BorderLayout (ocap 1.2 API)

java.lang.Object
- java.awt.BorderLayout

All Implemented Interfaces:

LayoutManager, LayoutManager2, Serializable
```
public class BorderLayout
extends Object
implements LayoutManager2, Serializable
```
A border layout lays out a container, arranging and resizing its components to fit in five regions: north, south, east, west, and center. Each region may contain no more than one component, and is identified by a corresponding constant: NORTH, SOUTH, EAST, WEST, and CENTER. When adding a component to a container with a border layout, use one of these five constants, for example:
Note: The following code examples include classes that do not appear in this specification. Their inclusion is purely to serve as a demonstration.
```
    Panel p = new Panel();
    p.setLayout(new BorderLayout());
    p.add(new Button("Okay"), BorderLayout.SOUTH);
 
```
As a convenience, BorderLayout interprets the absence of a string specification the same as the constant CENTER:
```
    Panel p2 = new Panel();
    p2.setLayout(new BorderLayout());
    p2.add(new TextArea());  // Same as p.add(new TextArea(), BorderLayout.CENTER);
 
```
The components are laid out according to their preferred sizes and the constraints of the container's size. The NORTH and SOUTH components may be stretched horizontally; the EAST and WEST components may be stretched vertically; the CENTER component may stretch both horizontally and vertically to fill any space left over.
Here is an example of five buttons in an applet laid out using the BorderLayout layout manager:

The code for this applet is as follows:
```
 import java.awt.*;
 import java.applet.Applet;

 public class buttonDir extends Applet {
   public void init() {
     setLayout(new BorderLayout());
     add(new Button("North"), BorderLayout.NORTH);
     add(new Button("South"), BorderLayout.SOUTH);
     add(new Button("East"), BorderLayout.EAST);
     add(new Button("West"), BorderLayout.WEST);
     add(new Button("Center"), BorderLayout.CENTER);
   }
 }
 
```
Since:

JDK1.0

Version:

1.53, 01/23/03

Author:

Arthur van Hoff

See Also:
, Serialized Form

Field Summary

Fields
Modifier and Type	Field and Description
`static String`	`CENTER` The center layout constraint (middle of container).
`static String`	`EAST` The east layout constraint (right side of container).
`static String`	`NORTH` The north layout constraint (top of container).
`static String`	`SOUTH` The south layout constraint (bottom of container).
`static String`	`WEST` The west layout constraint (left side of container).

Constructor Summary

Constructors
Constructor and Description
`BorderLayout()` Constructs a new border layout with no gaps between components.
`BorderLayout(int hgap, int vgap)` Constructs a border layout with the specified gaps between components.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`addLayoutComponent(Component comp, Object constraints)` Adds the specified component to the layout, using the specified constraint object.
`void`	`addLayoutComponent(String name, Component comp)` Deprecated. replaced by `addLayoutComponent(Component, Object)`.
`int`	`getHgap()` Returns the horizontal gap between components.
`float`	`getLayoutAlignmentX(Container parent)` Returns the alignment along the x axis.
`float`	`getLayoutAlignmentY(Container parent)` Returns the alignment along the y axis.
`int`	`getVgap()` Returns the vertical gap between components.
`void`	`invalidateLayout(Container target)` Invalidates the layout, indicating that if the layout manager has cached information it should be discarded.
`void`	`layoutContainer(Container target)` Lays out the container argument using this border layout.
`Dimension`	`maximumLayoutSize(Container target)` Returns the maximum dimensions for this layout given the components in the specified target container.
`Dimension`	`minimumLayoutSize(Container target)` Determines the minimum size of the `target` container using this layout manager.
`Dimension`	`preferredLayoutSize(Container target)` Determines the preferred size of the `target` container using this layout manager, based on the components in the container.
`void`	`removeLayoutComponent(Component comp)` Removes the specified component from this border layout.
`void`	`setHgap(int hgap)` Sets the horizontal gap between components.
`void`	`setVgap(int vgap)` Sets the vertical gap between components.
`String`	`toString()` Returns a string representation of the state of this border layout.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - NORTH
```
public static final String NORTH
```
    The north layout constraint (top of container).
    
    See Also:
    Constant Field Values
  - SOUTH
```
public static final String SOUTH
```
    The south layout constraint (bottom of container).
    
    See Also:
    Constant Field Values
  - EAST
```
public static final String EAST
```
    The east layout constraint (right side of container).
    
    See Also:
    Constant Field Values
  - WEST
```
public static final String WEST
```
    The west layout constraint (left side of container).
    
    See Also:
    Constant Field Values
  - CENTER
```
public static final String CENTER
```
    The center layout constraint (middle of container).
    
    See Also:
    Constant Field Values
- Constructor Detail
  - BorderLayout
```
public BorderLayout()
```
    Constructs a new border layout with no gaps between components.
  - BorderLayout
```
public BorderLayout(int hgap,
            int vgap)
```
    Constructs a border layout with the specified gaps between components. The horizontal gap is specified by hgap and the vertical gap is specified by vgap.
    
    Parameters:
    hgap - the horizontal gap.
    vgap - the vertical gap.
- Method Detail
  - getHgap
```
public int getHgap()
```
    Returns the horizontal gap between components.
    
    Since:
    
    JDK1.1
  - setHgap
```
public void setHgap(int hgap)
```
    Sets the horizontal gap between components.
    
    Parameters:
    hgap - the horizontal gap between components
    Since:
    
    JDK1.1
  - getVgap
```
public int getVgap()
```
    Returns the vertical gap between components.
    
    Since:
    
    JDK1.1
  - setVgap
```
public void setVgap(int vgap)
```
    Sets the vertical gap between components.
    
    Parameters:
    vgap - the vertical gap between components
    Since:
    
    JDK1.1
  - addLayoutComponent
```
public void addLayoutComponent(Component comp,
                      Object constraints)
```
    Adds the specified component to the layout, using the specified constraint object. For border layouts, the constraint must be one of the following constants: NORTH, SOUTH, EAST, WEST, or CENTER.
    Most applications do not call this method directly. This method is called when a component is added to a container using the Container.add method with the same argument types.
    
    Specified by:
    
    addLayoutComponent in interface LayoutManager2
    
    Parameters:
    comp - the component to be added.
    constraints - an object that specifies how and where the component is added to the layout.
    
    Throws:
    
    IllegalArgumentException - if the constraint object is not a string, or if it not one of the five specified constants.
    Since:
    
    JDK1.1
    
    See Also:
    Container.add(java.awt.Component, java.lang.Object)
  - addLayoutComponent
```
public void addLayoutComponent(String name,
                      Component comp)
```
    Deprecated. replaced by addLayoutComponent(Component, Object).
    
    Description copied from interface: LayoutManager
    
    If the layout manager uses a per-component string, adds the component comp to the layout, associating it with the string specified by name.
    
    Specified by:
    
    addLayoutComponent in interface LayoutManager
    
    Parameters:
    name - the string to be associated with the component
    comp - the component to be added
  - removeLayoutComponent
```
public void removeLayoutComponent(Component comp)
```
    Removes the specified component from this border layout. This method is called when a container calls its remove or removeAll methods. Most applications do not call this method directly.
    
    Specified by:
    
    removeLayoutComponent in interface LayoutManager
    
    Parameters:
    comp - the component to be removed.
    See Also:
    Container.remove(java.awt.Component), Container.removeAll()
  - minimumLayoutSize
```
public Dimension minimumLayoutSize(Container target)
```
    Determines the minimum size of the target container using this layout manager.
    This method is called when a container calls its getMinimumSize method. Most applications do not call this method directly.
    
    Specified by:
    
    minimumLayoutSize in interface LayoutManager
    
    Parameters:
    target - the container in which to do the layout.
    
    Returns:
    the minimum dimensions needed to lay out the subcomponents of the specified container.
    See Also:
    Container, preferredLayoutSize(java.awt.Container), Container.getMinimumSize()
  - preferredLayoutSize
```
public Dimension preferredLayoutSize(Container target)
```
    Determines the preferred size of the target container using this layout manager, based on the components in the container.
    Most applications do not call this method directly. This method is called when a container calls its getPreferredSize method.
    
    Specified by:
    
    preferredLayoutSize in interface LayoutManager
    
    Parameters:
    target - the container in which to do the layout.
    
    Returns:
    the preferred dimensions to lay out the subcomponents of the specified container.
    See Also:
    Container, minimumLayoutSize(java.awt.Container), Container.getPreferredSize()
  - maximumLayoutSize
```
public Dimension maximumLayoutSize(Container target)
```
    Returns the maximum dimensions for this layout given the components in the specified target container.
    
    Specified by:
    
    maximumLayoutSize in interface LayoutManager2
    
    Parameters:
    target - the component which needs to be laid out
    See Also:
    Container, minimumLayoutSize(java.awt.Container), preferredLayoutSize(java.awt.Container)
  - getLayoutAlignmentX
```
public float getLayoutAlignmentX(Container parent)
```
    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.
    
    Specified by:
    
    getLayoutAlignmentX in interface LayoutManager2
  - getLayoutAlignmentY
```
public float getLayoutAlignmentY(Container parent)
```
    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.
    
    Specified by:
    
    getLayoutAlignmentY in interface LayoutManager2
  - invalidateLayout
```
public void invalidateLayout(Container target)
```
    Invalidates the layout, indicating that if the layout manager has cached information it should be discarded.
    
    Specified by:
    
    invalidateLayout in interface LayoutManager2
  - layoutContainer
```
public void layoutContainer(Container target)
```
    Lays out the container argument using this border layout.
    This method actually reshapes the components in the specified container in order to satisfy the constraints of this BorderLayout object. The NORTH and SOUTH components, if any, are placed at the top and bottom of the container, respectively. The WEST and EAST components are then placed on the left and right, respectively. Finally, the CENTER object is placed in any remaining space in the middle.
    Most applications do not call this method directly. This method is called when a container calls its doLayout method.
    
    Specified by:
    
    layoutContainer in interface LayoutManager
    
    Parameters:
    target - the container in which to do the layout.
    See Also:
    Container, Container.doLayout()
  - toString
```
public String toString()
```
    Returns a string representation of the state of this border layout.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    a string representation of this border layout.

Class BorderLayout

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

NORTH

SOUTH

EAST

WEST

CENTER

Constructor Detail

BorderLayout

BorderLayout

Method Detail

getHgap

setHgap

getVgap

setVgap

addLayoutComponent

addLayoutComponent

removeLayoutComponent

minimumLayoutSize

preferredLayoutSize

maximumLayoutSize

getLayoutAlignmentX

getLayoutAlignmentY

invalidateLayout

layoutContainer

toString