Package com.google.errorprone.util

Class ASTHelpers

  • public class ASTHelpers
extends Object
    This class contains utility methods to work with the javac AST.

    • Method Summary

      All Methods Static Methods Concrete Methods Deprecated Methods 
      Modifier and Type Method Description
      static Set<com.sun.tools.javac.util.Name> annotationsAmong​(com.sun.tools.javac.code.Symbol sym, Set<? extends com.sun.tools.javac.util.Name> annotationClasses, VisitorState state)
      Determines which of a set of annotations are present on a symbol.
      static EnumSet<com.sun.tools.javac.code.Flags.Flag> asFlagSet​(long flags)  
      static boolean canBeRemoved​(com.sun.tools.javac.code.Symbol.ClassSymbol symbol)
      See canBeRemoved(Symbol, VisitorState).
      static boolean canBeRemoved​(com.sun.tools.javac.code.Symbol.VarSymbol symbol)
      See canBeRemoved(Symbol, VisitorState).
      static boolean canBeRemoved​(com.sun.tools.javac.code.Symbol symbol, VisitorState state)
      Returns whether this symbol is safe to remove.
      static Object constValue​(com.sun.source.tree.Tree tree)
      Returns the compile-time constant value of a tree if it has one, or null.
      static <T> T constValue​(com.sun.source.tree.Tree tree, Class<? extends T> clazz)
      Returns the compile-time constant value of a tree if it is of type clazz, or null.
      static boolean containsComments​(com.sun.source.tree.Tree tree, VisitorState state)
      Returns whether the given tree contains any comments in its source.
      static String createPrivateConstructor​(com.sun.source.tree.ClassTree classTree)
      Returns a no arg private constructor for the ClassTree.
      static com.sun.tools.javac.code.Symbol.ClassSymbol enclosingClass​(com.sun.tools.javac.code.Symbol sym)
      Return the enclosing ClassSymbol of the given symbol, or null.
      static Stream<com.sun.tools.javac.code.Symbol> enclosingElements​(com.sun.tools.javac.code.Symbol sym)
      Returns a stream of the owner hierarchy starting from sym, as described by Symbol.owner.
      static com.sun.tools.javac.code.Symbol.PackageSymbol enclosingPackage​(com.sun.tools.javac.code.Symbol sym)
      Return the enclosing PackageSymbol of the given symbol, or null.
      static LinkedHashSet<String> enumValues​(com.sun.tools.javac.code.Symbol.TypeSymbol enumType)  
      static com.sun.source.tree.ClassTree findClass​(com.sun.tools.javac.code.Symbol.ClassSymbol symbol, VisitorState state)
      Returns the class tree that matches the given symbol within the compilation unit, or null if none was found.
      static com.sun.source.tree.MethodTree findEnclosingMethod​(VisitorState state)
      Finds the enclosing MethodTree.
      static <T> T findEnclosingNode​(com.sun.source.util.TreePath path, Class<T> klass)
      Given a TreePath, walks up the tree until it finds a node of the given type.
      static com.google.common.collect.ImmutableSet<com.sun.tools.javac.code.Symbol.MethodSymbol> findMatchingMethods​(com.sun.tools.javac.util.Name name, Predicate<com.sun.tools.javac.code.Symbol.MethodSymbol> predicate, com.sun.tools.javac.code.Type startClass, com.sun.tools.javac.code.Types types)
      Finds all methods in any superclass of startClass with a certain name that match the given predicate.
      static com.sun.source.tree.MethodTree findMethod​(com.sun.tools.javac.code.Symbol.MethodSymbol symbol, VisitorState state)
      Returns the method tree that matches the given symbol within the compilation unit, or null if none was found.
      static <T> com.sun.source.util.TreePath findPathFromEnclosingNodeToTopLevel​(com.sun.source.util.TreePath path, Class<T> klass)
      Given a TreePath, finds the first enclosing node of the given type and returns the path from the enclosing node to the top-level CompilationUnitTree.
      static Optional<com.sun.tools.javac.code.Symbol.MethodSymbol> findSuperMethod​(com.sun.tools.javac.code.Symbol.MethodSymbol methodSymbol, com.sun.tools.javac.code.Types types)
      Finds (if it exists) first (in the class hierarchy) non-interface super method of given method.
      static com.sun.tools.javac.code.Symbol.MethodSymbol findSuperMethodInType​(com.sun.tools.javac.code.Symbol.MethodSymbol methodSymbol, com.sun.tools.javac.code.Type superType, com.sun.tools.javac.code.Types types)  
      static Set<com.sun.tools.javac.code.Symbol.MethodSymbol> findSuperMethods​(com.sun.tools.javac.code.Symbol.MethodSymbol methodSymbol, com.sun.tools.javac.code.Types types)
      Finds supermethods of methodSymbol, not including methodSymbol itself, and including interfaces.
      static <T extends Annotation>
      T      		 getAnnotation​(com.sun.source.tree.Tree tree, Class<T> annotationClass)
      Deprecated.
      If annotationClass contains a member that is a Class or an array of them, attempting to access that member from the Error Prone checker code will result in a runtime exception.
      static <T extends Annotation>
      T      		 getAnnotation​(com.sun.tools.javac.code.Symbol sym, Class<T> annotationClass)
      Deprecated.
      If annotationClass contains a member that is a Class or an array of them, attempting to access that member from the Error Prone checker code will result in a runtime exception.
      static AnnotationMirror getAnnotationMirror​(com.sun.source.tree.AnnotationTree annotationTree)
      Return a mirror of this annotation.
      static String getAnnotationName​(com.sun.source.tree.AnnotationTree tree)  
      static List<? extends com.sun.source.tree.AnnotationTree> getAnnotations​(com.sun.source.tree.Tree tree)
      Returns the annotations of the given tree, or an empty list.
      static List<com.sun.source.tree.AnnotationTree> getAnnotationsWithSimpleName​(List<? extends com.sun.source.tree.AnnotationTree> annotations, String name)
      Returns a list of AnnotationTree with the given simple name.
      static com.sun.tools.javac.code.TypeAnnotations.AnnotationType getAnnotationType​(com.sun.source.tree.AnnotationTree anno, com.sun.tools.javac.code.Symbol target, VisitorState state)
      Returns whether anno corresponds to a type annotation, or null if it could not be determined.
      static com.sun.source.tree.AnnotationTree getAnnotationWithSimpleName​(List<? extends com.sun.source.tree.AnnotationTree> annotations, String name)
      Returns an AnnotationTree with the given simple name, or null.
      static List<com.sun.source.tree.MethodTree> getConstructors​(com.sun.source.tree.ClassTree classTree)
      Returns the list of all constructors defined in the class (including generated ones).
      static com.google.common.collect.ImmutableList<com.sun.tools.javac.code.Symbol.MethodSymbol> getConstructors​(com.sun.tools.javac.code.Symbol.ClassSymbol classSymbol)
      Returns the list of all constructors defined in the class.
      static Stream<com.sun.tools.javac.code.Attribute.Compound> getDeclarationAndTypeAttributes​(com.sun.tools.javac.code.Symbol sym)
      Returns declaration annotations of the given symbol, as well as 'top-level' type annotations, including : Type annotations of the return type of a method.
      static com.sun.tools.javac.code.Symbol getDeclaredSymbol​(com.sun.source.tree.Tree tree)
      Gets the symbol declared by a tree.
      static com.sun.source.tree.Tree getErasedTypeTree​(com.sun.source.tree.Tree tree)
      Returns the erasure of the given type tree, i.e.
      static String getFileName​(com.sun.source.tree.CompilationUnitTree tree)
      Extract the filename from a CompilationUnitTree, with special handling for jar files.
      static String getFileNameFromUri​(URI uri)
      Extract the filename from the URI, with special handling for jar files.
      static com.google.common.collect.ImmutableSet<String> getGeneratedBy​(VisitorState state)
      Returns the value of the @Generated annotation on enclosing classes, if present.
      static com.google.common.collect.ImmutableSet<String> getGeneratedBy​(com.sun.tools.javac.code.Symbol symbol, VisitorState state)
      Returns the values of the given symbol's Generated annotations, if present.
      static com.sun.source.tree.ModifiersTree getModifiers​(com.sun.source.tree.Tree tree)
      Returns the modifiers tree of the given class, method, or variable declaration.
      static Nullness getNullnessValue​(com.sun.source.tree.ExpressionTree expr, VisitorState state, NullnessAnalysis nullnessAnalysis)
      Returns the Nullness for an expression as determined by the nullness dataflow analysis.
      static com.sun.source.tree.ExpressionTree getReceiver​(com.sun.source.tree.ExpressionTree expressionTree)
      Returns the receiver of an expression.
      static com.sun.tools.javac.code.Type getReceiverType​(com.sun.source.tree.ExpressionTree expressionTree)
      Returns the type of a receiver of a method call expression.
      static com.sun.tools.javac.code.Type getResultType​(com.sun.source.tree.ExpressionTree expressionTree)
      Returns the type that this expression tree will evaluate to.
      static com.sun.tools.javac.code.Type getReturnType​(com.sun.source.tree.ExpressionTree expressionTree)
      Gives the return type of an ExpressionTree that represents a method select.
      static com.sun.source.tree.ExpressionTree getRootAssignable​(com.sun.source.tree.MethodInvocationTree methodInvocationTree)
      Find the root assignable expression of a chain of field accesses.
      static int getStartPosition​(com.sun.source.tree.Tree tree)
      Returns the start position of the node.
      static com.sun.tools.javac.code.Symbol.ClassSymbol getSymbol​(com.sun.source.tree.ClassTree tree)
      Gets the symbol for a class.
      static com.sun.tools.javac.code.Symbol.MethodSymbol getSymbol​(com.sun.source.tree.MemberReferenceTree tree)
      Gets the symbol for a member reference.
      static com.sun.tools.javac.code.Symbol.MethodSymbol getSymbol​(com.sun.source.tree.MethodInvocationTree tree)
      Gets the symbol for a method invocation.
      static com.sun.tools.javac.code.Symbol.MethodSymbol getSymbol​(com.sun.source.tree.MethodTree tree)
      Gets the symbol for a method.
      static com.sun.tools.javac.code.Symbol.MethodSymbol getSymbol​(com.sun.source.tree.NewClassTree tree)
      Gets the method symbol for a new class.
      static com.sun.tools.javac.code.Symbol.PackageSymbol getSymbol​(com.sun.source.tree.PackageTree tree)
      Gets the symbol for a package.
      static com.sun.tools.javac.code.Symbol getSymbol​(com.sun.source.tree.Tree tree)
      Gets the symbol for a tree.
      static com.sun.tools.javac.code.Symbol.VarSymbol getSymbol​(com.sun.source.tree.VariableTree tree)
      Gets the symbol for a variable.
      static com.google.common.collect.ImmutableSet<com.sun.tools.javac.code.Type> getThrownExceptions​(com.sun.source.tree.Tree tree, VisitorState state)
      Returns the exceptions thrown by tree.
      static com.sun.tools.javac.code.Type.ClassType getType​(com.sun.source.tree.ClassTree tree)
      Returns the ClassType for the given type ClassTree or null if the type could not be determined.
      static com.sun.tools.javac.code.Type getType​(com.sun.source.tree.Tree tree)
      Returns the Type of the given tree, or null if the type could not be determined.
      static com.google.common.collect.ImmutableListMultimap<com.sun.tools.javac.code.Symbol.TypeVariableSymbol,​com.sun.tools.javac.code.Type> getTypeSubstitution​(com.sun.tools.javac.code.Type type, com.sun.tools.javac.code.Symbol sym)
      Returns the mapping between type variables and their instantiations in the given type.
      static com.sun.tools.javac.code.Type getUpperBound​(com.sun.tools.javac.code.Type type, com.sun.tools.javac.code.Types types)
      Returns the upper bound of a type if it has one, or the type itself if not.
      static boolean hasAnnotation​(com.sun.source.tree.Tree tree, Class<? extends Annotation> annotationClass, VisitorState state)
      Check for the presence of an annotation, considering annotation inheritance.
      static boolean hasAnnotation​(com.sun.source.tree.Tree tree, String annotationClass, VisitorState state)
      Check for the presence of an annotation, considering annotation inheritance.
      static boolean hasAnnotation​(com.sun.tools.javac.code.Symbol sym, Class<? extends Annotation> annotationClass, VisitorState state)
      Check for the presence of an annotation, considering annotation inheritance.
      static boolean hasAnnotation​(com.sun.tools.javac.code.Symbol sym, String annotationClass, VisitorState state)
      Determines whether a symbol has an annotation of the given type.
      static boolean hasDirectAnnotationWithSimpleName​(com.sun.source.tree.Tree tree, String simpleName)
      Check for the presence of an annotation with a specific simple name directly on this symbol.
      static boolean hasDirectAnnotationWithSimpleName​(com.sun.tools.javac.code.Symbol sym, String simpleName)
      Check for the presence of an annotation with a specific simple name directly on this symbol.
      static boolean hasNoExplicitType​(com.sun.source.tree.VariableTree tree, VisitorState state)
      Returns true if this is a `var` or a lambda parameter that has no explicit type.
      static boolean inSamePackage​(com.sun.tools.javac.code.Symbol targetSymbol, VisitorState state)
      Return true if the given symbol is defined in the current package.
      static boolean isAbstract​(com.sun.tools.javac.code.Symbol.MethodSymbol method)
      Returns true if the given method symbol is abstract.
      static boolean isBugCheckerCode​(VisitorState state)
      Returns true if the code is in a BugChecker class.
      static boolean isCastable​(com.sun.tools.javac.code.Type s, com.sun.tools.javac.code.Type t, VisitorState state)
      Returns true if erasure(s) is castable to erasure(t).
      static boolean isCheckedExceptionType​(com.sun.tools.javac.code.Type t, VisitorState state)
      Returns true if t is a subtype of Throwable but not a subtype of RuntimeException or Error.
      static boolean isConsideredFinal​(com.sun.tools.javac.code.Symbol symbol)
      Returns whether symbol is final or effectively final.
      static boolean isGeneratedConstructor​(com.sun.source.tree.MethodTree tree)
      Returns true if the given tree is a generated constructor.
      static boolean isJUnitTestCode​(VisitorState state)
      Returns true if the leaf node in the TreePath from state sits somewhere underneath a class or method that is marked as JUnit 3 or 4 test code.
      static boolean isLocal​(com.sun.tools.javac.code.Symbol symbol)
      Returns true if the symbol is directly or indirectly local to a method or variable initializer; see Symbol#isLocal or Symbol#isDirectlyOrIndirectlyLocal.
      static boolean isSameType​(com.sun.tools.javac.code.Type s, com.sun.tools.javac.code.Type t, VisitorState state)
      Returns true if erasure(s) == erasure(t).
      static boolean isStatic​(com.sun.tools.javac.code.Symbol symbol)
      Returns true if the symbol is static.
      static boolean isSubtype​(com.sun.tools.javac.code.Type s, com.sun.tools.javac.code.Type t, VisitorState state)
      Returns true if erasure(s) <: erasure(t).
      static boolean isSuper​(com.sun.source.tree.Tree tree)  
      static boolean isTestNgTestCode​(VisitorState state)
      Returns true if the leaf node in the TreePath from state sits somewhere underneath a class or method that is marked as TestNG test code.
      static boolean isUsedReflectively​(com.sun.source.tree.Tree tree)
      Deprecated.
      use shouldKeep(com.sun.source.tree.Tree) instead
      static boolean isVoidType​(com.sun.tools.javac.code.Type type, VisitorState state)
      Return true if the given type is 'void' or 'Void'.
      static List<com.sun.source.tree.ExpressionTree> matchBinaryTree​(com.sun.source.tree.BinaryTree tree, List<Matcher<com.sun.source.tree.ExpressionTree>> matchers, VisitorState state)
      Given a BinaryTree to match against and a list of two matchers, applies the matchers to the operands in both orders.
      static Stream<com.sun.tools.javac.code.Symbol.MethodSymbol> matchingMethods​(com.sun.tools.javac.util.Name name, Predicate<com.sun.tools.javac.code.Symbol.MethodSymbol> predicate, com.sun.tools.javac.code.Type startClass, com.sun.tools.javac.code.Types types)
      Finds all methods in any superclass of startClass with a certain name that match the given predicate.
      static boolean methodCanBeOverridden​(com.sun.tools.javac.code.Symbol.MethodSymbol methodSymbol)
      Determines whether a method can be overridden.
      static com.sun.tools.javac.code.Symbol.ClassSymbol outermostClass​(com.sun.tools.javac.code.Symbol symbol)
      Returns the outermost enclosing owning class, or null.
      static boolean requiresParentheses​(com.sun.source.tree.ExpressionTree expression, VisitorState state)
      Checks whether an expression requires parentheses.
      static com.sun.tools.javac.code.Symbol.MethodSymbol resolveExistingMethod​(VisitorState state, com.sun.tools.javac.code.Symbol.TypeSymbol base, com.sun.tools.javac.util.Name name, Iterable<com.sun.tools.javac.code.Type> argTypes, Iterable<com.sun.tools.javac.code.Type> tyargTypes)
      Given a Type (base), find the method named name, with the appropriate argTypes and tyargTypes and return its MethodSymbol.
      static boolean sameVariable​(com.sun.source.tree.ExpressionTree expr1, com.sun.source.tree.ExpressionTree expr2)
      Determines whether two expressions refer to the same variable.
      static ErrorProneScope scope​(com.sun.tools.javac.code.Scope scope)
      Returns a compatibility adapter around Scope.
      static boolean shouldKeep​(com.sun.source.tree.Tree tree)
      Returns true if any of the given tree is a declaration annotated with an annotation with the simple name @UsedReflectively or @Keep, or any annotations meta-annotated with an annotation with that simple name.
      static Stream<com.sun.source.tree.ExpressionTree> streamReceivers​(com.sun.source.tree.ExpressionTree tree)
      Returns a Stream of ExpressionTrees resulting from calling getReceiver(ExpressionTree) repeatedly until no receiver exists.
      static Stream<com.sun.tools.javac.code.Symbol.MethodSymbol> streamSuperMethods​(com.sun.tools.javac.code.Symbol.MethodSymbol methodSymbol, com.sun.tools.javac.code.Types types)
      See findSuperMethods(MethodSymbol, Types).
      static boolean stringContainsComments​(CharSequence source, com.sun.tools.javac.util.Context context)
      Returns true if the given source code contains comments.
      static com.sun.source.tree.ExpressionTree stripParentheses​(com.sun.source.tree.ExpressionTree tree)
      Given an ExpressionTree, removes any enclosing parentheses.
      static com.sun.source.tree.Tree stripParentheses​(com.sun.source.tree.Tree tree)
      Removes any enclosing parentheses from the tree.
      static ASTHelpers.TargetType targetType​(VisitorState state)
      Returns the target type of the tree at the given VisitorState's path, or else null.

    • Method Detail

      • sameVariable

        public static boolean sameVariable​(com.sun.source.tree.ExpressionTree expr1,
                                   com.sun.source.tree.ExpressionTree expr2)
        Determines whether two expressions refer to the same variable. Note that returning false doesn't necessarily mean the expressions do *not* refer to the same field. We don't attempt to do any complex analysis here, just catch the obvious cases.

      • getDeclaredSymbol

        @Nullable
public static com.sun.tools.javac.code.Symbol getDeclaredSymbol​(com.sun.source.tree.Tree tree)
        Gets the symbol declared by a tree. Returns null if tree does not declare a symbol or is null.

      • getSymbol

        public static com.sun.tools.javac.code.Symbol getSymbol​(com.sun.source.tree.Tree tree)
        Gets the symbol for a tree. Returns null if this tree does not have a symbol because it is of the wrong type, if tree is null, or if the symbol cannot be found due to a compilation error.

      • getSymbol

        public static com.sun.tools.javac.code.Symbol.ClassSymbol getSymbol​(com.sun.source.tree.ClassTree tree)
        Gets the symbol for a class.

      • getSymbol

        public static com.sun.tools.javac.code.Symbol.PackageSymbol getSymbol​(com.sun.source.tree.PackageTree tree)
        Gets the symbol for a package.

      • getSymbol

        public static com.sun.tools.javac.code.Symbol.MethodSymbol getSymbol​(com.sun.source.tree.MethodTree tree)
        Gets the symbol for a method.

      • getSymbol

        public static com.sun.tools.javac.code.Symbol.MethodSymbol getSymbol​(com.sun.source.tree.NewClassTree tree)
        Gets the method symbol for a new class.

      • getSymbol

        public static com.sun.tools.javac.code.Symbol.VarSymbol getSymbol​(com.sun.source.tree.VariableTree tree)
        Gets the symbol for a variable.

      • getSymbol

        public static com.sun.tools.javac.code.Symbol.MethodSymbol getSymbol​(com.sun.source.tree.MethodInvocationTree tree)
        Gets the symbol for a method invocation.

      • getSymbol

        public static com.sun.tools.javac.code.Symbol.MethodSymbol getSymbol​(com.sun.source.tree.MemberReferenceTree tree)
        Gets the symbol for a member reference.

      • canBeRemoved

        public static boolean canBeRemoved​(com.sun.tools.javac.code.Symbol symbol,
                                   VisitorState state)
        Returns whether this symbol is safe to remove. That is, if it cannot be accessed from outside its own compilation unit.

        For variables this just means that one of the enclosing elements is private; for methods, it also means that this symbol is not an override.

      • requiresParentheses

        public static boolean requiresParentheses​(com.sun.source.tree.ExpressionTree expression,
                                          VisitorState state)
        Checks whether an expression requires parentheses.

      • stripParentheses

        public static com.sun.source.tree.Tree stripParentheses​(com.sun.source.tree.Tree tree)
        Removes any enclosing parentheses from the tree.

      • stripParentheses

        public static com.sun.source.tree.ExpressionTree stripParentheses​(com.sun.source.tree.ExpressionTree tree)
        Given an ExpressionTree, removes any enclosing parentheses.

      • findPathFromEnclosingNodeToTopLevel

        public static <T> com.sun.source.util.TreePath findPathFromEnclosingNodeToTopLevel​(com.sun.source.util.TreePath path,
                                                                                   Class<T> klass)
        Given a TreePath, finds the first enclosing node of the given type and returns the path from the enclosing node to the top-level CompilationUnitTree.

      • enclosingElements

        public static Stream<com.sun.tools.javac.code.Symbol> enclosingElements​(com.sun.tools.javac.code.Symbol sym)
        Returns a stream of the owner hierarchy starting from sym, as described by Symbol.owner. Returns sym itself first, followed by its owners, closest first, up to the owning package and possibly module.

      • findEnclosingNode

        @Nullable
public static <T> T findEnclosingNode​(com.sun.source.util.TreePath path,
                                      Class<T> klass)
        Given a TreePath, walks up the tree until it finds a node of the given type. Returns null if no such node is found.

      • findEnclosingMethod

        @Nullable
public static com.sun.source.tree.MethodTree findEnclosingMethod​(VisitorState state)
        Finds the enclosing MethodTree. Returns null if no such node found.

      • getRootAssignable

        @Nullable
public static com.sun.source.tree.ExpressionTree getRootAssignable​(com.sun.source.tree.MethodInvocationTree methodInvocationTree)
        Find the root assignable expression of a chain of field accesses. If there is no root (i.e, a bare method call or a static method call), return null.

        Examples: 

        
 a.trim().intern() ==> a
 a.b.trim().intern() ==> a.b
 this.intValue.foo() ==> this.intValue
 this.foo() ==> this
 intern() ==> null
 String.format() ==> null
 java.lang.String.format() ==> null

      • getReturnType

        public static com.sun.tools.javac.code.Type getReturnType​(com.sun.source.tree.ExpressionTree expressionTree)
        Gives the return type of an ExpressionTree that represents a method select.

        TODO(eaftan): Are there other places this could be used?

      • getResultType

        @Nullable
public static com.sun.tools.javac.code.Type getResultType​(com.sun.source.tree.ExpressionTree expressionTree)
        Returns the type that this expression tree will evaluate to. If it's a literal, an identifier, or a member select this is the actual type, if it's a method invocation then it's the return type of the method (after instantiating generic types), if it's a constructor then it's the type of the returned class.

        TODO(andrewrice) consider replacing getReturnType with this method

        Parameters:
        expressionTree - the tree to evaluate
        Returns:
        the result type of this tree or null if unable to resolve it

      • getReceiverType

        public static com.sun.tools.javac.code.Type getReceiverType​(com.sun.source.tree.ExpressionTree expressionTree)
        Returns the type of a receiver of a method call expression. Precondition: the expressionTree corresponds to a method call.

        Examples: 

        
 a.b.foo() ==> type of a.b
 a.bar().foo() ==> type of a.bar()
 this.foo() ==> type of this
 foo() ==> type of this
 TheClass.aStaticMethod() ==> TheClass
 aStaticMethod() ==> type of class in which method is defined

      • getReceiver

        @Nullable
public static com.sun.source.tree.ExpressionTree getReceiver​(com.sun.source.tree.ExpressionTree expressionTree)
        Returns the receiver of an expression.

        Examples: 

        
 a.foo() ==> a
 a.b.foo() ==> a.b
 a.bar().foo() ==> a.bar()
 a.b.c ==> a.b
 a.b().c ==> a.b()
 this.foo() ==> this
 foo() ==> null
 TheClass.aStaticMethod() ==> TheClass
 aStaticMethod() ==> null
 aStaticallyImportedMethod() ==> null

      • streamReceivers

        public static Stream<com.sun.source.tree.ExpressionTree> streamReceivers​(com.sun.source.tree.ExpressionTree tree)
        Returns a Stream of ExpressionTrees resulting from calling getReceiver(ExpressionTree) repeatedly until no receiver exists.

        For example, give foo().bar().baz(), returns a stream of [foo().bar(), foo()].

        This can be more convenient than manually traversing up a tree, as it handles the termination condition automatically. Typical uses cases would include traversing fluent call chains.

      • matchBinaryTree

        @Nullable
public static List<com.sun.source.tree.ExpressionTree> matchBinaryTree​(com.sun.source.tree.BinaryTree tree,
                                                                       List<Matcher<com.sun.source.tree.ExpressionTree>> matchers,
                                                                       VisitorState state)
        Given a BinaryTree to match against and a list of two matchers, applies the matchers to the operands in both orders. If both matchers match, returns a list with the operand that matched each matcher in the corresponding position.
        Parameters:
        tree - a BinaryTree AST node
        matchers - a list of matchers
        state - the VisitorState
        Returns:
        a list of matched operands, or null if at least one did not match

      • findMethod

        @Nullable
public static com.sun.source.tree.MethodTree findMethod​(com.sun.tools.javac.code.Symbol.MethodSymbol symbol,
                                                        VisitorState state)
        Returns the method tree that matches the given symbol within the compilation unit, or null if none was found.

      • findClass

        @Nullable
public static com.sun.source.tree.ClassTree findClass​(com.sun.tools.javac.code.Symbol.ClassSymbol symbol,
                                                      VisitorState state)
        Returns the class tree that matches the given symbol within the compilation unit, or null if none was found.

      • findSuperMethodInType

        @Nullable
public static com.sun.tools.javac.code.Symbol.MethodSymbol findSuperMethodInType​(com.sun.tools.javac.code.Symbol.MethodSymbol methodSymbol,
                                                                                 com.sun.tools.javac.code.Type superType,
                                                                                 com.sun.tools.javac.code.Types types)

      • findSuperMethods

        public static Set<com.sun.tools.javac.code.Symbol.MethodSymbol> findSuperMethods​(com.sun.tools.javac.code.Symbol.MethodSymbol methodSymbol,
                                                                                 com.sun.tools.javac.code.Types types)
        Finds supermethods of methodSymbol, not including methodSymbol itself, and including interfaces.

      • streamSuperMethods

        public static Stream<com.sun.tools.javac.code.Symbol.MethodSymbol> streamSuperMethods​(com.sun.tools.javac.code.Symbol.MethodSymbol methodSymbol,
                                                                                      com.sun.tools.javac.code.Types types)
        See findSuperMethods(MethodSymbol, Types).

      • findSuperMethod

        public static Optional<com.sun.tools.javac.code.Symbol.MethodSymbol> findSuperMethod​(com.sun.tools.javac.code.Symbol.MethodSymbol methodSymbol,
                                                                                     com.sun.tools.javac.code.Types types)
        Finds (if it exists) first (in the class hierarchy) non-interface super method of given method.

      • matchingMethods

        public static Stream<com.sun.tools.javac.code.Symbol.MethodSymbol> matchingMethods​(com.sun.tools.javac.util.Name name,
                                                                                   Predicate<com.sun.tools.javac.code.Symbol.MethodSymbol> predicate,
                                                                                   com.sun.tools.javac.code.Type startClass,
                                                                                   com.sun.tools.javac.code.Types types)
        Finds all methods in any superclass of startClass with a certain name that match the given predicate.
        Returns:
        The (possibly empty) list of methods in any superclass that match predicate and have the given name. Results are returned least-abstract first, i.e., starting in the startClass itself, progressing through its superclasses, and finally interfaces in an unspecified order.

      • findMatchingMethods

        public static com.google.common.collect.ImmutableSet<com.sun.tools.javac.code.Symbol.MethodSymbol> findMatchingMethods​(com.sun.tools.javac.util.Name name,
                                                                                                                       Predicate<com.sun.tools.javac.code.Symbol.MethodSymbol> predicate,
                                                                                                                       com.sun.tools.javac.code.Type startClass,
                                                                                                                       com.sun.tools.javac.code.Types types)
        Finds all methods in any superclass of startClass with a certain name that match the given predicate.
        Returns:
        The (possibly empty) set of methods in any superclass that match predicate and have the given name. The set's iteration order will be the same as the order documented in matchingMethods(Name, java.util.function.Predicate, Type, Types).

      • methodCanBeOverridden

        public static boolean methodCanBeOverridden​(com.sun.tools.javac.code.Symbol.MethodSymbol methodSymbol)
        Determines whether a method can be overridden.
        Returns:
        true if the method can be overridden.

      • hasAnnotation

        public static boolean hasAnnotation​(com.sun.tools.javac.code.Symbol sym,
                                    String annotationClass,
                                    VisitorState state)
        Determines whether a symbol has an annotation of the given type. This includes annotations inherited from superclasses due to @Inherited.
        Parameters:
        annotationClass - the binary class name of the annotation (e.g. "javax.annotation.Nullable", or "some.package.OuterClassName$InnerClassName")
        Returns:
        true if the symbol is annotated with given type.

      • hasAnnotation

        public static boolean hasAnnotation​(com.sun.tools.javac.code.Symbol sym,
                                    Class<? extends Annotation> annotationClass,
                                    VisitorState state)
        Check for the presence of an annotation, considering annotation inheritance.
        Returns:
        true if the symbol is annotated with given type.

      • hasAnnotation

        public static boolean hasAnnotation​(com.sun.source.tree.Tree tree,
                                    String annotationClass,
                                    VisitorState state)
        Check for the presence of an annotation, considering annotation inheritance.
        Parameters:
        annotationClass - the binary class name of the annotation (e.g. "javax.annotation.Nullable", or "some.package.OuterClassName$InnerClassName")
        Returns:
        true if the tree is annotated with given type.

      • hasAnnotation

        public static boolean hasAnnotation​(com.sun.source.tree.Tree tree,
                                    Class<? extends Annotation> annotationClass,
                                    VisitorState state)
        Check for the presence of an annotation, considering annotation inheritance.
        Returns:
        true if the tree is annotated with given type.

      • annotationsAmong

        public static Set<com.sun.tools.javac.util.Name> annotationsAmong​(com.sun.tools.javac.code.Symbol sym,
                                                                  Set<? extends com.sun.tools.javac.util.Name> annotationClasses,
                                                                  VisitorState state)
        Determines which of a set of annotations are present on a symbol.
        Parameters:
        sym - The symbol to inspect for annotations
        annotationClasses - The annotations of interest to look for, Each name must be in binary form, e.g. "com.google.Foo$Bar", not "com.google.Foo.Bar".
        Returns:
        A possibly-empty set of annotations present on the queried element.

      • hasDirectAnnotationWithSimpleName

        public static boolean hasDirectAnnotationWithSimpleName​(com.sun.tools.javac.code.Symbol sym,
                                                        String simpleName)
        Check for the presence of an annotation with a specific simple name directly on this symbol. Does *not* consider annotation inheritance.
        Parameters:
        sym - the symbol to check for the presence of the annotation
        simpleName - the simple name of the annotation to look for, e.g. "Nullable" or "CheckReturnValue"

      • hasDirectAnnotationWithSimpleName

        public static boolean hasDirectAnnotationWithSimpleName​(com.sun.source.tree.Tree tree,
                                                        String simpleName)
        Check for the presence of an annotation with a specific simple name directly on this symbol. Does *not* consider annotation inheritance.
        Parameters:
        tree - the tree to check for the presence of the annotation
        simpleName - the simple name of the annotation to look for, e.g. "Nullable" or "CheckReturnValue"

      • shouldKeep

        public static boolean shouldKeep​(com.sun.source.tree.Tree tree)
        Returns true if any of the given tree is a declaration annotated with an annotation with the simple name @UsedReflectively or @Keep, or any annotations meta-annotated with an annotation with that simple name.

        This indicates the annotated element is used (e.g. by reflection, or referenced by generated code) and should not be removed.

      • getAnnotation

        @Nullable
@Deprecated
public static <T extends Annotation> T getAnnotation​(com.sun.source.tree.Tree tree,
                                                     Class<T> annotationClass)
        Deprecated.
        If annotationClass contains a member that is a Class or an array of them, attempting to access that member from the Error Prone checker code will result in a runtime exception. Instead, operate on sym.getAnnotationMirrors() to meta-syntactically inspect the annotation.
        Retrieves an annotation, considering annotation inheritance.

      • getAnnotation

        @Nullable
@Deprecated
public static <T extends Annotation> T getAnnotation​(com.sun.tools.javac.code.Symbol sym,
                                                     Class<T> annotationClass)
        Deprecated.
        If annotationClass contains a member that is a Class or an array of them, attempting to access that member from the Error Prone checker code will result in a runtime exception. Instead, operate on sym.getAnnotationMirrors() to meta-syntactically inspect the annotation.
        Retrieves an annotation, considering annotation inheritance.

      • enumValues

        public static LinkedHashSet<String> enumValues​(com.sun.tools.javac.code.Symbol.TypeSymbol enumType)
        Returns:
        all values of the given enum type, in declaration order.

      • isGeneratedConstructor

        public static boolean isGeneratedConstructor​(com.sun.source.tree.MethodTree tree)
        Returns true if the given tree is a generated constructor.

      • getConstructors

        public static List<com.sun.source.tree.MethodTree> getConstructors​(com.sun.source.tree.ClassTree classTree)
        Returns the list of all constructors defined in the class (including generated ones).

      • getConstructors

        public static com.google.common.collect.ImmutableList<com.sun.tools.javac.code.Symbol.MethodSymbol> getConstructors​(com.sun.tools.javac.code.Symbol.ClassSymbol classSymbol)
        Returns the list of all constructors defined in the class.

      • getType

        @Nullable
public static com.sun.tools.javac.code.Type getType​(@Nullable
                                                    com.sun.source.tree.Tree tree)
        Returns the Type of the given tree, or null if the type could not be determined.

      • getType

        @Nullable
public static com.sun.tools.javac.code.Type.ClassType getType​(@Nullable
                                                              com.sun.source.tree.ClassTree tree)
        Returns the ClassType for the given type ClassTree or null if the type could not be determined.

      • getAnnotationName

        @Nullable
public static String getAnnotationName​(com.sun.source.tree.AnnotationTree tree)

      • getErasedTypeTree

        public static com.sun.source.tree.Tree getErasedTypeTree​(com.sun.source.tree.Tree tree)
        Returns the erasure of the given type tree, i.e. List for List<Foo>.

      • enclosingClass

        @Nullable
public static com.sun.tools.javac.code.Symbol.ClassSymbol enclosingClass​(com.sun.tools.javac.code.Symbol sym)
        Return the enclosing ClassSymbol of the given symbol, or null.

      • enclosingPackage

        @Nullable
public static com.sun.tools.javac.code.Symbol.PackageSymbol enclosingPackage​(com.sun.tools.javac.code.Symbol sym)
        Return the enclosing PackageSymbol of the given symbol, or null.

        Prefer this to Symbol.packge(), which throws a NullPointerException for symbols that are not contained by a package: https://bugs.openjdk.java.net/browse/JDK-8231911

      • inSamePackage

        public static boolean inSamePackage​(com.sun.tools.javac.code.Symbol targetSymbol,
                                    VisitorState state)
        Return true if the given symbol is defined in the current package.

      • getNullnessValue

        public static Nullness getNullnessValue​(com.sun.source.tree.ExpressionTree expr,
                                        VisitorState state,
                                        NullnessAnalysis nullnessAnalysis)
        Returns the Nullness for an expression as determined by the nullness dataflow analysis.

      • constValue

        @Nullable
public static Object constValue​(com.sun.source.tree.Tree tree)
        Returns the compile-time constant value of a tree if it has one, or null.

      • constValue

        @Nullable
public static <T> T constValue​(com.sun.source.tree.Tree tree,
                               Class<? extends T> clazz)
        Returns the compile-time constant value of a tree if it is of type clazz, or null.

      • isVoidType

        public static boolean isVoidType​(com.sun.tools.javac.code.Type type,
                                 VisitorState state)
        Return true if the given type is 'void' or 'Void'.

      • isSubtype

        public static boolean isSubtype​(com.sun.tools.javac.code.Type s,
                                com.sun.tools.javac.code.Type t,
                                VisitorState state)
        Returns true if erasure(s) <: erasure(t).

      • isCheckedExceptionType

        public static boolean isCheckedExceptionType​(com.sun.tools.javac.code.Type t,
                                             VisitorState state)
        Returns true if t is a subtype of Throwable but not a subtype of RuntimeException or Error.

      • isCastable

        public static boolean isCastable​(com.sun.tools.javac.code.Type s,
                                 com.sun.tools.javac.code.Type t,
                                 VisitorState state)
        Returns true if erasure(s) is castable to erasure(t).

      • isSameType

        public static boolean isSameType​(com.sun.tools.javac.code.Type s,
                                 com.sun.tools.javac.code.Type t,
                                 VisitorState state)
        Returns true if erasure(s) == erasure(t).

      • getModifiers

        @Nullable
public static com.sun.source.tree.ModifiersTree getModifiers​(com.sun.source.tree.Tree tree)
        Returns the modifiers tree of the given class, method, or variable declaration.

      • getAnnotations

        public static List<? extends com.sun.source.tree.AnnotationTree> getAnnotations​(com.sun.source.tree.Tree tree)
        Returns the annotations of the given tree, or an empty list.

      • getUpperBound

        public static com.sun.tools.javac.code.Type getUpperBound​(com.sun.tools.javac.code.Type type,
                                                          com.sun.tools.javac.code.Types types)
        Returns the upper bound of a type if it has one, or the type itself if not. Correctly handles wildcards and capture variables.

      • isJUnitTestCode

        public static boolean isJUnitTestCode​(VisitorState state)
        Returns true if the leaf node in the TreePath from state sits somewhere underneath a class or method that is marked as JUnit 3 or 4 test code.

      • isTestNgTestCode

        public static boolean isTestNgTestCode​(VisitorState state)
        Returns true if the leaf node in the TreePath from state sits somewhere underneath a class or method that is marked as TestNG test code.

      • getAnnotationWithSimpleName

        @Nullable
public static com.sun.source.tree.AnnotationTree getAnnotationWithSimpleName​(List<? extends com.sun.source.tree.AnnotationTree> annotations,
                                                                             String name)
        Returns an AnnotationTree with the given simple name, or null.

      • getAnnotationsWithSimpleName

        public static List<com.sun.source.tree.AnnotationTree> getAnnotationsWithSimpleName​(List<? extends com.sun.source.tree.AnnotationTree> annotations,
                                                                                    String name)
        Returns a list of AnnotationTree with the given simple name. This is useful for Repeatable annotations

      • getAnnotationType

        @Nullable
public static com.sun.tools.javac.code.TypeAnnotations.AnnotationType getAnnotationType​(com.sun.source.tree.AnnotationTree anno,
                                                                                        @Nullable
                                                                                        com.sun.tools.javac.code.Symbol target,
                                                                                        VisitorState state)
        Returns whether anno corresponds to a type annotation, or null if it could not be determined.

      • getFileName

        @Nullable
public static String getFileName​(com.sun.source.tree.CompilationUnitTree tree)
        Extract the filename from a CompilationUnitTree, with special handling for jar files. The return value is normalized to always use '/' to separate elements of the path and to always have a leading '/'.

      • getFileNameFromUri

        @Nullable
public static String getFileNameFromUri​(URI uri)
        Extract the filename from the URI, with special handling for jar files. The return value is normalized to always use '/' to separate elements of the path and to always have a leading '/'.

      • resolveExistingMethod

        @Nullable
public static com.sun.tools.javac.code.Symbol.MethodSymbol resolveExistingMethod​(VisitorState state,
                                                                                 com.sun.tools.javac.code.Symbol.TypeSymbol base,
                                                                                 com.sun.tools.javac.util.Name name,
                                                                                 Iterable<com.sun.tools.javac.code.Type> argTypes,
                                                                                 Iterable<com.sun.tools.javac.code.Type> tyargTypes)
        Given a Type (base), find the method named name, with the appropriate argTypes and tyargTypes and return its MethodSymbol.

        Ex: 

        
 .....
 class A {}
 class B {
   public int hashCode() { return 42; }
 }
 .....

 MethodSymbol meth =  ASTHelpers.resolveExistingMethod(
    state,
    symbol,
    state.getName("hashCode"),
    ImmutableList.<Type>of(),
    ImmutableList.<Type>of());
        meth could be different MethodSymbol's depending on whether symbol represented B or A. (B's hashCode method or Object#hashCode).
        Returns:
        a MethodSymbol representing the method symbol resolved from the context of this type, or null if the method could not be resolved.

      • getGeneratedBy

        public static com.google.common.collect.ImmutableSet<String> getGeneratedBy​(VisitorState state)
        Returns the value of the @Generated annotation on enclosing classes, if present.

        Although @Generated can be applied to non-class program elements, there are no known cases of that happening, so it isn't supported here.

      • getGeneratedBy

        public static com.google.common.collect.ImmutableSet<String> getGeneratedBy​(com.sun.tools.javac.code.Symbol symbol,
                                                                            VisitorState state)
        Returns the values of the given symbol's Generated annotations, if present. If the annotation doesn't have values set, returns the string name of the annotation itself.

      • isSuper

        public static boolean isSuper​(com.sun.source.tree.Tree tree)

      • targetType

        @Nullable
public static ASTHelpers.TargetType targetType​(VisitorState state)
        Returns the target type of the tree at the given VisitorState's path, or else null.

        For example, the target type of an assignment expression is the variable's type, and the target type of a return statement is the enclosing method's type.

      • getDeclarationAndTypeAttributes

        public static Stream<com.sun.tools.javac.code.Attribute.Compound> getDeclarationAndTypeAttributes​(com.sun.tools.javac.code.Symbol sym)
        Returns declaration annotations of the given symbol, as well as 'top-level' type annotations, including :
        • Type annotations of the return type of a method.
        • Type annotations on the type of a formal parameter or field.

        One might expect this to be equivalent to information returned by Type.getAnnotationMirrors(), but javac doesn't associate type annotation information with types for symbols completed from class files, so that approach doesn't work across compilation boundaries.

      • getAnnotationMirror

        public static AnnotationMirror getAnnotationMirror​(com.sun.source.tree.AnnotationTree annotationTree)
        Return a mirror of this annotation.
        Returns:
        an AnnotationMirror for the annotation represented by annotationTree.

      • containsComments

        public static boolean containsComments​(com.sun.source.tree.Tree tree,
                                       VisitorState state)
        Returns whether the given tree contains any comments in its source.

      • outermostClass

        @Nullable
public static com.sun.tools.javac.code.Symbol.ClassSymbol outermostClass​(com.sun.tools.javac.code.Symbol symbol)
        Returns the outermost enclosing owning class, or null. Doesn't crash on symbols that aren't containing in a package, unlike Symbol.outermostClass() (see b/123431414).

      • isConsideredFinal

        public static boolean isConsideredFinal​(com.sun.tools.javac.code.Symbol symbol)
        Returns whether symbol is final or effectively final.

      • getThrownExceptions

        public static com.google.common.collect.ImmutableSet<com.sun.tools.javac.code.Type> getThrownExceptions​(com.sun.source.tree.Tree tree,
                                                                                                        VisitorState state)
        Returns the exceptions thrown by tree.

      • getStartPosition

        public static int getStartPosition​(com.sun.source.tree.Tree tree)
        Returns the start position of the node.

      • createPrivateConstructor

        public static String createPrivateConstructor​(com.sun.source.tree.ClassTree classTree)
        Returns a no arg private constructor for the ClassTree.

      • isBugCheckerCode

        public static boolean isBugCheckerCode​(VisitorState state)
        Returns true if the code is in a BugChecker class.

      • isLocal

        public static boolean isLocal​(com.sun.tools.javac.code.Symbol symbol)
        Returns true if the symbol is directly or indirectly local to a method or variable initializer; see Symbol#isLocal or Symbol#isDirectlyOrIndirectlyLocal.

      • isStatic

        public static boolean isStatic​(com.sun.tools.javac.code.Symbol symbol)
        Returns true if the symbol is static. Returns false for module symbols.

      • isAbstract

        public static boolean isAbstract​(com.sun.tools.javac.code.Symbol.MethodSymbol method)
        Returns true if the given method symbol is abstract.

        Note: this API does not consider interface default methods to be abstract.

      • scope

        public static ErrorProneScope scope​(com.sun.tools.javac.code.Scope scope)
        Returns a compatibility adapter around Scope.

      • asFlagSet

        public static EnumSet<com.sun.tools.javac.code.Flags.Flag> asFlagSet​(long flags)

      • stringContainsComments

        public static boolean stringContainsComments​(CharSequence source,
                                             com.sun.tools.javac.util.Context context)
        Returns true if the given source code contains comments.

      • getTypeSubstitution

        public static com.google.common.collect.ImmutableListMultimap<com.sun.tools.javac.code.Symbol.TypeVariableSymbol,​com.sun.tools.javac.code.Type> getTypeSubstitution​(com.sun.tools.javac.code.Type type,
                                                                                                                                                                          com.sun.tools.javac.code.Symbol sym)
        Returns the mapping between type variables and their instantiations in the given type. For example, the instantiation of Map<K, V> as Map<String, Integer> would be represented as a TypeSubstitution from [K, V] to [String, Integer].

      • hasNoExplicitType

        public static boolean hasNoExplicitType​(com.sun.source.tree.VariableTree tree,
                                        VisitorState state)
        Returns true if this is a `var` or a lambda parameter that has no explicit type.