content: // Protocol Buffers - Google's data interchange format
  // Copyright 2008 Google Inc.  All rights reserved.
  // https://developers.google.com/protocol-buffers/
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  //     * Redistributions of source code must retain the above copyright
  // notice, this list of conditions and the following disclaimer.
  //     * Redistributions in binary form must reproduce the above
  // copyright notice, this list of conditions and the following disclaimer
  // in the documentation and/or other materials provided with the
  // distribution.
  //     * Neither the name of Google Inc. nor the names of its
  // contributors may be used to endorse or promote products derived from
  // this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  package com.google.protobuf;
  
  import java.util.AbstractList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.List;
  import java.util.ListIterator;
  import java.util.RandomAccess;
  
  /**
   * An implementation of {@link LazyStringList} that wraps another {@link LazyStringList} such that
   * it cannot be modified via the wrapper.
   *
   * @author jonp@google.com (Jon Perlow)
   */
  public class UnmodifiableLazyStringList extends AbstractList<String>
      implements LazyStringList, RandomAccess {
  
    private final LazyStringList list;
  
    public UnmodifiableLazyStringList(LazyStringList list) {
      this.list = list;
    }
  
    @Override
    public String get(int index) {
      return list.get(index);
    }
  
    @Override
    public Object getRaw(int index) {
      return list.getRaw(index);
    }
  
    @Override
    public int size() {
      return list.size();
    }
  
    @Override
    public ByteString getByteString(int index) {
      return list.getByteString(index);
    }
  
    @Override
    public void add(ByteString element) {
      throw new UnsupportedOperationException();
    }
  
    @Override
    public void set(int index, ByteString element) {
      throw new UnsupportedOperationException();
    }
  
    @Override
    public boolean addAllByteString(Collection<? extends ByteString> element) {
      throw new UnsupportedOperationException();
    }
  
    @Override
    public byte[] getByteArray(int index) {
      return list.getByteArray(index);
    }
  
    @Override
    public void add(byte[] element) {
      throw new UnsupportedOperationException();
    }
  
    @Override
    public void set(int index, byte[] element) {
      throw new UnsupportedOperationException();
    }
  
    @Override
    public boolean addAllByteArray(Collection<byte[]> element) {
      throw new UnsupportedOperationException();
    }
  
    @Override
    public ListIterator<String> listIterator(final int index) {
      return new ListIterator<String>() {
        ListIterator<String> iter = list.listIterator(index);
  
        @Override
        public boolean hasNext() {
          return iter.hasNext();
        }
  
        @Override
        public String next() {
          return iter.next();
        }
  
        @Override
        public boolean hasPrevious() {
          return iter.hasPrevious();
        }
  
        @Override
        public String previous() {
          return iter.previous();
        }
  
        @Override
        public int nextIndex() {
          return iter.nextIndex();
        }
  
        @Override
        public int previousIndex() {
          return iter.previousIndex();
        }
  
        @Override
        public void remove() {
          throw new UnsupportedOperationException();
        }
  
        @Override
        public void set(String o) {
          throw new UnsupportedOperationException();
        }
  
        @Override
        public void add(String o) {
          throw new UnsupportedOperationException();
        }
      };
    }
  
    @Override
    public Iterator<String> iterator() {
      return new Iterator<String>() {
        Iterator<String> iter = list.iterator();
  
        @Override
        public boolean hasNext() {
          return iter.hasNext();
        }
  
        @Override
        public String next() {
          return iter.next();
        }
  
        @Override
        public void remove() {
          throw new UnsupportedOperationException();
        }
      };
    }
  
    @Override
    public List<?> getUnderlyingElements() {
      // The returned value is already unmodifiable.
      return list.getUnderlyingElements();
    }
  
    @Override
    public void mergeFrom(LazyStringList other) {
      throw new UnsupportedOperationException();
    }
  
    @Override
    public List<byte[]> asByteArrayList() {
      return Collections.unmodifiableList(list.asByteArrayList());
    }
  
    @Override
    public List<ByteString> asByteStringList() {
      return Collections.unmodifiableList(list.asByteStringList());
    }
  
    @Override
    public LazyStringList getUnmodifiableView() {
      return this;
    }
  }
  