenTypes.LITERAL_ELSE:
204                startToken = ast;
205                final DetailAST candidate = ast.getFirstChild();
206                brace = null;
207
208                if (candidate.getType() == TokenTypes.SLIST) {
209                    brace = candidate;
210                }
211                break;
212            default:
213                // ATTENTION! We have default here, but we expect case TokenTypes.METHOD_DEF,
214                // TokenTypes.LITERAL_FOR, TokenTypes.LITERAL_WHILE, TokenTypes.LITERAL_DO only.
215                // It has been done to improve coverage to 100%. I couldn't replace it with
216                // if-else-if block because code was ugly and didn't pass pmd check.
217
218                startToken = ast;
219                brace = ast.findFirstToken(TokenTypes.LCURLY);
220                break;
221        }
222
223        if (brace != null) {
224            verifyBrace(brace, startToken);
225        }
226    }
227
228    /**
229     * Skip lines that only contain {@code TokenTypes.ANNOTATION}s.
230     * If the received {@code DetailAST}
231     * has annotations within its modifiers then first token on the line
232     * of the first token after all annotations is return. This might be
233     * an annotation.
234     * Otherwise, the received {@code DetailAST} is returned.
235     * @param ast {@code DetailAST}.
236     * @return {@code DetailAST}.
237     */
238    private static DetailAST skipAnnotationOnlyLines(DetailAST ast) {
239        DetailAST resultNode = ast;
240        final DetailAST modifiers = ast.findFirstToken(TokenTypes.MODIFIERS);
241
242        if (modifiers != null) {
243            final DetailAST lastAnnotation = findLastAnnotation(modifiers);
244
245            if (lastAnnotation != null) {
246                final DetailAST tokenAfterLast;
247
248                if (lastAnnotation.getNextSibling() == null) {
249                    tokenAfterLast = modifiers.getNextSibling();
250                }
251                else {
252                    tokenAfterLast = lastAnnotation.getNextSibling();
253                }
254
255                if (tokenAfterLast.getLineNo() > lastAnnotation.getLineNo()) {
256                    resultNode = tokenAfterLast;
257                }
258                else {
259                    resultNode = getFirstAnnotationOnSameLine(lastAnnotation);
260                }
261            }
262        }
263        return resultNode;
264    }
265
266    /**
267     * Returns first annotation on same line.
268     * @param annotation
269     *            last annotation on the line
270     * @return first annotation on same line.
271     */
272    private static DetailAST getFirstAnnotationOnSameLine(DetailAST annotation) {
273        DetailAST previousAnnotation = annotation;
274        final int lastAnnotationLineNumber = previousAnnotation.getLineNo();
275        while (previousAnnotation.getPreviousSibling() != null
276                && previousAnnotation.getPreviousSibling().getLineNo()
277                    == lastAnnotationLineNumber) {
278            previousAnnotation = previousAnnotation.getPreviousSibling();
279        }
280        return previousAnnotation;
281    }
282
283    /**
284     * Find the last token of type {@code TokenTypes.ANNOTATION}
285     * under the given set of modifiers.
286     * @param modifiers {@code DetailAST}.
287     * @return {@code DetailAST} or null if there are no annotations.
288     */
289    private static DetailAST findLastAnnotation(DetailAST modifiers) {
290        DetailAST annotation = modifiers.findFirstToken(TokenTypes.ANNOTATION);
291        while (annotation != null && annotation.getNextSibling() != null
292               && annotation.getNextSibling().getType() == TokenTypes.ANNOTATION) {
293            annotation = annotation.getNextSibling();
294        }
295        return annotation;
296    }
297
298    /**
299     * Verifies that a specified left curly brace is placed correctly
300     * according to policy.
301     * @param brace token for left curly brace
302     * @param startToken token for start of expression
303     */
304    private void verifyBrace(final DetailAST brace,
305                             final DetailAST startToken) {
306        final String braceLine = getLine(brace.getLineNo() - 1);
307
308        // Check for being told to ignore, or have '{}' which is a special case
309        if (braceLine.length() <= brace.getColumnNo() + 1
310                || braceLine.charAt(brace.getColumnNo() + 1) != '}') {
311            if (option == LeftCurlyOption.NL) {
312                if (!CommonUtils.hasWhitespaceBefore(brace.getColumnNo(), braceLine)) {
313                    log(brace, MSG_KEY_LINE_NEW, OPEN_CURLY_BRACE, brace.getColumnNo() + 1);
314                }
315            }
316            else if (option == LeftCurlyOption.EOL) {
317                validateEol(brace, braceLine);
318            }
319            else if (startToken.getLineNo() != brace.getLineNo()) {
320                validateNewLinePosition(brace, startToken, braceLine);
321            }
322        }
323    }
324
325    /**
326     * Validate EOL case.
327     * @param brace brace AST
328     * @param braceLine line content
329     */
330    private void validateEol(DetailAST brace, String braceLine) {
331        if (CommonUtils.hasWhitespaceBefore(brace.getColumnNo(), braceLine)) {
332            log(brace, MSG_KEY_LINE_PREVIOUS, OPEN_CURLY_BRACE, brace.getColumnNo() + 1);
333        }
334        if (!hasLineBreakAfter(brace)) {
335            log(brace, MSG_KEY_LINE_BREAK_AFTER, OPEN_CURLY_BRACE, brace.getColumnNo() + 1);
336        }
337    }
338
339    /**
340     * Validate token on new Line position.
341     * @param brace brace AST
342     * @param startToken start Token
343     * @param braceLine content of line with Brace
344     */
345    private void validateNewLinePosition(DetailAST brace, DetailAST startToken, String braceLine) {
346        // not on the same line
347        if (startToken.getLineNo() + 1 == brace.getLineNo()) {
348            if (CommonUtils.hasWhitespaceBefore(brace.getColumnNo(), braceLine)) {
349                log(brace, MSG_KEY_LINE_PREVIOUS, OPEN_CURLY_BRACE, brace.getColumnNo() + 1);
350            }
351            else {
352                log(brace, MSG_KEY_LINE_NEW, OPEN_CURLY_BRACE, brace.getColumnNo() + 1);
353            }
354        }
355        else if (!CommonUtils.hasWhitespaceBefore(brace.getColumnNo(), braceLine)) {
356            log(brace, MSG_KEY_LINE_NEW, OPEN_CURLY_BRACE, brace.getColumnNo() + 1);
357        }
358    }
359
360    /**
361     * Checks if left curly has line break after.
362     * @param leftCurly
363     *        Left curly token.
364     * @return
365     *        True, left curly has line break after.
366     */
367    private boolean hasLineBreakAfter(DetailAST leftCurly) {
368        DetailAST nextToken = null;
369        if (leftCurly.getType() == TokenTypes.SLIST) {
370            nextToken = leftCurly.getFirstChild();
371        }
372        else {
373            if (!ignoreEnums
374                    && leftCurly.getParent().getParent().getType() == TokenTypes.ENUM_DEF) {
375                nextToken = leftCurly.getNextSibling();
376            }
377        }
378        return nextToken == null
379                || nextToken.getType() == TokenTypes.RCURLY
380                || leftCurly.getLineNo() != nextToken.getLineNo();
381    }
382
383}