| // Protocol Buffers - Google's data interchange format |
| // Copyright 2008 Google Inc. All rights reserved. |
| // http://code.google.com/p/protobuf/ |
| // |
| // 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.List; |
| import java.util.AbstractList; |
| import java.util.ArrayList; |
| import java.util.RandomAccess; |
| import java.util.Collection; |
| |
| /** |
| * An implementation of {@link LazyStringList} that wraps an ArrayList. Each |
| * element is either a ByteString or a String. It caches the last one requested |
| * which is most likely the one needed next. This minimizes memory usage while |
| * satisfying the most common use cases. |
| * <p> |
| * <strong>Note that this implementation is not synchronized.</strong> |
| * If multiple threads access an <tt>ArrayList</tt> instance concurrently, |
| * and at least one of the threads modifies the list structurally, it |
| * <i>must</i> be synchronized externally. (A structural modification is |
| * any operation that adds or deletes one or more elements, or explicitly |
| * resizes the backing array; merely setting the value of an element is not |
| * a structural modification.) This is typically accomplished by |
| * synchronizing on some object that naturally encapsulates the list. |
| * <p> |
| * If the implementation is accessed via concurrent reads, this is thread safe. |
| * Conversions are done in a thread safe manner. It's possible that the |
| * conversion may happen more than once if two threads attempt to access the |
| * same element and the modifications were not visible to each other, but this |
| * will not result in any corruption of the list or change in behavior other |
| * than performance. |
| * |
| * @author jonp@google.com (Jon Perlow) |
| */ |
| public class LazyStringArrayList extends AbstractList<String> |
| implements LazyStringList, RandomAccess { |
| |
| public final static LazyStringList EMPTY = new UnmodifiableLazyStringList( |
| new LazyStringArrayList()); |
| |
| private final List<Object> list; |
| |
| public LazyStringArrayList() { |
| list = new ArrayList<Object>(); |
| } |
| |
| public LazyStringArrayList(List<String> from) { |
| list = new ArrayList<Object>(from); |
| } |
| |
| @Override |
| public String get(int index) { |
| Object o = list.get(index); |
| if (o instanceof String) { |
| return (String) o; |
| } else { |
| ByteString bs = (ByteString) o; |
| String s = bs.toStringUtf8(); |
| if (Internal.isValidUtf8(bs)) { |
| list.set(index, s); |
| } |
| return s; |
| } |
| } |
| |
| @Override |
| public int size() { |
| return list.size(); |
| } |
| |
| @Override |
| public String set(int index, String s) { |
| Object o = list.set(index, s); |
| return asString(o); |
| } |
| |
| @Override |
| public void add(int index, String element) { |
| list.add(index, element); |
| modCount++; |
| } |
| |
| @Override |
| public boolean addAll(int index, Collection<? extends String> c) { |
| boolean ret = list.addAll(index, c); |
| modCount++; |
| return ret; |
| } |
| |
| @Override |
| public String remove(int index) { |
| Object o = list.remove(index); |
| modCount++; |
| return asString(o); |
| } |
| |
| public void clear() { |
| list.clear(); |
| modCount++; |
| } |
| |
| // @Override |
| public void add(ByteString element) { |
| list.add(element); |
| modCount++; |
| } |
| |
| // @Override |
| public ByteString getByteString(int index) { |
| Object o = list.get(index); |
| if (o instanceof String) { |
| ByteString b = ByteString.copyFromUtf8((String) o); |
| list.set(index, b); |
| return b; |
| } else { |
| return (ByteString) o; |
| } |
| } |
| |
| private String asString(Object o) { |
| if (o instanceof String) { |
| return (String) o; |
| } else { |
| return ((ByteString) o).toStringUtf8(); |
| } |
| } |
| } |