001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2024 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.filters;
021
022import java.util.Set;
023
024import com.puppycrawl.tools.checkstyle.AbstractAutomaticBean;
025import com.puppycrawl.tools.checkstyle.api.AuditEvent;
026import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
027import com.puppycrawl.tools.checkstyle.api.ExternalResourceHolder;
028import com.puppycrawl.tools.checkstyle.api.Filter;
029import com.puppycrawl.tools.checkstyle.api.FilterSet;
030import com.puppycrawl.tools.checkstyle.utils.FilterUtil;
031import com.puppycrawl.tools.checkstyle.utils.UnmodifiableCollectionUtil;
032
033/**
034 * <div>
035 * Filter {@code SuppressionFilter} rejects audit events for Check violations according to a
036 * <a href="https://checkstyle.org/dtds/suppressions_1_2.dtd">suppressions XML document</a>
037 * in a file. If there is no configured suppressions file or the optional is set to true and
038 * suppressions file was not found the Filter accepts all audit events.
039 * </div>
040 *
041 * <p>
042 * A <a href="https://checkstyle.org/dtds/suppressions_1_2.dtd">suppressions XML document</a>
043 * contains a set of {@code suppress} elements, where each {@code suppress}
044 * element can have the following attributes:
045 * </p>
046 * <ul>
047 * <li>
048 * {@code files} - a <a href="https://checkstyle.org/property_types.html#Pattern">
049 * Pattern</a> matched against the file name associated with an audit event.
050 * It is optional.
051 * </li>
052 * <li>
053 * {@code checks} - a <a href="https://checkstyle.org/property_types.html#Pattern">
054 * Pattern</a> matched against the name of the check associated with an audit event.
055 * Optional as long as {@code id} or {@code message} is specified.
056 * </li>
057 * <li>
058 * {@code message} - a <a href="https://checkstyle.org/property_types.html#Pattern">
059 * Pattern</a> matched against the message of the check associated with an audit event.
060 * Optional as long as {@code checks} or {@code id} is specified.
061 * </li>
062 * <li>
063 * {@code id} - a <a href="https://checkstyle.org/property_types.html#String">String</a>
064 * matched against the <a href="https://checkstyle.org/config.html#Id">check id</a>
065 * associated with an audit event.
066 * Optional as long as {@code checks} or {@code message} is specified.
067 * </li>
068 * <li>
069 * {@code lines} - a comma-separated list of values, where each value is an
070 * <a href="https://checkstyle.org/property_types.html#int">int</a>
071 * or a range of integers denoted by integer-integer.
072 * It is optional.
073 * </li>
074 * <li>
075 * {@code columns} - a comma-separated list of values, where each value is an
076 * <a href="https://checkstyle.org/property_types.html#int">int</a>
077 * or a range of integers denoted by integer-integer.
078 * It is optional.
079 * </li>
080 * </ul>
081 *
082 * <p>
083 * Each audit event is checked against each {@code suppress} element.
084 * It is suppressed if all specified attributes match against the audit event.
085 * </p>
086 *
087 * <p>
088 * ATTENTION: filtering by message is dependent on runtime locale.
089 * If project is running in different languages it is better to avoid filtering by message.
090 * </p>
091 *
092 * <p>
093 * You can download template of empty suppression filter
094 * <a href="https://checkstyle.org/files/suppressions_none.xml">here</a>.
095 * </p>
096 *
097 * <p>
098 * Location of the file defined in {@code file} property is checked in the following order:
099 * </p>
100 * <ol>
101 * <li>
102 * as a filesystem location
103 * </li>
104 * <li>
105 * if no file found, and the location starts with either {@code http://} or {@code https://},
106 * then it is interpreted as a URL
107 * </li>
108 * <li>
109 * if no file found, then passed to the {@code ClassLoader.getResource()} method.
110 * </li>
111 * </ol>
112 *
113 * <p>
114 * SuppressionFilter can suppress Checks that have Treewalker or Checker as parent module.
115 * </p>
116 * <ul>
117 * <li>
118 * Property {@code file} - Specify the location of the <em>suppressions XML document</em> file.
119 * Type is {@code java.lang.String}.
120 * Default value is {@code null}.
121 * </li>
122 * <li>
123 * Property {@code optional} - Control what to do when the file is not existing.
124 * If {@code optional} is set to {@code false} the file must exist, or else it
125 * ends with error. On the other hand if optional is {@code true} and file is
126 * not found, the filter accept all audit events.
127 * Type is {@code boolean}.
128 * Default value is {@code false}.
129 * </li>
130 * </ul>
131 *
132 * <p>
133 * Parent is {@code com.puppycrawl.tools.checkstyle.Checker}
134 * </p>
135 *
136 * @since 3.2
137 */
138public class SuppressionFilter
139        extends AbstractAutomaticBean
140        implements Filter, ExternalResourceHolder {
141
142    /** Specify the location of the <em>suppressions XML document</em> file. */
143    private String file;
144    /**
145     * Control what to do when the file is not existing. If {@code optional} is
146     * set to {@code false} the file must exist, or else it ends with error.
147     * On the other hand if optional is {@code true} and file is not found,
148     * the filter accept all audit events.
149     */
150    private boolean optional;
151    /** Set of individual suppresses. */
152    private FilterSet filters = new FilterSet();
153
154    /**
155     * Setter to specify the location of the <em>suppressions XML document</em> file.
156     *
157     * @param fileName name of the suppressions file.
158     * @since 3.2
159     */
160    public void setFile(String fileName) {
161        file = fileName;
162    }
163
164    /**
165     * Setter to control what to do when the file is not existing.
166     * If {@code optional} is set to {@code false} the file must exist, or else
167     * it ends with error. On the other hand if optional is {@code true}
168     * and file is not found, the filter accept all audit events.
169     *
170     * @param optional tells if config file existence is optional.
171     * @since 6.15
172     */
173    public void setOptional(boolean optional) {
174        this.optional = optional;
175    }
176
177    @Override
178    public boolean accept(AuditEvent event) {
179        return filters.accept(event);
180    }
181
182    @Override
183    protected void finishLocalSetup() throws CheckstyleException {
184        if (file != null) {
185            if (optional) {
186                if (FilterUtil.isFileExists(file)) {
187                    filters = SuppressionsLoader.loadSuppressions(file);
188                }
189            }
190            else {
191                filters = SuppressionsLoader.loadSuppressions(file);
192            }
193        }
194    }
195
196    @Override
197    public Set<String> getExternalResourceLocations() {
198        return UnmodifiableCollectionUtil.singleton(file);
199    }
200
201}