org.checkerframework.dataflow.expression

Class JavaExpression

java.lang.Object

org.checkerframework.dataflow.expression.JavaExpression

Direct Known Subclasses:

ArrayAccess, ArrayCreation, BinaryOperation, ClassName, FieldAccess, LocalVariable, MethodCall, ThisReference, Unknown, ValueLiteral

public abstract class JavaExpression
extends Object

This class represents a Java expression and its type. It does not represent all possible Java expressions (for example, it does not represent a ternary conditional expression ?:; use Unknown for unrepresentable expressions).

This class's representation is like an AST: subparts are also expressions. For declared names (fields, local variables, and methods), it also contains an Element.

Each subclass represents a different type of expression, such as MethodCall, ArrayAccess, LocalVariable, etc.

See Also:

the syntax of Java expressions supported by the Checker Framework

Field Summary

Fields

Modifier and Type	Field and Description
protected TypeMirror	type The type of this expression.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	JavaExpression(TypeMirror type) Create a JavaExpression.

Method Summary

Modifier and Type	Method and Description
boolean	containsModifiableAliasOf(Store<?> store, JavaExpression other) Returns true if and only if other appears anywhere in this receiver or an expression appears in this receiver such that other might alias this expression, and that expression is modifiable.
abstract boolean	containsOfClass(Class<? extends JavaExpression> clazz)
boolean	containsSyntacticEqualJavaExpression(JavaExpression other) Returns true if and only if this receiver contains a receiver that is syntactically equal to other.
boolean	containsUnknown()
static ArrayAccess	fromArrayAccess(AnnotationProvider provider, ArrayAccessNode node) Returns the internal representation (as FieldAccess) of a FieldAccessNode.
static JavaExpression	fromNode(AnnotationProvider provider, Node node) We ignore operations such as widening and narrowing when computing the internal representation.
static JavaExpression	fromNode(AnnotationProvider provider, Node receiverNode, boolean allowNonDeterministic) We ignore operations such as widening and narrowing when computing the internal representation.
static FieldAccess	fromNodeFieldAccess(AnnotationProvider provider, FieldAccessNode node) Returns the internal representation (as FieldAccess) of a FieldAccessNode.
static JavaExpression	fromTree(AnnotationProvider provider, ExpressionTree receiverTree) Returns the internal representation of any ExpressionTree.
static JavaExpression	fromTree(AnnotationProvider provider, ExpressionTree tree, boolean allowNonDeterministic) We ignore operations such as widening and narrowing when computing the internal representation.
static JavaExpression	getImplicitReceiver(Element ele) Returns the implicit receiver of ele.
static @Nullable List<JavaExpression>	getParametersOfEnclosingMethod(AnnotationProvider annotationProvider, TreePath path) Returns the formal parameters of the method in which path is enclosed.
static JavaExpression	getPseudoReceiver(TreePath path, TypeMirror enclosingType) Returns either a new ClassName or ThisReference JavaExpression object for the enclosingType.
static JavaExpression	getReceiver(ExpressionTree accessTree, AnnotationProvider provider) Returns the receiver of ele, whether explicit or implicit.
TypeMirror	getType()
abstract boolean	isUnassignableByOtherCode() Returns true if and only if the value this expression stands for cannot be changed (with respect to ==) by a method call.
abstract boolean	isUnmodifiableByOtherCode() Returns true if and only if the value this expression stands for cannot be changed by a method call, including changes to any of its fields.
boolean	syntacticEquals(JavaExpression other) Returns true if and only if the two receivers are syntactically identical.
String	toStringDebug() Print this verbosely, for debugging.

Methods inherited from class java.lang.Object

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

Field Detail

type

protected final TypeMirror type

The type of this expression.

Constructor Detail

JavaExpression

protected JavaExpression(TypeMirror type)

Create a JavaExpression.

Parameters:

type - the type of the expression

Method Detail

getType

public TypeMirror getType()

containsOfClass

public abstract boolean containsOfClass(Class<? extends JavaExpression> clazz)

containsUnknown

public boolean containsUnknown()

isUnassignableByOtherCode

public abstract boolean isUnassignableByOtherCode()

Returns true if and only if the value this expression stands for cannot be changed (with respect to ==) by a method call. This is the case for local variables, the self reference, final field accesses whose receiver is isUnassignableByOtherCode(), and binary operations whose left and right operands are both isUnmodifiableByOtherCode().

See Also:

isUnmodifiableByOtherCode()

isUnmodifiableByOtherCode

public abstract boolean isUnmodifiableByOtherCode()

Returns true if and only if the value this expression stands for cannot be changed by a method call, including changes to any of its fields.

Approximately, this returns true if the expression is isUnassignableByOtherCode() and its type is immutable.

See Also:

isUnassignableByOtherCode()

syntacticEquals

@EqualsMethod
public boolean syntacticEquals(JavaExpression other)

Returns true if and only if the two receivers are syntactically identical.

Parameters:

other - the other object to compare to this one

Returns:

true if and only if the two receivers are syntactically identical

containsSyntacticEqualJavaExpression

public boolean containsSyntacticEqualJavaExpression(JavaExpression other)

Returns true if and only if this receiver contains a receiver that is syntactically equal to other.

Returns:

true if and only if this receiver contains a receiver that is syntactically equal to other

containsModifiableAliasOf

public boolean containsModifiableAliasOf(Store<?> store,
                                         JavaExpression other)

Returns true if and only if other appears anywhere in this receiver or an expression appears in this receiver such that other might alias this expression, and that expression is modifiable.

This is always true, except for cases where the Java type information prevents aliasing and none of the subexpressions can alias 'other'.

toStringDebug

public String toStringDebug()

Print this verbosely, for debugging.

Returns:

a verbose string representation of this

fromNodeFieldAccess

public static FieldAccess fromNodeFieldAccess(AnnotationProvider provider,
                                              FieldAccessNode node)

Returns the internal representation (as FieldAccess) of a FieldAccessNode. Can contain Unknown as receiver.

Returns:

the internal representation (as FieldAccess) of a FieldAccessNode. Can contain Unknown as receiver.

fromArrayAccess

public static ArrayAccess fromArrayAccess(AnnotationProvider provider,
                                          ArrayAccessNode node)

Returns the internal representation (as FieldAccess) of a FieldAccessNode. Can contain Unknown as receiver.

Returns:

the internal representation (as FieldAccess) of a FieldAccessNode. Can contain Unknown as receiver.

fromNode

public static JavaExpression fromNode(AnnotationProvider provider,
                                      Node node)

We ignore operations such as widening and narrowing when computing the internal representation.

Returns:

the internal representation of any Node. Might contain Unknown.

fromNode

public static JavaExpression fromNode(AnnotationProvider provider,
                                      Node receiverNode,
                                      boolean allowNonDeterministic)

We ignore operations such as widening and narrowing when computing the internal representation.

Returns:

the internal representation of any Node. Might contain Unknown.

fromTree

public static JavaExpression fromTree(AnnotationProvider provider,
                                      ExpressionTree receiverTree)

Returns the internal representation of any ExpressionTree. Might contain Unknown.

Returns:

the internal representation of any ExpressionTree. Might contain Unknown.

fromTree

public static JavaExpression fromTree(AnnotationProvider provider,
                                      ExpressionTree tree,
                                      boolean allowNonDeterministic)

We ignore operations such as widening and narrowing when computing the internal representation.

Returns:

the internal representation of any ExpressionTree. Might contain Unknown.

getParametersOfEnclosingMethod

public static @Nullable List<JavaExpression> getParametersOfEnclosingMethod(AnnotationProvider annotationProvider,
                                                                            TreePath path)

Returns the formal parameters of the method in which path is enclosed.

Parameters:

annotationProvider - annotationProvider

path - TreePath that is enclosed by the method

Returns:

the formal parameters of the method in which path is enclosed, null otherwise

getReceiver

public static JavaExpression getReceiver(ExpressionTree accessTree,
                                         AnnotationProvider provider)

Returns the receiver of ele, whether explicit or implicit.

Parameters:

accessTree - method or constructor invocation

provider - an AnnotationProvider

Returns:

the receiver of ele, whether explicit or implicit

getImplicitReceiver

public static JavaExpression getImplicitReceiver(Element ele)

Returns the implicit receiver of ele.

Returns either a new ClassName or a new ThisReference depending on whether ele is static or not. The passed element must be a field, method, or class.

Parameters:

ele - field, method, or class

Returns:

either a new ClassName or a new ThisReference depending on whether ele is static or not

getPseudoReceiver

public static JavaExpression getPseudoReceiver(TreePath path,
                                               TypeMirror enclosingType)

Returns either a new ClassName or ThisReference JavaExpression object for the enclosingType.

The Tree should be an expression or a statement that does not have a receiver or an implicit receiver. For example, a local variable declaration.

Parameters:

path - TreePath to tree

enclosingType - type of the enclosing type

Returns:

a new ClassName or ThisReference that is a JavaExpression object for the enclosingType