StreamInterceptorsLoader.java
/*
* Copyright (c) 2021, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
*
* WSO2 Inc. 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.
*/
package org.apache.synapse.transport.passthru.util;
import org.apache.axiom.om.OMElement;
import org.apache.axiom.om.OMNode;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.synapse.commons.util.MiscellaneousUtil;
import org.apache.synapse.commons.util.PropertyHelper;
import org.apache.synapse.transport.passthru.StreamInterceptor;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import javax.xml.namespace.QName;
public class StreamInterceptorsLoader {
StreamInterceptorsLoader() {
}
private static Log log = LogFactory.getLog(StreamInterceptorsLoader.class);
private static final QName ROOT_Q = new QName("interceptors");
private static final QName INTERCEPTOR_Q = new QName("interceptor");
private static final QName CLASS_Q = new QName("class");
private static final QName NAME_ATT = new QName("name");
private static final QName PARAM_Q = new QName("parameter");
private static final QName VALUE_ATT = new QName("value");
private static List<StreamInterceptor> interceptors = new ArrayList<>();
private static boolean isLoadedAlready = false;
private static Lock lock = new ReentrantLock();
/**
* Load and get all synapse interceptors
*
* @return List of loaded synapse interceptors
*/
public static List<StreamInterceptor> getInterceptors() {
if (!isLoadedAlready) {
try {
lock.lock();
if (!isLoadedAlready) {
loadInterceptors();
isLoadedAlready = true;
}
} finally {
lock.unlock();
}
}
return Collections.unmodifiableList(interceptors);
}
private static void loadInterceptors() {
OMElement interceptorsConfig = MiscellaneousUtil.loadXMLConfig(RelayConstants.STREAM_INTERCEPTOR_FILE, false);
if (interceptorsConfig != null) {
if (!ROOT_Q.equals(interceptorsConfig.getQName())) {
handleException("Invalid interceptor configuration file");
}
Iterator iterator = interceptorsConfig.getChildrenWithName(INTERCEPTOR_Q);
while (iterator.hasNext()) {
OMElement interceptorElem = (OMElement) iterator.next();
if (interceptorElem.getAttribute(CLASS_Q) != null) {
String className = interceptorElem.getAttributeValue(CLASS_Q);
if (!"".equals(className)) {
StreamInterceptor interceptor = createInterceptor(className);
interceptors.add(interceptor);
populateParameters(interceptorElem, interceptor);
} else {
handleException("Class name is one or more interceptor");
}
} else {
handleException("Class name is one or more interceptor");
}
}
}
}
private static StreamInterceptor createInterceptor(String classFQName) {
Object obj = null;
try {
obj = Class.forName(classFQName).newInstance();
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException e) {
handleException("Error creating Interceptor for class name : " + classFQName, e);
}
if (obj instanceof StreamInterceptor) {
return (StreamInterceptor) obj;
} else {
handleException(
"Error creating StreamInterceptor. The Interceptor should be of type org.apache.synapse.transport.passthru.StreamInterceptor");
}
return null;
}
private static void populateParameters(OMElement handlerElem, StreamInterceptor interceptor) {
for (Iterator it = handlerElem.getChildrenWithName(PARAM_Q); it.hasNext(); ) {
OMElement child = (OMElement) it.next();
String propName = child.getAttribute(NAME_ATT).getAttributeValue();
if (propName == null) {
handleException("StreamInterceptor parameter must contain the name attribute");
} else {
if (child.getAttribute(VALUE_ATT) != null) {
String value = child.getAttribute(VALUE_ATT).getAttributeValue();
interceptor.addProperty(propName, value);
PropertyHelper.setInstanceProperty(propName, value, interceptor);
} else {
OMNode omElt = child.getFirstElement();
if (omElt != null) {
interceptor.addProperty(propName, omElt);
PropertyHelper.setInstanceProperty(propName, omElt, interceptor);
} else {
handleException(
"StreamInterceptor parameter must contain name and value attributes, or a name and a child XML fragment");
}
}
}
}
}
private static void handleException(String msg) {
log.error(msg);
throw new RuntimeException(msg);
}
private static void handleException(String msg, Exception ex) {
log.error(msg, ex);
throw new RuntimeException(msg, ex);
}
}