001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2017 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 com.puppycrawl.tools.checkstyle.api.AbstractCheck;
023import com.puppycrawl.tools.checkstyle.api.DetailAST;
024import com.puppycrawl.tools.checkstyle.api.TokenTypes;
025import com.puppycrawl.tools.checkstyle.utils.AnnotationUtility;
026import com.puppycrawl.tools.checkstyle.utils.CommonUtils;
027
028/**
029 * <p>
030 * Checks the number of parameters that a method or constructor has.
031 * The default allowable number of parameters is 7.
032 * To change the number of allowable parameters, set property max.
033 * Allows to ignore number of parameters for methods with
034 * &#064;{@link Override} annotation.
035 * </p>
036 * <p>
037 * An example of how to configure the check is:
038 * </p>
039 * <pre>
040 * &lt;module name="ParameterNumber"/&gt;
041 * </pre>
042 * <p>
043 * An example of how to configure the check to allow 10 parameters
044 * and ignoring parameters for methods with &#064;{@link Override}
045 * annotation is:
046 * </p>
047 * <pre>
048 * &lt;module name="ParameterNumber"&gt;
049 *    &lt;property name="max" value="10"/&gt;
050 *    &lt;property name="ignoreOverriddenMethods" value="true"/&gt;
051 * &lt;/module&gt;
052 * </pre>
053 * Java code that will be ignored:
054 * <pre>
055 * {@code
056 *
057 *  &#064;Override
058 *  public void needsLotsOfParameters(int a,
059 *      int b, int c, int d, int e, int f, int g, int h) {
060 *      ...
061 *  }
062 * }
063 * </pre>
064 * @author Oliver Burn
065 */
066public class ParameterNumberCheck
067    extends AbstractCheck {
068
069    /**
070     * A key is pointing to the warning message text in "messages.properties"
071     * file.
072     */
073    public static final String MSG_KEY = "maxParam";
074
075    /** {@link Override Override} annotation name. */
076    private static final String OVERRIDE = "Override";
077
078    /** Canonical {@link Override Override} annotation name. */
079    private static final String CANONICAL_OVERRIDE = "java.lang." + OVERRIDE;
080
081    /** Default maximum number of allowed parameters. */
082    private static final int DEFAULT_MAX_PARAMETERS = 7;
083
084    /** The maximum number of allowed parameters. */
085    private int max = DEFAULT_MAX_PARAMETERS;
086
087    /** Ignore overridden methods. */
088    private boolean ignoreOverriddenMethods;
089
090    /**
091     * Sets the maximum number of allowed parameters.
092     * @param max the max allowed parameters
093     */
094    public void setMax(int max) {
095        this.max = max;
096    }
097
098    /**
099     * Ignore number of parameters for methods with
100     * &#064;{@link Override} annotation.
101     * @param ignoreOverriddenMethods set ignore overridden methods
102     */
103    public void setIgnoreOverriddenMethods(boolean ignoreOverriddenMethods) {
104        this.ignoreOverriddenMethods = ignoreOverriddenMethods;
105    }
106
107    @Override
108    public int[] getDefaultTokens() {
109        return getAcceptableTokens();
110    }
111
112    @Override
113    public int[] getAcceptableTokens() {
114        return new int[] {TokenTypes.METHOD_DEF, TokenTypes.CTOR_DEF};
115    }
116
117    @Override
118    public int[] getRequiredTokens() {
119        return CommonUtils.EMPTY_INT_ARRAY;
120    }
121
122    @Override
123    public void visitToken(DetailAST ast) {
124        final DetailAST params = ast.findFirstToken(TokenTypes.PARAMETERS);
125        final int count = params.getChildCount(TokenTypes.PARAMETER_DEF);
126        if (count > max && !shouldIgnoreNumberOfParameters(ast)) {
127            final DetailAST name = ast.findFirstToken(TokenTypes.IDENT);
128            log(name.getLineNo(), name.getColumnNo(), MSG_KEY, max, count);
129        }
130    }
131
132    /** Determine whether to ignore number of parameters for the method.
133     *
134     * @param ast the token to process
135     * @return true if this is overridden method and number of parameters should be ignored
136     *         false otherwise
137     */
138    private boolean shouldIgnoreNumberOfParameters(DetailAST ast) {
139        //if you override a method, you have no power over the number of parameters
140        return ignoreOverriddenMethods
141                && (AnnotationUtility.containsAnnotation(ast, OVERRIDE)
142                || AnnotationUtility.containsAnnotation(ast, CANONICAL_OVERRIDE));
143    }
144}