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.builder.xml;
018
019 import java.util.HashMap;
020 import java.util.Map;
021
022 import javax.xml.namespace.QName;
023 import javax.xml.xpath.XPathVariableResolver;
024
025 import org.apache.camel.Exchange;
026 import org.apache.camel.Message;
027 import org.apache.commons.logging.Log;
028 import org.apache.commons.logging.LogFactory;
029
030 import static org.apache.camel.builder.xml.Namespaces.ENVIRONMENT_VARIABLES;
031 import static org.apache.camel.builder.xml.Namespaces.EXCHANGE_PROPERTY;
032 import static org.apache.camel.builder.xml.Namespaces.IN_NAMESPACE;
033 import static org.apache.camel.builder.xml.Namespaces.OUT_NAMESPACE;
034 import 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 * messge, exchange as well as making system properties and environment
039 * properties available.
040 *
041 * @version $Revision: 697361 $
042 */
043 public class MessageVariableResolver implements XPathVariableResolver {
044 private static final transient Log LOG = LogFactory.getLog(MessageVariableResolver.class);
045
046 private Exchange exchange;
047 private Map<String, Object> variables = new HashMap<String, Object>();
048
049 public Exchange getExchange() {
050 return exchange;
051 }
052
053 public void setExchange(Exchange exchange) {
054 this.exchange = exchange;
055 }
056
057 public Object resolveVariable(QName name) {
058 String uri = name.getNamespaceURI();
059 String localPart = name.getLocalPart();
060 Object answer = null;
061
062 Message in = exchange.getIn();
063 if (uri == null || uri.length() == 0) {
064 answer = variables.get(localPart);
065 if (answer == null) {
066 Message message = in;
067 if (message != null) {
068 answer = message.getHeader(localPart);
069 }
070 if (answer == null) {
071 answer = exchange.getProperty(localPart);
072 }
073 }
074 } else if (uri.equals(SYSTEM_PROPERTIES_NAMESPACE)) {
075 try {
076 answer = System.getProperty(localPart);
077 } catch (Exception e) {
078 LOG.debug("Security exception evaluating system property: " + localPart
079 + ". Reason: " + e, e);
080 }
081 } else if (uri.equals(ENVIRONMENT_VARIABLES)) {
082 answer = System.getenv().get(localPart);
083 } else if (uri.equals(EXCHANGE_PROPERTY)) {
084 answer = exchange.getProperty(localPart);
085 } else if (uri.equals(IN_NAMESPACE)) {
086 answer = in.getHeader(localPart);
087 if (answer == null && localPart.equals("body")) {
088 answer = in.getBody();
089 }
090 } else if (uri.equals(OUT_NAMESPACE)) {
091 Message out = exchange.getOut(false);
092 if (out != null) {
093 answer = out.getHeader(localPart);
094 if (answer == null && localPart.equals("body")) {
095 answer = out.getBody();
096 }
097 }
098 }
099
100 // If we can't find an answer we must return void.
101 // We can't return null then the xpath engine will throw a NullPointerException
102 if (answer == null) {
103 return Void.class;
104 } else {
105 return answer;
106 }
107 }
108
109 public void addVariable(String localPart, Object value) {
110 variables.put(localPart, value);
111 }
112 }