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public class

Segment

extends Object
implements CharSequence Cloneable CharacterIterator
java.lang.Object
   ↳ javax.swing.text.Segment

Class Overview

A segment of a character array representing a fragment of text. It should be treated as immutable even though the array is directly accessible. This gives fast access to fragments of text without the overhead of copying around characters. This is effectively an unprotected String.

The Segment implements the java.text.CharacterIterator interface to support use with the i18n support without copying text into a string.

Summary

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Inherited Constants
From interface java.text.CharacterIterator
Fields
public char[] array This is the array containing the text of interest.
public int count This is the number of array elements that make up the text of interest.
public int offset This is the offset into the array that the desired text begins.
Public Constructors
Segment()
Creates a new segment.
Segment(char[] array, int offset, int count)
Creates a new segment referring to an existing array.
Public Methods
char charAt(int index)
Returns the char value at the specified index.
Object clone()
Creates a shallow copy.
char current()
Gets the character at the current position (as returned by getIndex()).
char first()
Sets the position to getBeginIndex() and returns the character at that position.
int getBeginIndex()
Returns the start index of the text.
int getEndIndex()
Returns the end index of the text.
int getIndex()
Returns the current index.
boolean isPartialReturn()
Flag to indicate that partial returns are valid.
char last()
Sets the position to getEndIndex()-1 (getEndIndex() if the text is empty) and returns the character at that position.
int length()
Returns the length of this character sequence.
char next()
Increments the iterator's index by one and returns the character at the new index.
char previous()
Decrements the iterator's index by one and returns the character at the new index.
char setIndex(int position)
Sets the position to the specified position in the text and returns that character.
void setPartialReturn(boolean p)
Flag to indicate that partial returns are valid.
CharSequence subSequence(int start, int end)
Returns a new CharSequence that is a subsequence of this sequence.
String toString()
Converts a segment into a String.
[Expand]
Inherited Methods
From class java.lang.Object
From interface java.lang.CharSequence
From interface java.text.CharacterIterator

Fields

public char[] array

This is the array containing the text of interest. This array should never be modified; it is available only for efficiency.

public int count

This is the number of array elements that make up the text of interest.

public int offset

This is the offset into the array that the desired text begins.

Public Constructors

public Segment ()

Creates a new segment.

public Segment (char[] array, int offset, int count)

Creates a new segment referring to an existing array.

Parameters
array the array to refer to
offset the offset into the array
count the number of characters

Public Methods

public char charAt (int index)

Returns the char value at the specified index. An index ranges from zero to length() - 1. The first char value of the sequence is at index zero, the next at index one, and so on, as for array indexing.

If the char value specified by the index is a surrogate, the surrogate value is returned.

Parameters
index the index of the char value to be returned
Returns
  • the specified char value

public Object clone ()

Creates a shallow copy.

Returns
  • the copy

public char current ()

Gets the character at the current position (as returned by getIndex()).

Returns
  • the character at the current position or DONE if the current position is off the end of the text.
See Also

public char first ()

Sets the position to getBeginIndex() and returns the character at that position.

Returns
  • the first character in the text, or DONE if the text is empty
See Also

public int getBeginIndex ()

Returns the start index of the text.

Returns
  • the index at which the text begins.

public int getEndIndex ()

Returns the end index of the text. This index is the index of the first character following the end of the text.

Returns
  • the index after the last character in the text

public int getIndex ()

Returns the current index.

Returns
  • the current index.

public boolean isPartialReturn ()

Flag to indicate that partial returns are valid.

Returns
  • whether or not partial returns are valid.

public char last ()

Sets the position to getEndIndex()-1 (getEndIndex() if the text is empty) and returns the character at that position.

Returns
  • the last character in the text, or DONE if the text is empty
See Also

public int length ()

Returns the length of this character sequence. The length is the number of 16-bit chars in the sequence.

Returns
  • the number of chars in this sequence

public char next ()

Increments the iterator's index by one and returns the character at the new index. If the resulting index is greater or equal to getEndIndex(), the current index is reset to getEndIndex() and a value of DONE is returned.

Returns
  • the character at the new position or DONE if the new position is off the end of the text range.

public char previous ()

Decrements the iterator's index by one and returns the character at the new index. If the current index is getBeginIndex(), the index remains at getBeginIndex() and a value of DONE is returned.

Returns
  • the character at the new position or DONE if the current position is equal to getBeginIndex().

public char setIndex (int position)

Sets the position to the specified position in the text and returns that character.

Parameters
position the position within the text. Valid values range from getBeginIndex() to getEndIndex(). An IllegalArgumentException is thrown if an invalid value is supplied.
Returns
  • the character at the specified position or DONE if the specified position is equal to getEndIndex()

public void setPartialReturn (boolean p)

Flag to indicate that partial returns are valid. If the flag is true, an implementation of the interface method Document.getText(position,length,Segment) should return as much text as possible without making a copy. The default state of the flag is false which will cause Document.getText(position,length,Segment) to provide the same return behavior it always had, which may or may not make a copy of the text depending upon the request.

Parameters
p whether or not partial returns are valid.

public CharSequence subSequence (int start, int end)

Returns a new CharSequence that is a subsequence of this sequence. The subsequence starts with the char value at the specified index and ends with the char value at index end - 1. The length (in chars) of the returned sequence is end - start, so if start == end then an empty sequence is returned.

Parameters
start the start index, inclusive
end the end index, exclusive
Returns
  • the specified subsequence

public String toString ()

Converts a segment into a String.

Returns
  • the string