package org.apache.maven.plugin.checkstyle;

 /*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you under the Apache License, Version 2.0 (the

  * "License"); you may not use this file except in compliance

  * with the License.  You may obtain a copy of the License at

  *

  *   http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing,

  * software distributed under the License is distributed on an

  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

  * KIND, either express or implied.  See the License for the

  * specific language governing permissions and limitations

  * under the License.

  */

 import org.apache.maven.plugin.AbstractMojo;

 import org.apache.maven.plugin.MojoExecutionException;

 import org.apache.maven.plugin.MojoFailureException;

 import org.codehaus.plexus.util.xml.pull.MXParser;

 import org.codehaus.plexus.util.xml.pull.XmlPullParser;

 import org.codehaus.plexus.util.xml.pull.XmlPullParserException;

 import java.io.BufferedReader;

 import java.io.File;

 import java.io.FileInputStream;

 import java.io.IOException;

 import java.io.InputStreamReader;

 import java.io.Reader;

 /**

  * Perform a violation check against the last Checkstyle run to see if there are

  * any violations. It reads the Checkstyle output file, counts the number of

  * violations found and displays it on the console.

  *

  * @author <a href="mailto:joakim@erdfelt.net">Joakim Erdfelt</a>

  * @goal check

  * @phase verify

  * @execute goal="checkstyle"

  * @requiresDependencyResolution compile

  */

 public class CheckstyleViolationCheckMojo

     extends AbstractMojo

 {

     /**

      * Specifies the path and filename to save the Checkstyle output. The format

      * of the output file is determined by the <code>outputFileFormat</code>

      * parameter.

      *

      * @parameter expression="${checkstyle.output.file}"

      *            default-value="${project.build.directory}/checkstyle-result.xml"

      */

     private File outputFile;

     /**

      * Specifies the format of the output to be used when writing to the output

      * file. Valid values are "plain" and "xml".

      *

      * @parameter expression="${checkstyle.output.format}" default-value="xml"

      */

     private String outputFileFormat;

     /**

      * Do we fail the build on a violation?

      *

      * @parameter expression="${checkstyle.failOnViolation}"

      *            default-value="true"

      */

     private boolean failOnViolation;

     /**

      * The lowest severity level that is considered a violation.

      * Valid values are "error", "warning" and "info".

      *

      * @parameter expression="${checkstyle.violationSeverity}" default-value="error"

      * @since 2.2

      */

     private String violationSeverity = "error";

     /**

      * Skip entire check.

      *

      * @parameter expression="${checkstyle.skip}" default-value="false"

      * @since 2.2

      */

     private boolean skip;

     /**

      * @see org.apache.maven.plugin.Mojo#execute()

      */

     public void execute()

         throws MojoExecutionException, MojoFailureException

     {

         if ( !skip )

         {

             if ( !"xml".equals( outputFileFormat ) )

             {

                 throw new MojoExecutionException( "Output format is '" + outputFileFormat

                     + "', checkstyle:check requires format to be 'xml'." );

             }

             if ( !outputFile.exists() )

             {

                 getLog().info(

                                "Unable to perform checkstyle:check, "

                                    + "unable to find checkstyle:checkstyle outputFile." );

                 return;

             }

             try

             {

                 XmlPullParser xpp = new MXParser();

                 // TODO: use ReaderFactory.newXmlReader() when plexus-utils can be upgraded

                 Reader freader = new InputStreamReader( new FileInputStream( outputFile ), "UTF-8" );

                 BufferedReader breader = new BufferedReader( freader );

                 xpp.setInput( breader );

                 int violations = countViolations( xpp );

                 if ( violations > 0 )

                 {

                     if ( failOnViolation )

                     {

                         throw new MojoFailureException( "You have " + violations + " Checkstyle violation"

                             + ( ( violations > 1 ) ? "s" : "" ) + "." );

                     }

                     getLog().warn( "checkstyle:check violations detected but failOnViolation set to false" );

                 }

             }

             catch ( IOException e )

             {

                 throw new MojoExecutionException( "Unable to read Checkstyle results xml: "

                     + outputFile.getAbsolutePath(), e );

             }

             catch ( XmlPullParserException e )

             {

                 throw new MojoExecutionException( "Unable to read Checkstyle results xml: "

                     + outputFile.getAbsolutePath(), e );

             }

         }

     }

     private int countViolations( XmlPullParser xpp )

         throws XmlPullParserException, IOException

     {

         int count = 0;

         int eventType = xpp.getEventType();

         while ( eventType != XmlPullParser.END_DOCUMENT )

         {

             if ( eventType == XmlPullParser.START_TAG && "error".equals( xpp.getName() )

                 && isViolation( xpp.getAttributeValue( "", "severity" ) ) )

             {

                 count++;

             }

             eventType = xpp.next();

         }

         return count;

     }

     /**

      * Checks if the given severity is considered a violation.

      *

      * @param severity The severity to check

      * @return <code>true</code> if the given severity is a violation, otherwise <code>false</code>

      */

     private boolean isViolation( String severity )

     {

         if ( "error".equals( severity ) )

         {

             return "error".equals( violationSeverity ) || "warning".equals( violationSeverity )

                 || "info".equals( violationSeverity );

         }

         else if ( "warning".equals( severity ) )

         {

             return "warning".equals( violationSeverity ) || "info".equals( violationSeverity );

         }

         else if ( "info".equals( severity ) )

         {

             return "info".equals( violationSeverity );

         }

         else

         {

             return false;

         }

     }

 }