ptolemy.data.type
Class StructuredType

java.lang.Object
  ptolemy.data.type.StructuredType

All Implemented Interfaces:

Type

Direct Known Subclasses:

ArrayType, FixType, FunctionType, MatrixType, RecordType, UnionType

public abstract class StructuredType
extends java.lang.Object
implements Type

Base class for structured type. Making this an abstract class (not an interface) allows the methods to be protected. All the types of the same structured type (e.g. all the array types) must form a lattice. Each instance of a structured type must know how to compare itself with another instance of the same structured type, and compute the least upper bound and greatest lower bound. This class defines methods for these operations.

Subclasses should override clone() to do a deep cloning.

Since:

Ptolemy II 0.4

Version:

$Id: StructuredType.java 57040 2010-01-27 20:52:32Z cxh $

Author:

Yuhong Xiong, Steve Neuendorffer

Accepted Rating:

Red (cxh)

Proposed Rating:

Red (yuhong)

Field Summary

protected static int

MAXDEPTHBOUND Set up a bound for the max depth of structured types.

Fields inherited from interface ptolemy.data.type.Type

HASH_INVALID, HASH_MAX

Constructor Summary

StructuredType()

Method Summary

protected abstract int	_compare(StructuredType type) Compare this type with the specified type.
protected abstract StructuredType	_getRepresentative() Return a static instance of this structured type.
protected abstract StructuredType	_greatestLowerBound(StructuredType type) Return the greatest lower bound of this type with the specified type.
protected abstract StructuredType	_leastUpperBound(StructuredType type) Return the least upper bound of this type with the specified type.
Type	add(Type rightArgumentType) Return a new type which represents the type that results from adding a token of this type and a token of the given argument type.
abstract java.lang.Object	clone() Return a deep copy of this StructuredType.
int	depth() Return the depth of a structured type.
Type	divide(Type rightArgumentType) Return a new type which represents the type that results from dividing a token of this type and a token of the given argument type.
int	getTypeHash() Return a perfect hash for this type.
abstract void	initialize(Type type) Set the elements that have declared type BaseType.UNKNOWN to the specified type.
boolean	isAbstract() Return true if this type does not correspond to a single token class.
Type	modulo(Type rightArgumentType) Return a new type which represents the type that results from moduloing a token of this type and a token of the given argument type.
Type	multiply(Type rightArgumentType) Return a new type which represents the type that results from multiplying a token of this type and a token of the given argument type.
Type	one() Return the type of the multiplicative identity for elements of this type.
Type	subtract(Type rightArgumentType) Return a new type which represents the type that results from subtracting a token of this type and a token of the given argument type.
void	updateType(StructuredType newType) Update this StructuredType to the specified Structured Type.
Type	zero() Return the type of the additive identity for elements of this type.

Methods inherited from class java.lang.Object

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

Methods inherited from interface ptolemy.data.type.Type

convert, equals, getTokenClass, isCompatible, isConstant, isInstantiable, isSubstitutionInstance, toString

Field Detail

MAXDEPTHBOUND

protected static final int MAXDEPTHBOUND

Set up a bound for the max depth of structured types. This bound is used to detect infinite iterations.

See Also:

Constant Field Values

Constructor Detail

StructuredType

public StructuredType()

Method Detail

add

public Type add(Type rightArgumentType)

Return a new type which represents the type that results from adding a token of this type and a token of the given argument type.

Specified by:

add in interface Type

Parameters:

rightArgumentType - The type to add to this type.

Returns:

A new type, or BaseType.GENERAL, if the operation does not make sense for the given types.

clone

public abstract java.lang.Object clone()
                                throws java.lang.CloneNotSupportedException

Return a deep copy of this StructuredType.

Specified by:

clone in interface Type

Overrides:

clone in class java.lang.Object

Returns:

A StructuredType.

Throws:

java.lang.CloneNotSupportedException - Not thrown in this base class.

divide

public Type divide(Type rightArgumentType)

Return a new type which represents the type that results from dividing a token of this type and a token of the given argument type.

Specified by:

divide in interface Type

Parameters:

rightArgumentType - The type to divide with this type.

Returns:

A new type, or BaseType.GENERAL, if the operation does not make sense for the given types.

depth

public int depth()

Return the depth of a structured type. The depth of a structured type is the number of times a structured type contains other structured types. For example, an array of arrays has depth 2, and an array of arrays of records has depth 3.

Returns:

the depth of a structured type.

getTypeHash

public int getTypeHash()

Return a perfect hash for this type. This number corresponds uniquely to a particular type, and is used to improve performance of certain operations in the TypeLattice class. All instances of a particular type (e.g. integer array) must return the same number. Types that return HASH_INVALID will not have results in TypeLattice cached. Note that it is safer to return HASH_INVALID, than to return a number that is not unique, or different number for the same type from different instances. This base class returns HASH_INVALID.

Specified by:

getTypeHash in interface Type

Returns:

A number between 0 and HASH_MAX, or HASH_INVALID.

isAbstract

public boolean isAbstract()

Return true if this type does not correspond to a single token class. This occurs if the type is not instantiable, or it represents either an abstract base class or an interface. This method should be overridden in derived classes to return true only for types which are not abstract.

Specified by:

isAbstract in interface Type

Returns:

true.

initialize

public abstract void initialize(Type type)

Set the elements that have declared type BaseType.UNKNOWN to the specified type.

Parameters:

type - A Type.

modulo

public Type modulo(Type rightArgumentType)

Return a new type which represents the type that results from moduloing a token of this type and a token of the given argument type.

Specified by:

modulo in interface Type

Parameters:

rightArgumentType - The type to add to this type.

Returns:

A new type, or BaseType.GENERAL, if the operation does not make sense for the given types.

multiply

public Type multiply(Type rightArgumentType)

Return a new type which represents the type that results from multiplying a token of this type and a token of the given argument type.

Specified by:

multiply in interface Type

Parameters:

rightArgumentType - The type to multiply by this type.

Returns:

A new type, or BaseType.GENERAL, if the operation does not make sense for the given types.

one

public Type one()

Return the type of the multiplicative identity for elements of this type.

Specified by:

one in interface Type

Returns:

A new type, or BaseType.GENERAL, if the operation does not make sense for the given types.

subtract

public Type subtract(Type rightArgumentType)

Return a new type which represents the type that results from subtracting a token of this type and a token of the given argument type.

Specified by:

subtract in interface Type

Parameters:

rightArgumentType - The type to add to this type.

Returns:

A new type, or BaseType.GENERAL, if the operation does not make sense for the given types.

updateType

public void updateType(StructuredType newType)
                throws IllegalActionException

Update this StructuredType to the specified Structured Type. The specified type must have depth less than the MAXDEPTHBOUND, and have the same structure as this type. This method will only update the component type that is BaseType.UNKNOWN, and leave the constant part of this type intact.

Parameters:

newType - A StructuredType.

Throws:

IllegalActionException - If the specified type has a different structure.

zero

public Type zero()

Return the type of the additive identity for elements of this type.

Specified by:

zero in interface Type

Returns:

A new type, or BaseType.GENERAL, if the operation does not make sense for the given types.

_compare

protected abstract int _compare(StructuredType type)

Compare this type with the specified type. The specified type must be of the same structured type, otherwise an exception will be thrown. This method returns one of ptolemy.graph.CPO.LOWER, ptolemy.graph.CPO.SAME, ptolemy.graph.CPO.HIGHER, ptolemy.graph.CPO.INCOMPARABLE, indicating this type is lower than, equal to, higher than, or incomparable with the specified type in the type hierarchy, respectively.

Parameters:

type - a StructuredType.

Returns:

An integer.

Throws:

java.lang.IllegalArgumentException - If the specified type is not the same structured type as this one.

_getRepresentative

protected abstract StructuredType _getRepresentative()

Return a static instance of this structured type. The return value is used by TypeLattice to represent this type.

Returns:

a StructuredType.

_greatestLowerBound

protected abstract StructuredType _greatestLowerBound(StructuredType type)

Return the greatest lower bound of this type with the specified type. The specified type must be of the same structured type, otherwise an exception will be thrown.

Parameters:

type - a StructuredType.

Returns:

a StructuredType.

Throws:

java.lang.IllegalArgumentException - If the specified type is not the same structured type as this one.

_leastUpperBound

protected abstract StructuredType _leastUpperBound(StructuredType type)

Return the least upper bound of this type with the specified type. The specified type must be of the same structured type, otherwise an exception will be thrown.

Parameters:

type - a StructuredType.

Returns:

a StructuredType.

Throws:

java.lang.IllegalArgumentException - If the specified type is not the same structured type as this one.