001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2015 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.sizes;
021
022import org.apache.commons.lang3.ArrayUtils;
023
024import com.puppycrawl.tools.checkstyle.api.Check;
025import com.puppycrawl.tools.checkstyle.api.DetailAST;
026import com.puppycrawl.tools.checkstyle.api.TokenTypes;
027import com.puppycrawl.tools.checkstyle.utils.AnnotationUtility;
028
029/**
030 * <p>
031 * Checks the number of parameters that a method or constructor has.
032 * The default allowable number of parameters is 7.
033 * To change the number of allowable parameters, set property max.
034 * Allows to ignore number of parameters for methods with
035 * &#064;{@link Override} annotation.
036 * </p>
037 * <p>
038 * An example of how to configure the check is:
039 * </p>
040 * <pre>
041 * &lt;module name="ParameterNumber"/&gt;
042 * </pre>
043 * <p>
044 * An example of how to configure the check to allow 10 parameters
045 * and ignoring parameters for methods with &#064;{@link Override}
046 * annotation is:
047 * </p>
048 * <pre>
049 * &lt;module name="ParameterNumber"&gt;
050 *    &lt;property name="max" value="10"/&gt;
051 *    &lt;property name="ignoreOverriddenMethods" value="true"/&gt;
052 * &lt;/module&gt;
053 * </pre>
054 * Java code that will be ignored:
055 * <pre>
056 * {@code
057 *
058 *  &#064;Override
059 *  public void needsLotsOfParameters(int a,
060 *      int b, int c, int d, int e, int f, int g, int h) {
061 *      ...
062 *  }
063 * }
064 * </pre>
065 * @author Oliver Burn
066 */
067public class ParameterNumberCheck
068    extends Check {
069
070    /**
071     * A key is pointing to the warning message text in "messages.properties"
072     * file.
073     */
074    public static final String MSG_KEY = "maxParam";
075
076    /** {@link Override Override} annotation name. */
077    private static final String OVERRIDE = "Override";
078
079    /** Canonical {@link Override Override} annotation name. */
080    private static final String CANONICAL_OVERRIDE = "java.lang." + OVERRIDE;
081
082    /** Default maximum number of allowed parameters. */
083    private static final int DEFAULT_MAX_PARAMETERS = 7;
084
085    /** The maximum number of allowed parameters. */
086    private int max = DEFAULT_MAX_PARAMETERS;
087
088    /** Ignore overridden methods. */
089    private boolean ignoreOverriddenMethods;
090
091    /**
092     * Sets the maximum number of allowed parameters.
093     * @param max the max allowed parameters
094     */
095    public void setMax(int max) {
096        this.max = max;
097    }
098
099    /**
100     * Ignore number of parameters for methods with
101     * &#064;{@link Override} annotation.
102     * @param ignoreOverriddenMethods set ignore overridden methods
103     */
104    public void setIgnoreOverriddenMethods(boolean ignoreOverriddenMethods) {
105        this.ignoreOverriddenMethods = ignoreOverriddenMethods;
106    }
107
108    @Override
109    public int[] getDefaultTokens() {
110        return getAcceptableTokens();
111    }
112
113    @Override
114    public int[] getAcceptableTokens() {
115        return new int[] {TokenTypes.METHOD_DEF, TokenTypes.CTOR_DEF};
116    }
117
118    @Override
119    public int[] getRequiredTokens() {
120        return ArrayUtils.EMPTY_INT_ARRAY;
121    }
122
123    @Override
124    public void visitToken(DetailAST ast) {
125        final DetailAST params = ast.findFirstToken(TokenTypes.PARAMETERS);
126        final int count = params.getChildCount(TokenTypes.PARAMETER_DEF);
127        if (count > max && !shouldIgnoreNumberOfParameters(ast)) {
128            final DetailAST name = ast.findFirstToken(TokenTypes.IDENT);
129            log(name.getLineNo(), name.getColumnNo(), MSG_KEY, max, count);
130        }
131    }
132
133    /** Determine whether to ignore number of parameters for the method.
134     *
135     * @param ast the token to process
136     * @return true if this is overridden method and number of parameters should be ignored
137     *         false otherwise
138     */
139    private boolean shouldIgnoreNumberOfParameters(DetailAST ast) {
140        //if you override a method, you have no power over the number of parameters
141        return ignoreOverriddenMethods
142                && (AnnotationUtility.containsAnnotation(ast, OVERRIDE)
143                || AnnotationUtility.containsAnnotation(ast, CANONICAL_OVERRIDE));
144    }
145}