001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2014  Oliver Burn
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////////////////////////////////////////////////////////////////////////////////
019package com.puppycrawl.tools.checkstyle.checks.metrics;
020
021import com.puppycrawl.tools.checkstyle.api.Check;
022import com.puppycrawl.tools.checkstyle.api.DetailAST;
023import com.puppycrawl.tools.checkstyle.api.FastStack;
024import com.puppycrawl.tools.checkstyle.api.TokenTypes;
025import java.math.BigInteger;
026
027/**
028 * Base class for checks the calculate complexity based around methods.
029 *
030 * @author <a href="mailto:simon@redhillconsulting.com.au">Simon Harris</a>
031 * @author Oliver Burn
032 */
033public abstract class AbstractComplexityCheck
034    extends Check
035{
036    /** the initial current value */
037    private static final BigInteger INITIAL_VALUE = BigInteger.ONE;
038
039    /** stack of values - all but the current value */
040    private final FastStack<BigInteger> mValueStack = FastStack.newInstance();
041
042    /** the current value */
043    private BigInteger mCurrentValue = BigInteger.ZERO;
044
045    /** threshold to report error for */
046    private int mMax;
047
048    /**
049     * Creates an instance.
050     * @param aMax the threshold of when to report an error
051     */
052    public AbstractComplexityCheck(int aMax)
053    {
054        mMax = aMax;
055    }
056
057    /**
058     * @return the message ID to log violations with
059     */
060    protected abstract String getMessageID();
061
062    /**
063     * Hook called when visiting a token. Will not be called the method
064     * definition tokens.
065     *
066     * @param aAST the token being visited
067     */
068    protected void visitTokenHook(DetailAST aAST)
069    {
070    }
071
072    /**
073     * Hook called when leaving a token. Will not be called the method
074     * definition tokens.
075     *
076     * @param aAST the token being left
077     */
078    protected void leaveTokenHook(DetailAST aAST)
079    {
080    }
081
082    @Override
083    public final int[] getRequiredTokens()
084    {
085        return new int[] {
086            TokenTypes.CTOR_DEF,
087            TokenTypes.METHOD_DEF,
088            TokenTypes.INSTANCE_INIT,
089            TokenTypes.STATIC_INIT,
090        };
091    }
092
093    /** @return the maximum threshold allowed */
094    public final int getMax()
095    {
096        return mMax;
097    }
098
099    /**
100     * Set the maximum threshold allowed.
101     *
102     * @param aMax the maximum threshold
103     */
104    public final void setMax(int aMax)
105    {
106        mMax = aMax;
107    }
108
109    @Override
110    public void visitToken(DetailAST aAST)
111    {
112        switch (aAST.getType()) {
113        case TokenTypes.CTOR_DEF:
114        case TokenTypes.METHOD_DEF:
115        case TokenTypes.INSTANCE_INIT:
116        case TokenTypes.STATIC_INIT:
117            visitMethodDef();
118            break;
119        default:
120            visitTokenHook(aAST);
121        }
122    }
123
124    @Override
125    public void leaveToken(DetailAST aAST)
126    {
127        switch (aAST.getType()) {
128        case TokenTypes.CTOR_DEF:
129        case TokenTypes.METHOD_DEF:
130        case TokenTypes.INSTANCE_INIT:
131        case TokenTypes.STATIC_INIT:
132            leaveMethodDef(aAST);
133            break;
134        default:
135            leaveTokenHook(aAST);
136        }
137    }
138
139    /**
140     * @return the current value
141     */
142    protected final BigInteger getCurrentValue()
143    {
144        return mCurrentValue;
145    }
146
147    /**
148     * Set the current value
149     * @param aValue the new value
150     */
151    protected final void setCurrentValue(BigInteger aValue)
152    {
153        mCurrentValue = aValue;
154    }
155
156    /**
157     * Increments the current value by a specified amount.
158     *
159     * @param aBy the amount to increment by
160     */
161    protected final void incrementCurrentValue(BigInteger aBy)
162    {
163        setCurrentValue(getCurrentValue().add(aBy));
164    }
165
166    /** Push the current value on the stack */
167    protected final void pushValue()
168    {
169        mValueStack.push(mCurrentValue);
170        mCurrentValue = INITIAL_VALUE;
171    }
172
173    /**
174     * @return pop a value off the stack and make it the current value
175     */
176    protected final BigInteger popValue()
177    {
178        mCurrentValue = mValueStack.pop();
179        return mCurrentValue;
180    }
181
182    /** Process the start of the method definition */
183    private void visitMethodDef()
184    {
185        pushValue();
186    }
187
188    /**
189     * Process the end of a method definition.
190     *
191     * @param aAST the token representing the method definition
192     */
193    private void leaveMethodDef(DetailAST aAST)
194    {
195        final BigInteger max = BigInteger.valueOf(mMax);
196        if (mCurrentValue.compareTo(max) > 0) {
197            log(aAST, getMessageID(), mCurrentValue, max);
198        }
199        popValue();
200    }
201}