Module org.eclipse.persistence.jpa.jpql
Package org.eclipse.persistence.jpa.jpql.tools.model.query

Class ChangeSupport

java.lang.Object
org.eclipse.persistence.jpa.jpql.tools.model.query.ChangeSupport
public class ChangeSupport extends Object
This ChangeSupport is responsible to notifies registered listeners upon changes made to a StateObject, those changes are either a property has changed (IPropertyChangeListener) or the content of a list has changed (IListChangeListener).
Since:
2.4
Version:
2.4

  • Constructor Details

    • ChangeSupport

      public ChangeSupport(StateObject source)
      Creates a new ChangeSupport.
      Parameters:
      source - The object for which this object will take care of notifying the listeners upon changes made to the object's internal state
      Throws:
      NullPointerException - The source StateObject cannot be null

  • Method Details

    • addItem

      public <T> void addItem(ListHolderStateObject<T> source, List<T> items, String listName, T item)
      Adds the given item as a child to the given list.
      Type Parameters:
      T - The type of the items
      Parameters:
      source - The ListHolderStateObject from where the change is coming
      items - The list of to which the child is added
      listName - The name associated with the list
      item - The child to become a child of this one

    • addItems

      public <T> void addItems(ListHolderStateObject<T> source, List<T> list, String listName, List<? extends T> items)
      Adds the given items as children to the given list.
      Type Parameters:
      T - The type of the items
      Parameters:
      source - The ListHolderStateObject from where the change is coming
      list - The list of items to which the child is added
      listName - The name associated with the list
      items - The child to become children of this one

    • addListChangeListener

      public void addListChangeListener(String listName, IListChangeListener<?> listener)
      Registers the given IListChangeListener for the specified list. The listener will be notified only when items are added, removed, moved from the list.
      Parameters:
      listName - The name of the list for which the listener will be notified when the content of the list has changed
      listener - The listener to be notified upon changes
      Throws:
      NullPointerException - IListChangeListener cannot be null
      IllegalArgumentException - The listener is already registered with the list name

    • addListener

      protected <T> void addListener(Map<String,List<T>> listeners, Class<?> listenerType, String name, T listener)
      Registers the given list for the specified name. The listener will be notified upon changes.
      Parameters:
      listeners - The list of listeners from which the given listener is added
      listenerType - The type of the listener, which is only used in the exception's message
      name - The name of the event for which the listener is registered
      listener - The listener to register
      Throws:
      NullPointerException - IPropertyChangeListener cannot be null
      IllegalArgumentException - The listener is already registered with the given name

    • addPropertyChangeListener

      public void addPropertyChangeListener(String propertyName, IPropertyChangeListener<?> listener)
      Registers the given IPropertyChangeListener for the specified property. The listener will be notified only for changes to the specified property.
      Parameters:
      propertyName - The name of the property for which the listener was registered
      listener - The listener to be notified upon changes
      Throws:
      NullPointerException - IPropertyChangeListener cannot be null
      IllegalArgumentException - The listener is already registered with the property name

    • canMoveDown

      public <T> boolean canMoveDown(List<T> list, T stateObject)
      Determines whether the given item can be moved down by one position in the list owned by its parent.
      Parameters:
      list - The list used to determine if the given item can be moved down in that list
      stateObject - The item that could potentially be moved down
      Returns:
      true if the object can be moved down by one unit; false otherwise

    • canMoveUp

      public <T> boolean canMoveUp(List<T> list, T item)
      Determines whether the given item can be moved up by one position in the list owned by its parent.
      Parameters:
      list - The list used to determine if the given item can be moved up in that list
      item - The item that could potentially be moved up
      Returns:
      true if the object can be moved up by one unit; false otherwise

    • fireListChangeEvent

      protected <T> void fireListChangeEvent(IListChangeEvent<T> event)

    • firePropertyChanged

      public void firePropertyChanged(String propertyName, Object oldValue, Object newValue)
      Notifies the IPropertyChangeListeners that have been registered with the given property name that the property has changed.
      Parameters:
      propertyName - The name of the property associated with the property change
      oldValue - The old value of the property that changed
      newValue - The new value of the property that changed

    • hasListChangeListeners

      public boolean hasListChangeListeners(String listName)
      Determines whether there are at least one IListChangeListener registered to listen for changes made to the list with the given list name.
      Parameters:
      listName - The name of the list to check if it has registered listeners
      Returns:
      true if listeners have been registered for the given list name; false otherwise

    • hasListeners

      protected boolean hasListeners(Map<String,?> listeners, String name)
      Determines whether there are at least one listener registered.
      Parameters:
      name - The name of the property or list to check if it has registered listeners
      Returns:
      true if listeners have been registered for the given name; false otherwise

    • hasPropertyChangeListeners

      public boolean hasPropertyChangeListeners(String propertyName)
      Determines whether there are at least one IPropertyChangeListener registered to listen for changes made to the property with the given property name.
      Parameters:
      propertyName - The name of the property to check if it has registered listeners
      Returns:
      true if listeners have been registered for the given property name; false otherwise

    • initialize

      protected void initialize(StateObject source)
      Initializes this ChangeSupport.
      Parameters:
      source - The object for which this object will take care of notifying the listeners upon changes made to the object's internal state
      Throws:
      NullPointerException - The source StateObject cannot be null

    • listChangeListeners

      protected <T> ListIterable<IListChangeListener<T>> listChangeListeners(String listName)

    • moveDown

      public <T> void moveDown(ListHolderStateObject<T> source, List<T> items, String listName, T item)
      Moves the given StateObject down by one position in the list owned by its parent.
      Type Parameters:
      T - The type of the items
      Parameters:
      source - The ListHolderStateObject from where the change is coming
      items - The list of items to which the child is moved down
      listName - The name associated with the list
      item - The child to move down within the list

    • moveItem

      protected <T> void moveItem(ListHolderStateObject<T> source, List<T> items, IListChangeEvent.EventType eventType, String listName, T item, int oldIndex, int newIndex)
      Moves the given item from its current position to a new position in the list owned by its parent.
      Type Parameters:
      T - The type of the items
      Parameters:
      source - The ListHolderStateObject from where the change is coming
      items - The list of items to which the child is moved
      eventType - The type describing how the item was moved (up or down)
      listName - The name associated with the list
      item - The child to move within the list
      oldIndex - The current position of the item to move
      newIndex - The new position within the list

    • moveUp

      public <T> void moveUp(ListHolderStateObject<T> source, List<T> items, String listName, T item)
      Moves the given item up by one position in the list owned by its parent.
      Type Parameters:
      T - The type of the items
      Parameters:
      source - The ListHolderStateObject from where the change is coming
      items - The list of items to which the child is moved up
      listName - The name associated with the list
      item - The child to move up within the list

    • propertyChangeListeners

      protected ListIterable<IPropertyChangeListener<?>> propertyChangeListeners(String propertyName)

    • removeItem

      public <T> void removeItem(ListHolderStateObject<T> source, List<T> items, String listName, T item)
      Removes the given item from the list of children.
      Type Parameters:
      T - The type of the items
      Parameters:
      source - The ListHolderStateObject from where the change is coming
      items - The list of item to which the child is removed
      listName - The name associated with the list
      item - The child to removed from the list

    • removeItems

      public <T> void removeItems(ListHolderStateObject<T> source, List<? extends T> list, String listName, Collection<? extends T> items)
      Removes the given items from the list of children.
      Type Parameters:
      T - The type of the items
      Parameters:
      source - The ListHolderStateObject from where the change is coming
      list - The list of items to which the child is removed
      listName - The name associated with the list
      items - The items to removed from the list

    • removeListChangeListener

      public void removeListChangeListener(String listName, IListChangeListener<?> listener)
      Unregisters the given IListChangeListener that was registered for the specified list. The listener will no longer be notified only when items are added, removed, moved from the list.
      Parameters:
      listName - The name of the list for which the listener was registered
      listener - The listener to unregister
      Throws:
      NullPointerException - IListChangeListener cannot be null
      IllegalArgumentException - The listener was never registered with the list name

    • removeListener

      protected <T> void removeListener(Map<String,List<T>> listeners, Class<?> listenerType, String name, T listener)
      Unregisters the given listener that was registered for the specified name. The listener will no longer be notified upon changes.
      Parameters:
      listeners - The list of listeners from which the given listener is removed
      listenerType - The type of the listener, which is only used in the exception's message
      name - The name of the event for which the listener was registered
      listener - The listener to unregister
      Throws:
      NullPointerException - IPropertyChangeListener cannot be null
      IllegalArgumentException - The listener was never registered with the given name

    • removePropertyChangeListener

      public void removePropertyChangeListener(String propertyName, IPropertyChangeListener<?> listener)
      Unregisters the given IPropertyChangeListener that was registered for the specified property. The listener will no longer be notified when the property changes.
      Parameters:
      propertyName - The name of the property for which the listener was registered
      listener - The listener to unregister
      Throws:
      NullPointerException - IPropertyChangeListener cannot be null
      IllegalArgumentException - The listener was never registered with the property name

    • replaceItem

      public <T> void replaceItem(ListHolderStateObject<T> source, List<T> items, String listName, int index, T item)
      Replaces the item at the given position by a new one.
      Type Parameters:
      T - The type of the items
      Parameters:
      source - The ListHolderStateObject from where the change is coming
      items - The list of items to which a child is replaced
      listName - The name associated with the list
      index - The position of the item to replace
      item - The item to replace the one at the given position

    • replaceItems

      public <T> void replaceItems(ListHolderStateObject<T> source, List<T> items, String listName, List<T> newItems)
      Replaces the given list by removing any existing items and adding the items contained in the second list.
      Type Parameters:
      T - The type of the items
      Parameters:
      source - The ListHolderStateObject from where the change is coming
      items - The list of items to which the child is removed
      listName - The name associated with the list
      newItems - The items to removed from the list