package org.etk.model.apt;
/**
* Visitor pattern for a java class/interface type hierarchy. The visitor strategy
* for a specified type is recursive
* <ol>
* <li>Invoke the method {@link #enter(Class)} with the type. When the method returns false it ends the visit.</li>
* <li>Continue the visit recursively on the type superclass when it does have one.</li>
* <li>Continue the visit recursively on each implemented interfaces.</li>
* <li>Invoke the method {@link #leave(Class)} to signal that visit of the type is terminated.</li>
* </ol>
*
*/
public class TypeHierarchyVisitor {
public void accept(Class type) {
_accept(type);
}
private boolean _accept(Class type) {
if (enter(type)) {
if (type.isInterface()) {
for (Class superInterface : type.getInterfaces()) {
if (!_accept(superInterface)) {
return false;
}
}
} else {
Class superType = type.getSuperclass();
if (superType != null) {
if (!_accept(superType)) {
return false;
}
}
for (Class implementedInterface : type.getInterfaces()) {
if (!_accept(implementedInterface)) {
return false;
}
}
}
//
leave(type);
}
return true;
}
/**
* Subclass to control the visitor.
*
* @param type the visited type
* @return true if the type shall be visited
*/
protected boolean enter(Class type) {
return true;
}
/**
* Signal that the visit of the type is terminated.
*
* @param type the type
*/
protected void leave(Class type) {
}
}