JavaElements.java

package sk.stuba.fiit.perconik.core.java;

import java.util.LinkedList;

import javax.annotation.Nullable;

import com.google.common.base.Throwables;

import org.eclipse.core.resources.IResource;
import org.eclipse.jdt.core.IJavaElement;
import org.eclipse.jdt.core.JavaModelException;

import sk.stuba.fiit.perconik.eclipse.jdt.core.JavaException;

import static com.google.common.collect.Lists.newLinkedList;

public final class JavaElements {
  private JavaElements() {}

  public static IJavaElement parent(@Nullable final IJavaElement element) {
    return element != null ? element.getParent() : null;
  }

  public static LinkedList<IJavaElement> ancestors(@Nullable IJavaElement element) {
    final LinkedList<IJavaElement> ancestors = newLinkedList();

    while (element != null) {
      ancestors.add(element = element.getParent());
    }

    return ancestors;
  }

  public static LinkedList<IJavaElement> downToRoot(@Nullable IJavaElement element) {
    LinkedList<IJavaElement> branch = newLinkedList();

    if (element != null) {
      do {
        branch.add(element);
      } while ((element = element.getParent()) != null);
    }

    return branch;
  }

  private static <T> T handle(final Exception failure) {
    if (failure instanceof JavaModelException) {
      throw new JavaException(failure);
    }

    if (failure instanceof NullPointerException) {
      return null;
    }

    throw Throwables.propagate(failure);
  }

  public static IResource resource(@Nullable final IJavaElement element) {
    return element != null ? element.getResource() : null;
  }

  public static IResource correspondingResource(@Nullable final IJavaElement element) {
    try {
      return element != null ? element.getCorrespondingResource() : null;
    } catch (JavaModelException e) {
      return handle(e);
    }
  }

  public static IResource underlyingResource(@Nullable final IJavaElement element) {
    try {
      return element != null ? element.getUnderlyingResource() : null;
    } catch (JavaModelException e) {
      return handle(e);
    }
  }
}