platform/util/src/com/intellij/util/enumeration/EmptyEnumeration.java

/*
 * Copyright 2000-2013 JetBrains s.r.o.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.intellij.util.enumeration;

import org.jetbrains.annotations.NotNull;

import java.util.Enumeration;
import java.util.NoSuchElementException;

public final class EmptyEnumeration<E> implements Enumeration<E> {
  public static Enumeration INSTANCE = new EmptyEnumeration();

  private EmptyEnumeration(){
  }

  @Override
  public boolean hasMoreElements(){
    return false;
  }

  @Override
  public E nextElement(){
    throw new NoSuchElementException();
  }

  @NotNull
  public static <E> Enumeration<E> getInstance() {
    //noinspection unchecked
    return INSTANCE;
  }
}