package org.talos.model;

 import java.util.ArrayList;

 import java.util.Collection;

 import java.util.HashSet;

 import java.util.Set;

 import javax.persistence.DiscriminatorValue;

 import javax.persistence.Entity;

 import javax.persistence.ManyToMany;

 /**

  * This class represents the permission to perform a group of actions. A

  * GroupPermission can imply many different SimplePermissions. For instance, if a group permission called

  * "modify" has simple permissions "add" and "remove", then a subject which is granted "modify" automatically

  * becomes capable of "add" and "remove".

  * 

  * @see #getAllowedPermissions()

  */

 @Entity

 @DiscriminatorValue("Group")

 public class GroupPermission extends Permission implements NamedObject {

         @ManyToMany

         private Set<SimplePermission> simplePermissions = new HashSet<SimplePermission>();

         /**

          * Empty constructor needed by Hibernate.

          * @see #GroupPermission(String) 

          */

         protected GroupPermission() {

                 // empty constructor needed by Hibernate.

         }

         /**

          * Constructor with a name

          * 

          * @param name a non-null string

          */

         public GroupPermission(String name) {

                 super(name);

         }

         /**

          * Gets the simple permissions contained by this group permission.

          * 

          * @return the set of simple permissions contained by this group

          * @see #getAllowedPermissions()

          */

         protected Set<SimplePermission> getSimplePermissions() {

                 return simplePermissions;

         }

         /**

          * Sets the simple permissions contained by this group permission. This method is usually called

          * only by the persistence layer.

          * 

          * @param simplePermissions a set of simple permissions

          */

         protected void setSimplePermissions(Set<SimplePermission> simplePermissions) {

                 this.simplePermissions = simplePermissions;

         }

         /**

          * Adds a simple permission to this group permission. Must be a non-null, persistent 

          * SimplePermission instance.

          * 

          * @param simplePermission the simple permission to add to this group.

          * 

          * @see SimplePermission#add(GroupPermission)

          * @see #remove(SimplePermission)

          * @see #addAll(Collection)

          * @see #getAllowedPermissions()

          */

         public void add(SimplePermission simplePermission) {

                 if (simplePermission == null) {

                         throw new IllegalArgumentException("simplePermission can't be null");

                 }

                 this.getSimplePermissions().add(simplePermission);

                 simplePermission.add(this);

         }

         /**

          * Removes a simple permission from this group permission. Must be a non-null, persistent 

          * SimplePermission instance.

          * 

          * @param simplePermission the simple permission to remove from this group.

          * 

          * @see SimplePermission#remove(GroupPermission)

          * @see #add(SimplePermission)

          * @see #getAllowedPermissions()

          */

         public void remove(SimplePermission simplePermission) {

                 if (simplePermission == null) {

                         throw new IllegalArgumentException("simplePermission can't be null");

                 }

                 this.getSimplePermissions().remove(simplePermission);

                 simplePermission.remove(this);

         }

         /**

          * Gets all permissions allowed by this permission. This includes the group permission

          * itself plus all simple permissions it contains.

          * @return a collection of permissions.

          */

         @Override

         public Collection<Permission> getAllowedPermissions() {

                 Collection<Permission> result = new ArrayList<Permission>(this.getSimplePermissions());

                 result.add(this);

                 return result;

         }

         /**

          * Gets the type of permission. 

          * @return always returns "GroupPermission"

          */

         @Override

         public String getType() {

                 return "GroupPermission";

         }

         @Override

         public Permission copy(String name) {

                 GroupPermission result = new GroupPermission(name);

                 for (SimplePermission simple : this.getSimplePermissions()) {

                         result.add(simple);

                 }

                 return result;

         }

         /**

          * Adds several simple permissions to this group.

          * 

          * @param perms a list of simple permissions

          * @see #add(SimplePermission)

          * @see #getAllowedPermissions()

          */

         public void addAll(Collection<? extends SimplePermission> perms) {

                 for (SimplePermission p : perms) {

                         this.add(p);

                 }

         }

 }