- All Implemented Interfaces:
Serializable
,AbstractDocument.AttributeContext
- Direct Known Subclasses:
StyleSheet
This class also provides efficient support for small sets of attributes and compresses them by sharing across uses and taking advantage of their immutable nature. Since many styles are replicated, the potential for sharing is significant, and copies can be extremely cheap. Larger sets reduce the possibility of sharing, and therefore revert automatically to a less space-efficient implementation.
Warning:
Serialized objects of this class will not be compatible with
future Swing releases. The current serialization support is
appropriate for short term storage or RMI between applications running
the same version of Swing. As of 1.4, support for long term storage
of all JavaBeans
has been added to the java.beans
package.
Please see XMLEncoder
.
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Nested Class Summary
Modifier and TypeClassDescriptionclass
A collection of attributes, typically used to represent character and paragraph styles.class
This class holds a small number of attributes in an array. -
Field Summary
Modifier and TypeFieldDescriptionstatic final String
The name given to the default logical style attached to paragraphs. -
Constructor Summary
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Method Summary
Modifier and TypeMethodDescriptionaddAttribute
(AttributeSet old, Object name, Object value) Adds an attribute to the given set, and returns the new representative set.addAttributes
(AttributeSet old, AttributeSet attr) Adds a set of attributes to the element.void
Adds a listener to track when styles are added or removed.Adds a new style into the style hierarchy.protected MutableAttributeSet
Create a large set of attributes that should trade off space for time.protected StyleContext.SmallAttributeSet
Create a compact set of attributes that might be shared.getBackground
(AttributeSet attr) Takes a set of attributes and turn it into a background color specification.Returns an array of all theChangeListener
s added to this StyleContext with addChangeListener().protected int
Returns the maximum number of key/value pairs to try and compress into unique/immutable sets.static final StyleContext
Returns default AttributeContext shared by all documents that don't bother to define/supply their own context.Fetches an empty AttributeSet.Gets a new font.getFont
(AttributeSet attr) Gets the font from an attribute set.Returns font metrics for a font.getForeground
(AttributeSet attr) Takes a set of attributes and turn it into a foreground color specification.static Object
getStaticAttribute
(Object key) Returns the object previously registered withregisterStaticAttributeKey
.static Object
Returns the String thatkey
will be registered with.Fetches a named style previously added to the documentEnumeration
<?> Fetches the names of the styles defined.void
Context-specific handling of reading in attributesstatic void
Reads a set of attributes from the given object input stream that have been previously written out withwriteAttributeSet
.void
Returns a set no longer needed by the MutableAttributeSet implementation.static void
Registers an object as a static object that is being used as a key in attribute sets.removeAttribute
(AttributeSet old, Object name) Removes an attribute from the set.removeAttributes
(AttributeSet old, Enumeration<?> names) Removes a set of attributes for the element.removeAttributes
(AttributeSet old, AttributeSet attrs) Removes a set of attributes for the element.void
Removes a listener that was tracking styles being added or removed.void
removeStyle
(String nm) Removes a named style previously added to the document.toString()
Converts a StyleContext to a String.void
Context-specific handling of writing out attributesstatic void
Writes a set of attributes to the given object stream for the purpose of serialization.
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Field Details
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DEFAULT_STYLE
The name given to the default logical style attached to paragraphs.- See Also:
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Constructor Details
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StyleContext
public StyleContext()Creates a new StyleContext object.
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Method Details
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getDefaultStyleContext
Returns default AttributeContext shared by all documents that don't bother to define/supply their own context.- Returns:
- the context
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addStyle
Adds a new style into the style hierarchy. Style attributes resolve from bottom up so an attribute specified in a child will override an attribute specified in the parent.- Parameters:
nm
- the name of the style (must be unique within the collection of named styles in the document). The name may be null if the style is unnamed, but the caller is responsible for managing the reference returned as an unnamed style can't be fetched by name. An unnamed style may be useful for things like character attribute overrides such as found in a style run.parent
- the parent style. This may be null if unspecified attributes need not be resolved in some other style.- Returns:
- the created style
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removeStyle
Removes a named style previously added to the document.- Parameters:
nm
- the name of the style to remove
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getStyle
Fetches a named style previously added to the document- Parameters:
nm
- the name of the style- Returns:
- the style
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getStyleNames
Fetches the names of the styles defined.- Returns:
- the list of names as an enumeration
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addChangeListener
Adds a listener to track when styles are added or removed.- Parameters:
l
- the change listener
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removeChangeListener
Removes a listener that was tracking styles being added or removed.- Parameters:
l
- the change listener
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getChangeListeners
Returns an array of all theChangeListener
s added to this StyleContext with addChangeListener().- Returns:
- all of the
ChangeListener
s added or an empty array if no listeners have been added - Since:
- 1.4
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getFont
Gets the font from an attribute set. This is implemented to try and fetch a cached font for the given AttributeSet, and if that fails the font features are resolved and the font is fetched from the low-level font cache.- Parameters:
attr
- the attribute set- Returns:
- the font
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getForeground
Takes a set of attributes and turn it into a foreground color specification. This might be used to specify things like brighter, more hue, etc. By default it simply returns the value specified by the StyleConstants.Foreground attribute.- Parameters:
attr
- the set of attributes- Returns:
- the color
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getBackground
Takes a set of attributes and turn it into a background color specification. This might be used to specify things like brighter, more hue, etc. By default it simply returns the value specified by the StyleConstants.Background attribute.- Parameters:
attr
- the set of attributes- Returns:
- the color
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getFont
Gets a new font. This returns a Font from a cache if a cached font exists. If not, a Font is added to the cache. This is basically a low-level cache for 1.1 font features.- Parameters:
family
- the font family (such as "Monospaced")style
- the style of the font (such as Font.PLAIN)size
- the point size >= 1- Returns:
- the new font
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getFontMetrics
Returns font metrics for a font.- Parameters:
f
- the font- Returns:
- the metrics
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addAttribute
Adds an attribute to the given set, and returns the new representative set.This method is thread safe, although most Swing methods are not. Please see Concurrency in Swing for more information.
- Specified by:
addAttribute
in interfaceAbstractDocument.AttributeContext
- Parameters:
old
- the old attribute setname
- the non-null attribute namevalue
- the attribute value- Returns:
- the updated attribute set
- See Also:
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addAttributes
Adds a set of attributes to the element.This method is thread safe, although most Swing methods are not. Please see Concurrency in Swing for more information.
- Specified by:
addAttributes
in interfaceAbstractDocument.AttributeContext
- Parameters:
old
- the old attribute setattr
- the attributes to add- Returns:
- the updated attribute set
- See Also:
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removeAttribute
Removes an attribute from the set.This method is thread safe, although most Swing methods are not. Please see Concurrency in Swing for more information.
- Specified by:
removeAttribute
in interfaceAbstractDocument.AttributeContext
- Parameters:
old
- the old set of attributesname
- the non-null attribute name- Returns:
- the updated attribute set
- See Also:
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removeAttributes
Removes a set of attributes for the element.This method is thread safe, although most Swing methods are not. Please see Concurrency in Swing for more information.
- Specified by:
removeAttributes
in interfaceAbstractDocument.AttributeContext
- Parameters:
old
- the old attribute setnames
- the attribute names- Returns:
- the updated attribute set
- See Also:
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removeAttributes
Removes a set of attributes for the element.This method is thread safe, although most Swing methods are not. Please see Concurrency in Swing for more information.
- Specified by:
removeAttributes
in interfaceAbstractDocument.AttributeContext
- Parameters:
old
- the old attribute setattrs
- the attributes- Returns:
- the updated attribute set
- See Also:
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getEmptySet
Fetches an empty AttributeSet.- Specified by:
getEmptySet
in interfaceAbstractDocument.AttributeContext
- Returns:
- the set
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reclaim
Returns a set no longer needed by the MutableAttributeSet implementation. This is useful for operation under 1.1 where there are no weak references. This would typically be called by the finalize method of the MutableAttributeSet implementation.This method is thread safe, although most Swing methods are not. Please see Concurrency in Swing for more information.
- Specified by:
reclaim
in interfaceAbstractDocument.AttributeContext
- Parameters:
a
- the set to reclaim
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getCompressionThreshold
protected int getCompressionThreshold()Returns the maximum number of key/value pairs to try and compress into unique/immutable sets. Any sets above this limit will use hashtables and be a MutableAttributeSet.- Returns:
- the threshold
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createSmallAttributeSet
Create a compact set of attributes that might be shared. This is a hook for subclasses that want to alter the behavior of SmallAttributeSet. This can be reimplemented to return an AttributeSet that provides some sort of attribute conversion.- Parameters:
a
- The set of attributes to be represented in the the compact form.- Returns:
- a compact set of attributes that might be shared
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createLargeAttributeSet
Create a large set of attributes that should trade off space for time. This set will not be shared. This is a hook for subclasses that want to alter the behavior of the larger attribute storage format (which is SimpleAttributeSet by default). This can be reimplemented to return a MutableAttributeSet that provides some sort of attribute conversion.- Parameters:
a
- The set of attributes to be represented in the the larger form.- Returns:
- a large set of attributes that should trade off space for time
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toString
Converts a StyleContext to a String. -
writeAttributes
Context-specific handling of writing out attributes- Parameters:
out
- the output streama
- the attribute set- Throws:
IOException
- on any I/O error
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readAttributes
public void readAttributes(ObjectInputStream in, MutableAttributeSet a) throws ClassNotFoundException, IOException Context-specific handling of reading in attributes- Parameters:
in
- the object stream to read the attribute data from.a
- the attribute set to place the attribute definitions in.- Throws:
ClassNotFoundException
- passed upward if encountered when reading the object stream.IOException
- passed upward if encountered when reading the object stream.
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writeAttributeSet
Writes a set of attributes to the given object stream for the purpose of serialization. This will take special care to deal with static attribute keys that have been registered with theregisterStaticAttributeKey
method. Any attribute key not registered as a static key will be serialized directly. All values are expected to be serializable.- Parameters:
out
- the output streama
- the attribute set- Throws:
IOException
- on any I/O error
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readAttributeSet
public static void readAttributeSet(ObjectInputStream in, MutableAttributeSet a) throws ClassNotFoundException, IOException Reads a set of attributes from the given object input stream that have been previously written out withwriteAttributeSet
. This will try to restore keys that were static objects to the static objects in the current virtual machine considering only those keys that have been registered with theregisterStaticAttributeKey
method. The attributes retrieved from the stream will be placed into the given mutable set.- Parameters:
in
- the object stream to read the attribute data from.a
- the attribute set to place the attribute definitions in.- Throws:
ClassNotFoundException
- passed upward if encountered when reading the object stream.IOException
- passed upward if encountered when reading the object stream.
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registerStaticAttributeKey
Registers an object as a static object that is being used as a key in attribute sets. This allows the key to be treated specially for serialization.For operation under a 1.1 virtual machine, this uses the value returned by
toString
concatenated to the classname. The value returned by toString should not have the class reference in it (ie it should be reimplemented from the definition in Object) in order to be the same when recomputed later.- Parameters:
key
- the non-null object key
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getStaticAttribute
Returns the object previously registered withregisterStaticAttributeKey
.- Parameters:
key
- the object key- Returns:
- Returns the object previously registered with
registerStaticAttributeKey
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getStaticAttributeKey
Returns the String thatkey
will be registered with.- Parameters:
key
- the object key- Returns:
- the String that
key
will be registered with - See Also:
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