package liquibase.precondition;

 import java.util.HashMap;

 import java.util.Map;

 import java.util.SortedSet;

 import java.util.TreeSet;

 import liquibase.changelog.ChangeSet;

 import liquibase.changelog.DatabaseChangeLog;

 import liquibase.database.Database;

 import liquibase.exception.CustomPreconditionErrorException;

 import liquibase.exception.CustomPreconditionFailedException;

 import liquibase.exception.PreconditionErrorException;

 import liquibase.exception.PreconditionFailedException;

 import liquibase.exception.ValidationErrors;

 import liquibase.exception.Warnings;

 import liquibase.precondition.core.ErrorPrecondition;

 import liquibase.precondition.core.FailedPrecondition;

 import liquibase.util.ObjectUtil;

 public class CustomPreconditionWrapper implements Precondition {

     private String className;

     private ClassLoader classLoader;

     private SortedSet<String> params = new TreeSet<String>();

     private Map<String, String> paramValues = new HashMap<String, String>();

     public String getClassName() {

         return className;

     }

     public void setClassName(String className) {

         this.className = className;

     }

     public ClassLoader getClassLoader() {

         return classLoader;

     }

     public void setClassLoader(ClassLoader classLoader) {

         this.classLoader = classLoader;

     }

     public void setParam(String name, String value) {

         this.params.add(name);

         this.paramValues.put(name, value);

     }

     @Override

     public Warnings warn(Database database) {

         return new Warnings();

     }

     @Override

     public ValidationErrors validate(Database database) {

         return new ValidationErrors();

     }

     @Override

     public void check(Database database, DatabaseChangeLog changeLog, ChangeSet changeSet)

             throws PreconditionFailedException, PreconditionErrorException {

         CustomPrecondition customPrecondition;

         try {

             // System.out.println(classLoader.toString());

             try {

                 customPrecondition = (CustomPrecondition) Class.forName(className, true, classLoader).newInstance();

             } catch (ClassCastException e) { // fails in Ant in particular

                 customPrecondition = (CustomPrecondition) Class.forName(className).newInstance();

             }

         } catch (Exception e) {

             throw new PreconditionFailedException("Could not open custom precondition class " + className, changeLog,

                     this);

         }

         for (String param : params) {

             try {

                 ObjectUtil.setProperty(customPrecondition, param, paramValues.get(param));

             } catch (Exception e) {

                 throw new PreconditionFailedException("Error setting parameter " + param + " on custom precondition "

                         + className, changeLog, this);

             }

         }

         try {

             customPrecondition.check(database);

         } catch (CustomPreconditionFailedException e) {

             throw new PreconditionFailedException(new FailedPrecondition("Custom Precondition Failed: "

                     + e.getMessage(), changeLog, this));

         } catch (CustomPreconditionErrorException e) {

             throw new PreconditionErrorException(new ErrorPrecondition(e, changeLog, this));

         }

     }

     @Override

     public String getName() {

         return "customPrecondition";

     }

 }