package liquibase.precondition.core;
   
   import liquibase.changelog.DatabaseChangeLog;
   import liquibase.changelog.ChangeSet;
   import liquibase.database.Database;
   import liquibase.exception.PreconditionErrorException;
   import liquibase.exception.PreconditionFailedException;
   import liquibase.exception.ValidationErrors;
   import liquibase.exception.Warnings;
  import liquibase.precondition.Precondition;
  import liquibase.precondition.PreconditionLogic;
  
  import java.util.ArrayList;
  import java.util.List;
  
  /**
   * Class for controling "or" logic in preconditions.
   */
  public class OrPrecondition extends PreconditionLogic {
  
      public Warnings warn(Database database) {
          return new Warnings();
      }
  
      public ValidationErrors validate(Database database) {
          return new ValidationErrors();
      }
  
      public void check(Database database, DatabaseChangeLog changeLog, ChangeSet changeSet)
              throws PreconditionFailedException, PreconditionErrorException {
          boolean onePassed = false;
          List<FailedPrecondition> failures = new ArrayList<FailedPrecondition>();
          for (Precondition precondition : getNestedPreconditions()) {
              try {
                  precondition.check(database, changeLog, changeSet);
                  onePassed = true;
                  break;
              } catch (PreconditionFailedException e) {
                  failures.addAll(e.getFailedPreconditions());
              }
          }
          if (!onePassed) {
              throw new PreconditionFailedException(failures);
          }
      }
  
      public String getName() {
          return "or";
      }
  }