RegexpMultilineCheck.java
////////////////////////////////////////////////////////////////////////////////
// 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.regexp;
import java.io.File;
import java.util.regex.Pattern;
import com.puppycrawl.tools.checkstyle.StatelessCheck;
import com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck;
import com.puppycrawl.tools.checkstyle.api.FileText;
/**
* <p>
* Checks that a specified pattern matches across multiple lines in any file type.
* </p>
* <p>
* Rationale: This check can be used to when the regular expression can be span multiple lines.
* </p>
* <ul>
* <li>
* Property {@code format} - Specify the format of the regular expression to match.
* Type is {@code java.lang.String}.
* Default value is {@code "$."}.
* </li>
* <li>
* Property {@code message} - Specify the message which is used to notify about
* violations, if empty then default (hard-coded) message is used.
* Type is {@code java.lang.String}.
* Default value is {@code null}.
* </li>
* <li>
* Property {@code ignoreCase} - Control whether to ignore case when searching.
* Type is {@code boolean}.
* Default value is {@code false}.
* </li>
* <li>
* Property {@code minimum} - Specify the minimum number of matches required in each file.
* Type is {@code int}.
* Default value is {@code 0}.
* </li>
* <li>
* Property {@code maximum} - Specify the maximum number of matches required in each file.
* Type is {@code int}.
* Default value is {@code 0}.
* </li>
* <li>
* Property {@code matchAcrossLines} - Control whether to match expressions
* across multiple lines.
* Type is {@code boolean}.
* Default value is {@code false}.
* </li>
* <li>
* Property {@code fileExtensions} - Specify the file type extension of files to process.
* Type is {@code java.lang.String[]}.
* Default value is {@code ""}.
* </li>
* </ul>
* <p>
* To run the check with its default configuration (no matches will be):
* </p>
* <pre>
* <module name="RegexpMultiline"/>
* </pre>
* <p>Example: </p>
* <pre>
* void method() {
* int i = 5; // OK
* System.out.println(i); // OK
* }
* </pre>
* <p>
* To configure the check to find calls to print to the console:
* </p>
* <pre>
* <module name="RegexpMultiline">
* <property name="format" value="System\.(out)|(err)\.print(ln)?\("/>
* </module>
* </pre>
* <p>
* Example:
* </p>
* <pre>
* void method() {
* System.out.print("Example"); // violation
* System.err.println("Example"); // violation
* System.out.print
* ("Example"); // violation
* System.err.println
* ("Example"); // OK
* System
* .out.print("Example"); // OK
* System
* .err.println("Example"); // violation
* System.
* out.print("Example"); // OK
* System.
* err.println("Example"); // violation
* }
* </pre>
* <p>
* To configure the check to match text that spans multiple lines,
* like normal code in a Java file:
* </p>
* <pre>
* <module name="RegexpMultiline">
* <property name="matchAcrossLines" value="true"/>
* <property name="format" value="System\.out.*?print\("/>
* </module>
* </pre>
* <p>
* Example:
* </p>
* <pre>
* void method() {
* System.out.print("Example"); // violation
* System.err.println("Example");
* System.out.print // violation
* ("Example");
* System.err.println
* ("Example");
* System
* .out.print("Example");
* System
* .err.println("Example");
* System.
* out.print("Example");
* System.
* err.println("Example");
* }
* </pre>
* <p>
* Note: Beware of the greedy regular expression used in the above example.
* {@code .*} will match as much as possible and not produce multiple violations
* in the file if multiple groups of lines could match the expression. To prevent
* an expression being too greedy, avoid overusing matching all text or allow it
* to be optional, like {@code .*?}. Changing the example expression to not be
* greedy will allow multiple violations in the example to be found in the same file.
* </p>
* <p>
* To configure the check to match a maximum of three test strings:
* </p>
* <pre>
* <module name="RegexpMultiline">
* <property name="format" value="Test #[0-9]+:[A-Za-z ]+"/>
* <property name="ignoreCase" value="true"/>
* <property name="maximum" value="3"/>
* </module>
* </pre>
* <p>
* Example:
* </p>
* <pre>
* void method() {
* System.out.println("Test #1: this is a test string"); // OK
* System.out.println("TeSt #2: This is a test string"); // OK
* System.out.println("TEST #3: This is a test string"); // OK
* int i = 5;
* System.out.println("Value of i: " + i);
* System.out.println("Test #4: This is a test string"); // violation
* System.out.println("TEst #5: This is a test string"); // violation
* }
* </pre>
* <p>
* To configure the check to match a minimum of two test strings:
* </p>
* <pre>
* <module name="RegexpMultiline">
* <property name="format" value="Test #[0-9]+:[A-Za-z ]+"/>
* <property name="minimum" value="2"/>
* </module>
* </pre>
* <p>
* Example:
* </p>
* <pre>
* void method() {
* System.out.println("Test #1: this is a test string"); // violation
* System.out.println("TEST #2: This is a test string"); // OK, "ignoreCase" is false by default
* int i = 5;
* System.out.println("Value of i: " + i);
* System.out.println("Test #3: This is a test string"); // violation
* System.out.println("Test #4: This is a test string"); // violation
* }
* </pre>
* <p>
* To configure the check to restrict an empty file:
* </p>
* <pre>
* <module name="RegexpMultiline">
* <property name="format" value="^\s*$" />
* <property name="matchAcrossLines" value="true" />
* <property name="message" value="Empty file is not allowed" />
* </module>
* </pre>
* <p>
* Example of violation from the above config:
* </p>
* <pre>
* /var/tmp$ cat -n Test.java
* 1
* 2
* 3
* 4
* </pre>
* <p>Result:</p>
* <pre>
* /var/tmp/Test.java // violation, a file must not be empty.
* </pre>
* <p>
* Parent is {@code com.puppycrawl.tools.checkstyle.Checker}
* </p>
* <p>
* Violation Message Keys:
* </p>
* <ul>
* <li>
* {@code regexp.StackOverflowError}
* </li>
* <li>
* {@code regexp.empty}
* </li>
* <li>
* {@code regexp.exceeded}
* </li>
* <li>
* {@code regexp.minimum}
* </li>
* </ul>
*
* @since 5.0
*/
@StatelessCheck
public class RegexpMultilineCheck extends AbstractFileSetCheck {
/** Specify the format of the regular expression to match. */
private String format = "$.";
/**
* Specify the message which is used to notify about violations,
* if empty then default (hard-coded) message is used.
*/
private String message;
/** Specify the minimum number of matches required in each file. */
private int minimum;
/** Specify the maximum number of matches required in each file. */
private int maximum;
/** Control whether to ignore case when searching. */
private boolean ignoreCase;
/** Control whether to match expressions across multiple lines. */
private boolean matchAcrossLines;
/** The detector to use. */
private MultilineDetector detector;
@Override
public void beginProcessing(String charset) {
final DetectorOptions options = DetectorOptions.newBuilder()
.reporter(this)
.compileFlags(getRegexCompileFlags())
.format(format)
.message(message)
.minimum(minimum)
.maximum(maximum)
.ignoreCase(ignoreCase)
.build();
detector = new MultilineDetector(options);
}
@Override
protected void processFiltered(File file, FileText fileText) {
detector.processLines(fileText);
}
/**
* Retrieves the compile flags for the regular expression being built based
* on {@code matchAcrossLines}.
*
* @return The compile flags.
*/
private int getRegexCompileFlags() {
final int result;
if (matchAcrossLines) {
result = Pattern.DOTALL;
}
else {
result = Pattern.MULTILINE;
}
return result;
}
/**
* Setter to specify the format of the regular expression to match.
*
* @param format the format of the regular expression to match.
*/
public void setFormat(String format) {
this.format = format;
}
/**
* Setter to specify the message which is used to notify about violations,
* if empty then default (hard-coded) message is used.
*
* @param message the message to report for a match.
*/
public void setMessage(String message) {
this.message = message;
}
/**
* Setter to specify the minimum number of matches required in each file.
*
* @param minimum the minimum number of matches required in each file.
*/
public void setMinimum(int minimum) {
this.minimum = minimum;
}
/**
* Setter to specify the maximum number of matches required in each file.
*
* @param maximum the maximum number of matches required in each file.
*/
public void setMaximum(int maximum) {
this.maximum = maximum;
}
/**
* Setter to control whether to ignore case when searching.
*
* @param ignoreCase whether to ignore case when searching.
*/
public void setIgnoreCase(boolean ignoreCase) {
this.ignoreCase = ignoreCase;
}
/**
* Setter to control whether to match expressions across multiple lines.
*
* @param matchAcrossLines whether to match expressions across multiple lines.
*/
public void setMatchAcrossLines(boolean matchAcrossLines) {
this.matchAcrossLines = matchAcrossLines;
}
}