net.sf.saxon.tree.util

Class FastStringBuffer

java.lang.Object

net.sf.saxon.tree.util.FastStringBuffer

All Implemented Interfaces:

CharSequence, AppendableCharSequence

public final class FastStringBuffer
extends Object
implements AppendableCharSequence

A simple implementation of a class similar to StringBuffer. Unlike StringBuffer it is not synchronized. It also offers the capability to remove unused space. (This class could possibly be replaced by StringBuilder in JDK 1.5, but using our own class gives more control.)

Field Summary

Fields

Modifier and Type	Field and Description
static int	LARGE
static int	MEDIUM
static int	SMALL
static int	TINY

Constructor Summary

Constructors

Constructor and Description
FastStringBuffer(CharSequence cs) Create a FastStringBuffer with initial content
FastStringBuffer(int initialSize) Create a FastStringBuffer with a given initial capacity

Method Summary

Methods

Modifier and Type	Method and Description
void	append(char ch) Append a character to the buffer
void	append(char[] srcArray) Append the entire contents of a character array to the buffer
void	append(char[] srcArray, int start, int length) Append the contents of a character array to the buffer
void	append(CharSequence s) Append the contents of a general CharSequence to the buffer
void	append(CharSlice s) Append the contents of a CharSlice to the buffer
void	append(FastStringBuffer s) Append the contents of a FastStringBuffer to the buffer
void	append(String s) Append the contents of a String to the buffer
void	append(StringBuffer s) Append the contents of a StringBuffer to the buffer
void	append(UnicodeString str) Append a UnicodeString to the buffer (using surrogate pairs if necessary)
void	appendWideChar(int ch) Append a wide character to the buffer (as a surrogate pair if necessary)
char	charAt(int index) Returns the char value at the specified index.
CharSequence	condense() Remove surplus space from the array.
static String	diagnosticPrint(CharSequence in) Diagnostic print of the contents of a CharSequence.
void	ensureCapacity(int extra) Expand the character array if necessary to ensure capacity for appended data
boolean	equals(Object other) Compare equality
char[]	getCharArray() Get a char[] array containing the characters.
void	getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin) Copies characters from this FastStringBuffer into the destination character array.
int	hashCode() Generate a hash code
int	indexOf(char ch) Get the index of the first character equal to a given value
void	insert(int index, char ch) Insert a character at a particular offset
void	insertWideChar(int index, int ch) Insert wide character at a particular offset
int	length() Returns the length of this character sequence.
void	prepend(char ch) Insert a given character at the start of the buffer
void	prepend(CharSequence str) Insert a given string at the start of the buffer
void	prependRepeated(char ch, int repeat) Insert a given character N times at the start of the buffer
void	prependWideChar(int ch) Prepend a wide character to the buffer (as a surrogate pair if necessary)
void	removeCharAt(int index) Remove a character at a particular offset
void	setCharAt(int index, char ch) Set the character at a particular offset
void	setLength(int length) Set the length.
CharSequence	subSequence(int start, int end) Returns a new CharSequence that is a subsequence of this sequence.
String	toString() Convert contents of the FastStringBuffer 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

Field Detail

TINY

public static final int TINY

See Also:

Constant Field Values

SMALL

public static final int SMALL

See Also:

Constant Field Values

MEDIUM

public static final int MEDIUM

See Also:

Constant Field Values

LARGE

public static final int LARGE

See Also:

Constant Field Values

Constructor Detail

FastStringBuffer

public FastStringBuffer(int initialSize)

Create a FastStringBuffer with a given initial capacity

Parameters:

initialSize - the initial capacity

FastStringBuffer

public FastStringBuffer(CharSequence cs)

Create a FastStringBuffer with initial content

Parameters:

cs - the initial content. The buffer is created with just enough capacity for this content (it will be expanded if more content is added later).

Method Detail

append

public void append(String s)

Append the contents of a String to the buffer

Parameters:

s - the String to be appended

append

public void append(CharSlice s)

Append the contents of a CharSlice to the buffer

Parameters:

s - the String to be appended

append

public void append(FastStringBuffer s)

Append the contents of a FastStringBuffer to the buffer

Parameters:

s - the FastStringBuffer to be appended

append

public void append(StringBuffer s)

Append the contents of a StringBuffer to the buffer

Parameters:

s - the StringBuffer to be appended

append

public void append(CharSequence s)

Append the contents of a general CharSequence to the buffer

Specified by:

append in interface AppendableCharSequence

Parameters:

s - the CharSequence to be appended

append

public void append(char[] srcArray,
          int start,
          int length)

Append the contents of a character array to the buffer

Parameters:

srcArray - the array whose contents are to be added

start - the offset of the first character in the array to be copied

length - the number of characters to be copied

append

public void append(char[] srcArray)

Append the entire contents of a character array to the buffer

Parameters:

srcArray - the array whose contents are to be added

append

public void append(char ch)

Append a character to the buffer

Parameters:

ch - the character to be added

appendWideChar

public void appendWideChar(int ch)

Append a wide character to the buffer (as a surrogate pair if necessary)

Parameters:

ch - the character, as a 32-bit Unicode codepoint

append

public void append(UnicodeString str)

Append a UnicodeString to the buffer (using surrogate pairs if necessary)

Parameters:

str - the UnicodeString

prependWideChar

public void prependWideChar(int ch)

Prepend a wide character to the buffer (as a surrogate pair if necessary)

Parameters:

ch - the character, as a 32-bit Unicode codepoint

length

public int length()

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

Specified by:

length in interface CharSequence

Returns:

the number of chars in this sequence

charAt

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.

Specified by:

charAt in interface CharSequence

Parameters:

index - the index of the char value to be returned

Returns:

the specified char value

Throws:

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

subSequence

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.

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

getChars

public void getChars(int srcBegin,
            int srcEnd,
            char[] dst,
            int dstBegin)

Copies characters from this FastStringBuffer into the destination character array.

The first character to be copied is at index srcBegin; the last character to be copied is at index srcEnd-1 (thus the total number of characters to be copied is srcEnd-srcBegin). The characters are copied into the subarray of dst starting at index dstBegin and ending at index:

     dstbegin + (srcEnd-srcBegin) - 1
 

Parameters:

srcBegin - index of the first character in the string to copy.

srcEnd - index after the last character in the string to copy.

dst - the destination array.

dstBegin - the start offset in the destination array.

Throws:

IndexOutOfBoundsException - If any of the following is true:

• srcBegin is negative.
• srcBegin is greater than srcEnd
• srcEnd is greater than the length of this string
• dstBegin is negative
• dstBegin+(srcEnd-srcBegin) is larger than dst.length

indexOf

public int indexOf(char ch)

Get the index of the first character equal to a given value

Parameters:

ch - the character to search for

Returns:

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

toString

public String toString()

Convert contents of the FastStringBuffer 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

getCharArray

public char[] getCharArray()

Get a char[] array containing the characters. The caller should not modify the array.

Returns:

a char[] array containing the characters.

setCharAt

public void setCharAt(int index,
             char ch)

Set the character at a particular offset

Parameters:

index - the index of the character to be set

ch - the new character to overwrite the existing character at that location

Throws:

IndexOutOfBoundsException - if int<0 or int>=length()

insert

public void insert(int index,
          char ch)

Insert a character at a particular offset

Parameters:

index - the index of the character to be set

ch - the new character to insert at that location

Throws:

IndexOutOfBoundsException - if int<0 or int>=length()

insertWideChar

public void insertWideChar(int index,
                  int ch)

Insert wide character at a particular offset

Parameters:

index - the index of the character to be set

ch - the character, as a 32-bit Unicode codepoint

Throws:

IndexOutOfBoundsException - if int<0 or int>=length()

removeCharAt

public void removeCharAt(int index)

Remove a character at a particular offset

Parameters:

index - the index of the character to be set

Throws:

IndexOutOfBoundsException - if int<0 or int>=length()

prepend

public void prepend(char ch)

Insert a given character at the start of the buffer

Parameters:

ch - the character to insert

prepend

public void prepend(CharSequence str)

Insert a given string at the start of the buffer

Parameters:

str - the string to insert

prependRepeated

public void prependRepeated(char ch,
                   int repeat)

Insert a given character N times at the start of the buffer

Parameters:

ch - the character to insert

repeat - the number of occurrences required. Supplying 0 or a negative number is OK, and is treated as a no-op.

setLength

public void setLength(int length)

Set the length. If this exceeds the current length, this method is a no-op. If this is less than the current length, characters beyond the specified point are deleted.

Specified by:

setLength in interface AppendableCharSequence

Parameters:

length - the new length

ensureCapacity

public void ensureCapacity(int extra)

Expand the character array if necessary to ensure capacity for appended data

Parameters:

extra - the amount of additional capacity needed, in characters

condense

public CharSequence condense()

Remove surplus space from the array. This doesn't reduce the array to the minimum possible size; it only reclaims space if it seems worth doing. Specifically, it contracts the array if the amount of wasted space is more than 256 characters, or more than half the allocated size and more than 20 chars.

Returns:

the buffer after removing unused space

write

public void write(Writer writer)
           throws IOException

Write the value to a writer

Parameters:

writer - the writer to which the content is to be written

Throws:

IOException

diagnosticPrint

public static String diagnosticPrint(CharSequence in)

Diagnostic print of the contents of a CharSequence. Ordinary printable ASCII characters are displayed as themselves; anything else is displayed as a \\uNNNN escape sequence

Parameters:

in - the CharSequence whose contents are to be displayed.

Returns:

the diagnostic output