Source code

001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2026 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.indentation;
021
022import com.puppycrawl.tools.checkstyle.api.DetailAST;
023import com.puppycrawl.tools.checkstyle.api.TokenTypes;
024import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
025
026/**
027 * Handler for parents of blocks ('if', 'else', 'while', etc).
028 *
029 * <P>
030 * The "block" handler classes use a common superclass BlockParentHandler,
031 * employing the Template Method pattern.
032 * </P>
033 *
034 * <UL>
035 *   <LI>template method to get the lcurly</LI>
036 *   <LI>template method to get the rcurly</LI>
037 *   <LI>if curlies aren't present, then template method to get expressions
038 *       is called</LI>
039 *   <LI>now all the repetitious code which checks for BOL, if curlies are on
040 *       same line, etc. can be collapsed into the superclass</LI>
041 * </UL>
042 *
043 */
044public class BlockParentHandler extends AbstractExpressionHandler {
045
046    /**
047     * Children checked by parent handlers.
048     */
049    private static final int[] CHECKED_CHILDREN = {
050        TokenTypes.VARIABLE_DEF,
051        TokenTypes.EXPR,
052        TokenTypes.ANNOTATION,
053        TokenTypes.OBJBLOCK,
054        TokenTypes.LITERAL_BREAK,
055        TokenTypes.LITERAL_RETURN,
056        TokenTypes.LITERAL_THROW,
057        TokenTypes.LITERAL_CONTINUE,
058        TokenTypes.CTOR_CALL,
059        TokenTypes.SUPER_CTOR_CALL,
060    };
061
062    /**
063     * Construct an instance of this handler with the given indentation check,
064     * name, abstract syntax tree, and parent handler.
065     *
066     * @param indentCheck   the indentation check
067     * @param name          the name of the handler
068     * @param ast           the abstract syntax tree
069     * @param parent        the parent handler
070     * @noinspection WeakerAccess
071     * @noinspectionreason WeakerAccess - we avoid 'protected' when possible
072     */
073    public BlockParentHandler(IndentationCheck indentCheck,
074        String name, DetailAST ast, AbstractExpressionHandler parent) {
075        super(indentCheck, name, ast, parent);
076    }
077
078    /**
079     * Returns array of token types which should be checked among children.
080     *
081     * @return array of token types to check.
082     */
083    protected int[] getCheckedChildren() {
084        return CHECKED_CHILDREN.clone();
085    }
086
087    /**
088     * Get the top level expression being managed by this handler.
089     *
090     * @return the top level expression
091     */
092    protected DetailAST getTopLevelAst() {
093        return getMainAst();
094    }
095
096    /**
097     * Check the indent of the top level token.
098     */
099    protected void checkTopLevelToken() {
100        final DetailAST topLevel = getTopLevelAst();
101
102        if (topLevel != null
103                && !getIndent().isAcceptable(expandedTabsColumnNo(topLevel))
104                && isOnStartOfLine(topLevel)) {
105            logError(topLevel, "", expandedTabsColumnNo(topLevel));
106        }
107    }
108
109    /**
110     * Determines if this block expression has curly braces.
111     *
112     * @return true if curly braces are present, false otherwise
113     */
114    private boolean hasCurlies() {
115        return getLeftCurly() != null && getRightCurly() != null;
116    }
117
118    /**
119     * Get the left curly brace portion of the expression we are handling.
120     *
121     * @return the left curly brace expression
122     */
123    protected DetailAST getLeftCurly() {
124        return getMainAst().findFirstToken(TokenTypes.SLIST);
125    }
126
127    /**
128     * Get the right curly brace portion of the expression we are handling.
129     *
130     * @return the right curly brace expression
131     */
132    protected DetailAST getRightCurly() {
133        final DetailAST slist = getMainAst().findFirstToken(TokenTypes.SLIST);
134        return slist.findFirstToken(TokenTypes.RCURLY);
135    }
136
137    /**
138     * Check the indentation of the left curly brace.
139     */
140    private void checkLeftCurly() {
141        // the lcurly can either be at the correct indentation, or nested
142        // with a previous expression
143        final DetailAST lcurly = getLeftCurly();
144        final int lcurlyPos = expandedTabsColumnNo(lcurly);
145
146        if (!curlyIndent().isAcceptable(lcurlyPos) && isOnStartOfLine(lcurly)) {
147            logError(lcurly, "lcurly", lcurlyPos, curlyIndent());
148        }
149    }
150
151    /**
152     * Get the expected indentation level for the curly braces.
153     *
154     * @return the curly brace indentation level
155     */
156    protected IndentLevel curlyIndent() {
157        final DetailAST lcurly = getLeftCurly();
158        IndentLevel expIndentLevel = new IndentLevel(getIndent(), getBraceAdjustment());
159        if (!isOnStartOfLine(lcurly) || checkIfCodeBlock()) {
160            expIndentLevel = new IndentLevel(getIndent(), 0);
161        }
162        return expIndentLevel;
163    }
164
165    /**
166     * Checks if lcurly is a Code block.
167     *
168     * @return true if lcurly is a code block
169     */
170    private boolean checkIfCodeBlock() {
171        final AbstractExpressionHandler parent = getParent();
172        return getMainAst().getType() == TokenTypes.SLIST
173                && parent instanceof BlockParentHandler
174                && parent.getParent() instanceof BlockParentHandler;
175    }
176
177    /**
178     * Determines if child elements within the expression may be nested.
179     *
180     * @return false
181     */
182    protected boolean canChildrenBeNested() {
183        return false;
184    }
185
186    /**
187     * Check the indentation of the right curly brace.
188     */
189    private void checkRightCurly() {
190        final DetailAST rcurly = getRightCurly();
191        final int rcurlyPos = expandedTabsColumnNo(rcurly);
192
193        if (!curlyIndent().isAcceptable(rcurlyPos)
194                && isOnStartOfLine(rcurly)) {
195            logError(rcurly, "rcurly", rcurlyPos, curlyIndent());
196        }
197    }
198
199    /**
200     * Get the child element that is not a list of statements.
201     *
202     * @return the non-list child element
203     */
204    protected DetailAST getNonListChild() {
205        return getMainAst().findFirstToken(TokenTypes.RPAREN).getNextSibling();
206    }
207
208    /**
209     * Check the indentation level of a child that is not a list of statements.
210     */
211    private void checkNonListChild() {
212        final DetailAST nonList = getNonListChild();
213        if (nonList != null) {
214            final IndentLevel expected = new IndentLevel(getIndent(), getBasicOffset());
215            checkExpressionSubtree(nonList, expected, false, false);
216
217            final DetailAST nonListStartAst = getFirstAstNode(nonList);
218            if (nonList != nonListStartAst) {
219                checkExpressionSubtree(nonListStartAst, expected, false, false);
220            }
221        }
222    }
223
224    /**
225     * Get the child element representing the list of statements.
226     *
227     * @return the statement list child
228     */
229    protected DetailAST getListChild() {
230        return getMainAst().findFirstToken(TokenTypes.SLIST);
231    }
232
233    /**
234     * Get the right parenthesis portion of the expression we are handling.
235     *
236     * @return the right parenthesis expression
237     */
238    private DetailAST getRightParen() {
239        return getMainAst().findFirstToken(TokenTypes.RPAREN);
240    }
241
242    /**
243     * Get the left parenthesis portion of the expression we are handling.
244     *
245     * @return the left parenthesis expression
246     */
247    private DetailAST getLeftParen() {
248        return getMainAst().findFirstToken(TokenTypes.LPAREN);
249    }
250
251    @Override
252    public void checkIndentation() {
253        checkTopLevelToken();
254        // separate to allow for eventual configuration
255        checkLeftParen(getLeftParen());
256        checkRightParen(getLeftParen(), getRightParen());
257        if (hasCurlies()) {
258            checkLeftCurly();
259            checkRightCurly();
260        }
261        final DetailAST listChild = getListChild();
262        if (listChild == null) {
263            checkNonListChild();
264        }
265        else {
266            // NOTE: switch statements usually don't have curlies
267            if (!hasCurlies() || !TokenUtil.areOnSameLine(getLeftCurly(), getRightCurly())) {
268                checkChildren(listChild,
269                        getCheckedChildren(),
270                        getChildrenExpectedIndent(),
271                        true,
272                        canChildrenBeNested());
273            }
274        }
275    }
276
277    /**
278     * Gets indentation level expected for children.
279     *
280     * @return indentation level expected for children
281     */
282    protected IndentLevel getChildrenExpectedIndent() {
283        IndentLevel indentLevel = new IndentLevel(getIndent(), getBasicOffset());
284        // if we have multileveled expected level then we should
285        // try to suggest single level to children using curlies'
286        // levels.
287        if (getIndent().isMultiLevel() && hasCurlies()) {
288            final DetailAST leftCurly = getLeftCurly();
289            if (isOnStartOfLine(leftCurly)) {
290                indentLevel = new IndentLevel(expandedTabsColumnNo(leftCurly)
291                        + getBasicOffset());
292            }
293            else if (isOnStartOfLine(getRightCurly())) {
294                final IndentLevel level = new IndentLevel(curlyIndent(), getBasicOffset());
295                indentLevel = IndentLevel.addAcceptable(level, level.getFirstIndentLevel()
296                        + getLineWrappingIndent());
297            }
298        }
299        if (hasCurlies() && isOnStartOfLine(getLeftCurly())) {
300            indentLevel = IndentLevel.addAcceptable(indentLevel,
301                    curlyIndent().getFirstIndentLevel() + getBasicOffset());
302        }
303        return indentLevel;
304    }
305
306    @Override
307    public IndentLevel getSuggestedChildIndent(AbstractExpressionHandler child) {
308        return getChildrenExpectedIndent();
309    }
310
311    /**
312     * A shortcut for {@code IndentationCheck} property.
313     *
314     * @return value of lineWrappingIndentation property
315     *         of {@code IndentationCheck}
316     */
317    private int getLineWrappingIndent() {
318        return getIndentCheck().getLineWrappingIndentation();
319    }
320
321}