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   package org.miloss.fgsms.services.pcs.impl;
   
   import java.util.HashSet;
  import java.util.concurrent.atomic.AtomicReference;
  import java.util.regex.Pattern;
  import org.miloss.fgsms.common.Utility;
  import org.miloss.fgsms.plugins.federation.FederationInterface;
  import org.miloss.fgsms.services.interfaces.policyconfiguration.FederationPolicy;
  import org.miloss.fgsms.services.interfaces.policyconfiguration.FederationPolicyCollection;
  
  /**
   * eventually, all of the validation stuff for the PCS service will end up here
   * with the goal of reducing the line counts
   * @author AO
   */
  public class ValidationTools {
  
      //private static final String ID_PATTERN = "\\p{javaJavaIdentifierStart}\\p{javaJavaIdentifierPart}*";
      //private static final Pattern FQCN = Pattern.compile(ID_PATTERN + "(\\." + ID_PATTERN + ")*");
      // return FQCN.matcher(identifier).matches();
  
       // All Java reserved words that must not be used in a valid package name.
      private static final HashSet reserved;
  
      static {
          reserved = new HashSet();
          reserved.add("abstract");reserved.add("assert");reserved.add("boolean");
          reserved.add("break");reserved.add("byte");reserved.add("case");
          reserved.add("catch");reserved.add("char");reserved.add("class");
          reserved.add("const");reserved.add("continue");reserved.add("default");
          reserved.add("do");reserved.add("double");reserved.add("else");
          reserved.add("enum");reserved.add("extends");reserved.add("false");
          reserved.add("final");reserved.add("finally");reserved.add("float");
          reserved.add("for");reserved.add("if");reserved.add("goto");
          reserved.add("implements");reserved.add("import");reserved.add("instanceof");
          reserved.add("int");reserved.add("interface");reserved.add("long");
          reserved.add("native");reserved.add("new");reserved.add("null");
          reserved.add("package");reserved.add("private");reserved.add("protected");
          reserved.add("public");reserved.add("return");reserved.add("short");
          reserved.add("static");reserved.add("strictfp");reserved.add("super");
          reserved.add("switch");reserved.add("synchronized");reserved.add("this");
          reserved.add("throw");reserved.add("throws");reserved.add("transient");
          reserved.add("true");reserved.add("try");reserved.add("void");
          reserved.add("volatile");reserved.add("while");
      }
  
      /**
       * Checks if the string that is provided is a valid Java package name (contains only
       * [a-z,A-Z,_,$], every element is separated by a single '.' , an element can't be one of Java's
       * reserved words.
       *
       * @param name The package name that needs to be validated.
       * @return <b>true</b> if the package name is valid, <b>false</b> if its not valid.
       */
      public static final boolean isValidPackageName(String name) {
          String[] parts=name.split("\\.",-1);
          for (String part:parts){
              System.out.println(part);
              if (reserved.contains(part)) return false;
              if (!validPart(part)) return false;
          }
          
          return true;
      }
  
      /**
       * Checks that a part (a word between dots) is a valid part to be used in a Java package name.
       * @param part The part between dots (e.g. *PART*.*PART*.*PART*.*PART*).
       * @return <b>true</b> if the part is valid, <b>false</b> if its not valid.
       */
      private static boolean validPart(String part){
          if (part==null || part.length()<1){
              // Package part is null or empty !
              return false;
          }
          if (Character.isJavaIdentifierStart(part.charAt(0))){
              for (int i = 0; i < part.length(); i++){
                  char c = part.charAt(i);
                  if (!Character.isJavaIdentifierPart(c)){
                      // Package part contains invalid JavaIdentifier !
                      return false;
                  }
              }
          }else{
              // Package part does not begin with a valid JavaIdentifier !
              return false;
          }
  
          return true;
      }
      
  
      public static void validateFederationPolicies(FederationPolicyCollection federationPolicyCollection) {
         if (federationPolicyCollection == null) {
             return;
         }
         if (federationPolicyCollection.getFederationPolicy().isEmpty()) {
             return;
         }
         for (FederationPolicy pol : federationPolicyCollection.getFederationPolicy()) {
             if (Utility.stringIsNullOrEmpty(pol.getImplementingClassName())) {
                 throw new IllegalArgumentException("federation class name is null or empty");
             }
             AtomicReference<String> outMessage = new AtomicReference<String>("");
             try {
                 FederationInterface plugin = (FederationInterface) Class.forName(pol.getImplementingClassName()).newInstance();
                 if (!plugin.ValidateConfiguration(pol, outMessage)) {
                     throw new IllegalArgumentException("federation policy parameters are invalid, msg: " + outMessage.get());
                 }
             } catch (Throwable ex) {
                 PCS4jBean.log.error("Unable to load class " + pol.getImplementingClassName(), ex);
                 throw new IllegalArgumentException("federation policy class is invalid: " + pol.getImplementingClassName() + ": " + ex.getMessage());
             }
         }
     }
     
     
 }