Source code

001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2017 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     * Children checked by parent handlers.
047     */
048    private static final int[] CHECKED_CHILDREN = {
049        TokenTypes.VARIABLE_DEF,
050        TokenTypes.EXPR,
051        TokenTypes.OBJBLOCK,
052        TokenTypes.LITERAL_BREAK,
053        TokenTypes.LITERAL_RETURN,
054        TokenTypes.LITERAL_THROW,
055        TokenTypes.LITERAL_CONTINUE,
056    };
057
058    /**
059     * Construct an instance of this handler with the given indentation check,
060     * name, abstract syntax tree, and parent handler.
061     *
062     * @param indentCheck   the indentation check
063     * @param name          the name of the handler
064     * @param ast           the abstract syntax tree
065     * @param parent        the parent handler
066     */
067    public BlockParentHandler(IndentationCheck indentCheck,
068        String name, DetailAST ast, AbstractExpressionHandler parent) {
069        super(indentCheck, name, ast, parent);
070    }
071
072    /**
073     * Returns array of token types which should be checked among children.
074     * @return array of token types to check.
075     */
076    protected int[] getCheckedChildren() {
077        return CHECKED_CHILDREN.clone();
078    }
079
080    /**
081     * Get the top level expression being managed by this handler.
082     *
083     * @return the top level expression
084     */
085    protected DetailAST getTopLevelAst() {
086        return getMainAst();
087    }
088
089    /**
090     * Check the indent of the top level token.
091     */
092    protected void checkTopLevelToken() {
093        final DetailAST topLevel = getTopLevelAst();
094
095        if (topLevel != null
096                && !getIndent().isAcceptable(expandedTabsColumnNo(topLevel))
097                && !hasLabelBefore()
098                && (shouldTopLevelStartLine() || isOnStartOfLine(topLevel))) {
099            logError(topLevel, "", expandedTabsColumnNo(topLevel));
100        }
101    }
102
103    /**
104     * Check if the top level token has label before.
105     * @return true if the top level token has label before.
106     */
107    protected boolean hasLabelBefore() {
108        final DetailAST parent = getTopLevelAst().getParent();
109        return parent.getType() == TokenTypes.LABELED_STAT
110            && parent.getLineNo() == getTopLevelAst().getLineNo();
111    }
112
113    /**
114     * Determines if the top level token must start the line.
115     *
116     * @return true
117     */
118    protected boolean shouldTopLevelStartLine() {
119        return true;
120    }
121
122    /**
123     * Determines if this block expression has curly braces.
124     *
125     * @return true if curly braces are present, false otherwise
126     */
127    protected boolean hasCurlies() {
128        return getLeftCurly() != null && getRightCurly() != null;
129    }
130
131    /**
132     * Get the left curly brace portion of the expression we are handling.
133     *
134     * @return the left curly brace expression
135     */
136    protected DetailAST getLeftCurly() {
137        return getMainAst().findFirstToken(TokenTypes.SLIST);
138    }
139
140    /**
141     * Get the right curly brace portion of the expression we are handling.
142     *
143     * @return the right curly brace expression
144     */
145    protected DetailAST getRightCurly() {
146        final DetailAST slist = getMainAst().findFirstToken(TokenTypes.SLIST);
147        return slist.findFirstToken(TokenTypes.RCURLY);
148    }
149
150    /**
151     * Check the indentation of the left curly brace.
152     */
153    protected void checkLeftCurly() {
154        // the lcurly can either be at the correct indentation, or nested
155        // with a previous expression
156        final DetailAST lcurly = getLeftCurly();
157        final int lcurlyPos = expandedTabsColumnNo(lcurly);
158
159        if (!curlyIndent().isAcceptable(lcurlyPos) && isOnStartOfLine(lcurly)) {
160            logError(lcurly, "lcurly", lcurlyPos, curlyIndent());
161        }
162    }
163
164    /**
165     * Get the expected indentation level for the curly braces.
166     *
167     * @return the curly brace indentation level
168     */
169    protected IndentLevel curlyIndent() {
170        return new IndentLevel(getIndent(), getBraceAdjustment());
171    }
172
173    /**
174     * Determines if child elements within the expression may be nested.
175     *
176     * @return false
177     */
178    protected boolean canChildrenBeNested() {
179        return false;
180    }
181
182    /**
183     * Check the indentation of the right curly brace.
184     */
185    protected void checkRightCurly() {
186        final DetailAST rcurly = getRightCurly();
187        final int rcurlyPos = expandedTabsColumnNo(rcurly);
188
189        if (!curlyIndent().isAcceptable(rcurlyPos)
190                && isOnStartOfLine(rcurly)) {
191            logError(rcurly, "rcurly", rcurlyPos, curlyIndent());
192        }
193    }
194
195    /**
196     * Get the child element that is not a list of statements.
197     *
198     * @return the non-list child element
199     */
200    protected DetailAST getNonListChild() {
201        return getMainAst().findFirstToken(TokenTypes.RPAREN).getNextSibling();
202    }
203
204    /**
205     * Check the indentation level of a child that is not a list of statements.
206     */
207    private void checkNonListChild() {
208        final DetailAST nonList = getNonListChild();
209        if (nonList != null) {
210            final IndentLevel expected = new IndentLevel(getIndent(), getBasicOffset());
211            checkExpressionSubtree(nonList, expected, false, false);
212        }
213    }
214
215    /**
216     * Get the child element representing the list of statements.
217     *
218     * @return the statement list child
219     */
220    protected DetailAST getListChild() {
221        return getMainAst().findFirstToken(TokenTypes.SLIST);
222    }
223
224    /**
225     * Get the right parenthesis portion of the expression we are handling.
226     *
227     * @return the right parenthesis expression
228     */
229    protected DetailAST getRightParen() {
230        return getMainAst().findFirstToken(TokenTypes.RPAREN);
231    }
232
233    /**
234     * Get the left parenthesis portion of the expression we are handling.
235     *
236     * @return the left parenthesis expression
237     */
238    protected DetailAST getLeftParen() {
239        return getMainAst().findFirstToken(TokenTypes.LPAREN);
240    }
241
242    @Override
243    public void checkIndentation() {
244        checkTopLevelToken();
245        // separate to allow for eventual configuration
246        checkLeftParen(getLeftParen());
247        checkRightParen(getLeftParen(), getRightParen());
248        if (hasCurlies()) {
249            checkLeftCurly();
250            checkRightCurly();
251        }
252        final DetailAST listChild = getListChild();
253        if (listChild == null) {
254            checkNonListChild();
255        }
256        else {
257            // NOTE: switch statements usually don't have curlies
258            if (!hasCurlies() || !areOnSameLine(getLeftCurly(), getRightCurly())) {
259                checkChildren(listChild,
260                        getCheckedChildren(),
261                        getChildrenExpectedIndent(),
262                        true,
263                        canChildrenBeNested());
264            }
265        }
266    }
267
268    /**
269     * Gets indentation level expected for children.
270     * @return indentation level expected for children
271     */
272    protected IndentLevel getChildrenExpectedIndent() {
273        IndentLevel indentLevel = new IndentLevel(getIndent(), getBasicOffset());
274        // if we have multileveled expected level then we should
275        // try to suggest single level to children using curlies'
276        // levels.
277        if (getIndent().isMultiLevel() && hasCurlies()) {
278            if (isOnStartOfLine(getLeftCurly())) {
279                indentLevel = new IndentLevel(expandedTabsColumnNo(getLeftCurly())
280                        + getBasicOffset());
281            }
282            else if (isOnStartOfLine(getRightCurly())) {
283                final IndentLevel level = new IndentLevel(curlyIndent(), getBasicOffset());
284                level.addAcceptedIndent(level.getFirstIndentLevel() + getLineWrappingIndent());
285                indentLevel = level;
286            }
287        }
288        return indentLevel;
289    }
290
291    @Override
292    public IndentLevel getSuggestedChildIndent(AbstractExpressionHandler child) {
293        return getChildrenExpectedIndent();
294    }
295
296    /**
297     * A shortcut for {@code IndentationCheck} property.
298     * @return value of lineWrappingIndentation property
299     *         of {@code IndentationCheck}
300     */
301    private int getLineWrappingIndent() {
302        return getIndentCheck().getLineWrappingIndentation();
303    }
304}