Path

CtPath (javadoc)defines the path to aCtElement (javadoc)in a model, similarly to XPath for XML. For example,.spoon.test.path.testclasses.Foo.foo#body#statement[index=0] represents the first statement of the body of method foo.ACtPathis based on: names of elements (e.g.,foo), and roles of elements with respect to their parent (e.g.,body).A role is a relation between two AST nodes.For instance, a “then” branch in an if/then/else is a role (and not a node). All roles can be found inCtRole. In addition, each getter or setter in the metamodel is annotated with its role.

Evaluating AST paths

Paths are used to find code elements, from a given root element.

path=newCtPathStringBuilder().fromString(".spoon.test.path.testclasses.Foo.foo#body#statement[index=0]");List<CtElement>l=path.evaluateOn(root)

Creating AST paths

From an existing element

MethodgetPath inCtElement returns a path

CtPathpath=anElement.getPath();

From a string

CtPathStringBuilder (javadoc), creates a path object from a string according to the following syntax:

• .<name> which denotes a child element with namename, e.g.,.fr.inria.Spoon (the fully qualified name)
• #<role> which denotes all children onCtRolerole statements,#body#statement[index=2]#else is the else branch of the second statement of a method body
• name=<somename> - filter which accepts only elements withsomename. E.g.,#field[name=abc]
• signature=<somesignature> - filter which accepts only methods and constructors with signaturesomesignature.
  • Example of method signature:#method[signature=compare(java.lang.String,java.lang.String)]
  • Example of constructor signature:#constructor[signature=(int)]
• index=<idx> - fitler which accepts only idx-th element of the List. The first element has index 0. The fifth type member in a class#typeMember[index=4]

From the API

The low-levelCtPathBuilder (javadoc) defines a fluent API to build your path:

• name(String, String[]) (javadoc)adds a name matcher to the current path.
• type(Class, String[]) (javadoc)matches on element of a given type.
• role(CtPathRole, String[]) (javadoc)matches on elements by their role (whereCtPathRole gives all constants supported).
• wildcard() (javadoc)matches only on elements child of current one.
• recursiveWildcard() (javadoc)matches on any child and sub-children.

For instance, if we want all elements named by “toto” and with a default value ina project. UseCtPathBuilder like the example below.

CtPathp1=newCtPathBuilder().recursiveWildcard().name("toto").role(CtPathRole.DEFAULT_VALUE).build();// equivalent toCtPathp2=newCtPathStringBuilder().fromString(".**.toto#default_value").build();// takes all elements named "toto" in the project.newCtPathBuilder().recursiveWildcard().name("toto")// takes the first element named "toto", a package or a class in the default package, at the root of your project.newCtPathBuilder().name("toto").recursiveWildcard()