1 // Protocol Buffers - Google's data interchange format 2 // Copyright 2008 Google Inc. All rights reserved. 3 // https://developers.google.com/protocol-buffers/ 4 // 5 // Redistribution and use in source and binary forms, with or without 6 // modification, are permitted provided that the following conditions are 7 // met: 8 // 9 // * Redistributions of source code must retain the above copyright 10 // notice, this list of conditions and the following disclaimer. 11 // * Redistributions in binary form must reproduce the above 12 // copyright notice, this list of conditions and the following disclaimer 13 // in the documentation and/or other materials provided with the 14 // distribution. 15 // * Neither the name of Google Inc. nor the names of its 16 // contributors may be used to endorse or promote products derived from 17 // this software without specific prior written permission. 18 // 19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 21 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 22 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 23 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 24 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 25 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 29 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 31 package com.google.protobuf; 32 33 /** Parsers to discard unknown fields during parsing. */ 34 public final class DiscardUnknownFieldsParser { 35 36 /** 37 * Warps a given {@link Parser} into a new {@link Parser} that discards unknown fields during 38 * parsing. 39 * 40 * <p>Usage example: 41 * 42 * <pre>{@code 43 * private final static Parser<Foo> FOO_PARSER = DiscardUnknownFieldsParser.wrap(Foo.parser()); 44 * Foo parseFooDiscardUnknown(ByteBuffer input) throws IOException { 45 * return FOO_PARSER.parseFrom(input); 46 * } 47 * }</pre> 48 * 49 * <p>Like all other implementations of {@code Parser}, this parser is stateless and thread-safe. 50 * 51 * @param parser The delegated parser that parses messages. 52 * @return a {@link Parser} that will discard unknown fields during parsing. 53 */ wrap(final Parser<T> parser)54 public static final <T extends Message> Parser<T> wrap(final Parser<T> parser) { 55 return new AbstractParser<T>() { 56 @Override 57 public T parsePartialFrom(CodedInputStream input, ExtensionRegistryLite extensionRegistry) 58 throws InvalidProtocolBufferException { 59 try { 60 input.discardUnknownFields(); 61 return parser.parsePartialFrom(input, extensionRegistry); 62 } finally { 63 input.unsetDiscardUnknownFields(); 64 } 65 } 66 }; 67 } 68 69 private DiscardUnknownFieldsParser() {} 70 } 71