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 */ 017 package org.apache.camel; 018 019 import java.util.ArrayList; 020 import java.util.HashMap; 021 import java.util.List; 022 import java.util.Map; 023 024 /** 025 * Represents an instance and a type safe registry of well known Camel Exchange properties. 026 * <p/> 027 * <b>Usage pattern:</b> 028 * <br/>In your code register a property that you wish to pass via Camel Exchange: 029 * <pre> 030 * public static final ExchangeProperty<Boolean> myProperty = 031 * new ExchangeProperty<Boolean>("myProperty", "org.apache.myproject.mypackage.myproperty", Boolean.class); 032 * 033 * Then in your code set this property's value: 034 * myProperty.set(exchange, Boolean.TRUE); 035 * 036 * Check the value of this property where required: 037 * ExchangeProperty<?> property = ExchangeProperty.get("myProperty"); 038 * if (property != null && property.get(exchange) == Boolean.TRUE) { 039 * // do your thing ... 040 * } 041 * Or 042 * Boolean value = myProperty.get(exchange); 043 * if (value == Boolean.TRUE) { 044 * // do your thing 045 * } 046 * 047 * When your code no longer requires this property then deregister it: 048 * ExchangeProperty.deregister(myProperty); 049 * Or 050 * ExchangeProperty.deregister("myProperty"); 051 * </pre> 052 * 053 * <b>Note:</b> that if ExchangeProperty instance get or set methods are used then type checks 054 * of property's value are performed and a runtime exception can be thrown if type 055 * safety is violated. 056 */ 057 public class ExchangeProperty<T> { 058 059 private static final List<ExchangeProperty<?>> VALUES = 060 new ArrayList<ExchangeProperty<?>>(); 061 062 private static final Map<String, ExchangeProperty<?>> LITERAL_MAP = 063 new HashMap<String, ExchangeProperty<?>>(); 064 065 private static final Map<String, ExchangeProperty<?>> NAME_MAP = 066 new HashMap<String, ExchangeProperty<?>>(); 067 068 private final String literal; 069 private final String name; 070 private final Class<T> type; 071 072 public ExchangeProperty(String literal, String name, Class<T> type) { 073 this.literal = literal; 074 this.name = name; 075 this.type = type; 076 register(this); 077 } 078 079 public String literal() { 080 return literal; 081 } 082 083 public String name() { 084 return name; 085 } 086 087 public Class<T> type() { 088 return type; 089 } 090 091 public T get(Exchange exchange) { 092 return exchange.getProperty(name, type); 093 } 094 095 public static ExchangeProperty<?> get(String literal) { 096 return LITERAL_MAP.get(literal); 097 } 098 099 public static ExchangeProperty<?> getByName(String name) { 100 return NAME_MAP.get(name); 101 } 102 103 public T set(Exchange exchange, T value) { 104 T oldValue = get(exchange); 105 exchange.setProperty(name, value); 106 return oldValue; 107 } 108 109 public T remove(Exchange exchange) { 110 T oldValue = get(exchange); 111 exchange.removeProperty(name); 112 return oldValue; 113 } 114 115 @Override 116 public String toString() { 117 return type().getCanonicalName() + " " + name + " (" + literal() + ")"; 118 } 119 120 public static synchronized void register(ExchangeProperty<?> property) { 121 ExchangeProperty<?> existingProperty = LITERAL_MAP.get(property.literal()); 122 if (existingProperty != null && existingProperty != property) { 123 throw new RuntimeCamelException("An Exchange Property '" + property.literal() 124 + "' has already been registered; its traits are: " + existingProperty.toString()); 125 } 126 VALUES.add(property); 127 LITERAL_MAP.put(property.literal(), property); 128 NAME_MAP.put(property.name(), property); 129 } 130 131 public static synchronized void deregister(ExchangeProperty<?> property) { 132 if (property != null) { 133 VALUES.remove(property); 134 LITERAL_MAP.remove(property.literal()); 135 NAME_MAP.put(property.name(), property); 136 } 137 } 138 139 public static synchronized void deregister(String literal) { 140 ExchangeProperty<?> property = LITERAL_MAP.get(literal); 141 if (property != null) { 142 VALUES.remove(property); 143 LITERAL_MAP.remove(property.literal()); 144 NAME_MAP.put(property.name(), property); 145 } 146 } 147 148 public static synchronized ExchangeProperty<?>[] values() { 149 return VALUES.toArray(new ExchangeProperty[0]); 150 } 151 152 }