SequenceFlowObserversLoader.java
/**
* Copyright (c) 2023, WSO2 LLC. (http://www.wso2.org) All Rights Reserved.
*
* WSO2 LLC. licenses this file to you under the Apache License,
* Version 2.0 (the "License"); you may not use this file except
* in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
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package org.apache.synapse.config;
import org.apache.axiom.om.OMElement;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.synapse.SequenceFlowObserver;
import org.apache.synapse.SynapseConstants;
import org.apache.synapse.SynapseException;
import org.apache.synapse.commons.util.MiscellaneousUtil;
import javax.xml.namespace.QName;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
public class SequenceFlowObserversLoader {
private static final QName ROOT_Q = new QName("observers");
private static final QName OBSERVER_Q = new QName("observer");
private static final QName CLASS_Q = new QName("class");
private static final QName NAME_ATT = new QName("name");
private static Log log = LogFactory.getLog(SequenceFlowObserversLoader.class);
public static List<SequenceFlowObserver> loadObservers() {
List<SequenceFlowObserver> observers = new ArrayList<>();
OMElement observersConfig =
MiscellaneousUtil.loadXMLConfig(SynapseConstants.SEQUENCE_OBSERVERS_FILE);
if (observersConfig != null) {
if (!ROOT_Q.equals(observersConfig.getQName())) {
handleException("Invalid sequence observer configuration file");
}
Iterator iterator = observersConfig.getChildrenWithName(OBSERVER_Q);
while (iterator.hasNext()) {
OMElement observerElem = (OMElement) iterator.next();
String name = null;
if (observerElem.getAttribute(NAME_ATT) != null) {
name = observerElem.getAttributeValue(NAME_ATT);
} else {
handleException("Name not defined in one or more sequence observer");
}
if (observerElem.getAttribute(CLASS_Q) != null) {
String className = observerElem.getAttributeValue(CLASS_Q);
if (StringUtils.isNotBlank(className)) {
SequenceFlowObserver observer = createObserver(className);
if (observer != null) {
observers.add(observer);
observer.setName(name);
}
} else {
handleException("Class name is null for sequence observer name : " + name);
}
} else {
handleException("Class name not defined for sequence observer named : " + name);
}
}
}
return observers;
}
private static SequenceFlowObserver createObserver(String classFQName) {
Object obj = null;
try {
obj = Class.forName(classFQName).newInstance();
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException e) {
handleException("Error creating Sequence observer for class name : " + classFQName, e);
}
if (obj instanceof SequenceFlowObserver) {
return (SequenceFlowObserver) obj;
} else {
handleException("Error creating Sequence observer. The Sequence observer should be of type " +
"org.apache.synapse.SequenceFlowObserver");
}
return null;
}
private static void handleException(String msg) {
log.error(msg);
throw new SynapseException(msg);
}
private static void handleException(String msg, Exception ex) {
log.error(msg, ex);
throw new SynapseException(msg, ex);
}
}