org.codehaus.groovy.ast.tools

Class WideningCategories

java.lang.Object

org.codehaus.groovy.ast.tools.WideningCategories

public class WideningCategories
extends Object

This class provides helper methods to determine the type from a widening operation for example for a plus operation.

To determine the resulting type of for example a=exp1+exp2 we look at the conditions isIntCategory(ClassNode), isLongCategory(ClassNode), isBigIntCategory(ClassNode), isDoubleCategory(ClassNode) and isBigDecCategory(ClassNode) in that order. The first case applying to exp1 and exp2 is defining the result type of the expression.

If for example you look at x = 1 + 2l we have the first category applying to the number 1 being int, since the 1 is an int. The 2l is a long, therefore the int category will not apply and the result type can't be int. The next category in the list is long, and since both apply to long, the result type is a long.

Author:

Jochen "blackdrag" Theodorou, Cedric Champeau

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	WideningCategories.LowestUpperBoundClassNode This ClassNode specialization is used when the lowest upper bound of two types cannot be represented by an existing type.

Constructor Summary

Constructors

Constructor and Description
WideningCategories()

Method Summary

Methods

Modifier and Type	Method and Description
static boolean	implementsInterfaceOrSubclassOf(ClassNode source, ClassNode targetType) Determines if the source class implements an interface or subclasses the target type.
static boolean	isBigDecCategory(ClassNode type) It is of a BigDecimal category, if the provided type is a BigInteger category or a BigDecimal.
static boolean	isBigIntCategory(ClassNode type) It is of a BigInteger category, if the provided type is a long category or a BigInteger.
static boolean	isDouble(ClassNode type) Used to check if a type is an double or Double.
static boolean	isDoubleCategory(ClassNode type) It is of a double category, if the provided type is a BigDecimal, a float, double.
static boolean	isFloat(ClassNode type) Used to check if a type is a float or Float.
static boolean	isFloatingCategory(ClassNode type) It is of a floating category, if the provided type is a a float, double.
static boolean	isInt(ClassNode type) Used to check if a type is an int or Integer.
static boolean	isIntCategory(ClassNode type) It is of an int category, if the provided type is a byte, char, short, int.
static boolean	isLongCategory(ClassNode type) It is of a long category, if the provided type is a long, its wrapper or if it is a long category.
static boolean	isNumberCategory(ClassNode type)
static ClassNode	lowestUpperBound(ClassNode a, ClassNode b) Given two class nodes, returns the first common supertype, or the class itself if there are equal.
static ClassNode	lowestUpperBound(List<ClassNode> nodes) Given a list of class nodes, returns the first common supertype.

Methods inherited from class java.lang.Object

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

Constructor Detail

WideningCategories

public WideningCategories()

Method Detail

isInt

public static boolean isInt(ClassNode type)

Used to check if a type is an int or Integer.

Parameters:

type - the type to check

isDouble

public static boolean isDouble(ClassNode type)

Used to check if a type is an double or Double.

Parameters:

type - the type to check

isFloat

public static boolean isFloat(ClassNode type)

Used to check if a type is a float or Float.

Parameters:

type - the type to check

isIntCategory

public static boolean isIntCategory(ClassNode type)

It is of an int category, if the provided type is a byte, char, short, int.

isLongCategory

public static boolean isLongCategory(ClassNode type)

It is of a long category, if the provided type is a long, its wrapper or if it is a long category.

isBigIntCategory

public static boolean isBigIntCategory(ClassNode type)

It is of a BigInteger category, if the provided type is a long category or a BigInteger.

isBigDecCategory

public static boolean isBigDecCategory(ClassNode type)

It is of a BigDecimal category, if the provided type is a BigInteger category or a BigDecimal.

isDoubleCategory

public static boolean isDoubleCategory(ClassNode type)

It is of a double category, if the provided type is a BigDecimal, a float, double. C(type)=double

isFloatingCategory

public static boolean isFloatingCategory(ClassNode type)

It is of a floating category, if the provided type is a a float, double. C(type)=float

isNumberCategory

public static boolean isNumberCategory(ClassNode type)

lowestUpperBound

public static ClassNode lowestUpperBound(List<ClassNode> nodes)

Given a list of class nodes, returns the first common supertype. For example, Double and Float would return Number, while Set and String would return Object.

Parameters:

nodes - the list of nodes for which to find the first common super type.

Returns:

first common supertype

lowestUpperBound

public static ClassNode lowestUpperBound(ClassNode a,
                         ClassNode b)

Given two class nodes, returns the first common supertype, or the class itself if there are equal. For example, Double and Float would return Number, while Set and String would return Object. This method is not guaranteed to return a class node which corresponds to a real type. For example, if two types have more than one interface in common and are not in the same hierarchy branch, then the returned type will be a virtual type implementing all those interfaces. Calls to this method are supposed to be made with resolved generics. This means that you can have wildcards, but no placeholder.

Parameters:

a - first class node

b - second class node

Returns:

first common supertype

implementsInterfaceOrSubclassOf

public static boolean implementsInterfaceOrSubclassOf(ClassNode source,
                                      ClassNode targetType)

Determines if the source class implements an interface or subclasses the target type. This method takes the lowest upper bound class node type into account, allowing to remove unnecessary casts.

Parameters:

source - the type of interest

targetType - the target type of interest