Package convex.core.data

Class Symbol

java.lang.Object

convex.core.data.AObject

convex.core.data.ACell

convex.core.data.ACountable<CVMChar>

convex.core.data.ABlobLike<CVMChar>

convex.core.data.ASymbolic

convex.core.data.Symbol

All Implemented Interfaces:

IValidated, IWriteable, Comparable<ABlobLike<?>>

public final class Symbol
extends ASymbolic

Class representing a Symbol. Symbols are more commonly used in CVM code to refer to functions and values in the execution environment.

Symbols are simply small immutable data Objects, and can be used freely in data structures. They can be used as map keys, however for most normal circumstances Strings or Keywords are more appropriate as keys.

A Symbol comprises: - A name

"Becoming sufficiently familiar with something is a substitute for understanding it." - John Conway

Field Summary

Fields

Modifier and Type	Field	Description
protected static final WeakHashMap<AString,Symbol>	cache

Fields inherited from class convex.core.data.ASymbolic

name

Fields inherited from class convex.core.data.ACell

cachedRef, memorySize

Fields inherited from class convex.core.data.AObject

encoding

Method Summary

Modifier and Type	Method	Description
int	compareTo(ABlobLike<?> b)
int	compareTo(Symbol sym)
static Symbol	create(AString name)	Creates a Symbol with the given name.
static Symbol	create(String name)	Creates a Symbol with the given name
int	encode(byte[] bs, int pos)	Writes this Cell's encoding to a byte array, including a tag byte which will be written first.
int	encodeRaw(byte[] bs, int pos)	Writes this Cell's encoding to a byte array, excluding the tag byte.
boolean	equals(ACell o)	Checks for equality with another Cell.
boolean	equals(Symbol sym)	Tests if this Symbol is equal to another Symbol.
int	getRefCount()	Gets the number of Refs contained within this Cell.
byte	getTag()	Gets the tag byte for this cell.
AType	getType()	Gets the most specific known runtime Type for this Cell.
boolean	isCanonical()	Returns true if this Cell is in a canonical representation.
boolean	print(BlobBuilder bb, long limit)	Prints this Object to a readable String Representation.
static Symbol	read(Blob blob, int offset)	Reads a Symbol from the given Blob
Symbol	slice(long start, long end)	Gets a slice of this data structure
ACell	toCanonical()	Converts this Cell to a canonical version.
AString	toCVMString(long limit)	Returns the CVM String representation of this Cell.
static Symbol	unsafeCreate(StringShort rawName)	Creates a Symbol in an unsafe manner (possibly invalid name), used for testing
static Symbol	unsafeCreate(String rawName)	Creates a Symbol in an unsafe manner (possibly invalid name), used for testing
void	validateCell()	Validates this Symbolic value

Methods inherited from class convex.core.data.ASymbolic

byteAt, calcMemorySize, count, createRef, empty, equalsBytes, estimatedEncodingSize, get, getBytes, getElementRef, getName, getRef, hashCode, hexMatch, isCVMValue, isDataValue, isEmbedded, longValue, toBlob, updateRefs, validateName

Methods inherited from class convex.core.data.ABlobLike

appendHex, byteAtUnchecked, getBytes, getHexDigit, hexEquals, hexLength, hexMatch, toFlatBlob, toHexString, toHexString

Methods inherited from class convex.core.data.ACountable

isEmpty, size, slice

Methods inherited from class convex.core.data.ACell

attachMemorySize, attachRef, cachedEncoding, cachedHash, createEncoding, equals, genericEquals, getCanonical, getChildRefs, getEncoding, getEncodingLength, getHash, getMemorySize, getMemorySize, getRef, toString, validate

Methods inherited from class convex.core.data.AObject

attachEncoding, print, print

Methods inherited from class java.lang.Object

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

Field Details

cache

protected static final WeakHashMap<AString,Symbol> cache

Method Details

getType

public AType getType()

Description copied from class: ACell

Gets the most specific known runtime Type for this Cell.

Overrides:

getType in class ACell

Returns:

The Type of this Call

create

public static Symbol create(String name)

Creates a Symbol with the given name

Parameters:

name - Symbol name

Returns:

Symbol instance, or null if the Symbol is invalid

create

public static Symbol create(AString name)

Creates a Symbol with the given name. Must be an unqualified name.

Parameters:

name - Name for Symbol

Returns:

Symbol instance, or null if the name is invalid for a Symbol.

unsafeCreate

public static Symbol unsafeCreate(String rawName)

Creates a Symbol in an unsafe manner (possibly invalid name), used for testing

Parameters:

rawName - Raw Symbol name

Returns:

Possibly invalid Keyword

unsafeCreate

public static Symbol unsafeCreate(StringShort rawName)

Creates a Symbol in an unsafe manner (possibly invalid name), used for testing

Parameters:

rawName - Raw Symbol name

Returns:

Possibly invalid Keyword

equals

public boolean equals(ACell o)

Description copied from class: ACell

Checks for equality with another Cell. In general, Cells are considered equal if they have the same canonical representation, i.e. an identical encoding with the same hash value. Subclasses SHOULD override this if they have a more efficient equals implementation. MUST NOT require reads from Store.

Specified by:

equals in class ACell

Parameters:

o - Cell to compare with. May be null.

Returns:

True if this cell is equal to the other object

equals

public boolean equals(Symbol sym)

Tests if this Symbol is equal to another Symbol. Equality is defined by both namespace and name being equal.

Parameters:

sym - Symbol to compare with

Returns:

true if Symbols are equal, false otherwise

compareTo

public int compareTo(ABlobLike<?> b)

Specified by:

compareTo in interface Comparable<ABlobLike<?>>

Specified by:

compareTo in class ABlobLike<CVMChar>

compareTo

public int compareTo(Symbol sym)

encode

public int encode(byte[] bs,
 int pos)

Description copied from class: ACell

Writes this Cell's encoding to a byte array, including a tag byte which will be written first. Cell must be canonical, or else an error may occur.

Specified by:

encode in interface IWriteable

Specified by:

encode in class ACell

Parameters:

bs - A byte array to which to write the encoding

pos - The offset into the byte array

Returns:

New position after writing

encodeRaw

public int encodeRaw(byte[] bs,
 int pos)

Description copied from class: ACell

Writes this Cell's encoding to a byte array, excluding the tag byte.

Specified by:

encodeRaw in class ACell

Parameters:

bs - A byte array to which to write the encoding

pos - The offset into the byte array

Returns:

New position after writing

read

public static Symbol read(Blob blob,
 int offset)
                   throws BadFormatException

Reads a Symbol from the given Blob

Parameters:

blob - Encoding source

Returns:

The Symbol read

Throws:

BadFormatException - If a Symbol could not be read correctly.

isCanonical

public boolean isCanonical()

Description copied from class: ACell

Returns true if this Cell is in a canonical representation. Non-canonical objects may be used on a temporary internal basis, they should be converted to canonical representations for general purpose use.

Specified by:

isCanonical in class ACell

Returns:

true if the object is in canonical format, false otherwise

print

public boolean print(BlobBuilder bb,
 long limit)

Description copied from class: AObject

Prints this Object to a readable String Representation. SECURITY: Must halt and return false in O(1) time when limit of printing is exceeded otherwise DoS attacks may be possible.

Specified by:

print in class AObject

Parameters:

bb - BlobBuilder to append to. May be partially written if print limit exceeded

limit - Limit of printing in string bytes

Returns:

True if fully printed within limit, false otherwise

validateCell

public void validateCell()
                  throws InvalidDataException

Description copied from class: ASymbolic

Validates this Symbolic value

Specified by:

validateCell in class ASymbolic

Throws:

InvalidDataException - If the symbolic value is invalid

getRefCount

public int getRefCount()

Description copied from class: ACell

Gets the number of Refs contained within this Cell. This number is final / immutable for any given instance and is defined by the Cell encoding rules. Contained Refs may be either external or embedded.

Overrides:

getRefCount in class ASymbolic

Returns:

The number of Refs in this Cell

getTag

public byte getTag()

Description copied from class: ACell

Gets the tag byte for this cell. The tag byte is always equal to the first byte of the Cell's canonical Encoding, and is sufficient to distinguish how to read the rest of the encoding.

Specified by:

getTag in class ACell

Returns:

Tag byte for this Cell

toCanonical

public ACell toCanonical()

Description copied from class: ACell

Converts this Cell to a canonical version. Must return this Cell if already canonical, may be O(n) in size of value otherwise. Callers should usually use getCanonical(), which caches canonical instances once created

Specified by:

toCanonical in class ACell

Returns:

Canonical version of Cell

toCVMString

public AString toCVMString(long limit)

Description copied from class: ACell

Returns the CVM String representation of this Cell. Normally, this is as printed, but may be different for some types. SHOULD return null in O(1) time if the length of the CVM String can be proved to exceed the limit. MUST complete in O(limit) time and space otherwise The String representation is intended to be a easy-to-read textual representation of the Cell's data content.

Overrides:

toCVMString in class ACell

Parameters:

limit - Limit of CVM String length in UTF-8 bytes

Returns:

CVM String, or null if limit exceeded

slice

public Symbol slice(long start,
 long end)

Description copied from class: ACountable

Gets a slice of this data structure

Specified by:

slice in class ASymbolic

Parameters:

start - Start index (inclusive)

end - end index (exclusive)

Returns:

Slice of data structure, or null if invalid slice