package org.checkerframework.javacutil;

import com.sun.source.tree.CompilationUnitTree;
import com.sun.source.util.TreePath;
import com.sun.source.util.TreePathScanner;
import javax.lang.model.element.TypeElement;
import org.checkerframework.checker.nullness.qual.MonotonicNonNull;

/**
 * Process the types in an AST in a trivial manner, with hooks for derived classes to actually do
 * something.
 */
public abstract class BasicTypeProcessor extends AbstractTypeProcessor {
  /** The source tree that's being scanned. */
  protected @MonotonicNonNull CompilationUnitTree currentRoot;

  /**
   * Create a TreePathScanner at the given root.
   *
   * @param root where to start the tree traversal
   * @return a TreePathScanner at the given root
   */
  protected abstract TreePathScanner<?, ?> createTreePathScanner(CompilationUnitTree root);

  /** Visit the tree path for the type element. */
  @Override
  public void typeProcess(TypeElement e, TreePath p) {
    currentRoot = p.getCompilationUnit();

    TreePathScanner<?, ?> scanner = null;
    try {
      scanner = createTreePathScanner(currentRoot);
      scanner.scan(p, null);
    } catch (Throwable t) {
      System.err.println(
          "BasicTypeProcessor.typeProcess: unexpected Throwable ("
              + t.getClass().getSimpleName()
              + ")  when processing "
              + currentRoot.getSourceFile().getName()
              + (t.getMessage() != null ? "; message: " + t.getMessage() : ""));
    }
  }
}