content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to you 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 org.apache.calcite.runtime;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.Collection;
  import java.util.Iterator;
  import java.util.List;
  import java.util.ListIterator;
  
  import static org.apache.calcite.linq4j.Nullness.castNonNull;
  
  /**
   * Base class for lists whose contents are constant after creation.
   *
   * @param <E> Element type
   */
  abstract class AbstractImmutableList<E> implements List<E> {
    protected abstract List<E> toList();
  
    @Override public Iterator<E> iterator() {
      return toList().iterator();
    }
  
    @Override public ListIterator<E> listIterator() {
      return toList().listIterator();
    }
  
    @Override public boolean isEmpty() {
      return false;
    }
  
    @Override public boolean add(E t) {
      throw new UnsupportedOperationException();
    }
  
    @Override public boolean addAll(Collection<? extends E> c) {
      throw new UnsupportedOperationException();
    }
  
    @Override public boolean addAll(int index, Collection<? extends E> c) {
      throw new UnsupportedOperationException();
    }
  
    @Override public boolean removeAll(Collection<?> c) {
      throw new UnsupportedOperationException();
    }
  
    @Override public boolean retainAll(Collection<?> c) {
      throw new UnsupportedOperationException();
    }
  
    @Override public void clear() {
      throw new UnsupportedOperationException();
    }
  
    @Override public E set(int index, E element) {
      throw new UnsupportedOperationException();
    }
  
    @Override public void add(int index, E element) {
      throw new UnsupportedOperationException();
    }
  
    @Override public E remove(int index) {
      throw new UnsupportedOperationException();
    }
  
    @Override public ListIterator<E> listIterator(int index) {
      return toList().listIterator(index);
    }
  
    @Override public List<E> subList(int fromIndex, int toIndex) {
      return toList().subList(fromIndex, toIndex);
    }
  
    @Override public boolean contains(@Nullable Object o) {
      return indexOf(castNonNull(o)) >= 0;
    }
  
    @Override public boolean containsAll(Collection<?> c) {
      for (Object o : c) {
        if (!contains(o)) {
          return false;
        }
      }
      return true;
    }
  
    @Override public boolean remove(@Nullable Object o) {
      throw new UnsupportedOperationException();
    }
  }
  