com.allanbank.mongodb.bson.io

Class StringEncoder

java.lang.Object

com.allanbank.mongodb.bson.io.StringEncoder

public class StringEncoder
extends Object

StringEncoder provides a single location for the string encoding and sizing logic. This class if backed by a cache of strings to the encoded bytes.

The cache is controlled via two parameters:

API Warning:

This class is NOT part of the drivers API. This class may be mutated in incompatible ways between any two releases of the driver.

Copyright ©:

2013, Allanbank Consulting, Inc., All Rights Reserved

Constructor Summary

Constructors

Constructor and Description
StringEncoder() Creates a new StringEncoder.
StringEncoder(StringEncoderCache cache) Creates a new StringEncoder.

Method Summary

Methods

Modifier and Type	Method and Description
static int	computeCStringSize(String string) Returns the visitor's output buffer.
static int	computeStringSize(String string) Returns the visitor's output buffer.
void	encode(String string, OutputStream out) Writes the string as a UTF-8 string.
int	encodeSize(String string) Computes the size of the encoded UTF8 String based on the table below.
protected void	fastEncode(String string, OutputStream out) Writes the string as a UTF-8 string.
StringEncoderCache	getCache() Deprecated. The cache StringEncoderCache should be controlled directly. This method will be removed after the 2.1.0 release.
static int	utf8Size(String string) Computes the size of the encoded UTF8 String based on the table below.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

StringEncoder

public StringEncoder()

Creates a new StringEncoder.

StringEncoder

public StringEncoder(StringEncoderCache cache)

Creates a new StringEncoder.

Parameters:

cache - The cache for the encoder to use.

Method Detail

computeCStringSize

public static int computeCStringSize(String string)

Returns the visitor's output buffer.

Parameters:

string - The 'C' string to determine the size of.

Returns:

The visitor's output buffer.

computeStringSize

public static int computeStringSize(String string)

Returns the visitor's output buffer.

Parameters:

string - The 'UTF8' string to determine the size of.

Returns:

The visitor's output buffer.

utf8Size

public static int utf8Size(String string)

Computes the size of the encoded UTF8 String based on the table below.

 #    Code Points      Bytes
 1    U+0000..U+007F   1
 
 2    U+0080..U+07FF   2
 
 3    U+0800..U+0FFF   3
      U+1000..U+FFFF
 
 4   U+10000..U+3FFFF  4
     U+40000..U+FFFFF  4
    U+100000..U10FFFF  4
 

Parameters:

string - The string to determine the length of.

Returns:

The length of the string encoded as UTF8.

encode

public void encode(String string,
          OutputStream out)
            throws IOException

Writes the string as a UTF-8 string. This method handles the "normal/easy" cases and delegates to the full character set if things get complicated.

Parameters:

string - The string to encode.

out - The stream to write to.

Throws:

IOException - On a failure to write the bytes.

encodeSize

public int encodeSize(String string)

Computes the size of the encoded UTF8 String based on the table below. This method may use a cached copy of the encoded string to determine the size.

 #    Code Points      Bytes
 1    U+0000..U+007F   1
 
 2    U+0080..U+07FF   2
 
 3    U+0800..U+0FFF   3
      U+1000..U+FFFF
 
 4   U+10000..U+3FFFF  4
     U+40000..U+FFFFF  4
    U+100000..U10FFFF  4
 

Parameters:

string - The string to determine the length of.

Returns:

The length of the string encoded as UTF8.

getCache

@Deprecated
public StringEncoderCache getCache()

Deprecated. The cache StringEncoderCache should be controlled directly. This method will be removed after the 2.1.0 release.

Returns the cache value.

Returns:

The cache value.

fastEncode

protected void fastEncode(String string,
              OutputStream out)
                   throws IOException

Writes the string as a UTF-8 string. This method handles the "normal/easy" cases and delegates to the full character set if things get complicated.

Parameters:

string - The string to encode.

out - The stream to write to.

Throws:

IOException - On a failure to write the bytes.