/**
    * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
    */
   package net.sourceforge.pmd;
   
   import java.io.File;
   import java.util.Map;
   import java.util.concurrent.ConcurrentHashMap;
   
  import net.sourceforge.pmd.lang.LanguageVersion;
  
  /**
   * The RuleContext provides access to Rule processing state.  This information
   * includes the following global information:
   * <ul>
   * 	<li>The Report to which Rule Violations are sent.</li>
   * 	<li>Named attributes.</li>
   * </ul>
   * As well as the following source file specific information:
   * <ul>
   * 	<li>A File for the source file.</li>
   * 	<li>A String for the name of the source file.</li>
   * 	<li>The Language Version of the source file.</li>
   * </ul>
   * It is <strong>required</strong> that all source file specific options
   * be set between calls to difference source files.  Failure to do so, may
   * result in undefined behavior.
   */
  public class RuleContext {
  
      private Report report = new Report();
      private File sourceCodeFile;
      private String sourceCodeFilename;
      private LanguageVersion languageVersion;
      private final Map<String, Object> attributes;
  
      /**
       * Default constructor.
       */
      public RuleContext() {
  	attributes = new ConcurrentHashMap<String, Object>();
      }
  
      /**
       * Constructor which shares attributes and report listeners with the given RuleContext.
       */
      public RuleContext(RuleContext ruleContext) {
  	this.attributes = ruleContext.attributes;
  	this.report.addSynchronizedListeners(ruleContext.getReport().getSynchronizedListeners());
      }
  
      /**
       * Get the Report to which Rule Violations are sent.
       * @return The Report.
       */
      public Report getReport() {
  	return report;
      }
  
      /**
       * Set the Report to which Rule Violations are sent.
       * @param report The Report.
       */
      public void setReport(Report report) {
  	this.report = report;
      }
  
      /**
       * Get the File associated with the current source file.
       * @return The File.
       */
      public File getSourceCodeFile() {
  	return sourceCodeFile;
      }
  
      /**
       * Set the File associated with the current source file.
       * While this may be set to <code>null</code>, the exclude/include
       * facilities will not work properly without a File.
       * @param sourceCodeFile The File.
       */
      public void setSourceCodeFile(File sourceCodeFile) {
  	this.sourceCodeFile = sourceCodeFile;
      }
  
      /**
       * Get the file name associated with the current source file.
       * @return The file name.
       */
      public String getSourceCodeFilename() {
  	return sourceCodeFilename;
      }
  
      /**
       * Set the file name associated with the current source file.
       * @param filename The file name.
       */
      public void setSourceCodeFilename(String filename) {
  	this.sourceCodeFilename = filename;
     }
 
     /**
      * Get the LanguageVersion associated with the current source file.
      * @return The LanguageVersion, <code>null</code> if unknown.
      */
     public LanguageVersion getLanguageVersion() {
 	return this.languageVersion;
     }
 
     /**
      * Set the LanguageVersion associated with the current source file.
      * This may be set to <code>null</code> to indicate the version is
      * unknown and should be automatically determined.
      *
      * @param languageVersion The LanguageVersion.
      */
     public void setLanguageVersion(LanguageVersion languageVersion) {
 	this.languageVersion = languageVersion;
     }
 
     /**
      * Set an attribute value on the RuleContext, if it does not already exist.
      * <p>
      * Attributes can be shared between RuleContext instances.  This operation
      * is thread-safe.
      * <p>
      * Attribute values should be modified directly via the reference provided.
      * It is not necessary to call <code>setAttribute(String, Object)</code> to
      * update an attribute value.  Modifications made to the attribute value
      * will automatically be seen by other threads.  Because of this, you must
      * ensure the attribute values are themselves thread safe.
      *
      * @param name The attribute name.
      * @param value The attribute value.
      * @exception IllegalArgumentException if <code>name</code> or <code> value</code> are <code>null</code>
      * @return <code>true</code> if the attribute was set, <code>false</code> otherwise.
      */
     public boolean setAttribute(String name, Object value) {
 	if (name == null) {
 	    throw new IllegalArgumentException("Parameter 'name' cannot be null.");
 	}
 	if (value == null) {
 	    throw new IllegalArgumentException("Parameter 'value' cannot be null.");
 	}
 	synchronized (this.attributes) {
 	    if (!this.attributes.containsKey(name)) {
 		this.attributes.put(name, value);
 		return true;
 	    } else {
 		return false;
 	    }
 	}
     }
 
     /**
      * Get an attribute value on the RuleContext.
      * <p>
      * Attributes can be shared between RuleContext instances.  This operation
      * is thread-safe.
      * <p>
      * Attribute values should be modified directly via the reference provided.
      * It is not necessary to call <code>setAttribute(String, Object)</code> to
      * update an attribute value.  Modifications made to the attribute value
      * will automatically be seen by other threads.  Because of this, you must
      * ensure the attribute values are themselves thread safe.
      *
      * @param name The attribute name.
      * @return The current attribute value, or <code>null</code> if the attribute does not exist.
      */
     public Object getAttribute(String name) {
 	return this.attributes.get(name);
     }
 
     /**
      * Remove an attribute value on the RuleContext.
      * <p>
      * Attributes can be shared between RuleContext instances.  This operation
      * is thread-safe.
      * <p>
      * Attribute values should be modified directly via the reference provided.
      * It is not necessary to call <code>setAttribute(String, Object)</code> to
      * update an attribute value.  Modifications made to the attribute value
      * will automatically be seen by other threads.  Because of this, you must
      * ensure the attribute values are themselves thread safe.
      *
      * @param name The attribute name.
      * @return The current attribute value, or <code>null</code> if the attribute does not exist.
      */
     public Object removeAttribute(String name) {
 	return this.attributes.remove(name);
     }
 }