com.marketfactory.zerogc.api

Class MFString

java.lang.Object

com.marketfactory.zerogc.api.MFString

All Implemented Interfaces:

java.io.Serializable, java.lang.CharSequence, java.lang.Comparable

public class MFString
extends java.lang.Object
implements java.lang.Comparable, java.lang.CharSequence, java.io.Serializable

A mutable string to support zero gc applications. Its interface is modelled of of java.util.StringBuilder. These strings must contain strings that are part of the printable ASCII subset of Java's UTF-16 characters since whisperer strings are ASCII. It supports up to a max length of 1024 characters. Will throw an IndexOutOfBoundsException if there is an attempt to exceed the capacity.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static int	MAX_SIZE

Constructor Summary

Constructors

Constructor and Description
MFString() Default constructor.
MFString(java.lang.CharSequence str) Initializes using the characters from a CharSequence.
MFString(int maxSize) Creates an MFString with the specified maximum size.
MFString(MFString str) Copy constructor.

Method Summary

Modifier and Type	Method and Description
MFString	append(char c) Append a char at the end of the string.
MFString	append(char[] c) Append a char array at the end of the string.
MFString	append(java.lang.CharSequence s) Append the contents of a CharSequence to this string
MFString	append(java.lang.CharSequence s, int start, int end) Append the CharSequence to this string within the given range.
MFString	append(int i) Append an int representation of a string at the end of the string.
MFString	append(long l) Append an int representation of a string at the end of the string.
MFString	append(MFString s) Append the contents of a MFString to this string
char	charAt(int index) Get the length of the string.
int	compareTo(java.lang.Object o) Implements Comparable method compareTo.
void	deepCopy(MFString src) Copies the state of the source MFString to this string.
boolean	equals(java.lang.Object o)
void	freeze() Freeze the state.
int	hashCode() This is for the use case where the object needs to be in a pool (in order to avoid creating garbage) but also in a java collection, such as HashMap, which needs to have this in order to operate properly.
boolean	isEmpty() Convenience method which exists in String.
int	length() Get the length of the string.
void	reset() Resets the string so a new string can be created.
void	setCharAt(int index, char ch) Change the char at a specific index.
java.lang.CharSequence	subSequence(int start, int end) Returns a new CharSequence that is a subsequence of this sequence.
java.lang.String	toString() WARNING: Creates garbage.
void	unfreeze()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.CharSequence

chars, codePoints

Field Detail

MAX_SIZE

public static final int MAX_SIZE

See Also:

Constant Field Values

Constructor Detail

MFString

public MFString()

Default constructor. Creates an empty string.

MFString

public MFString(int maxSize)

Creates an MFString with the specified maximum size. This overrides the default provided by MAX_SIZE.

Parameters:

maxSize - max size of this MFString

MFString

public MFString(MFString str)

Copy constructor.

Parameters:

str - - the intial value of this string object.

MFString

public MFString(java.lang.CharSequence str)

Initializes using the characters from a CharSequence. WARNING: Be careful when using this constructor as java.lang.String is immutable and therefor can generate garbage easily. This method should be used sparingly for such cases as logging in and subscribing to markets, not for entering orders.

Parameters:

str - - the intial value of this string object.

Throws:

java.lang.IllegalArgumentException - - if any character is not printable ASCII.

java.lang.IndexOutOfBoundsException - - The length of str is greater than 1024.

Method Detail

deepCopy

public void deepCopy(MFString src)

Copies the state of the source MFString to this string.

Parameters:

src - -- the rhs string

Throws:

java.lang.IllegalStateException - - If called when the string has been frozen.

append

public MFString append(char c)

Append a char at the end of the string.

Parameters:

c - the character to be appended

Returns:

the appended string

Throws:

java.lang.IllegalArgumentException - - if any character is not printable ASCII.

java.lang.IndexOutOfBoundsException - - The length of str is greater than 1024.

java.lang.IllegalStateException - - If called when the string has been frozen.

append

public MFString append(char[] c)

Append a char array at the end of the string.

Parameters:

c - the string to be appended

Returns:

the appended string

Throws:

java.lang.IllegalArgumentException - - if any character is not printable ASCII.

java.lang.IndexOutOfBoundsException - - The length of str is greater than 1024.

java.lang.IllegalStateException - - If called when the string has been frozen.

append

public MFString append(MFString s)

Append the contents of a MFString to this string

Parameters:

s - the string to be appended

Returns:

the appended string

Throws:

java.lang.IllegalArgumentException - - if any character is not printable ASCII.

java.lang.IndexOutOfBoundsException - - The length of sr is greater than 1024.

java.lang.IllegalStateException - - If called when the string has been frozen.

append

public MFString append(java.lang.CharSequence s)

Append the contents of a CharSequence to this string

Parameters:

s - the string to be appended

Returns:

the appended string

Throws:

java.lang.IllegalArgumentException - - if any character is not printable ASCII.

java.lang.IndexOutOfBoundsException - - The length of str is greater than 1024.

java.lang.IllegalStateException - - If called when the string has been frozen.

append

public MFString append(java.lang.CharSequence s,
                       int start,
                       int end)

Append the CharSequence to this string within the given range.

Parameters:

s - the string to be appended

start - the start index

end - the end index

Returns:

the appended string

Throws:

java.lang.IllegalArgumentException - - if any character is not printable ASCII.

java.lang.IndexOutOfBoundsException - - if either index is not greater than zero and less than 1024 or start is greater than end or if end is greater than s.length();

java.lang.IllegalStateException - - If called when the string has been frozen.

append

public MFString append(int i)

Append an int representation of a string at the end of the string.

Parameters:

i - the integer

Returns:

the appended string

Throws:

java.lang.IndexOutOfBoundsException - - The length of str is greater than 1024.

java.lang.IllegalStateException - - If called when the string has been frozen.

append

public MFString append(long l)

Append an int representation of a string at the end of the string.

Parameters:

l - the long integer

Returns:

the appended string

Throws:

java.lang.IndexOutOfBoundsException - - The length of str is greater than 1024.

java.lang.IllegalStateException - - If called when the string has been frozen.

charAt

public char charAt(int index)

Get the length of the string.

Specified by:

charAt in interface java.lang.CharSequence

Throws:

java.lang.IndexOutOfBoundsException - - The length of str is greater than 1024.

setCharAt

public void setCharAt(int index,
                      char ch)

Change the char at a specific index.

Parameters:

index - the idx

ch - the character

Throws:

java.lang.IllegalArgumentException - - if any character is not printable ASCII.

java.lang.IndexOutOfBoundsException - - The length of str is greater than 1024.

java.lang.IllegalStateException - - If called when the string has been frozen.

length

public int length()

Get the length of the string.

Specified by:

length in interface java.lang.CharSequence

isEmpty

public boolean isEmpty()

Convenience method which exists in String.

Returns:

is empty?

subSequence

public java.lang.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 java.lang.CharSequence

Throws:

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

reset

public void reset()

Resets the string so a new string can be created.

Throws:

java.lang.IllegalStateException - - If called when the string has been frozen.

freeze

public void freeze()

Freeze the state. This will cause an exception to be thrown if there is an attempt to mutate the string. This is most useful when using this in a collection.

unfreeze

public void unfreeze()

toString

public java.lang.String toString()

WARNING: Creates garbage. For debug only!!! Creates a java.lang.String object.

Specified by:

toString in interface java.lang.CharSequence

Overrides:

toString in class java.lang.Object

compareTo

public int compareTo(java.lang.Object o)
              throws java.lang.ClassCastException

Implements Comparable method compareTo. Same comparison as implemented for java.lang.String.

Specified by:

compareTo in interface java.lang.Comparable

Throws:

java.lang.ClassCastException

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

This is for the use case where the object needs to be in a pool (in order to avoid creating garbage) but also in a java collection, such as HashMap, which needs to have this in order to operate properly. Care must be taken not to modify the MFString when used in a collection since collections assume the item will immutable.

Overrides:

hashCode in class java.lang.Object