com.sun.tools.javac.comp
Class Infer

java.lang.Object
  com.sun.tools.javac.comp.Infer

public class Infer
extends java.lang.Object

Helper class for type parameter inference, used by the attribution phase.

This is NOT part of any API supported by Sun Microsystems. If you write code that depends on this, you do so at your own risk. This code and its internal interfaces are subject to change or deletion without notice.

Nested Class Summary

static class

Infer.NoInstanceException

Field Summary

private Infer.NoInstanceException	ambiguousNoInstanceException
static Type	anyPoly A value for prototypes that admit any type, including polymorphic ones.
(package private) JCDiagnostic.Factory	diags
(package private) Type.Mapping	fromTypeVarFun A mapping that turns type variables into undetermined type variables.
(package private) Type.Mapping	getInstFun A mapping that returns its type argument with every UndetVar replaced by its `inst' field.
protected static Context.Key<Infer>	inferKey
(package private) Symtab	syms
(package private) Types	types
private Infer.NoInstanceException	unambiguousNoInstanceException

Constructor Summary

protected

Infer(Context context)

Method Summary

private void	checkWithinBounds(List<Type> tvars, List<Type> arguments, Warner warn) check that type parameters are within their bounds.
static Infer	instance(Context context)
private Type	instantiateArg(Type.ForAll that, Type to, List<Type> tvars, Warner warn) Try to instantiate argument type `that' to given type `to'.
Type	instantiateExpr(Type.ForAll that, Type to, Warner warn) Try to instantiate expression type `that' to given type `to'.
Type	instantiateMethod(List<Type> tvars, Type.MethodType mt, List<Type> argtypes, boolean allowBoxing, boolean useVarargs, Warner warn) Instantiate method type `mt' by finding instantiations of `tvars' so that method can be applied to `argtypes'.
private boolean	isSubClass(Type t, List<Type> ts)
(package private) void	maximizeInst(Type.UndetVar that, Warner warn) Instantiate undetermined type variable to its minimal upper bound.
(package private) void	minimizeInst(Type.UndetVar that, Warner warn) Instantiate undetermined type variable to the lub of all its lower bounds.

Methods inherited from class java.lang.Object

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

Field Detail

inferKey

protected static final Context.Key<Infer> inferKey

anyPoly

public static final Type anyPoly

A value for prototypes that admit any type, including polymorphic ones.

syms

Symtab syms

types

Types types

diags

JCDiagnostic.Factory diags

ambiguousNoInstanceException

private final Infer.NoInstanceException ambiguousNoInstanceException

unambiguousNoInstanceException

private final Infer.NoInstanceException unambiguousNoInstanceException

fromTypeVarFun

Type.Mapping fromTypeVarFun

A mapping that turns type variables into undetermined type variables.

getInstFun

Type.Mapping getInstFun

A mapping that returns its type argument with every UndetVar replaced by its `inst' field. Throws a NoInstanceException if this not possible because an `inst' field is null.

Constructor Detail

Infer

protected Infer(Context context)

Method Detail

instance

public static Infer instance(Context context)

maximizeInst

void maximizeInst(Type.UndetVar that,
                  Warner warn)
            throws Infer.NoInstanceException

Instantiate undetermined type variable to its minimal upper bound. Throw a NoInstanceException if this not possible.

Throws:

Infer.NoInstanceException

isSubClass

private boolean isSubClass(Type t,
                           List<Type> ts)

minimizeInst

void minimizeInst(Type.UndetVar that,
                  Warner warn)
            throws Infer.NoInstanceException

Instantiate undetermined type variable to the lub of all its lower bounds. Throw a NoInstanceException if this not possible.

Throws:

Infer.NoInstanceException

instantiateExpr

public Type instantiateExpr(Type.ForAll that,
                            Type to,
                            Warner warn)
                     throws Infer.NoInstanceException

Try to instantiate expression type `that' to given type `to'. If a maximal instantiation exists which makes this type a subtype of type `to', return the instantiated type. If no instantiation exists, or if several incomparable best instantiations exist throw a NoInstanceException.

Throws:

Infer.NoInstanceException

instantiateMethod

public Type instantiateMethod(List<Type> tvars,
                              Type.MethodType mt,
                              List<Type> argtypes,
                              boolean allowBoxing,
                              boolean useVarargs,
                              Warner warn)
                       throws Infer.NoInstanceException

Instantiate method type `mt' by finding instantiations of `tvars' so that method can be applied to `argtypes'.

Throws:

Infer.NoInstanceException

instantiateArg

private Type instantiateArg(Type.ForAll that,
                            Type to,
                            List<Type> tvars,
                            Warner warn)
                     throws Infer.NoInstanceException

Try to instantiate argument type `that' to given type `to'. If this fails, try to insantiate `that' to `to' where every occurrence of a type variable in `tvars' is replaced by an unknown type.

Throws:

Infer.NoInstanceException

checkWithinBounds

private void checkWithinBounds(List<Type> tvars,
                               List<Type> arguments,
                               Warner warn)
                        throws Infer.NoInstanceException

check that type parameters are within their bounds.

Throws:

Infer.NoInstanceException