com.jgoodies.forms.layout
Class LayoutMap

java.lang.Object
  com.jgoodies.forms.layout.LayoutMap

public final class LayoutMap
extends Object

Provides a hierarchical variable expansion useful to improve layout consistency, style guide compliance, and layout readability.

A LayoutMap maps variable names to layout expression Strings. The FormLayout, ColumnSpec, and RowSpec parsers expand variables before an encoded layout specification is parsed and converted into ColumnSpec and RowSpec values. Variables start with the '$' character. The variable name can be wrapped by braces ('{' and '}'). For example, you can write: new FormLayout("pref, $lcg, pref") or new FormLayout("pref, ${lcg}, pref").

LayoutMaps build a chain; each LayoutMap has an optional parent map. The root is defined by getRoot(). Application-wide variables should be defined in the root LayoutMap. If you want to override application-wide variables locally, obtain a LayoutMap using new LayoutMap(), configure it, and provide it as argument to the FormLayout, ColumnSpec, and RowSpec constructors/factory methods.

By default the root LayoutMap provides the following associations:

Variable Name	Abbreviations	Orientation	Description
label-component-gap	lcg, lcgap	both	gap between a label and the labeled component
related-gap	rg, rgap	both	gap between two related components
unrelated-gap	ug, ugap	both	gap between two unrelated components
button	b	horizontal	button column with minimum width
line-gap	lg, lgap	vertical	gap between two lines
narrow-line-gap	nlg, nlgap	vertical	narrow gap between two lines
paragraph	pg, pgap	vertical	gap between two paragraphs/sections

Examples:

 // Predefined variables
 new FormLayout(
     "pref, $lcgap, pref, $rgap, pref",
     "p, $lgap, p, $lgap, p");

 // Custom variables
 LayoutMap.getRoot().columnPut("half", "39dlu");
 LayoutMap.getRoot().columnPut("full", "80dlu");
 LayoutMap.getRoot().rowPut("table", "fill:0:grow");
 LayoutMap.getRoot().rowPut("table50", "fill:50dlu:grow");
 new FormLayout(
     "pref, $lcgap, $half, 2dlu, $half",
     "p, $lcgap, $table50");
 new FormLayout(
     "pref, $lcgap, $full",
     "p, $lcgap, $table50");

 // Nested variables
 LayoutMap.getRoot().columnPut("c-gap-c", "$half, 2dlu, $half");
 new FormLayout(
     "pref, $lcgap, ${c-gap-c}", // -> "pref, $lcgap, $half, 2dlu, $half",
     "p, $lcgap, $table");
 

LayoutMap holds two internal Maps that associate key Strings with expression Strings for the columns and rows respectively. Null values are not allowed.

Tips:

• You should carefully override predefined variables, because variable users may expect that these don't change.
• Set custom variables in the root LayoutMap.
• Avoid aliases for custom variables.

Since:

1.2

Version:

$Revision: 1.24 $

Author:

Karsten Lentzsch

See Also:

FormLayout, ColumnSpec, RowSpec

Constructor Summary

LayoutMap()
Constructs a LayoutMap that has the root LayoutMap as parent.

LayoutMap(LayoutMap parent)
Constructs a LayoutMap with the given optional parent.

Method Summary

boolean	columnContainsKey(String key) Returns true if this map or a parent map - if any - contains a mapping for the specified key.
String	columnGet(String key) Looks up and returns the String associated with the given key.
String	columnPut(String key, ColumnSpec value)
String	columnPut(String key, Size value)
String	columnPut(String key, String value) Associates the specified column String with the specified key in this map.
String	columnRemove(String key) Removes the column value mapping for this key from this map if it is present.
static LayoutMap	getRoot() Lazily initializes and returns the LayoutMap that is used for variable expansion, if no custom LayoutMap is provided.
boolean	rowContainsKey(String key) Returns true if this map or a parent map - if any - contains a RowSpec mapping for the specified key.
String	rowGet(String key) Looks up and returns the RowSpec associated with the given key.
String	rowPut(String key, RowSpec value) Associates the specified ColumnSpec with the specified key in this map.
String	rowPut(String key, Size value)
String	rowPut(String key, String value)
String	rowRemove(String key) Removes the row value mapping for this key from this map if it is present.
String	toString() Returns a string representation of this LayoutMap that lists the column and row associations.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

LayoutMap

public LayoutMap()

Constructs a LayoutMap that has the root LayoutMap as parent.

LayoutMap

public LayoutMap(LayoutMap parent)

Constructs a LayoutMap with the given optional parent.

Parameters:

parent - the parent LayoutMap, may be null

Method Detail

getRoot

public static LayoutMap getRoot()

Lazily initializes and returns the LayoutMap that is used for variable expansion, if no custom LayoutMap is provided.

Returns:

the LayoutMap that is used, if no custom LayoutMap is provided

columnContainsKey

public boolean columnContainsKey(String key)

Returns true if this map or a parent map - if any - contains a mapping for the specified key.

Parameters:

key - key whose presence in this LayoutMap chain is to be tested.

Returns:

true if this map contains a column mapping for the specified key.

Throws:

NullPointerException - if the key is null.

See Also:

Map.containsKey(Object)

columnGet

public String columnGet(String key)

Looks up and returns the String associated with the given key. First looks for an association in this LayoutMap. If there's no association, the lookup continues with the parent map - if any.

Parameters:

key - key whose associated value is to be returned.

Returns:

the column String associated with the key, or null if no LayoutMap in the parent chain contains an association.

Throws:

NullPointerException - if key is null

See Also:

Map.get(Object)

columnPut

public String columnPut(String key,
                        String value)

Associates the specified column String with the specified key in this map. If the map previously contained a mapping for this key, the old value is replaced by the specified value. The value set in this map overrides an association - if any - in the chain of parent LayoutMaps.

The value must not be null. To remove an association from this map use columnRemove(String).

Parameters:

key - key with which the specified value is to be associated.

value - column expression value to be associated with the specified key.

Returns:

previous String associated with specified key, or null if there was no mapping for key.

Throws:

NullPointerException - if the key or value is null.

See Also:

Map.put(Object, Object)

columnPut

public String columnPut(String key,
                        ColumnSpec value)

columnPut

public String columnPut(String key,
                        Size value)

columnRemove

public String columnRemove(String key)

Removes the column value mapping for this key from this map if it is present.

Returns the value to which the map previously associated the key, or null if the map contained no mapping for this key. The map will not contain a String mapping for the specified key once the call returns.

Parameters:

key - key whose mapping is to be removed from the map.

Returns:

previous value associated with specified key, or null if there was no mapping for key.

Throws:

NullPointerException - if key is null.

See Also:

Map.remove(Object)

rowContainsKey

public boolean rowContainsKey(String key)

Returns true if this map or a parent map - if any - contains a RowSpec mapping for the specified key.

Parameters:

key - key whose presence in this LayoutMap chain is to be tested.

Returns:

true if this map contains a row mapping for the specified key.

Throws:

NullPointerException - if the key is null.

See Also:

Map.containsKey(Object)

rowGet

public String rowGet(String key)

Looks up and returns the RowSpec associated with the given key. First looks for an association in this LayoutMap. If there's no association, the lookup continues with the parent map - if any.

Parameters:

key - key whose associated value is to be returned.

Returns:

the row specification associated with the key, or null if no LayoutMap in the parent chain contains an association.

Throws:

NullPointerException - if key is null

See Also:

Map.get(Object)

rowPut

public String rowPut(String key,
                     String value)

rowPut

public String rowPut(String key,
                     RowSpec value)

Associates the specified ColumnSpec with the specified key in this map. If the map previously contained a mapping for this key, the old value is replaced by the specified value. The RowSpec set in this map override an association - if any - in the chain of parent LayoutMaps.

The RowSpec must not be null. To remove an association from this map use rowRemove(String).

Parameters:

key - key with which the specified value is to be associated.

value - ColumnSpec to be associated with the specified key.

Returns:

previous ColumnSpec associated with specified key, or null if there was no mapping for key.

Throws:

NullPointerException - if the key or value is null.

See Also:

Map.put(Object, Object)

rowPut

public String rowPut(String key,
                     Size value)

rowRemove

public String rowRemove(String key)

Removes the row value mapping for this key from this map if it is present.

Returns the value to which the map previously associated the key, or null if the map contained no mapping for this key. The map will not contain a String mapping for the specified key once the call returns.

Parameters:

key - key whose mapping is to be removed from the map.

Returns:

previous value associated with specified key, or null if there was no mapping for key.

Throws:

NullPointerException - if key is null.

See Also:

Map.remove(Object)

toString

public String toString()

Returns a string representation of this LayoutMap that lists the column and row associations.

Overrides:

toString in class Object

Returns:

a string representation