net.sf.saxon.tinytree
Class LargeStringBuffer

java.lang.Object
  net.sf.saxon.tinytree.LargeStringBuffer

All Implemented Interfaces:

Serializable, CharSequence

public final class LargeStringBuffer
extends Object
implements CharSequence, Serializable

This is an implementation of the JDK 1.4 CharSequence interface: it implements a CharSequence as a list of arrays of characters (the individual arrays are known as segments). When characters are appended, a new segment is started if the previous array would otherwise overflow a threshold size (the maxAllocation size).

This is more efficient than a buffer backed by a contiguous array of characters in cases where the size is likely to grow very large, and where substring operations are rare. As used within the TinyTree, the value of each text node is contiguous within one segment, so extraction of the value of a text node is efficient.

See Also:

Serialized Form

Constructor Summary

LargeStringBuffer()
Create an empty LargeStringBuffer with default space allocation

LargeStringBuffer(int minAllocation, int maxAllocation)
Create an empty LargeStringBuffer

Method Summary

void	append(CharSequence data) Append a CharSequence to this LargeStringBuffer
char	charAt(int index) Returns the character at the specified index.
void	dumpDataStructure() Produce diagnostic dump
boolean	equals(Object other) Compare equality
int	hashCode() Generate a hash code
int	length() Returns the length of this character sequence.
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

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

LargeStringBuffer

public LargeStringBuffer()

Create an empty LargeStringBuffer with default space allocation

LargeStringBuffer

public LargeStringBuffer(int minAllocation,
                         int maxAllocation)

Create an empty LargeStringBuffer

Parameters:

minAllocation - initial allocation size for each segment (including the first). If minAllocation exceeds maxAllocation, it is rounded down to the value of maxAllocation

maxAllocation - maximum allocation size for each segment. When a segment reaches this size, a new segment is created rather than appending more characters to the existing segment. However, a segment may have size greater than maxAllocation if the data is appended in a single chunk of size maxAllocation.

Method Detail

append

public void append(CharSequence data)

Append a CharSequence to this LargeStringBuffer

Parameters:

data - the data to be appended

length

public int length()

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

Specified by:

length in interface CharSequence

Returns:

the number of characters in this sequence

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

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 - index of the first character to be included

end - index of the character after the last one to be included

Returns:

the substring at the given position

write

public void write(Writer writer)
           throws IOException

Write the value to a writer

Parameters:

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

Throws:

IOException

dumpDataStructure

public void dumpDataStructure()

Produce diagnostic dump