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.checks.coding;
021
022import java.util.Arrays;
023import java.util.Collections;
024import java.util.HashSet;
025import java.util.Set;
026import java.util.stream.Collectors;
027
028import com.puppycrawl.tools.checkstyle.StatelessCheck;
029import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
030import com.puppycrawl.tools.checkstyle.api.DetailAST;
031import com.puppycrawl.tools.checkstyle.api.FullIdent;
032import com.puppycrawl.tools.checkstyle.api.TokenTypes;
033import com.puppycrawl.tools.checkstyle.utils.AnnotationUtil;
034import com.puppycrawl.tools.checkstyle.utils.CheckUtil;
035
036/**
037 * <div>
038 * Checks that specified types are not declared to be thrown.
039 * Declaring that a method throws {@code java.lang.Error} or
040 * {@code java.lang.RuntimeException} is almost never acceptable.
041 * </div>
042 * <ul>
043 * <li>
044 * Property {@code ignoreOverriddenMethods} - Allow to ignore checking overridden methods
045 * (marked with {@code Override} or {@code java.lang.Override} annotation).
046 * Type is {@code boolean}.
047 * Default value is {@code true}.
048 * </li>
049 * <li>
050 * Property {@code ignoredMethodNames} - Specify names of methods to ignore.
051 * Type is {@code java.lang.String[]}.
052 * Default value is {@code finalize}.
053 * </li>
054 * <li>
055 * Property {@code illegalClassNames} - Specify throw class names to reject.
056 * Type is {@code java.lang.String[]}.
057 * Default value is {@code Error, RuntimeException, Throwable, java.lang.Error,
058 * java.lang.RuntimeException, java.lang.Throwable}.
059 * </li>
060 * </ul>
061 *
062 * <p>
063 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
064 * </p>
065 *
066 * <p>
067 * Violation Message Keys:
068 * </p>
069 * <ul>
070 * <li>
071 * {@code illegal.throw}
072 * </li>
073 * </ul>
074 *
075 * @since 4.0
076 */
077@StatelessCheck
078public final class IllegalThrowsCheck extends AbstractCheck {
079
080    /**
081     * A key is pointing to the warning message text in "messages.properties"
082     * file.
083     */
084    public static final String MSG_KEY = "illegal.throw";
085
086    /** Specify names of methods to ignore. */
087    private final Set<String> ignoredMethodNames =
088        Arrays.stream(new String[] {"finalize", }).collect(Collectors.toCollection(HashSet::new));
089
090    /** Specify throw class names to reject. */
091    private final Set<String> illegalClassNames = Arrays.stream(
092        new String[] {"Error", "RuntimeException", "Throwable", "java.lang.Error",
093                      "java.lang.RuntimeException", "java.lang.Throwable", })
094        .collect(Collectors.toCollection(HashSet::new));
095
096    /**
097     * Allow to ignore checking overridden methods (marked with {@code Override}
098     * or {@code java.lang.Override} annotation).
099     */
100    private boolean ignoreOverriddenMethods = true;
101
102    /**
103     * Setter to specify throw class names to reject.
104     *
105     * @param classNames
106     *            array of illegal exception classes
107     * @since 4.0
108     */
109    public void setIllegalClassNames(final String... classNames) {
110        illegalClassNames.clear();
111        illegalClassNames.addAll(
112                CheckUtil.parseClassNames(classNames));
113    }
114
115    @Override
116    public int[] getDefaultTokens() {
117        return getRequiredTokens();
118    }
119
120    @Override
121    public int[] getRequiredTokens() {
122        return new int[] {TokenTypes.LITERAL_THROWS};
123    }
124
125    @Override
126    public int[] getAcceptableTokens() {
127        return getRequiredTokens();
128    }
129
130    @Override
131    public void visitToken(DetailAST detailAST) {
132        final DetailAST methodDef = detailAST.getParent();
133        // Check if the method with the given name should be ignored.
134        if (!isIgnorableMethod(methodDef)) {
135            DetailAST token = detailAST.getFirstChild();
136            while (token != null) {
137                final FullIdent ident = FullIdent.createFullIdent(token);
138                final String identText = ident.getText();
139                if (illegalClassNames.contains(identText)) {
140                    log(token, MSG_KEY, identText);
141                }
142                token = token.getNextSibling();
143            }
144        }
145    }
146
147    /**
148     * Checks if current method is ignorable due to Check's properties.
149     *
150     * @param methodDef {@link TokenTypes#METHOD_DEF METHOD_DEF}
151     * @return true if method is ignorable.
152     */
153    private boolean isIgnorableMethod(DetailAST methodDef) {
154        return shouldIgnoreMethod(methodDef.findFirstToken(TokenTypes.IDENT).getText())
155            || ignoreOverriddenMethods
156               && AnnotationUtil.hasOverrideAnnotation(methodDef);
157    }
158
159    /**
160     * Check if the method is specified in the ignore method list.
161     *
162     * @param name the name to check
163     * @return whether the method with the passed name should be ignored
164     */
165    private boolean shouldIgnoreMethod(String name) {
166        return ignoredMethodNames.contains(name);
167    }
168
169    /**
170     * Setter to specify names of methods to ignore.
171     *
172     * @param methodNames array of ignored method names
173     * @since 5.4
174     */
175    public void setIgnoredMethodNames(String... methodNames) {
176        ignoredMethodNames.clear();
177        Collections.addAll(ignoredMethodNames, methodNames);
178    }
179
180    /**
181     * Setter to allow to ignore checking overridden methods
182     * (marked with {@code Override} or {@code java.lang.Override} annotation).
183     *
184     * @param ignoreOverriddenMethods Check's property.
185     * @since 6.4
186     */
187    public void setIgnoreOverriddenMethods(boolean ignoreOverriddenMethods) {
188        this.ignoreOverriddenMethods = ignoreOverriddenMethods;
189    }
190
191}