Package convex.core.lang.ops

Class Constant<T extends ACell>

java.lang.Object

convex.core.data.AObject

convex.core.data.ACell

convex.core.lang.AOp<T>

convex.core.lang.ops.Constant<T>

Type Parameters:

T - Type of constant value

All Implemented Interfaces:

IValidated, IWriteable

public class Constant<T extends ACell>
extends AOp<T>

Operation representing a constant value "One man's constant is another man's variable." - Alan Perlis

Field Summary

Fields

Modifier and Type	Field	Description
static final Constant<AList<?>>	EMPTY_LIST
static final Constant<AMap<?,?>>	EMPTY_MAP
static final Constant<ASet<?>>	EMPTY_SET
static final Constant<StringShort>	EMPTY_STRING
static final Constant<AVector<?>>	EMPTY_VECTOR
static final Constant<CVMBool>	FALSE
static final Constant<?>	NULL
static final Constant<CVMBool>	TRUE

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
static <T extends ACell> Constant<T>	create(T value)
static <T extends ACell> Constant<T>	createFromRef(Ref<T> valueRef)
static Constant<AString>	createString(String stringValue)
int	encodeRaw(byte[] bs, int pos)	Writes the raw data for this Op to the specified bytebuffer.
int	estimatedEncodingSize()	Estimate the encoded data size for this Cell.
Context	execute(Context context)	Executes this op with the given context.
static Constant<CVMBool>	forBoolean(boolean value)
<R extends ACell> Ref<R>	getRef(int i)	Gets a numbered child Ref from within this Cell.
int	getRefCount()	Gets the number of Refs contained within this Cell.
T	getValue()
static <T extends ACell> AOp<T>	nil()
static <T extends ACell> Constant<T>	of(Object value)
static <T extends ACell> Constant<T>	of(T value)
byte	opCode()	Returns the opcode for this op
boolean	print(BlobBuilder sb, long limit)	Prints this Object to a readable String Representation.
static <T extends ACell> Constant<T>	read(Blob b, int pos)
Constant<T>	updateRefs(IRefFunction func)	Updates all Refs in this object using the given function.
void	validateCell()	Validates the local structure and invariants of this cell.

Methods inherited from class convex.core.lang.AOp

encode, equals, getTag, getType, isCanonical, isCVMValue, isDataValue, toCanonical

Methods inherited from class convex.core.data.ACell

attachMemorySize, attachRef, cachedEncoding, cachedHash, calcMemorySize, createEncoding, createRef, equals, genericEquals, getCanonical, getChildRefs, getEncoding, getEncodingLength, getHash, getMemorySize, getMemorySize, getRef, hashCode, isEmbedded, toCVMString, 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

NULL

public static final Constant<?> NULL

TRUE

public static final Constant<CVMBool> TRUE

FALSE

public static final Constant<CVMBool> FALSE

EMPTY_STRING

public static final Constant<StringShort> EMPTY_STRING

EMPTY_VECTOR

public static final Constant<AVector<?>> EMPTY_VECTOR

EMPTY_LIST

public static final Constant<AList<?>> EMPTY_LIST

EMPTY_MAP

public static final Constant<AMap<?,?>> EMPTY_MAP

EMPTY_SET

public static final Constant<ASet<?>> EMPTY_SET

Method Details

create

public static <T extends ACell> Constant<T> create(T value)

of

public static <T extends ACell> Constant<T> of(Object value)

of

public static <T extends ACell> Constant<T> of(T value)

forBoolean

public static Constant<CVMBool> forBoolean(boolean value)

createString

public static Constant<AString> createString(String stringValue)

createFromRef

public static <T extends ACell> Constant<T> createFromRef(Ref<T> valueRef)

execute

public Context execute(Context context)

Description copied from class: AOp

Executes this op with the given context. Must preserve depth unless an exceptional is returned.

Specified by:

execute in class AOp<T extends ACell>

Parameters:

context - Initial Context

Returns:

The updated Context after executing this operation

print

public boolean print(BlobBuilder sb,
 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:

sb - 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

encodeRaw

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

Description copied from class: AOp

Writes the raw data for this Op to the specified bytebuffer. Assumes Op tag and opcode already written.

Specified by:

encodeRaw in class AOp<T extends ACell>

Parameters:

bs - Byte array to write to

pos - Position to write in byte array

Returns:

The updated position

estimatedEncodingSize

public int estimatedEncodingSize()

Description copied from interface: IWriteable

Estimate the encoded data size for this Cell. Used for quickly sizing buffers. Implementations should try to return a size that is highly likely to contain the entire object when encoded, including the tag byte. Should not traverse soft Refs, i.e. must be usable on arbitrary partial data structures

Specified by:

estimatedEncodingSize in interface IWriteable

Overrides:

estimatedEncodingSize in class AOp<T extends ACell>

Returns:

The estimated size for the binary representation of this object.

read

public static <T extends ACell> Constant<T> read(Blob b,
 int pos)
                                          throws BadFormatException

Throws:

BadFormatException

opCode

public byte opCode()

Description copied from class: AOp

Returns the opcode for this op

Specified by:

opCode in class AOp<T extends ACell>

Returns:

Opcode as a byte

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 ACell

Returns:

The number of Refs in this Cell

getRef

public <R extends ACell> Ref<R> getRef(int i)

Description copied from class: ACell

Gets a numbered child Ref from within this Cell. WARNING: May need to convert to a canonical instance

Overrides:

getRef in class ACell

Type Parameters:

R - Type of referenced Cell

Parameters:

i - Index of ref to get

Returns:

The Ref at the specified index

getValue

public T getValue()

updateRefs

public Constant<T> updateRefs(IRefFunction func)

Description copied from class: ACell

Updates all Refs in this object using the given function. The function *must not* change the hash value of Refs, in order to ensure structural integrity of modified data structures. The implementation *should* re-attach any original encoding in order to prevent re-encoding or surplus hashing This is a building block for a very sneaky trick that enables use to do a lot of efficient operations on large trees of smart references. Must return the same object if no Refs are altered.

Specified by:

updateRefs in class AOp<T extends ACell>

Parameters:

func - Ref update function

Returns:

Cell with updated Refs

nil

public static <T extends ACell> AOp<T> nil()

validateCell

public void validateCell()
                  throws InvalidDataException

Description copied from class: ACell

Validates the local structure and invariants of this cell. Called by validate() super implementation. Should validate directly contained data, but should not validate all other structure of this cell. In particular, should not traverse potentially missing child Refs.

Specified by:

validateCell in class ACell

Throws:

InvalidDataException - If the Cell is invalid