001/**************************************************************** 002 * Licensed to the Apache Software Foundation (ASF) under one * 003 * or more contributor license agreements. See the NOTICE file * 004 * distributed with this work for additional information * 005 * regarding copyright ownership. The ASF licenses this file * 006 * to you under the Apache License, Version 2.0 (the * 007 * "License"); you may not use this file except in compliance * 008 * with the License. You may obtain a copy of the License at * 009 * * 010 * http://www.apache.org/licenses/LICENSE-2.0 * 011 * * 012 * Unless required by applicable law or agreed to in writing, * 013 * software distributed under the License is distributed on an * 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * 015 * KIND, either express or implied. See the License for the * 016 * specific language governing permissions and limitations * 017 * under the License. * 018 ****************************************************************/ 019 020package org.apache.james.mime4j.stream; 021 022import org.apache.james.mime4j.MimeException; 023import org.apache.james.mime4j.util.ByteArrayBuffer; 024 025/** 026 * Field builders are intended to construct {@link RawField} instances from multiple lines 027 * contained in {@link ByteArrayBuffer}s. 028 * <p/> 029 * Field builders are stateful and modal as they have to store intermediate results between 030 * method invocations and also rely on a particular sequence of method invocations 031 * (the mode of operation). 032 * <p/> 033 * Consumers are expected to interact with field builder in the following way: 034 * <ul> 035 * <li>Invoke {@link #reset()} method in order to reset builder's internal state and make it 036 * ready to start the process of building a new {@link RawField}.</li> 037 * <li>Invoke {@link #append(ByteArrayBuffer)} method one or multiple times in order to build 038 * an internal representation of a MIME field from individual lines of text.</li> 039 * <li>Optionally {@link #getRaw()} method can be invoked in order to get combined content 040 * of all lines processed so far. Please note builder implementations can return 041 * <code>null</code> if they do not retain original raw content.</li> 042 * <li>Invoke {@link #build()} method in order to generate a {@link RawField} instance 043 * based on the internal state of the builder.</li> 044 * </ul> 045 */ 046public interface FieldBuilder { 047 048 /** 049 * Resets the internal state of the builder making it ready to process new input. 050 */ 051 void reset(); 052 053 /** 054 * Updates builder's internal state by adding a new line of text. 055 */ 056 void append(ByteArrayBuffer line) throws MimeException; 057 058 /** 059 * Builds an instance of {@link RawField} based on the internal state. 060 */ 061 RawField build() throws MimeException; 062 063 /** 064 * Returns combined content of all lines processed so far or <code>null</code> 065 * if the builder does not retain original raw content. 066 */ 067 ByteArrayBuffer getRaw(); 068 069}