com.ibm.lpex.bidi
Class BidiText

java.lang.Object
  com.ibm.lpex.bidi.BidiText

public class BidiText
extends Object

Bidi text is a combination of a sequence of characters and a set of Bidi flags which represent Bidi attributes used during Bidi Layout transformations.

Layout transformations allow to convert a given instance of Bidi text into another instance with possibly different Bidi flags while conserving the semantics of the text.

A BidiText object contains a BidiFlagSet to store the Bidi flags characterizing its character data. The characters are contained in a character array. This array may contain more data than the Bidi text to process. The part of the array to process is called the "interesting" data, and is defined by its length and its offset from the beginning of the character array.

Multi-threading considerations: Each thread must use its own instances of this class.

Field Summary

int	count length of the "interesting" data within the character array
char[]	data character array containing the data
BidiFlagSet	flags BidiFlagSet qualifying the character data
int	offset offset of the "interesting" data within the character array

Constructor Summary

BidiText()
Constructor with no arguments to create a flags member with a DEFAULT value.

BidiText(BidiFlagSet initFlags)
Constructs a BidiText object based on an existing BidiFlagSet.

BidiText(BidiFlagSet initFlags, char[] initData)
Constructs a BidiText object based on an existing BidiFlagSet and the data in a character array.

BidiText(BidiFlagSet initFlags, char[] initData, int offset, int length, int capacity)
Constructs a BidiText object based on an existing BidiFlagSet and the data in part of a character array.

BidiText(BidiFlagSet initFlags, String str)
Constructs a BidiText object based on an existing BidiFlagSet and the data in a string.

Method Summary

boolean	equals(BidiText other) Compares two BidiText objects.
boolean	equals(Object obj)
int	hashCode()
void	setCharsRef(char[] newData, int newOffset, int newLength) Replaces the character data reference in the BidiText object.
char[]	toCharArray() Extracts the character data from a BidiText in character array format
String	toString() Extracts the character data from a BidiText in string format
BidiText	transform(BidiFlagSet dstFlags) Transforms the data in the "this" BidiText object and return the resulting BidiText object.
BidiText	transform(BidiTransform bdx) Transforms the data in the "this" BidiText object and return the resulting BidiText object.

Methods inherited from class java.lang.Object

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

Field Detail

flags

public BidiFlagSet flags

BidiFlagSet qualifying the character data

data

public char[] data

character array containing the data

offset

public int offset

offset of the "interesting" data within the character array

count

public int count

length of the "interesting" data within the character array

Constructor Detail

BidiText

public BidiText()

Constructor with no arguments to create a flags member with a DEFAULT value. There is no data and no character array, but a default BidiFlagSet is created and referred to in "flags".

BidiText

public BidiText(BidiFlagSet initFlags)

Constructs a BidiText object based on an existing BidiFlagSet. There is no data and no character array.

BidiText

public BidiText(BidiFlagSet initFlags,
                char[] initData)

Constructs a BidiText object based on an existing BidiFlagSet and the data in a character array.

The argument flags and data are duplicated. Changing them will not affect the BidiText instance.

Parameters:

initFlags - The Bidi flags of the data.

initData - The character data.

BidiText

public BidiText(BidiFlagSet initFlags,
                char[] initData,
                int offset,
                int length,
                int capacity)

Constructs a BidiText object based on an existing BidiFlagSet and the data in part of a character array.

The argument flags and data are duplicated. Changing them will not affect the BidiText instance.

Parameters:

initFlags - The Bidi flags of the data.

initData - The character data.

offset - The offset of the "interesting" data in initData.

length - The length of the "interesting" data in initData.

capacity - The length of the created character array (may be larger than "length" to reserve space for adding more data).

BidiText

public BidiText(BidiFlagSet initFlags,
                String str)

Constructs a BidiText object based on an existing BidiFlagSet and the data in a string.

The argument flags and data are duplicated. Changing them will not affect the BidiText instance.

Parameters:

initFlags - The Bidi flags of the data.

str - The character data.

Method Detail

equals

public boolean equals(BidiText other)

Compares two BidiText objects. Two BidiText objects are considered equal if they have the same Bidi flags and the same "interesting" character data,

Parameters:

other - The BidiText to compare to this.

Returns:

true if the BidiText objects are equal, false otherwise.

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

setCharsRef

public void setCharsRef(char[] newData,
                        int newOffset,
                        int newLength)

Replaces the character data reference in the BidiText object. Note that the data is not duplicated, only its reference is written in the BidiText object.

This method avoids the overhead of creating a character array and copying the source data to it, when the source data is already contained in a character array.

This method can be used after creating a BidiText object with no arguments, or to reuse a BidiText object with new data.

This is a convenience method. It is also possible to manipulate directly the data, offset and count members of the BidiText instance.

Parameters:

newData - A reference to the character data.

newOffset - The offset of the "interesting" data in newData.

newLength - The length of the "interesting" data in newData.

toCharArray

public char[] toCharArray()

Extracts the character data from a BidiText in character array format

Returns:

A char array containing a copy of the "interesting" data.

toString

public String toString()

Extracts the character data from a BidiText in string format

Overrides:

toString in class Object

Returns:

A string containing a copy of the "interesting" data.

transform

public BidiText transform(BidiFlagSet dstFlags)

Transforms the data in the "this" BidiText object and return the resulting BidiText object. The transformation is done according to the Bidi flags of the source BidiText and the Bidi flags specified in the argument.

The source BidiText is never modified by the transform.

The destination BidiText has its Bidi flags set to those of the argument.

A typical usage of this method could be:

  BidiText        src = new BidiText();       // source text
  BidiFlagSet     dstFlags;                   // Bidi flags for destination
  BidiText        dst;                        // destination reference
  src.flags.setAllFlags( {flag values for source} );
  dstFlags.setAllFlags( {flag values for destination} );
  // assign values to src.data, src.offset, src.count
  dst = src.transform(dstFlags);
  

Parameters:

dstFlags - Bidi flags of the destination BidiText.

Returns:

A BidiText which is the transformation of the "this" BidiText.

transform

public BidiText transform(BidiTransform bdx)

Transforms the data in the "this" BidiText object and return the resulting BidiText object. The transformation is done according to the Bidi flags of the source BidiText and the Bidi flags specified in the BidiTransform argument.

The source BidiText is never modified by the transform.

The destination BidiText has its Bidi flags set to those of the argument.

Output fields of the BidiTransform object are set by this method. srcToDstMap, DstToSrcMap and propertyMap may be set by this method if the corresponding options have been required in BidiTransform when calling it.

By default, transformed output data is written to the destination BidiText character array but no maps are created.

A typical usage of this method could be:

  BidiTransform   bdx = new BidiTransform();
  BidiText        src = new BidiText();       // source text
  BidiText        dst;                        // destination reference
  src.flags.setAllFlags( {flag values for source} );
  bdx.flags.setAllFlags( {flag values for destination} );
  // assign values to src.data, src.offset, src.count
  dst = src.transform(bdx);
  

This method is still in construction. Currently only the default options are implemented. No maps are created.

Parameters:

bdx - The BidiTransform object defining the transformation.

Returns:

A BidiText which is the transformation of the "this" BidiText. If destination data is not required, a null is returned.