Package net.sourceforge.pmd.lang.java.typeresolution.typeinference

Class TypeInferenceResolver

java.lang.Object

net.sourceforge.pmd.lang.java.typeresolution.typeinference.TypeInferenceResolver

public final class TypeInferenceResolver
extends java.lang.Object

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	TypeInferenceResolver.ResolutionFailedException

Method Summary

Modifier and Type	Method	Description
static boolean	boundsHaveAnEqualityBetween(java.util.List<Variable> firstList, Variable second, java.util.List<Bound> bounds)
static java.util.Set<java.lang.Class<?>>	getErasedCandidateSet(java.util.List<JavaTypeDefinition> erasedSuperTypeSets)
static java.util.Map<Variable,JavaTypeDefinition>	getInstantiations(java.util.List<Bound> bounds)
static java.util.List<JavaTypeDefinition>	getLowerBoundsOf(Variable var, java.util.List<Bound> bounds)
static java.util.Set<Variable>	getMentionedVariables(java.util.List<Bound> bounds)
static java.util.Set<java.lang.Class<?>>	getMinimalErasedCandidateSet(java.util.Set<java.lang.Class<?>> erasedSet)
static java.util.Set<Variable>	getUninstantiatedVariables(java.util.List<Bound> bounds)
static java.util.Map<Variable,java.util.Set<Variable>>	getVariableDependencies(java.util.List<Bound> bounds)
static java.util.List<Constraint>	incorporateBounds(java.util.List<Bound> currentBounds, java.util.List<Bound> newBounds)	https://docs.oracle.com/javase/specs/jls/se8/html/jls-18.html#jls-18.3
static java.util.List<JavaTypeDefinition>	inferTypes(java.util.List<Constraint> constraints, java.util.List<Bound> bounds, java.util.List<Variable> variables)
static JavaTypeDefinition	intersect(JavaTypeDefinition first, JavaTypeDefinition second)
static boolean	isProperSubsetOfVariables(java.util.List<Variable> variables, java.util.Map<Variable,JavaTypeDefinition> instantiations, java.util.Map<Variable,java.util.Set<Variable>> dependencies, java.util.List<Bound> bounds)	Given a set of inference variables to resolve, let V be the union of this set and all variables upon which the resolution of at least one variable in this set depends.
static JavaTypeDefinition	lub(java.util.List<JavaTypeDefinition> types)
static JavaTypeDefinition	merge(JavaTypeDefinition first, JavaTypeDefinition second)	Merge two types of the same class to something both can be assigned to and is most specific.
static java.util.Map<Variable,JavaTypeDefinition>	resolveVariables(java.util.List<Bound> bounds)	Resolve unresolved variables in a list of bounds.

Methods inherited from class java.lang.Object

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

Method Detail

inferTypes

public static java.util.List<JavaTypeDefinition> inferTypes(java.util.List<Constraint> constraints,
                                                            java.util.List<Bound> bounds,
                                                            java.util.List<Variable> variables)

lub

public static JavaTypeDefinition lub(java.util.List<JavaTypeDefinition> types)

intersect

public static JavaTypeDefinition intersect(JavaTypeDefinition first,
                                           JavaTypeDefinition second)

Returns:

the intersection of the two types

merge

public static JavaTypeDefinition merge(JavaTypeDefinition first,
                                       JavaTypeDefinition second)

Merge two types of the same class to something both can be assigned to and is most specific.

getErasedCandidateSet

public static java.util.Set<java.lang.Class<?>> getErasedCandidateSet(java.util.List<JavaTypeDefinition> erasedSuperTypeSets)

getMinimalErasedCandidateSet

public static java.util.Set<java.lang.Class<?>> getMinimalErasedCandidateSet(java.util.Set<java.lang.Class<?>> erasedSet)

resolveVariables

public static java.util.Map<Variable,JavaTypeDefinition> resolveVariables(java.util.List<Bound> bounds)

Resolve unresolved variables in a list of bounds.

getLowerBoundsOf

public static java.util.List<JavaTypeDefinition> getLowerBoundsOf(Variable var,
                                                                  java.util.List<Bound> bounds)

isProperSubsetOfVariables

public static boolean isProperSubsetOfVariables(java.util.List<Variable> variables,
                                                java.util.Map<Variable,JavaTypeDefinition> instantiations,
                                                java.util.Map<Variable,java.util.Set<Variable>> dependencies,
                                                java.util.List<Bound> bounds)

Given a set of inference variables to resolve, let V be the union of this set and all variables upon which the resolution of at least one variable in this set depends.

...

Otherwise, let { α1, ..., αn } be a non-empty subset of uninstantiated variables in V such that i) for all i (1 ≤ i ≤ n), if αi depends on the resolution of a variable β, then either β has an instantiation or there is some j such that β = αj; and Resolution proceeds by generating an instantiation for each of α1, ..., αn based on the bounds in the bound set:

Returns:

true, if 'variables' is a resolvable subset

boundsHaveAnEqualityBetween

public static boolean boundsHaveAnEqualityBetween(java.util.List<Variable> firstList,
                                                  Variable second,
                                                  java.util.List<Bound> bounds)

Returns:

true, if 'bounds' contains an equality between 'second' and an element from 'firstList'

getInstantiations

public static java.util.Map<Variable,JavaTypeDefinition> getInstantiations(java.util.List<Bound> bounds)

Returns:

A map of variable -> proper type produced by searching for α = T or T = α bounds

getUninstantiatedVariables

public static java.util.Set<Variable> getUninstantiatedVariables(java.util.List<Bound> bounds)

Returns:

A list of variables which have no direct instantiations

getVariableDependencies

public static java.util.Map<Variable,java.util.Set<Variable>> getVariableDependencies(java.util.List<Bound> bounds)

getMentionedVariables

public static java.util.Set<Variable> getMentionedVariables(java.util.List<Bound> bounds)

Returns:

a set of variables mentioned by the bounds

incorporateBounds

public static java.util.List<Constraint> incorporateBounds(java.util.List<Bound> currentBounds,
                                                           java.util.List<Bound> newBounds)

https://docs.oracle.com/javase/specs/jls/se8/html/jls-18.html#jls-18.3