java.lang.Object | |
↳ | java.text.Bidi |
Implements the Unicode Bidirectional Algorithm.
Use a Bidi
object to get the information on the position reordering of a
bidirectional text, such as Arabic or Hebrew. The natural display ordering of
horizontal text in these languages is from right to left, while they order
numbers from left to right.
If the text contains multiple runs, the information of each run can be obtained from the run index. The level of any particular run indicates the direction of the text as well as the nesting level. Left-to-right runs have even levels while right-to-left runs have odd levels.
Constants | |||||||||||
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int | DIRECTION_DEFAULT_LEFT_TO_RIGHT | Constant that indicates the default base level. | |||||||||
int | DIRECTION_DEFAULT_RIGHT_TO_LEFT | Constant that indicates the default base level. | |||||||||
int | DIRECTION_LEFT_TO_RIGHT | Constant that specifies the default base level as 0 (left-to-right). | |||||||||
int | DIRECTION_RIGHT_TO_LEFT | Constant that specifies the default base level as 1 (right-to-left). |
Public Constructors | |||||||||||
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Creates a
Bidi object from the AttributedCharacterIterator of a paragraph text. | |||||||||||
Creates a
Bidi object. | |||||||||||
Creates a
Bidi object. |
Public Methods | |||||||||||
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Returns whether the base level is from left to right.
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Creates a new
Bidi object containing the information of one line
from this object. | |||||||||||
Returns the base level.
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Returns the length of the text.
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Returns the level of the given character.
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Returns the number of runs in the text, at least 1.
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Returns the level of the given run.
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Returns the limit offset of the given run.
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Returns the start offset of the given run.
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Returns true if the text is from left to right, that is, both the base
direction and the text direction is from left to right.
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Returns true if the text direction is mixed.
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Returns true if the text is from right to left, that is, both the base
direction and the text direction is from right to left.
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Reorders a range of objects according to their specified levels.
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Indicates whether a range of characters of a text requires a
Bidi
object to display properly. | |||||||||||
Returns a string containing a concise, human-readable description of this
object.
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[Expand]
Inherited Methods | |||||||||||
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From class
java.lang.Object
|
Constant that indicates the default base level. If there is no strong character, then set the paragraph level to 0 (left-to-right).
Constant that indicates the default base level. If there is no strong character, then set the paragraph level to 1 (right-to-left).
Constant that specifies the default base level as 0 (left-to-right).
Constant that specifies the default base level as 1 (right-to-left).
Creates a Bidi
object from the AttributedCharacterIterator
of a paragraph text. The RUN_DIRECTION
attribute determines the base direction of the bidirectional text. If it
is not specified explicitly, the algorithm uses
DIRECTION_DEFAULT_LEFT_TO_RIGHT by default. The BIDI_EMBEDDING attribute
specifies the level of embedding for each character. Values between -1
and -62 denote overrides at the level's absolute value, values from 1 to
62 indicate embeddings, and the 0 value indicates the level is calculated
by the algorithm automatically. For the character with no BIDI_EMBEDDING
attribute or with a improper attribute value, such as a null
value, the algorithm treats its embedding level as 0. The NUMERIC_SHAPING
attribute specifies the instance of NumericShaper used to convert
European digits to other decimal digits before performing the bidi
algorithm.
paragraph | the String containing the paragraph text to perform the algorithm. |
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IllegalArgumentException | if paragraph == null |
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Creates a Bidi
object.
text | the char array of the paragraph text that is processed. |
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textStart | the index in text of the start of the paragraph. |
embeddings | the embedding level array of the paragraph text, specifying the embedding level information for each character. Values between -1 and -61 denote overrides at the level's absolute value, values from 1 to 61 indicate embeddings, and the 0 value indicates the level is calculated by the algorithm automatically. |
embStart | the index in embeddings of the start of the paragraph. |
paragraphLength | the length of the text to perform the algorithm. |
flags | indicates the base direction of the bidirectional text. It is expected that this will be one of the direction constant values defined in this class. An unknown value is treated as DIRECTION_DEFAULT_LEFT_TO_RIGHT. |
IllegalArgumentException | if textStart , embStart , or paragraphLength is negative; if
text.length < textStart + paragraphLength or
embeddings.length < embStart + paragraphLength . |
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Creates a Bidi
object.
paragraph | the string containing the paragraph text to perform the algorithm on. |
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flags | indicates the base direction of the bidirectional text. It is expected that this will be one of the direction constant values defined in this class. An unknown value is treated as DIRECTION_DEFAULT_LEFT_TO_RIGHT. |
Returns whether the base level is from left to right.
Creates a new Bidi
object containing the information of one line
from this object.
lineStart | the start offset of the line. |
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lineLimit | the limit of the line. |
IllegalArgumentException | if lineStart < 0 , lineLimit < 0 , lineStart > lineLimit or if lineStart is greater
than the length of this object's paragraph text.
|
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Returns true if the text is from left to right, that is, both the base direction and the text direction is from left to right.
Returns true if the text is from right to left, that is, both the base direction and the text direction is from right to left.
Reorders a range of objects according to their specified levels. This is
a convenience function that does not use a Bidi
object. The range
of objects at index
from objectStart
to objectStart + count
will be reordered according to the range of levels
at index
from levelStart
to levelStart + count
.
levels | the level array, which is already determined. |
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levelStart | the start offset of the range of the levels. |
objects | the object array to reorder. |
objectStart | the start offset of the range of objects. |
count | the count of the range of objects to reorder. |
IllegalArgumentException | if count , levelStart or objectStart
is negative; if count > levels.length - levelStart or
if count > objects.length - objectStart .
|
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Indicates whether a range of characters of a text requires a Bidi
object to display properly.
text | the char array of the text. |
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start | the start offset of the range of characters. |
limit | the limit offset of the range of characters. |
true
if the range of characters requires a Bidi
object; false
otherwise.IllegalArgumentException | if start or limit is negative; start >
limit or limit is greater than the length of this
object's paragraph text.
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Returns a string containing a concise, human-readable description of this object. Subclasses are encouraged to override this method and provide an implementation that takes into account the object's type and data. The default implementation is equivalent to the following expression:
getClass().getName() + '@' + Integer.toHexString(hashCode())
See Writing a useful
toString
method
if you intend implementing your own toString
method.