package org.kuali.rice.krms.api.engine;

 import java.util.Collections;

 import java.util.HashMap;

 import java.util.Map;

 import org.joda.time.DateTime;

 public final class SelectionCriteria {

         private final Long effectiveExecutionTime;

         private final String eventName;

         private final Map<String, String> contextQualifiers;

         private final Map<String, String> agendaQualifiers;

         private SelectionCriteria(String eventName, DateTime effectiveDate) {

                 if (eventName == null || "".equals(eventName.trim())) {

                         throw new IllegalArgumentException("Event name must not be null or empty.");

                 }

                 this.eventName = eventName;

                 if (effectiveDate != null) {

                         this.effectiveExecutionTime = effectiveDate.getMillis();

                 } else {

                         this.effectiveExecutionTime = null;

                 }

                 this.contextQualifiers = new HashMap<String, String>();

                 this.agendaQualifiers = new HashMap<String, String>();

         }

         /**

          * This static factory method creates a SelectionCriteria used to select an Agenda to execute.

          * 

          * @param eventName the event that is triggering rule execution.  Must not be null.

          * @param effectiveExecutionTime the time that the rule is being executed at.  If null, the time of engine execution will be used.

          * @param contextQualifiers qualifiers used to select the context

          * @param agendaQualifiers qualifiers used to select the agenda from the context

          * @return the {@link SelectionCriteria}

          */

         public static SelectionCriteria createCriteria(String eventName, DateTime effectiveExecutionTime, Map<String, String> contextQualifiers, Map<String, String> agendaQualifiers) {

                 SelectionCriteria criteria = new SelectionCriteria(eventName, effectiveExecutionTime);

                 criteria.contextQualifiers.putAll(contextQualifiers);

                 criteria.agendaQualifiers.putAll(agendaQualifiers);

                 return criteria;

         }

         public String getEventName() {

                 return eventName;

         }

         /**

          * This method gets the effective date/time in epoch time, suitable for 

          * converting to a {@link java.util.Date} via {@link java.util.Date#Date(long)}

          * @return the epoch time for effective execution, or null 

          * (which defers to the {@link Engine} but implies that the actual time when execution begins will be used).

          */

         public Long getEffectiveExecutionTime() {

                 return effectiveExecutionTime;

         }

         public Map<String, String> getContextQualifiers() {

                 return Collections.unmodifiableMap(contextQualifiers);

         }

         public Map<String, String> getAgendaQualifiers() {

                 return Collections.unmodifiableMap(agendaQualifiers);

         }

 }