////////////////////////////////////////////////////////////////////////////////
// checkstyle: Checks Java source code for adherence to a set of rules.
// Copyright (C) 2001-2017 the original author or authors.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
////////////////////////////////////////////////////////////////////////////////
package com.puppycrawl.tools.checkstyle.checks.metrics;
import java.math.BigInteger;
import java.util.ArrayDeque;
import java.util.Deque;
import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
import com.puppycrawl.tools.checkstyle.api.DetailAST;
import com.puppycrawl.tools.checkstyle.api.TokenTypes;
/**
* Checks cyclomatic complexity against a specified limit. The complexity is
* measured by the number of "if", "while", "do", "for", "?:", "catch",
* "switch", "case", "&&" and "||" statements (plus one) in the body of
* the member. It is a measure of the minimum number of possible paths through
* the source and therefore the number of required tests. Generally 1-4 is
* considered good, 5-7 ok, 8-10 consider re-factoring, and 11+ re-factor now!
*
* <p>Check has following properties:
*
* <p><b>switchBlockAsSingleDecisionPoint</b> - controls whether to treat the whole switch
* block as a single decision point. Default value is <b>false</b>
*
*
* @author <a href="mailto:simon@redhillconsulting.com.au">Simon Harris</a>
* @author Oliver Burn
* @author <a href="mailto:andreyselkin@gmail.com">Andrei Selkin</a>
*/
public class CyclomaticComplexityCheck
extends AbstractCheck {
/**
* A key is pointing to the warning message text in "messages.properties"
* file.
*/
public static final String MSG_KEY = "cyclomaticComplexity";
/** The initial current value. */
private static final BigInteger INITIAL_VALUE = BigInteger.ONE;
/** Default allowed complexity. */
private static final int DEFAULT_COMPLEXITY_VALUE = 10;
/** Stack of values - all but the current value. */
private final Deque<BigInteger> valueStack = new ArrayDeque<>();
/** Whether to treat the whole switch block as a single decision point.*/
private boolean switchBlockAsSingleDecisionPoint;
/** The current value. */
private BigInteger currentValue = INITIAL_VALUE;
/** Threshold to report error for. */
private int max = DEFAULT_COMPLEXITY_VALUE;
/**
* Sets whether to treat the whole switch block as a single decision point.
* @param switchBlockAsSingleDecisionPoint whether to treat the whole switch
* block as a single decision point.
*/
public void setSwitchBlockAsSingleDecisionPoint(boolean switchBlockAsSingleDecisionPoint) {
this.switchBlockAsSingleDecisionPoint = switchBlockAsSingleDecisionPoint;
}
/**
* Set the maximum threshold allowed.
*
* @param max the maximum threshold
*/
public final void setMax(int max) {
this.max = max;
}
@Override
public int[] getDefaultTokens() {
return new int[] {
TokenTypes.CTOR_DEF,
TokenTypes.METHOD_DEF,
TokenTypes.INSTANCE_INIT,
TokenTypes.STATIC_INIT,
TokenTypes.LITERAL_WHILE,
TokenTypes.LITERAL_DO,
TokenTypes.LITERAL_FOR,
TokenTypes.LITERAL_IF,
TokenTypes.LITERAL_SWITCH,
TokenTypes.LITERAL_CASE,
TokenTypes.LITERAL_CATCH,
TokenTypes.QUESTION,
TokenTypes.LAND,
TokenTypes.LOR,
};
}
@Override
public int[] getAcceptableTokens() {
return new int[] {
TokenTypes.CTOR_DEF,
TokenTypes.METHOD_DEF,
TokenTypes.INSTANCE_INIT,
TokenTypes.STATIC_INIT,
TokenTypes.LITERAL_WHILE,
TokenTypes.LITERAL_DO,
TokenTypes.LITERAL_FOR,
TokenTypes.LITERAL_IF,
TokenTypes.LITERAL_SWITCH,
TokenTypes.LITERAL_CASE,
TokenTypes.LITERAL_CATCH,
TokenTypes.QUESTION,
TokenTypes.LAND,
TokenTypes.LOR,
};
}
@Override
public final int[] getRequiredTokens() {
return new int[] {
TokenTypes.CTOR_DEF,
TokenTypes.METHOD_DEF,
TokenTypes.INSTANCE_INIT,
TokenTypes.STATIC_INIT,
};
}
@Override
public void visitToken(DetailAST ast) {
switch (ast.getType()) {
case TokenTypes.CTOR_DEF:
case TokenTypes.METHOD_DEF:
case TokenTypes.INSTANCE_INIT:
case TokenTypes.STATIC_INIT:
visitMethodDef();
break;
default:
visitTokenHook(ast);
}
}
@Override
public void leaveToken(DetailAST ast) {
switch (ast.getType()) {
case TokenTypes.CTOR_DEF:
case TokenTypes.METHOD_DEF:
case TokenTypes.INSTANCE_INIT:
case TokenTypes.STATIC_INIT:
leaveMethodDef(ast);
break;
default:
break;
}
}
/**
* Hook called when visiting a token. Will not be called the method
* definition tokens.
*
* @param ast the token being visited
*/
protected final void visitTokenHook(DetailAST ast) {
if (switchBlockAsSingleDecisionPoint) {
if (ast.getType() != TokenTypes.LITERAL_CASE) {
incrementCurrentValue(BigInteger.ONE);
}
}
else if (ast.getType() != TokenTypes.LITERAL_SWITCH) {
incrementCurrentValue(BigInteger.ONE);
}
}
/**
* Process the end of a method definition.
*
* @param ast the token representing the method definition
*/
private void leaveMethodDef(DetailAST ast) {
final BigInteger bigIntegerMax = BigInteger.valueOf(max);
if (currentValue.compareTo(bigIntegerMax) > 0) {
log(ast, MSG_KEY, currentValue, bigIntegerMax);
}
popValue();
}
/**
* Increments the current value by a specified amount.
*
* @param amount the amount to increment by
*/
protected final void incrementCurrentValue(BigInteger amount) {
currentValue = currentValue.add(amount);
}
/** Push the current value on the stack. */
protected final void pushValue() {
valueStack.push(currentValue);
currentValue = INITIAL_VALUE;
}
/**
* Pops a value off the stack and makes it the current value.
* @return pop a value off the stack and make it the current value
*/
protected final BigInteger popValue() {
currentValue = valueStack.pop();
return currentValue;
}
/** Process the start of the method definition. */
private void visitMethodDef() {
pushValue();
}
}