com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/util/ProtobufElementFinder.java

/*
 * Copyright (c) 2011 Google Inc.
 *
 * All rights reserved. This program and the accompanying materials are made available under the terms of the Eclipse
 * Public License v1.0 which accompanies this distribution, and is available at
 *
 * http://www.eclipse.org/legal/epl-v10.html
 */
package com.google.eclipse.protobuf.util;

import org.eclipse.emf.ecore.EObject;

import com.google.eclipse.protobuf.protobuf.*;
import com.google.eclipse.protobuf.protobuf.Enum;
import com.google.eclipse.protobuf.protobuf.Package;
import com.google.inject.Singleton;

/**
 * Utility methods to find elements in a parser proto file.
 *
 * @author alruiz@google.com (Alex Ruiz)
 */
@Singleton
public class ProtobufElementFinder {

  /**
   * Returns the enum type of the given property, only if the type of the given property is an enum.
   * @param p the given property.
   * @return the enum type of the given property or {@code null} if the type of the given property is not enum.
   */
  public Enum enumTypeOf(Property p) {
    AbstractTypeReference aTypeRef = (p).getType();
    if (aTypeRef instanceof TypeReference) {
      Type type = ((TypeReference) aTypeRef).getType();
      if (type instanceof Enum) return (Enum) type;
    }
    return null;
  }

  /**
   * Returns the scalar type of the given property, only if the type of the given property is a scalar.
   * @param p the given property.
   * @return the scalar type of the given property or {@code null} if the type of the given property is not a scalar.
   */
  public ScalarType scalarTypeOf(Property p) {
    AbstractTypeReference aTypeRef = (p).getType();
    if (aTypeRef instanceof ScalarTypeReference)
      return ((ScalarTypeReference) aTypeRef).getScalar();
    return null;
  }

  /**
   * Returns the package of the proto file containing the given object.
   * @param o the given object.
   * @return the package of the proto file containing the given object or {@code null} if the proto file does not have a
   * package.
   */
  public Package packageOf(EObject o) {
    return rootOf(o).getPackage();
  }

  /**
   * Returns the root element of the proto file containing the given object.
   * @param o the given object.
   * @return the root element of the proto file containing the given object.
   */
  public Protobuf rootOf(EObject o) {
    EObject current = o;
    while (!(current instanceof Protobuf)) current = current.eContainer();
    return (Protobuf) current;
  }
}