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1   ///////////////////////////////////////////////////////////////////////////////////////////////
2   // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
3   // Copyright (C) 2001-2025 the original author or authors.
4   //
5   // This library is free software; you can redistribute it and/or
6   // modify it under the terms of the GNU Lesser General Public
7   // License as published by the Free Software Foundation; either
8   // version 2.1 of the License, or (at your option) any later version.
9   //
10  // This library is distributed in the hope that it will be useful,
11  // but WITHOUT ANY WARRANTY; without even the implied warranty of
12  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  // Lesser General Public License for more details.
14  //
15  // You should have received a copy of the GNU Lesser General Public
16  // License along with this library; if not, write to the Free Software
17  // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18  ///////////////////////////////////////////////////////////////////////////////////////////////
19  
20  package com.puppycrawl.tools.checkstyle.checks.coding;
21  
22  import java.util.Arrays;
23  import java.util.Collections;
24  import java.util.HashSet;
25  import java.util.Set;
26  import java.util.stream.Collectors;
27  
28  import com.puppycrawl.tools.checkstyle.StatelessCheck;
29  import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
30  import com.puppycrawl.tools.checkstyle.api.DetailAST;
31  import com.puppycrawl.tools.checkstyle.api.FullIdent;
32  import com.puppycrawl.tools.checkstyle.api.TokenTypes;
33  import com.puppycrawl.tools.checkstyle.utils.AnnotationUtil;
34  import com.puppycrawl.tools.checkstyle.utils.CheckUtil;
35  
36  /**
37   * <div>
38   * Checks that specified types are not declared to be thrown.
39   * Declaring that a method throws {@code java.lang.Error} or
40   * {@code java.lang.RuntimeException} is almost never acceptable.
41   * </div>
42   *
43   * @since 4.0
44   */
45  @StatelessCheck
46  public final class IllegalThrowsCheck extends AbstractCheck {
47  
48      /**
49       * A key is pointing to the warning message text in "messages.properties"
50       * file.
51       */
52      public static final String MSG_KEY = "illegal.throw";
53  
54      /** Specify names of methods to ignore. */
55      private final Set<String> ignoredMethodNames =
56          Arrays.stream(new String[] {"finalize", }).collect(Collectors.toCollection(HashSet::new));
57  
58      /** Specify throw class names to reject. */
59      private final Set<String> illegalClassNames = Arrays.stream(
60          new String[] {"Error", "RuntimeException", "Throwable", "java.lang.Error",
61                        "java.lang.RuntimeException", "java.lang.Throwable", })
62          .collect(Collectors.toCollection(HashSet::new));
63  
64      /**
65       * Allow to ignore checking overridden methods (marked with {@code Override}
66       * or {@code java.lang.Override} annotation).
67       */
68      private boolean ignoreOverriddenMethods = true;
69  
70      /**
71       * Setter to specify throw class names to reject.
72       *
73       * @param classNames
74       *            array of illegal exception classes
75       * @since 4.0
76       */
77      public void setIllegalClassNames(final String... classNames) {
78          illegalClassNames.clear();
79          illegalClassNames.addAll(
80                  CheckUtil.parseClassNames(classNames));
81      }
82  
83      @Override
84      public int[] getDefaultTokens() {
85          return getRequiredTokens();
86      }
87  
88      @Override
89      public int[] getRequiredTokens() {
90          return new int[] {TokenTypes.LITERAL_THROWS};
91      }
92  
93      @Override
94      public int[] getAcceptableTokens() {
95          return getRequiredTokens();
96      }
97  
98      @Override
99      public void visitToken(DetailAST detailAST) {
100         final DetailAST methodDef = detailAST.getParent();
101         // Check if the method with the given name should be ignored.
102         if (!isIgnorableMethod(methodDef)) {
103             DetailAST token = detailAST.getFirstChild();
104             while (token != null) {
105                 final FullIdent ident = FullIdent.createFullIdent(token);
106                 final String identText = ident.getText();
107                 if (illegalClassNames.contains(identText)) {
108                     log(token, MSG_KEY, identText);
109                 }
110                 token = token.getNextSibling();
111             }
112         }
113     }
114 
115     /**
116      * Checks if current method is ignorable due to Check's properties.
117      *
118      * @param methodDef {@link TokenTypes#METHOD_DEF METHOD_DEF}
119      * @return true if method is ignorable.
120      */
121     private boolean isIgnorableMethod(DetailAST methodDef) {
122         return shouldIgnoreMethod(methodDef.findFirstToken(TokenTypes.IDENT).getText())
123             || ignoreOverriddenMethods
124                && AnnotationUtil.hasOverrideAnnotation(methodDef);
125     }
126 
127     /**
128      * Check if the method is specified in the ignore method list.
129      *
130      * @param name the name to check
131      * @return whether the method with the passed name should be ignored
132      */
133     private boolean shouldIgnoreMethod(String name) {
134         return ignoredMethodNames.contains(name);
135     }
136 
137     /**
138      * Setter to specify names of methods to ignore.
139      *
140      * @param methodNames array of ignored method names
141      * @since 5.4
142      */
143     public void setIgnoredMethodNames(String... methodNames) {
144         ignoredMethodNames.clear();
145         Collections.addAll(ignoredMethodNames, methodNames);
146     }
147 
148     /**
149      * Setter to allow to ignore checking overridden methods
150      * (marked with {@code Override} or {@code java.lang.Override} annotation).
151      *
152      * @param ignoreOverriddenMethods Check's property.
153      * @since 6.4
154      */
155     public void setIgnoreOverriddenMethods(boolean ignoreOverriddenMethods) {
156         this.ignoreOverriddenMethods = ignoreOverriddenMethods;
157     }
158 
159 }