package org.checkerframework.javacutil;
/*>>>
import org.checkerframework.checker.nullness.qual.*;
*/
import com.sun.source.tree.AnnotatedTypeTree;
import com.sun.source.tree.ArrayAccessTree;
import com.sun.source.tree.BinaryTree;
import com.sun.source.tree.BlockTree;
import com.sun.source.tree.ClassTree;
import com.sun.source.tree.CompoundAssignmentTree;
import com.sun.source.tree.ConditionalExpressionTree;
import com.sun.source.tree.ExpressionStatementTree;
import com.sun.source.tree.ExpressionTree;
import com.sun.source.tree.IdentifierTree;
import com.sun.source.tree.LiteralTree;
import com.sun.source.tree.MemberSelectTree;
import com.sun.source.tree.MethodInvocationTree;
import com.sun.source.tree.MethodTree;
import com.sun.source.tree.NewClassTree;
import com.sun.source.tree.ParameterizedTypeTree;
import com.sun.source.tree.ParenthesizedTree;
import com.sun.source.tree.PrimitiveTypeTree;
import com.sun.source.tree.StatementTree;
import com.sun.source.tree.Tree;
import com.sun.source.tree.Tree.Kind;
import com.sun.source.tree.TypeCastTree;
import com.sun.source.tree.VariableTree;
import com.sun.source.util.TreePath;
import com.sun.source.util.Trees;
import com.sun.tools.javac.code.Flags;
import com.sun.tools.javac.code.Symbol.MethodSymbol;
import com.sun.tools.javac.tree.JCTree;
import java.util.ArrayList;
import java.util.EnumSet;
import java.util.List;
import java.util.Set;
import javax.annotation.processing.ProcessingEnvironment;
import javax.lang.model.element.Element;
import javax.lang.model.element.ElementKind;
import javax.lang.model.element.ExecutableElement;
import javax.lang.model.element.Modifier;
import javax.lang.model.element.Name;
import javax.lang.model.element.TypeElement;
import javax.lang.model.element.VariableElement;
import javax.lang.model.type.TypeKind;
import javax.lang.model.util.ElementFilter;
/** A utility class made for helping to analyze a given {@code Tree}. */
// TODO: This class needs significant restructuring
public final class TreeUtils {
// Class cannot be instantiated.
private TreeUtils() {
throw new AssertionError("Class TreeUtils cannot be instantiated.");
}
/**
* Checks if the provided method is a constructor method or no.
*
* @param tree a tree defining the method
* @return true iff tree describes a constructor
*/
public static boolean isConstructor(final MethodTree tree) {
return tree.getName().contentEquals("<init>");
}
/**
* Checks if the method invocation is a call to super.
*
* @param tree a tree defining a method invocation
* @return true iff tree describes a call to super
*/
public static boolean isSuperCall(MethodInvocationTree tree) {
return isNamedMethodCall("super", tree);
}
/**
* Checks if the method invocation is a call to this.
*
* @param tree a tree defining a method invocation
* @return true iff tree describes a call to this
*/
public static boolean isThisCall(MethodInvocationTree tree) {
return isNamedMethodCall("this", tree);
}
protected static boolean isNamedMethodCall(String name, MethodInvocationTree tree) {
/*@Nullable*/ ExpressionTree mst = tree.getMethodSelect();
assert mst != null; /*nninvariant*/
if (mst.getKind() == Tree.Kind.IDENTIFIER) {
return ((IdentifierTree) mst).getName().contentEquals(name);
}
if (mst.getKind() == Tree.Kind.MEMBER_SELECT) {
MemberSelectTree selectTree = (MemberSelectTree) mst;
if (selectTree.getExpression().getKind() != Tree.Kind.IDENTIFIER) {
return false;
}
return ((IdentifierTree) selectTree.getExpression()).getName().contentEquals(name);
}
return false;
}
/**
* Returns true if the tree is a tree that 'looks like' either an access of a field or an
* invocation of a method that are owned by the same accessing instance.
*
* <p>It would only return true if the access tree is of the form:
*
* <pre>
* field
* this.field
*
* method()
* this.method()
* </pre>
*
* It does not perform any semantical check to differentiate between fields and local variables;
* local methods or imported static methods.
*
* @param tree expression tree representing an access to object member
* @return {@code true} iff the member is a member of {@code this} instance
*/
public static boolean isSelfAccess(final ExpressionTree tree) {
ExpressionTree tr = TreeUtils.skipParens(tree);
// If method invocation check the method select
if (tr.getKind() == Tree.Kind.ARRAY_ACCESS) {
return false;
}
if (tree.getKind() == Tree.Kind.METHOD_INVOCATION) {
tr = ((MethodInvocationTree) tree).getMethodSelect();
}
tr = TreeUtils.skipParens(tr);
if (tr.getKind() == Tree.Kind.TYPE_CAST) {
tr = ((TypeCastTree) tr).getExpression();
}
tr = TreeUtils.skipParens(tr);
if (tr.getKind() == Tree.Kind.IDENTIFIER) {
return true;
}
if (tr.getKind() == Tree.Kind.MEMBER_SELECT) {
tr = ((MemberSelectTree) tr).getExpression();
if (tr.getKind() == Tree.Kind.IDENTIFIER) {
Name ident = ((IdentifierTree) tr).getName();
return ident.contentEquals("this") || ident.contentEquals("super");
}
}
return false;
}
/**
* Gets the first enclosing tree in path, of the specified kind.
*
* @param path the path defining the tree node
* @param kind the kind of the desired tree
* @return the enclosing tree of the given type as given by the path
*/
public static Tree enclosingOfKind(final TreePath path, final Tree.Kind kind) {
return enclosingOfKind(path, EnumSet.of(kind));
}
/**
* Gets the first enclosing tree in path, with any one of the specified kinds.
*
* @param path the path defining the tree node
* @param kinds the set of kinds of the desired tree
* @return the enclosing tree of the given type as given by the path
*/
public static Tree enclosingOfKind(final TreePath path, final Set<Tree.Kind> kinds) {
TreePath p = path;
while (p != null) {
Tree leaf = p.getLeaf();
assert leaf != null; /*nninvariant*/
if (kinds.contains(leaf.getKind())) {
return leaf;
}
p = p.getParentPath();
}
return null;
}
/**
* Gets path to the first enclosing class tree, where class is defined by the classTreeKinds
* method.
*
* @param path the path defining the tree node
* @return the path to the enclosing class tree
*/
public static TreePath pathTillClass(final TreePath path) {
return pathTillOfKind(path, classTreeKinds());
}
/**
* Gets path to the first enclosing tree of the specified kind.
*
* @param path the path defining the tree node
* @param kind the kind of the desired tree
* @return the path to the enclosing tree of the given type
*/
public static TreePath pathTillOfKind(final TreePath path, final Tree.Kind kind) {
return pathTillOfKind(path, EnumSet.of(kind));
}
/**
* Gets path to the first enclosing tree with any one of the specified kinds.
*
* @param path the path defining the tree node
* @param kinds the set of kinds of the desired tree
* @return the path to the enclosing tree of the given type
*/
public static TreePath pathTillOfKind(final TreePath path, final Set<Tree.Kind> kinds) {
TreePath p = path;
while (p != null) {
Tree leaf = p.getLeaf();
assert leaf != null; /*nninvariant*/
if (kinds.contains(leaf.getKind())) {
return p;
}
p = p.getParentPath();
}
return null;
}
/**
* Gets the first enclosing tree in path, of the specified class
*
* @param path the path defining the tree node
* @param treeClass the class of the desired tree
* @return the enclosing tree of the given type as given by the path
*/
public static <T extends Tree> T enclosingOfClass(
final TreePath path, final Class<T> treeClass) {
TreePath p = path;
while (p != null) {
Tree leaf = p.getLeaf();
if (treeClass.isInstance(leaf)) {
return treeClass.cast(leaf);
}
p = p.getParentPath();
}
return null;
}
/**
* Gets the enclosing class of the tree node defined by the given {@link TreePath}. It returns a
* {@link Tree}, from which {@code checkers.types.AnnotatedTypeMirror} or {@link Element} can be
* obtained.
*
* @param path the path defining the tree node
* @return the enclosing class (or interface) as given by the path, or null if one does not
* exist
*/
public static /*@Nullable*/ ClassTree enclosingClass(final /*@Nullable*/ TreePath path) {
return (ClassTree) enclosingOfKind(path, classTreeKinds());
}
/**
* Gets the enclosing variable of a tree node defined by the given {@link TreePath}.
*
* @param path the path defining the tree node
* @return the enclosing variable as given by the path, or null if one does not exist
*/
public static VariableTree enclosingVariable(final TreePath path) {
return (VariableTree) enclosingOfKind(path, Tree.Kind.VARIABLE);
}
/**
* Gets the enclosing method of the tree node defined by the given {@link TreePath}. It returns
* a {@link Tree}, from which an {@code checkers.types.AnnotatedTypeMirror} or {@link Element}
* can be obtained.
*
* @param path the path defining the tree node
* @return the enclosing method as given by the path, or null if one does not exist
*/
public static /*@Nullable*/ MethodTree enclosingMethod(final /*@Nullable*/ TreePath path) {
return (MethodTree) enclosingOfKind(path, Tree.Kind.METHOD);
}
public static /*@Nullable*/ BlockTree enclosingTopLevelBlock(TreePath path) {
TreePath parpath = path.getParentPath();
while (parpath != null && !classTreeKinds.contains(parpath.getLeaf().getKind())) {
path = parpath;
parpath = parpath.getParentPath();
}
if (path.getLeaf().getKind() == Tree.Kind.BLOCK) {
return (BlockTree) path.getLeaf();
}
return null;
}
/**
* If the given tree is a parenthesized tree, it returns the enclosed non-parenthesized tree.
* Otherwise, it returns the same tree.
*
* @param tree an expression tree
* @return the outermost non-parenthesized tree enclosed by the given tree
*/
public static ExpressionTree skipParens(final ExpressionTree tree) {
ExpressionTree t = tree;
while (t.getKind() == Tree.Kind.PARENTHESIZED) {
t = ((ParenthesizedTree) t).getExpression();
}
return t;
}
/**
* Returns the tree with the assignment context for the treePath leaf node. (Does not handle
* pseudo-assignment of an argument to a parameter or a receiver expression to a receiver.)
*
* <p>The assignment context for the {@code treePath} is the leaf of its parent, if the parent
* is one of the following trees:
*
* <ul>
* <li>AssignmentTree
* <li>CompoundAssignmentTree
* <li>MethodInvocationTree
* <li>NewArrayTree
* <li>NewClassTree
* <li>ReturnTree
* <li>VariableTree
* </ul>
*
* If the parent is a ConditionalExpressionTree we need to distinguish two cases: If the leaf is
* either the then or else branch of the ConditionalExpressionTree, then recurse on the parent.
* If the leaf is the condition of the ConditionalExpressionTree, then return null to not
* consider this assignment context.
*
* <p>If the leaf is a ParenthesizedTree, then recurse on the parent.
*
* <p>Otherwise, null is returned.
*
* @return the assignment context as described
*/
public static Tree getAssignmentContext(final TreePath treePath) {
TreePath parentPath = treePath.getParentPath();
if (parentPath == null) {
return null;
}
Tree parent = parentPath.getLeaf();
switch (parent.getKind()) {
case PARENTHESIZED:
return getAssignmentContext(parentPath);
case CONDITIONAL_EXPRESSION:
ConditionalExpressionTree cet = (ConditionalExpressionTree) parent;
if (cet.getCondition() == treePath.getLeaf()) {
// The assignment context for the condition is simply boolean.
// No point in going on.
return null;
}
// Otherwise use the context of the ConditionalExpressionTree.
return getAssignmentContext(parentPath);
case ASSIGNMENT:
case METHOD_INVOCATION:
case NEW_ARRAY:
case NEW_CLASS:
case RETURN:
case VARIABLE:
return parent;
default:
// 11 Tree.Kinds are CompoundAssignmentTrees,
// so use instanceof rather than listing all 11.
if (parent instanceof CompoundAssignmentTree) {
return parent;
}
return null;
}
}
/**
* Gets the element for a class corresponding to a declaration.
*
* @return the element for the given class
*/
public static final TypeElement elementFromDeclaration(ClassTree node) {
TypeElement elt = (TypeElement) InternalUtils.symbol(node);
return elt;
}
/**
* Gets the element for a method corresponding to a declaration.
*
* @return the element for the given method
*/
public static final ExecutableElement elementFromDeclaration(MethodTree node) {
ExecutableElement elt = (ExecutableElement) InternalUtils.symbol(node);
return elt;
}
/**
* Gets the element for a variable corresponding to its declaration.
*
* @return the element for the given variable
*/
public static final VariableElement elementFromDeclaration(VariableTree node) {
VariableElement elt = (VariableElement) InternalUtils.symbol(node);
return elt;
}
/**
* Gets the element for the declaration corresponding to this use of an element. To get the
* element for a declaration, use {@link Trees#getElement(TreePath)} instead.
*
* <p>TODO: remove this method, as it really doesn't do anything.
*
* @param node the tree corresponding to a use of an element
* @return the element for the corresponding declaration
*/
public static final Element elementFromUse(ExpressionTree node) {
return InternalUtils.symbol(node);
}
// Specialization for return type.
// Might return null if element wasn't found.
public static final ExecutableElement elementFromUse(MethodInvocationTree node) {
Element el = elementFromUse((ExpressionTree) node);
if (el instanceof ExecutableElement) {
return (ExecutableElement) el;
} else {
return null;
}
}
// Specialization for return type.
public static final ExecutableElement elementFromUse(NewClassTree node) {
return (ExecutableElement) elementFromUse((ExpressionTree) node);
}
/**
* Determine whether the given ExpressionTree has an underlying element.
*
* @param node the ExpressionTree to test
* @return whether the tree refers to an identifier, member select, or method invocation
*/
public static final boolean isUseOfElement(ExpressionTree node) {
node = TreeUtils.skipParens(node);
switch (node.getKind()) {
case IDENTIFIER:
case MEMBER_SELECT:
case METHOD_INVOCATION:
case NEW_CLASS:
return true;
default:
return false;
}
}
/** @return the name of the invoked method */
public static final Name methodName(MethodInvocationTree node) {
ExpressionTree expr = node.getMethodSelect();
if (expr.getKind() == Tree.Kind.IDENTIFIER) {
return ((IdentifierTree) expr).getName();
} else if (expr.getKind() == Tree.Kind.MEMBER_SELECT) {
return ((MemberSelectTree) expr).getIdentifier();
}
ErrorReporter.errorAbort("TreeUtils.methodName: cannot be here: " + node);
return null; // dead code
}
/**
* @return true if the first statement in the body is a self constructor invocation within a
* constructor
*/
public static final boolean containsThisConstructorInvocation(MethodTree node) {
if (!TreeUtils.isConstructor(node) || node.getBody().getStatements().isEmpty())
return false;
StatementTree st = node.getBody().getStatements().get(0);
if (!(st instanceof ExpressionStatementTree)
|| !(((ExpressionStatementTree) st).getExpression()
instanceof MethodInvocationTree)) {
return false;
}
MethodInvocationTree invocation =
(MethodInvocationTree) ((ExpressionStatementTree) st).getExpression();
return "this".contentEquals(TreeUtils.methodName(invocation));
}
public static final Tree firstStatement(Tree tree) {
Tree first;
if (tree.getKind() == Tree.Kind.BLOCK) {
BlockTree block = (BlockTree) tree;
if (block.getStatements().isEmpty()) {
first = block;
} else {
first = block.getStatements().iterator().next();
}
} else {
first = tree;
}
return first;
}
/**
* Determine whether the given class contains an explicit constructor.
*
* @param node a class tree
* @return true, iff there is an explicit constructor
*/
public static boolean hasExplicitConstructor(ClassTree node) {
TypeElement elem = TreeUtils.elementFromDeclaration(node);
for (ExecutableElement ee : ElementFilter.constructorsIn(elem.getEnclosedElements())) {
MethodSymbol ms = (MethodSymbol) ee;
long mod = ms.flags();
if ((mod & Flags.SYNTHETIC) == 0) {
return true;
}
}
return false;
}
/**
* Returns true if the tree is of a diamond type. In contrast to the implementation in TreeInfo,
* this version works on Trees.
*
* @see com.sun.tools.javac.tree.TreeInfo#isDiamond(JCTree)
*/
public static final boolean isDiamondTree(Tree tree) {
switch (tree.getKind()) {
case ANNOTATED_TYPE:
return isDiamondTree(((AnnotatedTypeTree) tree).getUnderlyingType());
case PARAMETERIZED_TYPE:
return ((ParameterizedTypeTree) tree).getTypeArguments().isEmpty();
case NEW_CLASS:
return isDiamondTree(((NewClassTree) tree).getIdentifier());
default:
return false;
}
}
/** Returns true if the tree represents a {@code String} concatenation operation */
public static final boolean isStringConcatenation(Tree tree) {
return (tree.getKind() == Tree.Kind.PLUS
&& TypesUtils.isString(InternalUtils.typeOf(tree)));
}
/** Returns true if the compound assignment tree is a string concatenation */
public static final boolean isStringCompoundConcatenation(CompoundAssignmentTree tree) {
return (tree.getKind() == Tree.Kind.PLUS_ASSIGNMENT
&& TypesUtils.isString(InternalUtils.typeOf(tree)));
}
/**
* Returns true if the node is a constant-time expression.
*
* <p>A tree is a constant-time expression if it is:
*
* <ol>
* <li>a literal tree
* <li>a reference to a final variable initialized with a compile time constant
* <li>a String concatenation of two compile time constants
* </ol>
*/
public static boolean isCompileTimeString(ExpressionTree node) {
ExpressionTree tree = TreeUtils.skipParens(node);
if (tree instanceof LiteralTree) {
return true;
}
if (TreeUtils.isUseOfElement(tree)) {
Element elt = TreeUtils.elementFromUse(tree);
return ElementUtils.isCompileTimeConstant(elt);
} else if (TreeUtils.isStringConcatenation(tree)) {
BinaryTree binOp = (BinaryTree) tree;
return isCompileTimeString(binOp.getLeftOperand())
&& isCompileTimeString(binOp.getRightOperand());
} else {
return false;
}
}
/** Returns the receiver tree of a field access or a method invocation */
public static ExpressionTree getReceiverTree(ExpressionTree expression) {
ExpressionTree receiver = TreeUtils.skipParens(expression);
if (!(receiver.getKind() == Tree.Kind.METHOD_INVOCATION
|| receiver.getKind() == Tree.Kind.MEMBER_SELECT
|| receiver.getKind() == Tree.Kind.IDENTIFIER
|| receiver.getKind() == Tree.Kind.ARRAY_ACCESS)) {
// No receiver tree for anything but these four kinds.
return null;
}
if (receiver.getKind() == Tree.Kind.METHOD_INVOCATION) {
// Trying to handle receiver calls to trees of the form
// ((m).getArray())
// returns the type of 'm' in this case
receiver = ((MethodInvocationTree) receiver).getMethodSelect();
if (receiver.getKind() == Tree.Kind.IDENTIFIER) {
// It's a method call "m(foo)" without an explicit receiver
return null;
} else if (receiver.getKind() == Tree.Kind.MEMBER_SELECT) {
receiver = ((MemberSelectTree) receiver).getExpression();
} else {
// Otherwise, e.g. a NEW_CLASS: nothing to do.
}
} else if (receiver.getKind() == Tree.Kind.IDENTIFIER) {
// It's a field access on implicit this or a local variable/parameter.
return null;
} else if (receiver.getKind() == Tree.Kind.ARRAY_ACCESS) {
return TreeUtils.skipParens(((ArrayAccessTree) receiver).getExpression());
} else if (receiver.getKind() == Tree.Kind.MEMBER_SELECT) {
receiver = ((MemberSelectTree) receiver).getExpression();
// Avoid int.class
if (receiver instanceof PrimitiveTypeTree) {
return null;
}
}
// Receiver is now really just the receiver tree.
return TreeUtils.skipParens(receiver);
}
// TODO: What about anonymous classes?
// Adding Tree.Kind.NEW_CLASS here doesn't work, because then a
// tree gets cast to ClassTree when it is actually a NewClassTree,
// for example in enclosingClass above.
private static final Set<Tree.Kind> classTreeKinds =
EnumSet.of(
Tree.Kind.CLASS,
Tree.Kind.ENUM,
Tree.Kind.INTERFACE,
Tree.Kind.ANNOTATION_TYPE);
public static Set<Tree.Kind> classTreeKinds() {
return classTreeKinds;
}
/**
* Is the given tree kind a class, i.e. a class, enum, interface, or annotation type.
*
* @param tree the tree to test
* @return true, iff the given kind is a class kind
*/
public static boolean isClassTree(Tree tree) {
return classTreeKinds().contains(tree.getKind());
}
private static final Set<Tree.Kind> typeTreeKinds =
EnumSet.of(
Tree.Kind.PRIMITIVE_TYPE,
Tree.Kind.PARAMETERIZED_TYPE,
Tree.Kind.TYPE_PARAMETER,
Tree.Kind.ARRAY_TYPE,
Tree.Kind.UNBOUNDED_WILDCARD,
Tree.Kind.EXTENDS_WILDCARD,
Tree.Kind.SUPER_WILDCARD,
Tree.Kind.ANNOTATED_TYPE);
public static Set<Tree.Kind> typeTreeKinds() {
return typeTreeKinds;
}
/**
* Is the given tree a type instantiation?
*
* <p>TODO: this is an under-approximation: e.g. an identifier could be either a type use or an
* expression. How can we distinguish.
*
* @param tree the tree to test
* @return true, iff the given tree is a type
*/
public static boolean isTypeTree(Tree tree) {
return typeTreeKinds().contains(tree.getKind());
}
/**
* Returns true if the given element is an invocation of the method, or of any method that
* overrides that one.
*/
public static boolean isMethodInvocation(
Tree tree, ExecutableElement method, ProcessingEnvironment env) {
if (!(tree instanceof MethodInvocationTree)) {
return false;
}
MethodInvocationTree methInvok = (MethodInvocationTree) tree;
ExecutableElement invoked = TreeUtils.elementFromUse(methInvok);
return ElementUtils.isMethod(invoked, method, env);
}
/**
* Returns the ExecutableElement for a method declaration of methodName, in class typeName, with
* params parameters.
*
* <p>TODO: to precisely resolve method overloading, we should use parameter types and not just
* the number of parameters!
*/
public static ExecutableElement getMethod(
String typeName, String methodName, int params, ProcessingEnvironment env) {
TypeElement typeElt = env.getElementUtils().getTypeElement(typeName);
for (ExecutableElement exec : ElementFilter.methodsIn(typeElt.getEnclosedElements())) {
if (exec.getSimpleName().contentEquals(methodName)
&& exec.getParameters().size() == params) {
return exec;
}
}
ErrorReporter.errorAbort("TreeUtils.getMethod: shouldn't be here!");
return null; // dead code
}
public static List<ExecutableElement> getMethodList(
String typeName, String methodName, int params, ProcessingEnvironment env) {
List<ExecutableElement> methods = new ArrayList<>();
TypeElement typeElement = env.getElementUtils().getTypeElement(typeName);
for (ExecutableElement exec : ElementFilter.methodsIn(typeElement.getEnclosedElements())) {
if (exec.getSimpleName().contentEquals(methodName)
&& exec.getParameters().size() == params) {
methods.add(exec);
}
}
return methods;
}
/**
* Determine whether the given expression is either "this" or an outer "C.this".
*
* <p>TODO: Should this also handle "super"?
*/
public static final boolean isExplicitThisDereference(ExpressionTree tree) {
if (tree.getKind() == Tree.Kind.IDENTIFIER
&& ((IdentifierTree) tree).getName().contentEquals("this")) {
// Explicit this reference "this"
return true;
}
if (tree.getKind() != Tree.Kind.MEMBER_SELECT) {
return false;
}
MemberSelectTree memSelTree = (MemberSelectTree) tree;
if (memSelTree.getIdentifier().contentEquals("this")) {
// Outer this reference "C.this"
return true;
}
return false;
}
/**
* Determine whether {@code tree} is a class literal, such as
*
* <pre>
* <em>Object</em> . <em>class</em>
* </pre>
*
* @return true iff if tree is a class literal
*/
public static boolean isClassLiteral(Tree tree) {
if (tree.getKind() != Tree.Kind.MEMBER_SELECT) {
return false;
}
return "class".equals(((MemberSelectTree) tree).getIdentifier().toString());
}
/**
* Determine whether {@code tree} is a field access expressions, such as
*
* <pre>
* <em>f</em>
* <em>obj</em> . <em>f</em>
* </pre>
*
* @return true iff if tree is a field access expression (implicit or explicit)
*/
public static boolean isFieldAccess(Tree tree) {
if (tree.getKind().equals(Tree.Kind.MEMBER_SELECT)) {
// explicit field access
MemberSelectTree memberSelect = (MemberSelectTree) tree;
Element el = TreeUtils.elementFromUse(memberSelect);
return el.getKind().isField();
} else if (tree.getKind().equals(Tree.Kind.IDENTIFIER)) {
// implicit field access
IdentifierTree ident = (IdentifierTree) tree;
Element el = TreeUtils.elementFromUse(ident);
return el.getKind().isField()
&& !ident.getName().contentEquals("this")
&& !ident.getName().contentEquals("super");
}
return false;
}
/**
* Compute the name of the field that the field access {@code tree} accesses. Requires {@code
* tree} to be a field access, as determined by {@code isFieldAccess}.
*
* @return the name of the field accessed by {@code tree}.
*/
public static String getFieldName(Tree tree) {
assert isFieldAccess(tree);
if (tree.getKind().equals(Tree.Kind.MEMBER_SELECT)) {
MemberSelectTree mtree = (MemberSelectTree) tree;
return mtree.getIdentifier().toString();
} else {
IdentifierTree itree = (IdentifierTree) tree;
return itree.getName().toString();
}
}
/**
* Determine whether {@code tree} refers to a method element, such as
*
* <pre>
* <em>m</em>(...)
* <em>obj</em> . <em>m</em>(...)
* </pre>
*
* @return true iff if tree is a method access expression (implicit or explicit)
*/
public static boolean isMethodAccess(Tree tree) {
if (tree.getKind().equals(Tree.Kind.MEMBER_SELECT)) {
// explicit method access
MemberSelectTree memberSelect = (MemberSelectTree) tree;
Element el = TreeUtils.elementFromUse(memberSelect);
return el.getKind() == ElementKind.METHOD || el.getKind() == ElementKind.CONSTRUCTOR;
} else if (tree.getKind().equals(Tree.Kind.IDENTIFIER)) {
// implicit method access
IdentifierTree ident = (IdentifierTree) tree;
// The field "super" and "this" are also legal methods
if (ident.getName().contentEquals("super") || ident.getName().contentEquals("this")) {
return true;
}
Element el = TreeUtils.elementFromUse(ident);
return el.getKind() == ElementKind.METHOD || el.getKind() == ElementKind.CONSTRUCTOR;
}
return false;
}
/**
* Compute the name of the method that the method access {@code tree} accesses. Requires {@code
* tree} to be a method access, as determined by {@code isMethodAccess}.
*
* @return the name of the method accessed by {@code tree}.
*/
public static String getMethodName(Tree tree) {
assert isMethodAccess(tree);
if (tree.getKind().equals(Tree.Kind.MEMBER_SELECT)) {
MemberSelectTree mtree = (MemberSelectTree) tree;
return mtree.getIdentifier().toString();
} else {
IdentifierTree itree = (IdentifierTree) tree;
return itree.getName().toString();
}
}
/**
* @return {@code true} if and only if {@code tree} can have a type annotation.
* <p>TODO: is this implementation precise enough? E.g. does a .class literal work
* correctly?
*/
public static boolean canHaveTypeAnnotation(Tree tree) {
return ((JCTree) tree).type != null;
}
/**
* Returns true if and only if the given {@code tree} represents a field access of the given
* {@link VariableElement}.
*/
public static boolean isSpecificFieldAccess(Tree tree, VariableElement var) {
if (tree instanceof MemberSelectTree) {
MemberSelectTree memSel = (MemberSelectTree) tree;
Element field = TreeUtils.elementFromUse(memSel);
return field.equals(var);
} else if (tree instanceof IdentifierTree) {
IdentifierTree idTree = (IdentifierTree) tree;
Element field = TreeUtils.elementFromUse(idTree);
return field.equals(var);
} else {
return false;
}
}
/**
* Returns the VariableElement for a field declaration.
*
* @param typeName the class where the field is declared
* @param fieldName the name of the field
* @param env the processing environment
* @return the VariableElement for typeName.fieldName
*/
public static VariableElement getField(
String typeName, String fieldName, ProcessingEnvironment env) {
TypeElement mapElt = env.getElementUtils().getTypeElement(typeName);
for (VariableElement var : ElementFilter.fieldsIn(mapElt.getEnclosedElements())) {
if (var.getSimpleName().contentEquals(fieldName)) {
return var;
}
}
ErrorReporter.errorAbort("TreeUtils.getField: shouldn't be here!");
return null; // dead code
}
/**
* Determine whether the given tree represents an ExpressionTree.
*
* <p>TODO: is there a nicer way than an instanceof?
*
* @param tree the Tree to test
* @return whether the tree is an ExpressionTree
*/
public static boolean isExpressionTree(Tree tree) {
return tree instanceof ExpressionTree;
}
/**
* @param node the method invocation to check
* @return true if this is a super call to the {@link Enum} constructor
*/
public static boolean isEnumSuper(MethodInvocationTree node) {
ExecutableElement ex = TreeUtils.elementFromUse(node);
Name name = ElementUtils.getQualifiedClassName(ex);
boolean correctClass = "java.lang.Enum".contentEquals(name);
boolean correctMethod = "<init>".contentEquals(ex.getSimpleName());
return correctClass && correctMethod;
}
/**
* Determine whether the given tree represents a declaration of a type (including type
* parameters).
*
* @param node the Tree to test
* @return true if the tree is a type declaration
*/
public static boolean isTypeDeclaration(Tree node) {
switch (node.getKind()) {
// These tree kinds are always declarations. Uses of the declared
// types have tree kind IDENTIFIER.
case ANNOTATION_TYPE:
case CLASS:
case ENUM:
case INTERFACE:
case TYPE_PARAMETER:
return true;
default:
return false;
}
}
/**
* @see Object#getClass()
* @return true iff invocationTree is an instance of getClass()
*/
public static boolean isGetClassInvocation(MethodInvocationTree invocationTree) {
final Element declarationElement = elementFromUse(invocationTree);
String ownerName =
ElementUtils.getQualifiedClassName(declarationElement.getEnclosingElement())
.toString();
return ownerName.equals("java.lang.Object")
&& declarationElement.getSimpleName().toString().equals("getClass");
}
/**
* Returns whether or not the leaf of the tree path is in a static scope.
*
* @param path TreePath whose leaf may or may not be in static scope
* @return returns whether or not the leaf of the tree path is in a static scope
*/
public static boolean isTreeInStaticScope(TreePath path) {
MethodTree enclosingMethod = TreeUtils.enclosingMethod(path);
if (enclosingMethod != null) {
return enclosingMethod.getModifiers().getFlags().contains(Modifier.STATIC);
}
// no enclosing method, check for static or initializer block
BlockTree block = enclosingTopLevelBlock(path);
if (block != null) {
return block.isStatic();
}
// check if its in a variable initializer
Tree t = enclosingVariable(path);
if (t != null) {
return ((VariableTree) t).getModifiers().getFlags().contains((Modifier.STATIC));
}
ClassTree classTree = enclosingClass(path);
if (classTree != null) {
return classTree.getModifiers().getFlags().contains((Modifier.STATIC));
}
return false;
}
/**
* Returns whether or not tree is an access of array length.
*
* @param tree tree to check
* @return true if tree is an access of array length
*/
public static boolean isArrayLengthAccess(Tree tree) {
if (tree.getKind() == Kind.MEMBER_SELECT
&& isFieldAccess(tree)
&& getFieldName(tree).equals("length")) {
ExpressionTree expressionTree = ((MemberSelectTree) tree).getExpression();
if (InternalUtils.typeOf(expressionTree).getKind() == TypeKind.ARRAY) {
return true;
}
}
return false;
}
}