com.sas.swing.visuals.wizard
Class ButtonLayout

com.sas.swing.visuals.wizard.ButtonLayout

All Implemented Interfaces:

java.awt.LayoutManager, java.awt.LayoutManager2

public class ButtonLayout
implements java.awt.LayoutManager2

A layout manager for a container that lays out components in a single horizontal row, allowing components to specify the amount of space to place to the right of themselves. This space can be specified as a fixed amount (in number of pixels), a percentage of the leftover space, or the remainder of leftover space. The components are laid out according to their preferred sizes, and are centered within the container's vertical space.

After space is given to components requesting fixed space, any leftover space is divided among components requesting a percentage, and/or the remainder of this space. First, components requesting a percentage are given space, followed by the component requesting the remainder receiving the rest for placement to its right. Only one component may request the remainder.

If no component requests the remaining space, then leftover space will be used to justify the buttons to the left or right side of the container. If the buttons are right justified, then remaining space left after button spacing requests are made is placed to the far left, before any buttons are layed out. If left justified, the buttons are layed out first following the left insets, and any remaining space is placed to the far right.

The default behavior is to justify the components to the right, assuming no component requests the remainder space. If a component has requested the remainder space, then setting the justification will have no effect. The justification can be set by invoking the setJustification method.

A ButtonLayout layout manager object cannot be shared among containers.

When adding a component to a container with a button layout, use one of these alternatives:

To place a fixed amount of space to the right of the component:

    Panel p = new Panel();
    p.setLayout(new ButtonLayout());
    p.add(new Button("Cancel"), new Integer(10));//Puts 10 pixels of space to right of this component 
 

To place a percentage of any remaining space to the right of the component:

    Panel p = new Panel();
    p.setLayout(new ButtonLayout());
    p.add(new Button("Help"), new Float(.25));  //Puts 25% of leftover space to right of this component 
 

One component in the container may claim any remaining space to the right of the component, for example:

    Panel p = new Panel();
    p.setLayout(new ButtonLayout());
    p.add(new Button("Quit"), ButtonLayout.REMAINDER);  //Puts leftover space to right of this component 
 

ButtonLayout interprets the absence of a constraint specification the same as a request for fixed spacing of 0 pixels for placement to the right of the component:

    Panel p = new Panel();
    p.setLayout(new ButtonLayout());
    p.add(new Button("Next"));  // Same as p.add(new Button("Next"), new Integer(0) );
 

Field Summary

protected int	justify An int value indicating if the components are to be justified to the left or right within the container.
static java.lang.String	RB_KEY
static java.lang.String	REMAINDER The remainder layout constraint.
protected java.awt.Component	remainderComponent The component requesting the remainder of any leftover space
protected float	remainingPercentSpace Value representing percent of remainder space left available to components.
protected java.util.Hashtable	rightSpaceTable Holds a pixel value indicating how much space to layout to the right of each component depending on the current size of the parent container
protected java.util.Hashtable	spaceRequestTable Holds values that reflect the spacing requests for components.

Constructor Summary

ButtonLayout()
Constructs a new button layout

Method Summary

void	addLayoutComponent(java.awt.Component comp, java.lang.Object constraint) Adds the specified component to the layout, using the specified constraint object.
void	addLayoutComponent(java.lang.String string, java.awt.Component comp) Adds the specified component with the specified string to the layout.
java.lang.Object	getConstraint(java.awt.Component comp) Returns the spacing constraint for a component, or null if the component is not found.
float	getLayoutAlignmentX(java.awt.Container parent) Returns the alignment along the x axis.
float	getLayoutAlignmentY(java.awt.Container parent) Returns the alignment along the y axis.
void	invalidateLayout(java.awt.Container target) Invalidates the layout, indicating that if the layout manager has cached information it should be discarded.
void	layoutContainer(java.awt.Container parent) Lays out the container argument using this button layout.
java.awt.Dimension	maximumLayoutSize(java.awt.Container target) Returns the maximum dimensions for this layout given the component in the specified target container.
java.awt.Dimension	minimumLayoutSize(java.awt.Container parent) Returns the minimum dimensions needed to layout the components contained in the specified panel.
java.awt.Dimension	preferredLayoutSize(java.awt.Container parent) Returns the preferred dimensions needed to layout the components contained in the specified panel.
void	removeLayoutComponent(java.awt.Component comp) Removes the specified component from this button layout.
void	setConstraint(java.awt.Component comp, java.lang.Object constraint) Sets the spacing constraint for a component.
void	setJustification(int align) Sets the Horizontal justification in the parent container.

Field Detail

RB_KEY

public static final java.lang.String RB_KEY

See Also:

Constant Field Values

REMAINDER

public static final java.lang.String REMAINDER

The remainder layout constraint. A component added with this constraint is requesting to have any remaining leftover space placed to its right.

See Also:

Constant Field Values

spaceRequestTable

protected java.util.Hashtable spaceRequestTable

Holds values that reflect the spacing requests for components. Can be an Integer object holding a pixel value for fixed spacing, a Float object holding a decimal value for percentage spacing, or a String object equal to ButtonLayout.REMAINDER indicating to use any remaining leftover space.

rightSpaceTable

protected java.util.Hashtable rightSpaceTable

Holds a pixel value indicating how much space to layout to the right of each component depending on the current size of the parent container

remainderComponent

protected java.awt.Component remainderComponent

The component requesting the remainder of any leftover space

justify

protected int justify

An int value indicating if the components are to be justified to the left or right within the container. Valid values are Orientations.LEFT and Orientations.RIGHT. The default setting is Orientations.RIGHT.

See Also:

setJustification(int)

remainingPercentSpace

protected float remainingPercentSpace

Value representing percent of remainder space left available to components.

Constructor Detail

ButtonLayout

public ButtonLayout()

Constructs a new button layout

Method Detail

addLayoutComponent

public void addLayoutComponent(java.lang.String string,
                               java.awt.Component comp)

Adds the specified component with the specified string to the layout. By default, the addLayoutComponent method with an object constraint argument is called. The string is passed through directly. The only valid value for string is ButtonLayout.REMAINDER.

Specified by:

addLayoutComponent in interface java.awt.LayoutManager

Parameters:

string - a constraint specifying the amount of space to place to the right of the component

comp - the component to be added

addLayoutComponent

public void addLayoutComponent(java.awt.Component comp,
                               java.lang.Object constraint)

Adds the specified component to the layout, using the specified constraint object.

For components requesting fixed spacing to their right, constraint should be an Integer object, whose value is non-negative and represents the number of pixels to place to the right of the component.

For components requesting a percentage of leftover space to their right, constraint should be a Float object. The valid range is between 0 and 1.0, where the value represents the percent of leftover space to place to the right of the component.

For components requesting the remainder of leftover space, constraint should be a String equal to ButtonLayout.REMAINDER.

An IllegalArgumentException is thrown for values outside of the above mentioned ranges on the Float and Integer constraints.

Specified by:

addLayoutComponent in interface java.awt.LayoutManager2

Parameters:

comp - the component to be added

constraint - an Integer, Float, or String object which specifies the amount of space to place to the right of the component

removeLayoutComponent

public void removeLayoutComponent(java.awt.Component comp)

Removes the specified component from this button layout. This method is called when a container calls its remove or removeAll methods.

Specified by:

removeLayoutComponent in interface java.awt.LayoutManager

Parameters:

comp - the component to be removed

preferredLayoutSize

public java.awt.Dimension preferredLayoutSize(java.awt.Container parent)

Returns the preferred dimensions needed to layout the components contained in the specified panel.

Specified by:

preferredLayoutSize in interface java.awt.LayoutManager

Parameters:

parent - the component which needs to be laid out

See Also:

minimumLayoutSize(java.awt.Container)

minimumLayoutSize

public java.awt.Dimension minimumLayoutSize(java.awt.Container parent)

Returns the minimum dimensions needed to layout the components contained in the specified panel.

Specified by:

minimumLayoutSize in interface java.awt.LayoutManager

Parameters:

parent - the component which needs to be laid out

See Also:

preferredLayoutSize(java.awt.Container)

layoutContainer

public void layoutContainer(java.awt.Container parent)

Lays out the container argument using this button layout.

Specified by:

layoutContainer in interface java.awt.LayoutManager

Parameters:

parent - the specified component being laid out

maximumLayoutSize

public java.awt.Dimension maximumLayoutSize(java.awt.Container target)

Returns the maximum dimensions for this layout given the component in the specified target container.

Specified by:

maximumLayoutSize in interface java.awt.LayoutManager2

Parameters:

target - The component which needs to be laid out

getLayoutAlignmentX

public float getLayoutAlignmentX(java.awt.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 java.awt.LayoutManager2

Parameters:

parent - the specified component being laid out

getLayoutAlignmentY

public float getLayoutAlignmentY(java.awt.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 java.awt.LayoutManager2

Parameters:

parent - the specified component being laid out

invalidateLayout

public void invalidateLayout(java.awt.Container target)

Invalidates the layout, indicating that if the layout manager has cached information it should be discarded.

Specified by:

invalidateLayout in interface java.awt.LayoutManager2

setJustification

public void setJustification(int align)

Sets the Horizontal justification in the parent container. If the buttons are right justified, then remaining space left after button spacing requests are made is placed to the far left, before any buttons are layed out. If left justified, the buttons are layed out first following the left insets, and any remaining space is placed to the far right.

If a button is already requesting the remainder space, then setting the justification has no affect.

The default is set to Orientations.RIGHT.

Parameters:

parent - the specified component being laid out

align - int representation of com.sas.geometry.Orientations. values can be either Orientations.LEFT, or Orientations.RIGHT.

setConstraint

public void setConstraint(java.awt.Component comp,
                          java.lang.Object constraint)

Sets the spacing constraint for a component.

Parameters:

parent - the specified component being laid out

comp - the component in the parent container to set the spacing constraint for

constraint - an Integer, Float, or String object which specifies the amount of space to place to the right of the button

getConstraint

public java.lang.Object getConstraint(java.awt.Component comp)

Returns the spacing constraint for a component, or null if the component is not found.

Parameters:

comp - the component in the parent container to get the spacing constraint for