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# Class java.awt.Container

    java.lang.Object
       |
       +----java.awt.Component
               |
               +----java.awt.Container

public class Container
extends Component

A generic Abstract Window Toolkit(AWT) container object is a component that can contain other AWT components.

Components added to a container are tracked in a list. The order of the list will define the components' front-to-back stacking order within the container. If no index is specified when adding a component to a container, it will be added to the end of the list (and hence to the bottom of the stacking order).

##

Container()
  Constructs a new Container.

##

add(Component)
  Adds the specified component to this container.
add(Component, int)
  Adds the specified component to this container at the given position in the container's component list.
add(Component, Object)
  Adds the specified component to this container at the specified index.
add(Component, Object, int)
  Adds the specified component to this container with the specified constraints at the specified index.
add(String, Component)
  Adds the specified component to this container.
addContainerListener(ContainerListener)
  Adds the specified container listener to receive container events from this container.
addImpl(Component, Object, int)
  Adds the specified component to this container at the specified index.
addNotify()
  Notifies the container to create a peer.
countComponents()
  Deprecated.
deliverEvent(Event)
  Deprecated.
doLayout()
  Does a layout on this Container.
getAlignmentX()
  Returns the alignment along the x axis.
getAlignmentY()
  Returns the alignment along the y axis.
getComponent(int)
  Gets the nth component in this container.
getComponentAt(int, int)
  Locates the component that contains the x,y position.
getComponentAt(Point)
  Locates the component that contains the specified point.
getComponentCount()
  Returns the number of components in this panel.
getComponents()
  Gets all the components in this container.
getInsets()
  Returns the insets of the container.
getLayout()
  Gets the layout manager for this container.
getMaximumSize()
  Returns the maximum size of this container.
getMinimumSize()
  Returns the minimum size of this container.
getPreferredSize()
  Returns the preferred size of this container.
insets()
  Deprecated.
invalidate()
  Invalidates the container.
isAncestorOf(Component)
  Checks if the component is contained in the component hierarchy of this container.
layout()
  Deprecated.
list(PrintStream, int)
  Prints out a list, starting at the specified indention, to the specified out stream.
list(PrintWriter, int)
  Prints out a list, starting at the specified indention, to the specified print writer.
locate(int, int)
  Deprecated.
minimumSize()
  Deprecated.
paint(Graphics)
  Paints the container.
paintComponents(Graphics)
  Paints the components in this container.
paramString()
  Returns the parameter String of this Container.
preferredSize()
  Deprecated.
print(Graphics)
  Prints the container.
printComponents(Graphics)
  Prints the components in this container.
processContainerEvent(ContainerEvent)
  Processes container events occurring on this container by dispatching them to any registered ContainerListener objects.
processEvent(AWTEvent)
  Processes events on this container.
remove(Component)
  Removes the specified component from this container.
remove(int)
  Removes the component at the specified index from this container.
removeAll()
  Removes all the components from this container.
removeContainerListener(ContainerListener)
  Removes the specified container listener so it no longer receives container events from this container.
removeNotify()
  Notifies the container to remove its peer.
setLayout(LayoutManager)
  Sets the layout manager for this container.
validate()
  Validates this Container and all of the components contained within it.
validateTree()
  Recursively descends the container tree and recomputes the layout for any subtrees marked as needing it (those marked as invalid).

##

Container

      protected Container()

  Constructs a new Container. Containers can be extended directly, but are lightweight in this case and must be contained by a parent somewhere higher up in the component tree that is native. (such as Frame for example).

##

getComponentCount

      public int getComponentCount()

  Returns the number of components in this panel.

  See Also:
    getComponent

countComponents

      public int countComponents()

  Note: countComponents() is deprecated. As of JDK version 1.1, replaced by getComponentCount().

getComponent

      public Component getComponent(int n)

  Gets the nth component in this container.

  Parameters:
    n - the number of the component to get
  Throws: ArrayIndexOutOfBoundsException
    If the nth value does not exist.

getComponents

      public Component[] getComponents()

  Gets all the components in this container.

getInsets

      public Insets getInsets()

  Returns the insets of the container. The insets indicate the size of the border of the container. A Frame, for example, will have a top inset that corresponds to the height of the Frame's title bar.

  See Also:
    LayoutManager

insets

      public Insets insets()

  Note: insets() is deprecated. As of JDK version 1.1, replaced by getInsets().

add

      public Component add(Component comp)

  Adds the specified component to this container.

  Parameters:
    comp - the component to be added

add

      public Component add(String name,
                           Component comp)

  Adds the specified component to this container. It is strongly advised to use the 1.1 method, add(Component, Object), in place of this method.

add

      public Component add(Component comp,
                           int index)

  Adds the specified component to this container at the given position in the container's component list.

  Parameters:
    comp - the component to be added
    index - the position in the container's list at which to insert the component. -1 means insert at the end.
  See Also:
    remove

add

      public void add(Component comp,
                      Object constraints)

  Adds the specified component to this container at the specified index. Also notifies the layout manager to add the component to the this container's layout using the specified constraints object.

  Parameters:
    comp - the component to be added
    constraints - an object expressing layout contraints for this component
  See Also:
    remove, LayoutManager

add

      public void add(Component comp,
                      Object constraints,
                      int index)

  Adds the specified component to this container with the specified constraints at the specified index. Also notifies the layout manager to add the component to the this container's layout using the specified constraints object.

  Parameters:
    comp - the component to be added
    constraints - an object expressing layout contraints for this
    index - the position in the container's list at which to insert the component. -1 means insert at the end. component
  See Also:
    remove, LayoutManager

addImpl

      protected void addImpl(Component comp,
                             Object constraints,
                             int index)

  Adds the specified component to this container at the specified index. Also notifies the layout manager to add the component to the this container's layout using the specified constraints object.

  This is the method to override if you want to track every add request to a container. An overriding method should usually include a call to super.addImpl(comp, constraints, index).

  Parameters:
    comp - the component to be added
    constraints - an object expressing layout contraints for this component
    index - the position in the container's list at which to insert the component. -1 means insert at the end.
  See Also:
    remove, LayoutManager

remove

      public void remove(int index)

  Removes the component at the specified index from this container.

  Parameters:
    index - the index of the component to be removed
  See Also:
    add

remove

      public void remove(Component comp)

  Removes the specified component from this container.

  Parameters:
    comp - the component to be removed
  See Also:
    add

removeAll

      public void removeAll()

  Removes all the components from this container.

  See Also:
    add, remove

getLayout

      public LayoutManager getLayout()

  Gets the layout manager for this container.

  See Also:
    doLayout, setLayout

setLayout

      public void setLayout(LayoutManager mgr)

  Sets the layout manager for this container.

  Parameters:
    mgr - the specified layout manager
  See Also:
    doLayout, getLayout

doLayout

      public void doLayout()

  Does a layout on this Container. Most programs should not call this directly, but should invoke validate instead.

  Overrides:
    doLayout in class Component
  See Also:
    setLayout, validate

layout

      public void layout()

  Note: layout() is deprecated. As of JDK version 1.1, replaced by doLayout().

  Overrides:
    layout in class Component

invalidate

      public void invalidate()

  Invalidates the container. The container and all parents above it are marked as needing to be laid out. This method can be called often, so it needs to execute quickly.

  Overrides:
    invalidate in class Component
  See Also:
    validate, layout, LayoutManager

validate

      public void validate()

  Validates this Container and all of the components contained within it.

  Overrides:
    validate in class Component
  See Also:
    validate, invalidate

validateTree

      protected void validateTree()

  Recursively descends the container tree and recomputes the layout for any subtrees marked as needing it (those marked as invalid). Synchronization should be provided by the method that calls this: validate.

getPreferredSize

      public Dimension getPreferredSize()

  Returns the preferred size of this container.

  Overrides:
    getPreferredSize in class Component
  See Also:
    getMinimumSize

preferredSize

      public Dimension preferredSize()

  Note: preferredSize() is deprecated. As of JDK version 1.1, replaced by getPreferredSize().

  Overrides:
    preferredSize in class Component

getMinimumSize

      public Dimension getMinimumSize()

  Returns the minimum size of this container.

  Overrides:
    getMinimumSize in class Component
  See Also:
    getPreferredSize

minimumSize

      public Dimension minimumSize()

  Note: minimumSize() is deprecated. As of JDK version 1.1, replaced by getMinimumSize().

  Overrides:
    minimumSize in class Component

getMaximumSize

      public Dimension getMaximumSize()

  Returns the maximum size of this container.

  Overrides:
    getMaximumSize in class Component
  See Also:
    getPreferredSize

getAlignmentX

      public float getAlignmentX()

  Returns the alignment along the x axis. This specifies how the component would like to be aligned relative to other components. The value should be a number between 0 and 1 where 0 represents alignment along the origin, 1 is aligned the furthest away from the origin, 0.5 is centered, etc.

  Overrides:
    getAlignmentX in class Component

getAlignmentY

      public float getAlignmentY()

  Returns the alignment along the y axis. This specifies how the component would like to be aligned relative to other components. The value should be a number between 0 and 1 where 0 represents alignment along the origin, 1 is aligned the furthest away from the origin, 0.5 is centered, etc.

  Overrides:
    getAlignmentY in class Component

paint

      public void paint(Graphics g)

  Paints the container. This forwards the paint to any lightweight components that are children of this container. If this method is reimplemented, super.paint(g) should be called so that lightweight components are properly rendered. If a child component is entirely clipped by the current clipping setting in g, paint() will not be forwarded to that child.

  Parameters:
    g - the specified Graphics window
  Overrides:
    paint in class Component
  See Also:
    update

print

      public void print(Graphics g)

  Prints the container. This forwards the print to any lightweight components that are children of this container. If this method is reimplemented, super.print(g) should be called so that lightweight components are properly rendered. If a child component is entirely clipped by the current clipping setting in g, print() will not be forwarded to that child.

  Parameters:
    g - the specified Graphics window
  Overrides:
    print in class Component
  See Also:
    update

paintComponents

      public void paintComponents(Graphics g)

  Paints the components in this container.

  Parameters:
    g - the specified Graphics window
  See Also:
    paint, paintAll

printComponents

      public void printComponents(Graphics g)

  Prints the components in this container.

  Parameters:
    g - the specified Graphics window
  See Also:
    print, printAll

addContainerListener

      public void addContainerListener(ContainerListener l)

  Adds the specified container listener to receive container events from this container.

  Parameters:
    l - the container listener

removeContainerListener

      public void removeContainerListener(ContainerListener l)

  Removes the specified container listener so it no longer receives container events from this container.

  Parameters:
    l - the container listener

processEvent

      protected void processEvent(AWTEvent e)

  Processes events on this container. If the event is a ContainerEvent, it invokes the processContainerEvent method, else it invokes its superclass's processEvent.

  Parameters:
    e - the event
  Overrides:
    processEvent in class Component

processContainerEvent

      protected void processContainerEvent(ContainerEvent e)

  Processes container events occurring on this container by dispatching them to any registered ContainerListener objects. NOTE: This method will not be called unless container events are enabled for this component; this happens when one of the following occurs: a) A ContainerListener object is registered via addContainerListener() b) Container events are enabled via enableEvents()

  Parameters:
    e - the container event
  See Also:
    enableEvents

deliverEvent

      public void deliverEvent(Event e)

  Note: deliverEvent() is deprecated. As of JDK version 1.1, replaced by dispatchEvent(AWTEvent e)

  Overrides:
    deliverEvent in class Component

getComponentAt

      public Component getComponentAt(int x,
                                      int y)

  Locates the component that contains the x,y position. The top-most child component is returned in the case where there is overlap in the components. This is determined by finding the component closest to the index 0 that claims to contain the given point via Component.contains().

  Parameters:
    x - the x coordinate
    y - the y coordinate
  Returns:
    null if the component does not contain the position. If there is no child component at the requested point and the point is within the bounds of the container the container itself is returned, otherwise the top-most child is returned.
  Overrides:
    getComponentAt in class Component
  See Also:
    contains

locate

      public Component locate(int x,
                              int y)

  Note: locate() is deprecated. As of JDK version 1.1, replaced by getComponentAt(int, int).

  Overrides:
    locate in class Component

getComponentAt

      public Component getComponentAt(Point p)

  Locates the component that contains the specified point.

  Parameters:
    p - the point
  Returns:
    null if the component does not contain the point; returns the component otherwise.
  Overrides:
    getComponentAt in class Component
  See Also:
    contains

addNotify

      public void addNotify()

  Notifies the container to create a peer. It will also notify the components contained in this container. This method should be called by Container.add, and not by user code directly.

  Overrides:
    addNotify in class Component
  See Also:
    removeNotify

removeNotify

      public void removeNotify()

  Notifies the container to remove its peer. It will also notify the components contained in this container. This method should be called by Container.remove, and not by user code directly.

  Overrides:
    removeNotify in class Component
  See Also:
    addNotify

isAncestorOf

      public boolean isAncestorOf(Component c)

  Checks if the component is contained in the component hierarchy of this container.

  Parameters:
    c - the component

paramString

      protected String paramString()

  Returns the parameter String of this Container.

  Overrides:
    paramString in class Component

list

      public void list(PrintStream out,
                       int indent)

  Prints out a list, starting at the specified indention, to the specified out stream.

  Parameters:
    out - the Stream name
    indent - the start of the list
  Overrides:
    list in class Component

list

      public void list(PrintWriter out,
                       int indent)

  Prints out a list, starting at the specified indention, to the specified print writer.

  Overrides:
    list in class Component

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