package gw.search
uses gw.api.database.IQueryBeanResult
uses gw.api.util.DisplayableException
uses java.io.Serializable

/**
 * Abstract class defining a search criteria used for searching via the UI.
 */
@ReadOnly
abstract class EntitySearchCriteria<T extends KeyableBean> implements Serializable {
  
  /**
   * Return null if we have valid search criteria.  Otherwise, return the error message.
   */
  abstract protected property get InvalidSearchCriteriaMessage() : String
  
  /**
   * Return true if we have valid search criteria.
   */
  final property get HasValidSearchCriteria() : boolean {
    return InvalidSearchCriteriaMessage == null
  }
  
  /**
   * Return null if we have sufficient information for a meaningful search.  Otherwise
   * return the error message.
   */
  abstract protected property get MinimumSearchCriteriaMessage() : String

  /**
   * Return true if we have sufficient information for a meaningful search.
   */
  final property get HasMinimumSearchCriteria() : boolean {
    return MinimumSearchCriteriaMessage == null
  }
  
  /**
   * Execute a search for this search criteria and return the result.
   */
  abstract protected function doSearch() : IQueryBeanResult

  /**
   * Throw the MinimumSearchCriteriaMessage as a DisplayableException if
   * this search criteria doesn't have enough information.  Otherwise
   * execute the search and return the result.
   */
  final function performSearch() : IQueryBeanResult<T> {
    if (not HasValidSearchCriteria) {
      throw new DisplayableException(InvalidSearchCriteriaMessage)
    }
    if (not HasMinimumSearchCriteria) {
      throw new DisplayableException(MinimumSearchCriteriaMessage)
    }
    return doSearch() as IQueryBeanResult<T>
  }

}