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