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 * <p>
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 * </p>
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 * <p>
062 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
063 * </p>
064 * <p>
065 * Violation Message Keys:
066 * </p>
067 * <ul>
068 * <li>
069 * {@code illegal.throw}
070 * </li>
071 * </ul>
072 *
073 * @since 4.0
074 */
075@StatelessCheck
076public final class IllegalThrowsCheck extends AbstractCheck {
077
078    /**
079     * A key is pointing to the warning message text in "messages.properties"
080     * file.
081     */
082    public static final String MSG_KEY = "illegal.throw";
083
084    /** Specify names of methods to ignore. */
085    private final Set<String> ignoredMethodNames =
086        Arrays.stream(new String[] {"finalize", }).collect(Collectors.toCollection(HashSet::new));
087
088    /** Specify throw class names to reject. */
089    private final Set<String> illegalClassNames = Arrays.stream(
090        new String[] {"Error", "RuntimeException", "Throwable", "java.lang.Error",
091                      "java.lang.RuntimeException", "java.lang.Throwable", })
092        .collect(Collectors.toCollection(HashSet::new));
093
094    /**
095     * Allow to ignore checking overridden methods (marked with {@code Override}
096     * or {@code java.lang.Override} annotation).
097     */
098    private boolean ignoreOverriddenMethods = true;
099
100    /**
101     * Setter to specify throw class names to reject.
102     *
103     * @param classNames
104     *            array of illegal exception classes
105     * @since 4.0
106     */
107    public void setIllegalClassNames(final String... classNames) {
108        illegalClassNames.clear();
109        illegalClassNames.addAll(
110                CheckUtil.parseClassNames(classNames));
111    }
112
113    @Override
114    public int[] getDefaultTokens() {
115        return getRequiredTokens();
116    }
117
118    @Override
119    public int[] getRequiredTokens() {
120        return new int[] {TokenTypes.LITERAL_THROWS};
121    }
122
123    @Override
124    public int[] getAcceptableTokens() {
125        return getRequiredTokens();
126    }
127
128    @Override
129    public void visitToken(DetailAST detailAST) {
130        final DetailAST methodDef = detailAST.getParent();
131        // Check if the method with the given name should be ignored.
132        if (!isIgnorableMethod(methodDef)) {
133            DetailAST token = detailAST.getFirstChild();
134            while (token != null) {
135                final FullIdent ident = FullIdent.createFullIdent(token);
136                final String identText = ident.getText();
137                if (illegalClassNames.contains(identText)) {
138                    log(token, MSG_KEY, identText);
139                }
140                token = token.getNextSibling();
141            }
142        }
143    }
144
145    /**
146     * Checks if current method is ignorable due to Check's properties.
147     *
148     * @param methodDef {@link TokenTypes#METHOD_DEF METHOD_DEF}
149     * @return true if method is ignorable.
150     */
151    private boolean isIgnorableMethod(DetailAST methodDef) {
152        return shouldIgnoreMethod(methodDef.findFirstToken(TokenTypes.IDENT).getText())
153            || ignoreOverriddenMethods
154               && AnnotationUtil.hasOverrideAnnotation(methodDef);
155    }
156
157    /**
158     * Check if the method is specified in the ignore method list.
159     *
160     * @param name the name to check
161     * @return whether the method with the passed name should be ignored
162     */
163    private boolean shouldIgnoreMethod(String name) {
164        return ignoredMethodNames.contains(name);
165    }
166
167    /**
168     * Setter to specify names of methods to ignore.
169     *
170     * @param methodNames array of ignored method names
171     * @since 5.4
172     */
173    public void setIgnoredMethodNames(String... methodNames) {
174        ignoredMethodNames.clear();
175        Collections.addAll(ignoredMethodNames, methodNames);
176    }
177
178    /**
179     * Setter to allow to ignore checking overridden methods
180     * (marked with {@code Override} or {@code java.lang.Override} annotation).
181     *
182     * @param ignoreOverriddenMethods Check's property.
183     * @since 6.4
184     */
185    public void setIgnoreOverriddenMethods(boolean ignoreOverriddenMethods) {
186        this.ignoreOverriddenMethods = ignoreOverriddenMethods;
187    }
188
189}