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.builder.xml; 018 019import java.util.HashMap; 020import java.util.Map; 021 022import javax.xml.namespace.QName; 023import javax.xml.xpath.XPathVariableResolver; 024 025import org.apache.camel.Exchange; 026import org.apache.camel.Message; 027import org.slf4j.Logger; 028import org.slf4j.LoggerFactory; 029 030import static org.apache.camel.builder.xml.Namespaces.ENVIRONMENT_VARIABLES; 031import static org.apache.camel.builder.xml.Namespaces.EXCHANGE_PROPERTY; 032import static org.apache.camel.builder.xml.Namespaces.IN_NAMESPACE; 033import static org.apache.camel.builder.xml.Namespaces.OUT_NAMESPACE; 034import static org.apache.camel.builder.xml.Namespaces.SYSTEM_PROPERTIES_NAMESPACE; 035 036/** 037 * A variable resolver for XPath expressions which support properties on the 038 * message, exchange as well as making system properties and environment 039 * properties available. 040 * <p/> 041 * Implementations of this resolver must be thread safe 042 * 043 * @version 044 */ 045public class MessageVariableResolver implements XPathVariableResolver { 046 private static final Logger LOG = LoggerFactory.getLogger(MessageVariableResolver.class); 047 048 private Map<String, Object> variables = new HashMap<String, Object>(); 049 private final ThreadLocal<Exchange> exchange; 050 051 public MessageVariableResolver(ThreadLocal<Exchange> exchange) { 052 this.exchange = exchange; 053 } 054 055 public Object resolveVariable(QName name) { 056 String uri = name.getNamespaceURI(); 057 String localPart = name.getLocalPart(); 058 Object answer = null; 059 060 Message in = exchange.get().getIn(); 061 if (uri == null || uri.length() == 0) { 062 answer = variables.get(localPart); 063 if (answer == null) { 064 Message message = in; 065 if (message != null) { 066 answer = message.getHeader(localPart); 067 } 068 if (answer == null) { 069 answer = exchange.get().getProperty(localPart); 070 } 071 } 072 } else if (uri.equals(SYSTEM_PROPERTIES_NAMESPACE)) { 073 try { 074 answer = System.getProperty(localPart); 075 } catch (Exception e) { 076 LOG.debug("Security exception evaluating system property: " + localPart + ". Reason: " + e, e); 077 } 078 } else if (uri.equals(ENVIRONMENT_VARIABLES)) { 079 answer = System.getenv().get(localPart); 080 } else if (uri.equals(EXCHANGE_PROPERTY)) { 081 answer = exchange.get().getProperty(localPart); 082 } else if (uri.equals(IN_NAMESPACE)) { 083 answer = in.getHeader(localPart); 084 if (answer == null && localPart.equals("body")) { 085 answer = in.getBody(); 086 } 087 } else if (uri.equals(OUT_NAMESPACE)) { 088 if (exchange.get().hasOut()) { 089 Message out = exchange.get().getOut(); 090 answer = out.getHeader(localPart); 091 if (answer == null && localPart.equals("body")) { 092 answer = out.getBody(); 093 } 094 } 095 } 096 097 // if we can't find an answer we must return an empty String. 098 // if we return null, then the JDK default XPathEngine will throw an exception 099 if (answer == null) { 100 return ""; 101 } else { 102 return answer; 103 } 104 } 105 106 public void addVariable(String localPart, Object value) { 107 variables.put(localPart, value); 108 } 109}