com.puppycrawl.tools.checkstyle.checks.sizes.MethodLengthCheck Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of checkstyle Show documentation
Show all versions of checkstyle Show documentation
Checkstyle is a development tool to help programmers write Java code
that adheres to a coding standard
////////////////////////////////////////////////////////////////////////////////
// checkstyle: Checks Java source code for adherence to a set of rules.
// Copyright (C) 2001-2021 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.sizes;
import com.puppycrawl.tools.checkstyle.StatelessCheck;
import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
import com.puppycrawl.tools.checkstyle.api.DetailAST;
import com.puppycrawl.tools.checkstyle.api.FileContents;
import com.puppycrawl.tools.checkstyle.api.TokenTypes;
import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
/**
*
* Checks for long methods and constructors.
*
*
* Rationale: If a method becomes very long it is hard to understand.
* Therefore long methods should usually be refactored into several
* individual methods that focus on a specific task.
*
*
* -
* Property {@code max} - Specify the maximum number of lines allowed.
* Type is {@code int}.
* Default value is {@code 150}.
*
* -
* Property {@code countEmpty} - Control whether to count empty lines and single
* line comments of the form {@code //}.
* Type is {@code boolean}.
* Default value is {@code true}.
*
* -
* Property {@code tokens} - tokens to check
* Type is {@code java.lang.String[]}.
* Validation type is {@code tokenSet}.
* Default value is:
*
* METHOD_DEF,
*
* CTOR_DEF,
*
* COMPACT_CTOR_DEF.
*
*
*
* To configure the check:
*
*
* <module name="MethodLength"/>
*
*
* To configure the check so that it accepts methods with at most 60 lines:
*
*
* <module name="MethodLength">
* <property name="tokens" value="METHOD_DEF"/>
* <property name="max" value="60"/>
* </module>
*
*
* To configure the check so that it accepts methods with at most 60 lines,
* not counting empty lines and single line comments:
*
*
* <module name="MethodLength">
* <property name="tokens" value="METHOD_DEF"/>
* <property name="max" value="60"/>
* <property name="countEmpty" value="false"/>
* </module>
*
*
* Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
*
*
* Violation Message Keys:
*
*
* -
* {@code maxLen.method}
*
*
*
* @since 3.0
*/
@StatelessCheck
public class MethodLengthCheck extends AbstractCheck {
/**
* A key is pointing to the warning message text in "messages.properties"
* file.
*/
public static final String MSG_KEY = "maxLen.method";
/** Default maximum number of lines. */
private static final int DEFAULT_MAX_LINES = 150;
/** Control whether to count empty lines and single line comments of the form {@code //}. */
private boolean countEmpty = true;
/** Specify the maximum number of lines allowed. */
private int max = DEFAULT_MAX_LINES;
@Override
public int[] getDefaultTokens() {
return getAcceptableTokens();
}
@Override
public int[] getAcceptableTokens() {
return new int[] {
TokenTypes.METHOD_DEF,
TokenTypes.CTOR_DEF,
TokenTypes.COMPACT_CTOR_DEF,
};
}
@Override
public int[] getRequiredTokens() {
return CommonUtil.EMPTY_INT_ARRAY;
}
@Override
public void visitToken(DetailAST ast) {
final DetailAST openingBrace = ast.findFirstToken(TokenTypes.SLIST);
if (openingBrace != null) {
final DetailAST closingBrace =
openingBrace.findFirstToken(TokenTypes.RCURLY);
final int length = getLengthOfBlock(openingBrace, closingBrace);
if (length > max) {
final String methodName = ast.findFirstToken(TokenTypes.IDENT).getText();
log(ast, MSG_KEY, length, max, methodName);
}
}
}
/**
* Returns length of code only without comments and blank lines.
*
* @param openingBrace block opening brace
* @param closingBrace block closing brace
* @return number of lines with code for current block
*/
private int getLengthOfBlock(DetailAST openingBrace, DetailAST closingBrace) {
int length = closingBrace.getLineNo() - openingBrace.getLineNo() + 1;
if (!countEmpty) {
final FileContents contents = getFileContents();
final int lastLine = closingBrace.getLineNo();
// lastLine - 1 is actual last line index. Last line is line with curly brace,
// which is always not empty. So, we make it lastLine - 2 to cover last line that
// actually may be empty.
for (int i = openingBrace.getLineNo() - 1; i <= lastLine - 2; i++) {
if (contents.lineIsBlank(i) || contents.lineIsComment(i)) {
length--;
}
}
}
return length;
}
/**
* Setter to specify the maximum number of lines allowed.
*
* @param length the maximum length of a method.
*/
public void setMax(int length) {
max = length;
}
/**
* Setter to control whether to count empty lines and single line comments
* of the form {@code //}.
*
* @param countEmpty whether to count empty and single line comments
* of the form //.
*/
public void setCountEmpty(boolean countEmpty) {
this.countEmpty = countEmpty;
}
}