src/main/java/org/apache/maven/plugins/pmd/exec/PmdExecutor.java - maven-pmd-plugin - Git at Google

 package org.apache.maven.plugins.pmd.exec;

 /*
  * 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 java.io.Closeable;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.io.OutputStreamWriter;
 import java.io.Writer;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;

 import org.apache.maven.plugin.MojoExecutionException;
 import org.apache.maven.plugins.pmd.ExcludeViolationsFromFile;
 import org.apache.maven.reporting.MavenReportException;
 import org.codehaus.plexus.util.FileUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 import net.sourceforge.pmd.PmdAnalysis;
 import net.sourceforge.pmd.PMDConfiguration;
 import net.sourceforge.pmd.Report;
 import net.sourceforge.pmd.RulePriority;
 import net.sourceforge.pmd.RuleSetLoadException;
 import net.sourceforge.pmd.RuleSetLoader;
 import net.sourceforge.pmd.RuleViolation;
 import net.sourceforge.pmd.benchmark.TextTimingReportRenderer;
 import net.sourceforge.pmd.benchmark.TimeTracker;
 import net.sourceforge.pmd.benchmark.TimingReport;
 import net.sourceforge.pmd.benchmark.TimingReportRenderer;
 import net.sourceforge.pmd.lang.Language;
 import net.sourceforge.pmd.lang.LanguageRegistry;
 import net.sourceforge.pmd.lang.LanguageVersion;
 import net.sourceforge.pmd.renderers.CSVRenderer;
 import net.sourceforge.pmd.renderers.HTMLRenderer;
 import net.sourceforge.pmd.renderers.Renderer;
 import net.sourceforge.pmd.renderers.TextRenderer;
 import net.sourceforge.pmd.renderers.XMLRenderer;
 import net.sourceforge.pmd.util.Predicate;

 /**
  * Executes PMD with the configuration provided via {@link PmdRequest}.
  */
 public class PmdExecutor extends Executor
 {
     private static final Logger LOG = LoggerFactory.getLogger( PmdExecutor.class );

     public static PmdResult execute( PmdRequest request ) throws MavenReportException
     {
         if ( request.getJavaExecutable() != null )
         {
             return fork( request );
         }

         // make sure the class loaders are correct and call this in the same JVM
         ClassLoader origLoader = Thread.currentThread().getContextClassLoader();
         try
         {
             Thread.currentThread().setContextClassLoader( PmdExecutor.class.getClassLoader() );
             PmdExecutor executor = new PmdExecutor( request );
             return executor.run();
         }
         finally
         {
             Thread.currentThread().setContextClassLoader( origLoader );
         }
     }

     private static PmdResult fork( PmdRequest request )
             throws MavenReportException
     {
         File basePmdDir = new File ( request.getTargetDirectory(), "pmd" );
         basePmdDir.mkdirs();
         File pmdRequestFile = new File( basePmdDir, "pmdrequest.bin" );
         try ( ObjectOutputStream out = new ObjectOutputStream( new FileOutputStream( pmdRequestFile ) ) )
         {
             out.writeObject( request );
         }
         catch ( IOException e )
         {
             throw new MavenReportException( e.getMessage(), e );
         }

         String classpath = buildClasspath();
         ProcessBuilder pb = new ProcessBuilder();
         // note: using env variable instead of -cp cli arg to avoid length limitations under Windows
         pb.environment().put( "CLASSPATH", classpath );
         pb.command().add( request.getJavaExecutable() );
         pb.command().add( PmdExecutor.class.getName() );
         pb.command().add( pmdRequestFile.getAbsolutePath() );

         LOG.debug( "Executing: CLASSPATH={}, command={}", classpath, pb.command() );
         try
         {
             final Process p = pb.start();
             // Note: can't use pb.inheritIO(), since System.out/System.err has been modified after process start
             // and inheritIO would only inherit file handles, not the changed streams.
             ProcessStreamHandler.start( p.getInputStream(), System.out );
             ProcessStreamHandler.start( p.getErrorStream(), System.err );
             int exit = p.waitFor();
             LOG.debug( "PmdExecutor exit code: {}", exit );
             if ( exit != 0 )
             {
                 throw new MavenReportException( "PmdExecutor exited with exit code " + exit );
             }
             return new PmdResult( new File( request.getTargetDirectory(), "pmd.xml" ), request.getOutputEncoding() );
         }
         catch ( IOException e )
         {
             throw new MavenReportException( e.getMessage(), e );
         }
         catch ( InterruptedException e )
         {
             Thread.currentThread().interrupt();
             throw new MavenReportException( e.getMessage(), e );
         }
     }

     /**
      * Execute PMD analysis from CLI.
      *
      * <p>
      * Single arg with the filename to the serialized {@link PmdRequest}.
      *
      * <p>
      * Exit-code: 0 = success, 1 = failure in executing
      *
      * @param args
      */
     public static void main( String[] args )
     {
         File requestFile = new File( args[0] );
         try ( ObjectInputStream in = new ObjectInputStream( new FileInputStream( requestFile ) ) )
         {
             PmdRequest request = (PmdRequest) in.readObject();
             PmdExecutor pmdExecutor = new PmdExecutor( request );
             pmdExecutor.setupLogLevel( request.getLogLevel() );
             pmdExecutor.run();
             System.exit( 0 );
         }
         catch ( IOException | ClassNotFoundException | MavenReportException e )
         {
             LOG.error( e.getMessage(), e );
         }
         System.exit( 1 );
     }

     private final PmdRequest request;

     public PmdExecutor( PmdRequest request )
     {
         this.request = Objects.requireNonNull( request );
     }

     private PmdResult run() throws MavenReportException
     {
         setupPmdLogging( request.isShowPmdLog(), request.getLogLevel() );

         PMDConfiguration configuration = new PMDConfiguration();
         LanguageVersion languageVersion = null;
         Language language = LanguageRegistry
                 .findLanguageByTerseName( request.getLanguage() != null ? request.getLanguage() : "java" );
         if ( language == null )
         {
             throw new MavenReportException( "Unsupported language: " + request.getLanguage() );
         }
         if ( request.getLanguageVersion() != null )
         {
             languageVersion = language.getVersion( request.getLanguageVersion() );
             if ( languageVersion == null )
             {
                 throw new MavenReportException( "Unsupported targetJdk value '" + request.getLanguageVersion() + "'." );
             }
         }
         else
         {
             languageVersion = language.getDefaultVersion();
         }
         LOG.debug( "Using language " + languageVersion );
         configuration.setDefaultLanguageVersion( languageVersion );

         if ( request.getSourceEncoding() != null )
         {
             configuration.setSourceEncoding( request.getSourceEncoding() );
         }

         configuration.prependAuxClasspath( request.getAuxClasspath() );

         if ( request.getSuppressMarker() != null )
         {
             configuration.setSuppressMarker( request.getSuppressMarker() );
         }
         if ( request.getAnalysisCacheLocation() != null )
         {
             configuration.setAnalysisCacheLocation( request.getAnalysisCacheLocation() );
             LOG.debug( "Using analysis cache location: " + request.getAnalysisCacheLocation() );
         }
         else
         {
             configuration.setIgnoreIncrementalAnalysis( true );
         }

         configuration.setRuleSets( request.getRulesets() );
         configuration.setMinimumPriority( RulePriority.valueOf( request.getMinimumPriority() ) );
         if ( request.getBenchmarkOutputLocation() != null )
         {
             configuration.setBenchmark( true );
         }
         List<File> files = request.getFiles();

         Report report = null;

         if ( request.getRulesets().isEmpty() )
         {
             LOG.debug( "Skipping PMD execution as no rulesets are defined." );
         }
         else
         {
             if ( request.getBenchmarkOutputLocation() != null )
             {
                 TimeTracker.startGlobalTracking();
             }

             try
             {
                 report = processFilesWithPMD( configuration, files );
             }
             finally
             {
                 if ( request.getAuxClasspath() != null )
                 {
                     ClassLoader classLoader = configuration.getClassLoader();
                     if ( classLoader instanceof Closeable )
                     {
                         Closeable closeable = (Closeable) classLoader;
                         try
                         {
                             closeable.close();
                         }
                         catch ( IOException ex )
                         {
                             // ignore
                         }
                     }
                 }
                 if ( request.getBenchmarkOutputLocation() != null )
                 {
                     TimingReport timingReport = TimeTracker.stopGlobalTracking();
                     writeBenchmarkReport( timingReport, request.getBenchmarkOutputLocation(),
                             request.getOutputEncoding() );
                 }
             }
         }

         if ( report != null && !report.getProcessingErrors().isEmpty() )
         {
             List<Report.ProcessingError> errors = report.getProcessingErrors();
             if ( !request.isSkipPmdError() )
             {
                 LOG.error( "PMD processing errors:" );
                 LOG.error( getErrorsAsString( errors, request.isDebugEnabled() ) );
                 throw new MavenReportException( "Found " + errors.size()
                         + " PMD processing errors" );
             }
             LOG.warn( "There are {} PMD processing errors:", errors.size() );
             LOG.warn( getErrorsAsString( errors, request.isDebugEnabled() ) );
         }

         report = removeExcludedViolations( report );
         // always write XML report, as this might be needed by the check mojo
         // we need to output it even if the file list is empty or we have no violations
         // so the "check" goals can check for violations
         writeXmlReport( report );

         // write any other format except for xml and html. xml has just been produced.
         // html format is produced by the maven site formatter. Excluding html here
         // avoids using PMD's own html formatter, which doesn't fit into the maven site
         // considering the html/css styling
         String format = request.getFormat();
         if ( !"html".equals( format ) && !"xml".equals( format ) )
         {
             writeFormattedReport( report );
         }

         return new PmdResult( new File( request.getTargetDirectory(), "pmd.xml" ), request.getOutputEncoding() );
     }

     /**
      * Gets the errors as a single string. Each error is in its own line.
      * @param withDetails if <code>true</code> then add the error details additionally (contains e.g. the stacktrace)
      * @return the errors as string
      */
     private String getErrorsAsString( List<Report.ProcessingError> errors, boolean withDetails )
     {
         List<String> errorsAsString = new ArrayList<>( errors.size() );
         for ( Report.ProcessingError error : errors )
         {
             errorsAsString.add( error.getFile() + ": " + error.getMsg() );
             if ( withDetails )
             {
                 errorsAsString.add( error.getDetail() );
             }
         }
         return String.join( System.lineSeparator(), errorsAsString );
     }

     private void writeBenchmarkReport( TimingReport timingReport, String benchmarkOutputLocation, String encoding )
     {
         try ( Writer writer = new OutputStreamWriter( new FileOutputStream( benchmarkOutputLocation ), encoding ) )
         {
             final TimingReportRenderer renderer = new TextTimingReportRenderer();
             renderer.render( timingReport, writer );
         }
         catch ( IOException e )
         {
             LOG.error( "Unable to generate benchmark file: {}", benchmarkOutputLocation, e );
         }
     }

     private Report processFilesWithPMD( PMDConfiguration pmdConfiguration, List<File> files )
             throws MavenReportException
     {
         Report report = null;
         RuleSetLoader rulesetLoader = RuleSetLoader.fromPmdConfig( pmdConfiguration )
                 .warnDeprecated( true );
         try
         {
             // load the ruleset once to log out any deprecated rules as warnings
             rulesetLoader.loadFromResources( pmdConfiguration.getRuleSetPaths() );
         }
         catch ( RuleSetLoadException e1 )
         {
             throw new MavenReportException( "The ruleset could not be loaded", e1 );
         }

         try ( PmdAnalysis pmdAnalysis = PmdAnalysis.create( pmdConfiguration ) )
         {
             for ( File file : files )
             {
                 pmdAnalysis.files().addFile( file.toPath() );
             }
             LOG.debug( "Executing PMD..." );
             report = pmdAnalysis.performAnalysisAndCollectReport();
             LOG.debug( "PMD finished. Found {} violations.", report.getViolations().size() );
         }
         catch ( Exception e )
         {
             String message = "Failure executing PMD: " + e.getLocalizedMessage();
             if ( !request.isSkipPmdError() )
             {
                 throw new MavenReportException( message, e );
             }
             LOG.warn( message, e );

         }
         return report;
     }

     /**
      * Use the PMD XML renderer to create the XML report format used by the
      * check mojo later on.
      *
      * @param report
      * @throws MavenReportException
      */
     private void writeXmlReport( Report report ) throws MavenReportException
     {
         File targetFile = writeReport( report, new XMLRenderer( request.getOutputEncoding() ) );
         if ( request.isIncludeXmlInSite() )
         {
             File siteDir = new File( request.getReportOutputDirectory() );
             siteDir.mkdirs();
             try
             {
                 FileUtils.copyFile( targetFile, new File( siteDir, "pmd.xml" ) );
             }
             catch ( IOException e )
             {
                 throw new MavenReportException( e.getMessage(), e );
             }
         }
     }

     private File writeReport( Report report, Renderer r ) throws MavenReportException
     {
         if ( r == null )
         {
             return null;
         }

         File targetDir = new File( request.getTargetDirectory() );
         targetDir.mkdirs();
         String extension = r.defaultFileExtension();
         File targetFile = new File( targetDir, "pmd." + extension );
         LOG.debug( "Target PMD output file: {}", targetFile  );
         try ( Writer writer = new OutputStreamWriter( new FileOutputStream( targetFile ),
                 request.getOutputEncoding() ) )
         {
             r.setWriter( writer );
             r.start();
             if ( report != null )
             {
                 r.renderFileReport( report );
             }
             r.end();
             r.flush();
         }
         catch ( IOException ioe )
         {
             throw new MavenReportException( ioe.getMessage(), ioe );
         }

         return targetFile;
     }

     /**
      * Use the PMD renderers to render in any format aside from HTML and XML.
      *
      * @param report
      * @throws MavenReportException
      */
     private void writeFormattedReport( Report report )
             throws MavenReportException
     {
         Renderer renderer = createRenderer( request.getFormat(), request.getOutputEncoding() );
         writeReport( report, renderer );
     }

     /**
      * Create and return the correct renderer for the output type.
      *
      * @return the renderer based on the configured output
      * @throws org.apache.maven.reporting.MavenReportException
      *             if no renderer found for the output type
      */
     public static Renderer createRenderer( String format, String outputEncoding ) throws MavenReportException
     {
         LOG.debug( "Renderer requested: {}", format );
         Renderer result = null;
         if ( "xml".equals( format ) )
         {
             result = new XMLRenderer( outputEncoding );
         }
         else if ( "txt".equals( format ) )
         {
             result = new TextRenderer();
         }
         else if ( "csv".equals( format ) )
         {
             result = new CSVRenderer();
         }
         else if ( "html".equals( format ) )
         {
             result = new HTMLRenderer();
         }
         else if ( !"".equals( format ) && !"none".equals( format ) )
         {
             try
             {
                 result = (Renderer) Class.forName( format ).getConstructor().newInstance();
             }
             catch ( Exception e )
             {
                 throw new MavenReportException(
                         "Can't find PMD custom format " + format + ": " + e.getClass().getName(), e );
             }
         }

         return result;
     }

     private Report removeExcludedViolations( Report report )
             throws MavenReportException
     {
         if ( report == null )
         {
             return null;
         }

         ExcludeViolationsFromFile excludeFromFile = new ExcludeViolationsFromFile();

         try
         {
             excludeFromFile.loadExcludeFromFailuresData( request.getExcludeFromFailureFile() );
         }
         catch ( MojoExecutionException e )
         {
             throw new MavenReportException( "Unable to load exclusions", e );
         }

         LOG.debug( "Removing excluded violations. Using {} configured exclusions.",
                 excludeFromFile.countExclusions() );
         int violationsBefore = report.getViolations().size();

         Report filtered = report.filterViolations( new Predicate<RuleViolation>()
         {
             @Override
             public boolean test( RuleViolation ruleViolation )
             {
                 return !excludeFromFile.isExcludedFromFailure( ruleViolation );
             }
         } );

         int numberOfExcludedViolations = violationsBefore - filtered.getViolations().size();
         LOG.debug( "Excluded {} violations.", numberOfExcludedViolations );
         return filtered;
     }
 }
	package org.apache.maven.plugins.pmd.exec;

	/*
	* 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 java.io.Closeable;
	import java.io.File;
	import java.io.FileInputStream;
	import java.io.FileOutputStream;
	import java.io.IOException;
	import java.io.ObjectInputStream;
	import java.io.ObjectOutputStream;
	import java.io.OutputStreamWriter;
	import java.io.Writer;
	import java.util.ArrayList;
	import java.util.List;
	import java.util.Objects;

	import org.apache.maven.plugin.MojoExecutionException;
	import org.apache.maven.plugins.pmd.ExcludeViolationsFromFile;
	import org.apache.maven.reporting.MavenReportException;
	import org.codehaus.plexus.util.FileUtils;
	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;

	import net.sourceforge.pmd.PmdAnalysis;
	import net.sourceforge.pmd.PMDConfiguration;
	import net.sourceforge.pmd.Report;
	import net.sourceforge.pmd.RulePriority;
	import net.sourceforge.pmd.RuleSetLoadException;
	import net.sourceforge.pmd.RuleSetLoader;
	import net.sourceforge.pmd.RuleViolation;
	import net.sourceforge.pmd.benchmark.TextTimingReportRenderer;
	import net.sourceforge.pmd.benchmark.TimeTracker;
	import net.sourceforge.pmd.benchmark.TimingReport;
	import net.sourceforge.pmd.benchmark.TimingReportRenderer;
	import net.sourceforge.pmd.lang.Language;
	import net.sourceforge.pmd.lang.LanguageRegistry;
	import net.sourceforge.pmd.lang.LanguageVersion;
	import net.sourceforge.pmd.renderers.CSVRenderer;
	import net.sourceforge.pmd.renderers.HTMLRenderer;
	import net.sourceforge.pmd.renderers.Renderer;
	import net.sourceforge.pmd.renderers.TextRenderer;
	import net.sourceforge.pmd.renderers.XMLRenderer;
	import net.sourceforge.pmd.util.Predicate;

	/**
	* Executes PMD with the configuration provided via {@link PmdRequest}.
	*/
	public class PmdExecutor extends Executor
	{
	private static final Logger LOG = LoggerFactory.getLogger( PmdExecutor.class );

	public static PmdResult execute( PmdRequest request ) throws MavenReportException
	{
	if ( request.getJavaExecutable() != null )
	{
	return fork( request );
	}

	// make sure the class loaders are correct and call this in the same JVM
	ClassLoader origLoader = Thread.currentThread().getContextClassLoader();
	try
	{
	Thread.currentThread().setContextClassLoader( PmdExecutor.class.getClassLoader() );
	PmdExecutor executor = new PmdExecutor( request );
	return executor.run();
	}
	finally
	{
	Thread.currentThread().setContextClassLoader( origLoader );
	}
	}

	private static PmdResult fork( PmdRequest request )
	throws MavenReportException
	{
	File basePmdDir = new File ( request.getTargetDirectory(), "pmd" );
	basePmdDir.mkdirs();
	File pmdRequestFile = new File( basePmdDir, "pmdrequest.bin" );
	try ( ObjectOutputStream out = new ObjectOutputStream( new FileOutputStream( pmdRequestFile ) ) )
	{
	out.writeObject( request );
	}
	catch ( IOException e )
	{
	throw new MavenReportException( e.getMessage(), e );
	}

	String classpath = buildClasspath();
	ProcessBuilder pb = new ProcessBuilder();
	// note: using env variable instead of -cp cli arg to avoid length limitations under Windows
	pb.environment().put( "CLASSPATH", classpath );
	pb.command().add( request.getJavaExecutable() );
	pb.command().add( PmdExecutor.class.getName() );
	pb.command().add( pmdRequestFile.getAbsolutePath() );

	LOG.debug( "Executing: CLASSPATH={}, command={}", classpath, pb.command() );
	try
	{
	final Process p = pb.start();
	// Note: can't use pb.inheritIO(), since System.out/System.err has been modified after process start
	// and inheritIO would only inherit file handles, not the changed streams.
	ProcessStreamHandler.start( p.getInputStream(), System.out );
	ProcessStreamHandler.start( p.getErrorStream(), System.err );
	int exit = p.waitFor();
	LOG.debug( "PmdExecutor exit code: {}", exit );
	if ( exit != 0 )
	{
	throw new MavenReportException( "PmdExecutor exited with exit code " + exit );
	}
	return new PmdResult( new File( request.getTargetDirectory(), "pmd.xml" ), request.getOutputEncoding() );
	}
	catch ( IOException e )
	{
	throw new MavenReportException( e.getMessage(), e );
	}
	catch ( InterruptedException e )
	{
	Thread.currentThread().interrupt();
	throw new MavenReportException( e.getMessage(), e );
	}
	}

	/**
	* Execute PMD analysis from CLI.
	*
	* <p>
	* Single arg with the filename to the serialized {@link PmdRequest}.
	*
	* <p>
	* Exit-code: 0 = success, 1 = failure in executing
	*
	* @param args
	*/
	public static void main( String[] args )
	{
	File requestFile = new File( args[0] );
	try ( ObjectInputStream in = new ObjectInputStream( new FileInputStream( requestFile ) ) )
	{
	PmdRequest request = (PmdRequest) in.readObject();
	PmdExecutor pmdExecutor = new PmdExecutor( request );
	pmdExecutor.setupLogLevel( request.getLogLevel() );
	pmdExecutor.run();
	System.exit( 0 );
	}
	catch ( IOException \| ClassNotFoundException \| MavenReportException e )
	{
	LOG.error( e.getMessage(), e );
	}
	System.exit( 1 );
	}

	private final PmdRequest request;

	public PmdExecutor( PmdRequest request )
	{
	this.request = Objects.requireNonNull( request );
	}

	private PmdResult run() throws MavenReportException
	{
	setupPmdLogging( request.isShowPmdLog(), request.getLogLevel() );

	PMDConfiguration configuration = new PMDConfiguration();
	LanguageVersion languageVersion = null;
	Language language = LanguageRegistry
	.findLanguageByTerseName( request.getLanguage() != null ? request.getLanguage() : "java" );
	if ( language == null )
	{
	throw new MavenReportException( "Unsupported language: " + request.getLanguage() );
	}
	if ( request.getLanguageVersion() != null )
	{
	languageVersion = language.getVersion( request.getLanguageVersion() );
	if ( languageVersion == null )
	{
	throw new MavenReportException( "Unsupported targetJdk value '" + request.getLanguageVersion() + "'." );
	}
	}
	else
	{
	languageVersion = language.getDefaultVersion();
	}
	LOG.debug( "Using language " + languageVersion );
	configuration.setDefaultLanguageVersion( languageVersion );

	if ( request.getSourceEncoding() != null )
	{
	configuration.setSourceEncoding( request.getSourceEncoding() );
	}

	configuration.prependAuxClasspath( request.getAuxClasspath() );

	if ( request.getSuppressMarker() != null )
	{
	configuration.setSuppressMarker( request.getSuppressMarker() );
	}
	if ( request.getAnalysisCacheLocation() != null )
	{
	configuration.setAnalysisCacheLocation( request.getAnalysisCacheLocation() );
	LOG.debug( "Using analysis cache location: " + request.getAnalysisCacheLocation() );
	}
	else
	{
	configuration.setIgnoreIncrementalAnalysis( true );
	}

	configuration.setRuleSets( request.getRulesets() );
	configuration.setMinimumPriority( RulePriority.valueOf( request.getMinimumPriority() ) );
	if ( request.getBenchmarkOutputLocation() != null )
	{
	configuration.setBenchmark( true );
	}
	List<File> files = request.getFiles();

	Report report = null;

	if ( request.getRulesets().isEmpty() )
	{
	LOG.debug( "Skipping PMD execution as no rulesets are defined." );
	}
	else
	{
	if ( request.getBenchmarkOutputLocation() != null )
	{
	TimeTracker.startGlobalTracking();
	}

	try
	{
	report = processFilesWithPMD( configuration, files );
	}
	finally
	{
	if ( request.getAuxClasspath() != null )
	{
	ClassLoader classLoader = configuration.getClassLoader();
	if ( classLoader instanceof Closeable )
	{
	Closeable closeable = (Closeable) classLoader;
	try
	{
	closeable.close();
	}
	catch ( IOException ex )
	{
	// ignore
	}
	}
	}
	if ( request.getBenchmarkOutputLocation() != null )
	{
	TimingReport timingReport = TimeTracker.stopGlobalTracking();
	writeBenchmarkReport( timingReport, request.getBenchmarkOutputLocation(),
	request.getOutputEncoding() );
	}
	}
	}

	if ( report != null && !report.getProcessingErrors().isEmpty() )
	{
	List<Report.ProcessingError> errors = report.getProcessingErrors();
	if ( !request.isSkipPmdError() )
	{
	LOG.error( "PMD processing errors:" );
	LOG.error( getErrorsAsString( errors, request.isDebugEnabled() ) );
	throw new MavenReportException( "Found " + errors.size()
	+ " PMD processing errors" );
	}
	LOG.warn( "There are {} PMD processing errors:", errors.size() );
	LOG.warn( getErrorsAsString( errors, request.isDebugEnabled() ) );
	}

	report = removeExcludedViolations( report );
	// always write XML report, as this might be needed by the check mojo
	// we need to output it even if the file list is empty or we have no violations
	// so the "check" goals can check for violations
	writeXmlReport( report );

	// write any other format except for xml and html. xml has just been produced.
	// html format is produced by the maven site formatter. Excluding html here
	// avoids using PMD's own html formatter, which doesn't fit into the maven site
	// considering the html/css styling
	String format = request.getFormat();
	if ( !"html".equals( format ) && !"xml".equals( format ) )
	{
	writeFormattedReport( report );
	}

	return new PmdResult( new File( request.getTargetDirectory(), "pmd.xml" ), request.getOutputEncoding() );
	}

	/**
	* Gets the errors as a single string. Each error is in its own line.
	* @param withDetails if <code>true</code> then add the error details additionally (contains e.g. the stacktrace)
	* @return the errors as string
	*/
	private String getErrorsAsString( List<Report.ProcessingError> errors, boolean withDetails )
	{
	List<String> errorsAsString = new ArrayList<>( errors.size() );
	for ( Report.ProcessingError error : errors )
	{
	errorsAsString.add( error.getFile() + ": " + error.getMsg() );
	if ( withDetails )
	{
	errorsAsString.add( error.getDetail() );
	}
	}
	return String.join( System.lineSeparator(), errorsAsString );
	}

	private void writeBenchmarkReport( TimingReport timingReport, String benchmarkOutputLocation, String encoding )
	{
	try ( Writer writer = new OutputStreamWriter( new FileOutputStream( benchmarkOutputLocation ), encoding ) )
	{
	final TimingReportRenderer renderer = new TextTimingReportRenderer();
	renderer.render( timingReport, writer );
	}
	catch ( IOException e )
	{
	LOG.error( "Unable to generate benchmark file: {}", benchmarkOutputLocation, e );
	}
	}

	private Report processFilesWithPMD( PMDConfiguration pmdConfiguration, List<File> files )
	throws MavenReportException
	{
	Report report = null;
	RuleSetLoader rulesetLoader = RuleSetLoader.fromPmdConfig( pmdConfiguration )
	.warnDeprecated( true );
	try
	{
	// load the ruleset once to log out any deprecated rules as warnings
	rulesetLoader.loadFromResources( pmdConfiguration.getRuleSetPaths() );
	}
	catch ( RuleSetLoadException e1 )
	{
	throw new MavenReportException( "The ruleset could not be loaded", e1 );
	}

	try ( PmdAnalysis pmdAnalysis = PmdAnalysis.create( pmdConfiguration ) )
	{
	for ( File file : files )
	{
	pmdAnalysis.files().addFile( file.toPath() );
	}
	LOG.debug( "Executing PMD..." );
	report = pmdAnalysis.performAnalysisAndCollectReport();
	LOG.debug( "PMD finished. Found {} violations.", report.getViolations().size() );
	}
	catch ( Exception e )
	{
	String message = "Failure executing PMD: " + e.getLocalizedMessage();
	if ( !request.isSkipPmdError() )
	{
	throw new MavenReportException( message, e );
	}
	LOG.warn( message, e );

	}
	return report;
	}

	/**
	* Use the PMD XML renderer to create the XML report format used by the
	* check mojo later on.
	*
	* @param report
	* @throws MavenReportException
	*/
	private void writeXmlReport( Report report ) throws MavenReportException
	{
	File targetFile = writeReport( report, new XMLRenderer( request.getOutputEncoding() ) );
	if ( request.isIncludeXmlInSite() )
	{
	File siteDir = new File( request.getReportOutputDirectory() );
	siteDir.mkdirs();
	try
	{
	FileUtils.copyFile( targetFile, new File( siteDir, "pmd.xml" ) );
	}
	catch ( IOException e )
	{
	throw new MavenReportException( e.getMessage(), e );
	}
	}
	}

	private File writeReport( Report report, Renderer r ) throws MavenReportException
	{
	if ( r == null )
	{
	return null;
	}

	File targetDir = new File( request.getTargetDirectory() );
	targetDir.mkdirs();
	String extension = r.defaultFileExtension();
	File targetFile = new File( targetDir, "pmd." + extension );
	LOG.debug( "Target PMD output file: {}", targetFile );
	try ( Writer writer = new OutputStreamWriter( new FileOutputStream( targetFile ),
	request.getOutputEncoding() ) )
	{
	r.setWriter( writer );
	r.start();
	if ( report != null )
	{
	r.renderFileReport( report );
	}
	r.end();
	r.flush();
	}
	catch ( IOException ioe )
	{
	throw new MavenReportException( ioe.getMessage(), ioe );
	}

	return targetFile;
	}

	/**
	* Use the PMD renderers to render in any format aside from HTML and XML.
	*
	* @param report
	* @throws MavenReportException
	*/
	private void writeFormattedReport( Report report )
	throws MavenReportException
	{
	Renderer renderer = createRenderer( request.getFormat(), request.getOutputEncoding() );
	writeReport( report, renderer );
	}

	/**
	* Create and return the correct renderer for the output type.
	*
	* @return the renderer based on the configured output
	* @throws org.apache.maven.reporting.MavenReportException
	* if no renderer found for the output type
	*/
	public static Renderer createRenderer( String format, String outputEncoding ) throws MavenReportException
	{
	LOG.debug( "Renderer requested: {}", format );
	Renderer result = null;
	if ( "xml".equals( format ) )
	{
	result = new XMLRenderer( outputEncoding );
	}
	else if ( "txt".equals( format ) )
	{
	result = new TextRenderer();
	}
	else if ( "csv".equals( format ) )
	{
	result = new CSVRenderer();
	}
	else if ( "html".equals( format ) )
	{
	result = new HTMLRenderer();
	}
	else if ( !"".equals( format ) && !"none".equals( format ) )
	{
	try
	{
	result = (Renderer) Class.forName( format ).getConstructor().newInstance();
	}
	catch ( Exception e )
	{
	throw new MavenReportException(
	"Can't find PMD custom format " + format + ": " + e.getClass().getName(), e );
	}
	}

	return result;
	}

	private Report removeExcludedViolations( Report report )
	throws MavenReportException
	{
	if ( report == null )
	{
	return null;
	}

	ExcludeViolationsFromFile excludeFromFile = new ExcludeViolationsFromFile();

	try
	{
	excludeFromFile.loadExcludeFromFailuresData( request.getExcludeFromFailureFile() );
	}
	catch ( MojoExecutionException e )
	{
	throw new MavenReportException( "Unable to load exclusions", e );
	}

	LOG.debug( "Removing excluded violations. Using {} configured exclusions.",
	excludeFromFile.countExclusions() );
	int violationsBefore = report.getViolations().size();

	Report filtered = report.filterViolations( new Predicate<RuleViolation>()
	{
	@Override
	public boolean test( RuleViolation ruleViolation )
	{
	return !excludeFromFile.isExcludedFromFailure( ruleViolation );
	}
	} );

	int numberOfExcludedViolations = violationsBefore - filtered.getViolations().size();
	LOG.debug( "Excluded {} violations.", numberOfExcludedViolations );
	return filtered;
	}
	}