com.jgoodies.forms.layout

Class LayoutMap

java.lang.Object

com.jgoodies.forms.layout.LayoutMap

public final class LayoutMap
extends java.lang.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 $

See Also:

FormLayout, ColumnSpec, RowSpec

Field Summary

Fields

Modifier and Type	Field and Description
private static java.util.Map<java.lang.String,java.lang.String>	COLUMN_ALIASES Maps column aliases to their default name, for example "rgap" -> "related-gap".
private java.util.Map<java.lang.String,java.lang.String>	columnMap Holds the raw associations from variable names to expressions.
private java.util.Map<java.lang.String,java.lang.String>	columnMapCache Holds the cached associations from variable names to expressions.
private LayoutMap	parent Refers to the parent map that is used to look up values if this map contains no association for a given key.
private static LayoutMap	root Holds the lazily initialized root map.
private static java.util.Map<java.lang.String,java.lang.String>	ROW_ALIASES Maps row aliases to their default name, for example "rgap" -> "related-gap".
private java.util.Map<java.lang.String,java.lang.String>	rowMap Holds the raw associations from variable names to expressions.
private java.util.Map<java.lang.String,java.lang.String>	rowMapCache Holds the cached associations from variable names to expressions.
private static char	VARIABLE_PREFIX_CHAR Marks a layout variable; used by the Forms parsers.

Constructor Summary

Constructors

Constructor and Description
LayoutMap() Constructs a LayoutMap that has the root LayoutMap as parent.
LayoutMap(LayoutMap parent) Constructs a LayoutMap with the given optional parent.

Method Summary

Modifier and Type	Method and Description
boolean	columnContainsKey(java.lang.String key) Returns true if this map or a parent map - if any - contains a mapping for the specified key.
java.lang.String	columnGet(java.lang.String key) Looks up and returns the String associated with the given key.
java.lang.String	columnPut(java.lang.String key, ColumnSpec value)
java.lang.String	columnPut(java.lang.String key, Size value)
java.lang.String	columnPut(java.lang.String key, java.lang.String value) Associates the specified column String with the specified key in this map.
private void	columnPut(java.lang.String key, java.lang.String[] aliases, ColumnSpec value)
java.lang.String	columnRemove(java.lang.String key) Removes the column value mapping for this key from this map if it is present.
private static LayoutMap	createRoot()
private static void	ensureLowerCase(java.lang.String str)
(package private) java.lang.String	expand(java.lang.String expression, boolean horizontal)
private java.lang.String	expansion(java.lang.String variableName, boolean horizontal)
static LayoutMap	getRoot() Lazily initializes and returns the LayoutMap that is used for variable expansion, if no custom LayoutMap is provided.
private static java.lang.String	nextVariableName(java.lang.String expression, int start)
private static java.lang.String	resolveColumnKey(java.lang.String key)
private static java.lang.String	resolveRowKey(java.lang.String key)
boolean	rowContainsKey(java.lang.String key) Returns true if this map or a parent map - if any - contains a RowSpec mapping for the specified key.
java.lang.String	rowGet(java.lang.String key) Looks up and returns the RowSpec associated with the given key.
java.lang.String	rowPut(java.lang.String key, RowSpec value) Associates the specified ColumnSpec with the specified key in this map.
java.lang.String	rowPut(java.lang.String key, Size value)
java.lang.String	rowPut(java.lang.String key, java.lang.String value)
private void	rowPut(java.lang.String key, java.lang.String[] aliases, RowSpec value)
java.lang.String	rowRemove(java.lang.String key) Removes the row value mapping for this key from this map if it is present.
private static java.lang.String	stripBraces(java.lang.String variableName)
java.lang.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

Field Detail

VARIABLE_PREFIX_CHAR

private static final char VARIABLE_PREFIX_CHAR

Marks a layout variable; used by the Forms parsers.

See Also:

Constant Field Values

COLUMN_ALIASES

private static final java.util.Map<java.lang.String,java.lang.String> COLUMN_ALIASES

Maps column aliases to their default name, for example "rgap" -> "related-gap".

ROW_ALIASES

private static final java.util.Map<java.lang.String,java.lang.String> ROW_ALIASES

Maps row aliases to their default name, for example "rgap" -> "related-gap".

root

private static LayoutMap root

Holds the lazily initialized root map.

parent

private final LayoutMap parent

Refers to the parent map that is used to look up values if this map contains no association for a given key. The parent maps can build chains.

columnMap

private final java.util.Map<java.lang.String,java.lang.String> columnMap

Holds the raw associations from variable names to expressions. The expression may contain variables that are not expanded.

columnMapCache

private final java.util.Map<java.lang.String,java.lang.String> columnMapCache

Holds the cached associations from variable names to expressions. The expression are fully expanded and contain no variables.

rowMap

private final java.util.Map<java.lang.String,java.lang.String> rowMap

Holds the raw associations from variable names to expressions. The expression may contain variables that are not expanded.

rowMapCache

private final java.util.Map<java.lang.String,java.lang.String> rowMapCache

Holds the cached associations from variable names to expressions. The expression are fully expanded and contain no variables.

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(java.lang.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:

java.lang.NullPointerException - if the key is null.

See Also:

Map.containsKey(Object)

columnGet

public java.lang.String columnGet(java.lang.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:

java.lang.NullPointerException - if key is null

See Also:

Map.get(Object)

columnPut

public java.lang.String columnPut(java.lang.String key,
                                  java.lang.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:

java.lang.NullPointerException - if the key or value is null.

See Also:

Map.put(Object, Object)

columnPut

public java.lang.String columnPut(java.lang.String key,
                                  ColumnSpec value)

columnPut

public java.lang.String columnPut(java.lang.String key,
                                  Size value)

columnRemove

public java.lang.String columnRemove(java.lang.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:

java.lang.NullPointerException - if key is null.

See Also:

Map.remove(Object)

rowContainsKey

public boolean rowContainsKey(java.lang.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:

java.lang.NullPointerException - if the key is null.

See Also:

Map.containsKey(Object)

rowGet

public java.lang.String rowGet(java.lang.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:

java.lang.NullPointerException - if key is null

See Also:

Map.get(Object)

rowPut

public java.lang.String rowPut(java.lang.String key,
                               java.lang.String value)

rowPut

public java.lang.String rowPut(java.lang.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:

java.lang.NullPointerException - if the key or value is null.

See Also:

Map.put(Object, Object)

rowPut

public java.lang.String rowPut(java.lang.String key,
                               Size value)

rowRemove

public java.lang.String rowRemove(java.lang.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:

java.lang.NullPointerException - if key is null.

See Also:

Map.remove(Object)

toString

public java.lang.String toString()

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

Overrides:

toString in class java.lang.Object

Returns:

a string representation

expand

java.lang.String expand(java.lang.String expression,
                        boolean horizontal)

nextVariableName

private static java.lang.String nextVariableName(java.lang.String expression,
                                                 int start)

expansion

private java.lang.String expansion(java.lang.String variableName,
                                   boolean horizontal)

stripBraces

private static java.lang.String stripBraces(java.lang.String variableName)

resolveColumnKey

private static java.lang.String resolveColumnKey(java.lang.String key)

resolveRowKey

private static java.lang.String resolveRowKey(java.lang.String key)

createRoot

private static LayoutMap createRoot()

columnPut

private void columnPut(java.lang.String key,
                       java.lang.String[] aliases,
                       ColumnSpec value)

rowPut

private void rowPut(java.lang.String key,
                    java.lang.String[] aliases,
                    RowSpec value)

ensureLowerCase

private static void ensureLowerCase(java.lang.String str)