001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2020 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.HashMap;
023import java.util.Map;
024
025import com.puppycrawl.tools.checkstyle.StatelessCheck;
026import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
027import com.puppycrawl.tools.checkstyle.api.DetailAST;
028import com.puppycrawl.tools.checkstyle.api.TokenTypes;
029
030/**
031 * <p>
032 * Checks that overloaded methods are grouped together. Overloaded methods have the same
033 * name but different signatures where the signature can differ by the number of
034 * input parameters or type of input parameters or both.
035 * </p>
036 * <p>
037 * To configure the check:
038 * </p>
039 * <pre>
040 * &lt;module name=&quot;OverloadMethodsDeclarationOrder&quot;/&gt;
041 * </pre>
042 * <p>
043 * Example of correct grouping of overloaded methods:
044 * </p>
045 * <pre>
046 * public void foo(int i) {}
047 * public void foo(String s) {}
048 * public void foo(String s, int i) {}
049 * public void foo(int i, String s) {}
050 * public void notFoo() {}
051 * </pre>
052 * <p>
053 * Example of incorrect grouping of overloaded methods:
054 * </p>
055 * <pre>
056 * public void foo(int i) {} // OK
057 * public void foo(String s) {} // OK
058 * public void notFoo() {} // violation. Have to be after foo(String s, int i)
059 * public void foo(int i, String s) {}
060 * public void foo(String s, int i) {}
061 * </pre>
062 * <p>
063 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
064 * </p>
065 * <p>
066 * Violation Message Keys:
067 * </p>
068 * <ul>
069 * <li>
070 * {@code overload.methods.declaration}
071 * </li>
072 * </ul>
073 *
074 * @since 5.8
075 */
076@StatelessCheck
077public class OverloadMethodsDeclarationOrderCheck extends AbstractCheck {
078
079    /**
080     * A key is pointing to the warning message text in "messages.properties"
081     * file.
082     */
083    public static final String MSG_KEY = "overload.methods.declaration";
084
085    @Override
086    public int[] getDefaultTokens() {
087        return getRequiredTokens();
088    }
089
090    @Override
091    public int[] getAcceptableTokens() {
092        return getRequiredTokens();
093    }
094
095    @Override
096    public int[] getRequiredTokens() {
097        return new int[] {
098            TokenTypes.OBJBLOCK,
099        };
100    }
101
102    @Override
103    public void visitToken(DetailAST ast) {
104        final int parentType = ast.getParent().getType();
105        if (parentType == TokenTypes.CLASS_DEF
106                || parentType == TokenTypes.ENUM_DEF
107                || parentType == TokenTypes.INTERFACE_DEF
108                || parentType == TokenTypes.LITERAL_NEW) {
109            checkOverloadMethodsGrouping(ast);
110        }
111    }
112
113    /**
114     * Checks that if overload methods are grouped together they should not be
115     * separated from each other.
116     *
117     * @param objectBlock
118     *        is a class, interface or enum object block.
119     */
120    private void checkOverloadMethodsGrouping(DetailAST objectBlock) {
121        final int allowedDistance = 1;
122        DetailAST currentToken = objectBlock.getFirstChild();
123        final Map<String, Integer> methodIndexMap = new HashMap<>();
124        final Map<String, Integer> methodLineNumberMap = new HashMap<>();
125        int currentIndex = 0;
126        while (currentToken != null) {
127            if (currentToken.getType() == TokenTypes.METHOD_DEF) {
128                currentIndex++;
129                final String methodName =
130                        currentToken.findFirstToken(TokenTypes.IDENT).getText();
131                if (methodIndexMap.containsKey(methodName)) {
132                    final int previousIndex = methodIndexMap.get(methodName);
133                    if (currentIndex - previousIndex > allowedDistance) {
134                        final int previousLineWithOverloadMethod =
135                                methodLineNumberMap.get(methodName);
136                        log(currentToken, MSG_KEY,
137                                previousLineWithOverloadMethod);
138                    }
139                }
140                methodIndexMap.put(methodName, currentIndex);
141                methodLineNumberMap.put(methodName, currentToken.getLineNo());
142            }
143            currentToken = currentToken.getNextSibling();
144        }
145    }
146
147}