java.awt.event

Class ContainerEvent

  • All Implemented Interfaces:
    Serializable 

    public class ContainerEvent
extends ComponentEvent
    A low-level event which indicates that a container's contents changed because a component was added or removed.

    Container events are provided for notification purposes ONLY; The AWT will automatically handle changes to the containers contents internally so that the program works properly regardless of whether the program is receiving these events or not.

    This low-level event is generated by a container object (such as a Panel) when a component is added to it or removed from it. The event is passed to every ContainerListener or ContainerAdapter object which registered to receive such events using the component's addContainerListener method. (ContainerAdapter objects implement the ContainerListener interface.) Each such listener object gets this ContainerEvent when the event occurs.

    An unspecified behavior will be caused if the id parameter of any particular ContainerEvent instance is not in the range from CONTAINER_FIRST to CONTAINER_LAST.

    Since:
    1.1
    See Also:
    ContainerAdapter, ContainerListener, Tutorial: Writing a Container Listener, Serialized Form

    • Field Detail

      • CONTAINER_FIRST

        public static final int CONTAINER_FIRST
        The first number in the range of ids used for container events.
        See Also:
        Constant Field Values

      • CONTAINER_LAST

        public static final int CONTAINER_LAST
        The last number in the range of ids used for container events.
        See Also:
        Constant Field Values

      • COMPONENT_ADDED

        public static final int COMPONENT_ADDED
        This event indicates that a component was added to the container.
        See Also:
        Constant Field Values

      • COMPONENT_REMOVED

        public static final int COMPONENT_REMOVED
        This event indicates that a component was removed from the container.
        See Also:
        Constant Field Values

    • Constructor Detail

      • ContainerEvent

        public ContainerEvent(Component source,
                      int id,
                      Component child)
        Constructs a ContainerEvent object.

        This method throws an IllegalArgumentException if source is null.

        Parameters:
        source - The Component object (container) that originated the event
        id - An integer indicating the type of event. For information on allowable values, see the class description for ContainerEvent
        child - the component that was added or removed
        Throws:
        IllegalArgumentException - if source is null
        See Also:
        getContainer(), AWTEvent.getID(), getChild()

    • Method Detail

      • getContainer

        public Container getContainer()
        Returns the originator of the event.
        Returns:
        the Container object that originated the event, or null if the object is not a Container.

      • getChild

        public Component getChild()
        Returns the component that was affected by the event.
        Returns:
        the Component object that was added or removed

      • paramString

        public String paramString()
        Returns a parameter string identifying this event. This method is useful for event-logging and for debugging.
        Overrides:
        paramString in class  ComponentEvent
        Returns:
        a string identifying the event and its attributes