org.jhotdraw.draw
Class AttributeKey<T>

java.lang.Object
  org.jhotdraw.draw.AttributeKey<T>

All Implemented Interfaces:

java.io.Serializable

public class AttributeKey<T>
extends java.lang.Object
implements java.io.Serializable

An attribute key provides typesafe access to an attribute of a Figure.

An AttributeKey has a name, a type and a default value. The default value is returned by Figure.get, if a Figure does not have an attribute of the specified key.

The following code example shows how to basicSet and get an attribute on a Figure.

 Figure aFigure;
 AttributeKeys.STROKE_COLOR.put(aFigure, Color.blue);
 

See AttributeKeys for a list of useful attribute keys.

Version:

$Id: AttributeKey.java 564 2009-10-10 10:21:01Z rawcoder $

Author:

Werner Randelshofer

See Also:

Serialized Form

Field Summary

private java.lang.Class<T>	clazz This variable is used as a "type token" so that we can check for assignability of attribute values at runtime.
private T	defaultValue Holds the default value.
private boolean	isNullValueAllowed Specifies whether null values are allowed.
private java.lang.String	key Holds a String representation of the attribute key.
private ResourceBundleUtil	labels Holds labels for the localization of the attribute.

Constructor Summary

AttributeKey(java.lang.String key, java.lang.Class<T> clazz)
Creates a new instance with the specified attribute key, type token class, default value null, and allowing null values.

AttributeKey(java.lang.String key, java.lang.Class<T> clazz, T defaultValue)
Creates a new instance with the specified attribute key, type token class, and default value, and allowing null values.

AttributeKey(java.lang.String key, java.lang.Class<T> clazz, T defaultValue, boolean isNullValueAllowed)
Creates a new instance with the specified attribute key, type token class, default value, and allowing or disallowing null values.

AttributeKey(java.lang.String key, java.lang.Class<T> clazz, T defaultValue, boolean isNullValueAllowed, ResourceBundleUtil labels)
Creates a new instance with the specified attribute key, type token class, default value, and allowing or disallowing null values.

Method Summary

boolean	equals(java.lang.Object that)
T	get(Figure f) Gets the value of the attribute denoted by this AttributeKey from a Figure.
T	get(java.util.Map<AttributeKey,java.lang.Object> a) Gets the value of the attribute denoted by this AttributeKey from a Map.
T	getClone(Figure f) Gets a clone of the value from the Figure.
T	getDefaultValue() Returns the default value of the attribute.
java.lang.String	getKey() Returns the key string.
java.lang.String	getPresentationName() Returns a localized human friendly presentation of the key.
int	hashCode()
boolean	isAssignable(java.lang.Object value) Returns true if the specified value is assignable with this key.
boolean	isNullValueAllowed() Returns true if null values are allowed.
T	put(java.util.Map<AttributeKey,java.lang.Object> a, T value) Use this method to perform a type-safe put operation of an attribute into a Map.
void	putClone(java.util.Map<AttributeKey,java.lang.Object> a, T value) Convenience method for putting a clone of a value on a map.
void	set(Figure f, T value) Convenience method for setting a value on a Figure.
void	setClone(Figure f, T value) Convenience method for setting a clone of a value on a figure.
javax.swing.undo.UndoableEdit	setUndoable(Figure f, T value) Sets the attribute and returns an UndoableEditEvent which can be used to undo it.
java.lang.String	toString() Returns the key string.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

key

private java.lang.String key

Holds a String representation of the attribute key.

defaultValue

private T defaultValue

Holds the default value.

isNullValueAllowed

private boolean isNullValueAllowed

Specifies whether null values are allowed.

labels

private ResourceBundleUtil labels

Holds labels for the localization of the attribute.

clazz

private java.lang.Class<T> clazz

This variable is used as a "type token" so that we can check for assignability of attribute values at runtime.

Constructor Detail

AttributeKey

public AttributeKey(java.lang.String key,
                    java.lang.Class<T> clazz)

Creates a new instance with the specified attribute key, type token class, default value null, and allowing null values.

AttributeKey

public AttributeKey(java.lang.String key,
                    java.lang.Class<T> clazz,
                    T defaultValue)

Creates a new instance with the specified attribute key, type token class, and default value, and allowing null values.

AttributeKey

public AttributeKey(java.lang.String key,
                    java.lang.Class<T> clazz,
                    T defaultValue,
                    boolean isNullValueAllowed)

Creates a new instance with the specified attribute key, type token class, default value, and allowing or disallowing null values.

AttributeKey

public AttributeKey(java.lang.String key,
                    java.lang.Class<T> clazz,
                    T defaultValue,
                    boolean isNullValueAllowed,
                    ResourceBundleUtil labels)

Creates a new instance with the specified attribute key, type token class, default value, and allowing or disallowing null values.

Parameters:

key - The key string.

clazz - This is used as a "type token" for assignability checks at runtime.

isNullValueAllowed - whether null values are allowed.

labels - ResourceBundle for human friendly representation of this attribute key. The ResourceBundle must have a property named "attribute." + key + ".text".

Method Detail

getKey

public java.lang.String getKey()

Returns the key string.

Returns:

key string.

getPresentationName

public java.lang.String getPresentationName()

Returns a localized human friendly presentation of the key.

Returns:

the presentation name of the key.

getDefaultValue

public T getDefaultValue()

Returns the default value of the attribute.

Returns:

the default value.

getClone

public T getClone(Figure f)

Gets a clone of the value from the Figure.

get

public T get(Figure f)

Gets the value of the attribute denoted by this AttributeKey from a Figure.

Parameters:

f - A figure.

Returns:

The value of the attribute.

get

public T get(java.util.Map<AttributeKey,java.lang.Object> a)

Gets the value of the attribute denoted by this AttributeKey from a Map.

Parameters:

a - A Map.

Returns:

The value of the attribute.

set

public void set(Figure f,
                T value)

Convenience method for setting a value on a Figure.

Note: Unlike in previous versions of JHotDraw 7, this method does not call f.willChange() before setting the value, and f.changed() afterwards.

Parameters:

f - the Figure

value - the attribute value

setUndoable

public javax.swing.undo.UndoableEdit setUndoable(Figure f,
                                                 T value)

Sets the attribute and returns an UndoableEditEvent which can be used to undo it.

Note: Unlike in previous versions of JHotDraw 7, this method does not call f.willChange() before setting the value, and f.changed() afterwards.

setClone

public void setClone(Figure f,
                     T value)

Convenience method for setting a clone of a value on a figure.

Note: Unlike in previous versions of JHotDraw 7, this method does not call f.willChange() before setting the value, and f.changed() afterwards.

Parameters:

f - the Figure

value - the attribute value

putClone

public void putClone(java.util.Map<AttributeKey,java.lang.Object> a,
                     T value)

Convenience method for putting a clone of a value on a map.

Parameters:

a - the map

value - the attribute value

put

public T put(java.util.Map<AttributeKey,java.lang.Object> a,
             T value)

Use this method to perform a type-safe put operation of an attribute into a Map.

Parameters:

a - An attribute map.

value - The new value.

Returns:

The old value.

isNullValueAllowed

public boolean isNullValueAllowed()

Returns true if null values are allowed.

Returns:

true if null values are allowed.

isAssignable

public boolean isAssignable(java.lang.Object value)

Returns true if the specified value is assignable with this key.

Parameters:

value -

Returns:

True if assignable.

toString

public java.lang.String toString()

Returns the key string.

Overrides:

toString in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object that)

Overrides:

equals in class java.lang.Object