001/** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.camel; 018 019 020/** 021 * A pluggable strategy to be able to convert objects <a 022 * href="http://camel.apache.org/type-converter.html">to different 023 * types</a> such as to and from String, InputStream/OutputStream, 024 * Reader/Writer, Document, byte[], ByteBuffer etc 025 */ 026public interface TypeConverter { 027 028 Object MISS_VALUE = Void.TYPE; 029 030 /** 031 * Whether the type converter allows returning null as a valid response. 032 * <p/> 033 * By default <tt>null</tt> is not a valid response, returning <tt>false</tt> from this method. 034 */ 035 boolean allowNull(); 036 037 /** 038 * Converts the value to the specified type 039 * 040 * @param type the requested type 041 * @param value the value to be converted 042 * @return the converted value, or <tt>null</tt> if not possible to convert 043 * @throws TypeConversionException is thrown if error during type conversion 044 */ 045 <T> T convertTo(Class<T> type, Object value) throws TypeConversionException; 046 047 /** 048 * Converts the value to the specified type in the context of an exchange 049 * <p/> 050 * Used when conversion requires extra information from the current 051 * exchange (such as encoding). 052 * 053 * @param type the requested type 054 * @param exchange the current exchange 055 * @param value the value to be converted 056 * @return the converted value, or <tt>null</tt> if not possible to convert 057 * @throws TypeConversionException is thrown if error during type conversion 058 */ 059 <T> T convertTo(Class<T> type, Exchange exchange, Object value) throws TypeConversionException; 060 061 /** 062 * Converts the value to the specified type 063 * 064 * @param type the requested type 065 * @param value the value to be converted 066 * @return the converted value, is never <tt>null</tt> 067 * @throws TypeConversionException is thrown if error during type conversion 068 * @throws NoTypeConversionAvailableException if no type converters exists to convert to the given type 069 */ 070 <T> T mandatoryConvertTo(Class<T> type, Object value) throws TypeConversionException, NoTypeConversionAvailableException; 071 072 /** 073 * Converts the value to the specified type in the context of an exchange 074 * <p/> 075 * Used when conversion requires extra information from the current 076 * exchange (such as encoding). 077 * 078 * @param type the requested type 079 * @param exchange the current exchange 080 * @param value the value to be converted 081 * @return the converted value, is never <tt>null</tt> 082 * @throws TypeConversionException is thrown if error during type conversion 083 * @throws NoTypeConversionAvailableException if no type converters exists to convert to the given type 084 */ 085 <T> T mandatoryConvertTo(Class<T> type, Exchange exchange, Object value) throws TypeConversionException, NoTypeConversionAvailableException; 086 087 /** 088 * Tries to convert the value to the specified type, 089 * returning <tt>null</tt> if not possible to convert. 090 * <p/> 091 * This method will <b>not</b> throw an exception if an exception occurred during conversion. 092 * 093 * @param type the requested type 094 * @param value the value to be converted 095 * @return the converted value, or <tt>null</tt> if not possible to convert 096 */ 097 <T> T tryConvertTo(Class<T> type, Object value); 098 099 /** 100 * Tries to convert the value to the specified type in the context of an exchange, 101 * returning <tt>null</tt> if not possible to convert. 102 * <p/> 103 * This method will <b>not</b> throw an exception if an exception occurred during conversion. 104 * Converts the value to the specified type in the context of an exchange 105 * <p/> 106 * Used when conversion requires extra information from the current 107 * exchange (such as encoding). 108 * 109 * @param type the requested type 110 * @param exchange the current exchange 111 * @param value the value to be converted 112 * @return the converted value, or <tt>null</tt> if not possible to convert 113 */ 114 <T> T tryConvertTo(Class<T> type, Exchange exchange, Object value); 115 116}