net.sf.saxon.tree.tiny

Class CharSlice

java.lang.Object

net.sf.saxon.tree.tiny.CharSlice

All Implemented Interfaces:

CharSequence

public final class CharSlice
extends Object
implements CharSequence

This is an implementation of the JDK 1.4 CharSequence interface: it implements a CharSequence as a view of an array. The implementation relies on the array being immutable: as a minimum, the caller is required to ensure that the array contents will not change so long as the CharSlice remains in existence.

This class should be more efficient than String because it avoids copying the characters unnecessarily.

The methods in the class don't check their arguments. Incorrect arguments will generally result in exceptions from lower-level classes.

Constructor Summary

Constructors

Constructor and Description
CharSlice(char[] array) Create a CharSlice that maps to the whole of a char[] array
CharSlice(char[] array, int start, int length) Create a CharSlice that maps to a section of a char[] array

Method Summary

Methods

Modifier and Type	Method and Description
char	charAt(int index) Returns the character at the specified index.
void	copyTo(char[] destination, int destOffset) Append the contents to another array at a given offset.
boolean	equals(Object other) Compare equality
void	getChars(int start, int end, char[] destination, int destOffset) Append the contents to another array at a given offset.
int	hashCode() Generate a hash code
int	indexOf(char c) Get the index of a specific character in the sequence.
int	length() Returns the length of this character sequence.
void	setLength(int length) Set the length of this character sequence, without changing the array and start offset to which it is bound
CharSequence	subSequence(int start, int end) Returns a new character sequence that is a subsequence of this sequence.
String	substring(int start, int end) Returns a new character sequence that is a subsequence of this sequence.
String	toString() Convert to a string
void	write(Writer writer) Write the value to a writer

Methods inherited from class java.lang.Object

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

Constructor Detail

CharSlice

public CharSlice(char[] array)

Create a CharSlice that maps to the whole of a char[] array

Parameters:

array - the char[] array

CharSlice

public CharSlice(char[] array,
         int start,
         int length)

Create a CharSlice that maps to a section of a char[] array

Parameters:

array - the char[] array

start - position of the first character to be included

length - number of characters to be included

Method Detail

length

public int length()

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

Specified by:

length in interface CharSequence

Returns:

the number of characters in this sequence

setLength

public void setLength(int length)

Set the length of this character sequence, without changing the array and start offset to which it is bound

Parameters:

length - the new length of the CharSlice (which must be less than the existing length, though this is not enforced)

charAt

public char charAt(int index)

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

Specified by:

charAt in interface CharSequence

Parameters:

index - the index of the character to be returned

Returns:

the specified character

Throws:

IndexOutOfBoundsException - if the index argument is negative or not less than length()

subSequence

public CharSequence subSequence(int start,
                       int end)

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

Specified by:

subSequence in interface CharSequence

Parameters:

start - the start index, inclusive

end - the end index, exclusive

Returns:

the specified subsequence

Throws:

IndexOutOfBoundsException - if start or end are negative, if end is greater than length(), or if start is greater than end

toString

public String toString()

Convert to a string

Specified by:

toString in interface CharSequence

Overrides:

toString in class Object

equals

public boolean equals(Object other)

Compare equality

Overrides:

equals in class Object

hashCode

public int hashCode()

Generate a hash code

Overrides:

hashCode in class Object

indexOf

public int indexOf(char c)

Get the index of a specific character in the sequence. Returns -1 if not found. This method mimics String.indexOf(int)

Parameters:

c - the character to be found

Returns:

the position of the first occurrence of that character, or -1 if not found.

substring

public String substring(int start,
               int end)

Returns a new character sequence that is a subsequence of this sequence. Unlike subSequence, this is guaranteed to return a String.

Parameters:

start - position of the first character to be included (relative to the start of the CharSlice, not the underlying array)

end - position of the first character not to be included (relative to the start of the CharSlice)

Returns:

the substring, as a String object

copyTo

public void copyTo(char[] destination,
          int destOffset)

Append the contents to another array at a given offset. The caller is responsible for ensuring that sufficient space is available.

Parameters:

destination - the array to which the characters will be copied

destOffset - the offset in the target array where the copy will start

getChars

public void getChars(int start,
            int end,
            char[] destination,
            int destOffset)

Append the contents to another array at a given offset. The caller is responsible for ensuring that sufficient space is available. Otherwise this behaves like String.getChars()

Parameters:

start - offset of first character to be copied

end - offset of the first character that is not copied

destination - the array to which the characters will be copied

destOffset - the offset in the target array where the copy will start

write

public void write(Writer writer)
           throws IOException

Write the value to a writer

Parameters:

writer - the writer to be written to

Throws:

IOException - if writing fails