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.whitespace;
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.CodePointUtil;
029import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
030
031/**
032 * <div>
033 * Checks the padding between the identifier of a method definition,
034 * constructor definition, method call, constructor invocation, record, or record pattern;
035 * and the left parenthesis of the parameter list.
036 * That is, if the identifier and left parenthesis are on the same line,
037 * checks whether a space is required immediately after the identifier or such a space is forbidden.
038 * If they are not on the same line, reports a violation, unless configured to
039 * allow line breaks. To allow linebreaks after the identifier, set property
040 * {@code allowLineBreaks} to {@code true}.
041 * </div>
042 *
043 * @since 3.4
044 */
045
046@StatelessCheck
047public class MethodParamPadCheck extends AbstractCheck {
048
049    /**
050     * A key is pointing to the warning message text in "messages.properties" file.
051     */
052    public static final String MSG_LINE_PREVIOUS = "line.previous";
053
054    /**
055     * A key is pointing to the warning message text in "messages.properties" file.
056     */
057    public static final String MSG_WS_PRECEDED = "ws.preceded";
058
059    /**
060     * A key is pointing to the warning message text in "messages.properties" file.
061     */
062    public static final String MSG_WS_NOT_PRECEDED = "ws.notPreceded";
063
064    /**
065     * Allow a line break between the identifier and left parenthesis.
066     */
067    private boolean allowLineBreaks;
068
069    /** Specify policy on how to pad method parameter. */
070    private PadOption option = PadOption.NOSPACE;
071
072    /**
073     * Creates a new {@code MethodParamPadCheck} instance.
074     */
075    public MethodParamPadCheck() {
076        // no code by default
077    }
078
079    @Override
080    public int[] getDefaultTokens() {
081        return getAcceptableTokens();
082    }
083
084    @Override
085    public int[] getAcceptableTokens() {
086        return new int[] {
087            TokenTypes.CTOR_DEF,
088            TokenTypes.CTOR_CALL,
089            TokenTypes.LITERAL_NEW,
090            TokenTypes.METHOD_CALL,
091            TokenTypes.METHOD_DEF,
092            TokenTypes.SUPER_CTOR_CALL,
093            TokenTypes.ENUM_CONSTANT_DEF,
094            TokenTypes.RECORD_DEF,
095            TokenTypes.RECORD_PATTERN_DEF,
096        };
097    }
098
099    @Override
100    public int[] getRequiredTokens() {
101        return CommonUtil.EMPTY_INT_ARRAY;
102    }
103
104    @Override
105    public void visitToken(DetailAST ast) {
106        final DetailAST parenAST;
107        if (ast.getType() == TokenTypes.METHOD_CALL) {
108            parenAST = ast;
109        }
110        else {
111            parenAST = ast.findFirstToken(TokenTypes.LPAREN);
112            // array construction => parenAST == null
113        }
114
115        if (parenAST != null) {
116            final int[] line = getLineCodePoints(parenAST.getLineNo() - 1);
117            if (CodePointUtil.hasWhitespaceBefore(parenAST.getColumnNo(), line)) {
118                if (!allowLineBreaks) {
119                    log(parenAST, MSG_LINE_PREVIOUS, parenAST.getText());
120                }
121            }
122            else {
123                final int before = parenAST.getColumnNo() - 1;
124                if (option == PadOption.NOSPACE
125                    && CommonUtil.isCodePointWhitespace(line, before)) {
126                    log(parenAST, MSG_WS_PRECEDED, parenAST.getText());
127                }
128                else if (option == PadOption.SPACE
129                         && !CommonUtil.isCodePointWhitespace(line, before)) {
130                    log(parenAST, MSG_WS_NOT_PRECEDED, parenAST.getText());
131                }
132            }
133        }
134    }
135
136    /**
137     * Setter to allow a line break between the identifier and left parenthesis.
138     *
139     * @param allowLineBreaks whether whitespace should be flagged at line breaks.
140     * @since 3.4
141     */
142    public void setAllowLineBreaks(boolean allowLineBreaks) {
143        this.allowLineBreaks = allowLineBreaks;
144    }
145
146    /**
147     * Setter to specify policy on how to pad method parameter.
148     *
149     * @param optionStr string to decode option from
150     * @throws IllegalArgumentException if unable to decode
151     * @since 3.4
152     */
153    public void setOption(String optionStr) {
154        option = PadOption.valueOf(optionStr.trim().toUpperCase(Locale.ENGLISH));
155    }
156
157}