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