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The Core Camel Java DSL based router
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.camel.model;
import java.lang.reflect.Method;
import java.util.Map;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlTransient;
import org.apache.camel.NoSuchBeanException;
import org.apache.camel.Processor;
import org.apache.camel.RuntimeCamelException;
import org.apache.camel.Service;
import org.apache.camel.processor.WrapProcessor;
import org.apache.camel.spi.Metadata;
import org.apache.camel.spi.Policy;
import org.apache.camel.spi.RouteContext;
import org.apache.camel.spi.TransactedPolicy;
import org.apache.camel.util.CamelContextHelper;
import org.apache.camel.util.ObjectHelper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Enables transaction on the route
*
* @version
*/
@Metadata(label = "configuration")
@XmlRootElement(name = "transacted")
@XmlAccessorType(XmlAccessType.FIELD)
public class TransactedDefinition extends OutputDefinition {
// TODO: Align this code with PolicyDefinition
// JAXB does not support changing the ref attribute from required to optional
// if we extend PolicyDefinition so we must make a copy of the class
@XmlTransient
public static final String PROPAGATION_REQUIRED = "PROPAGATION_REQUIRED";
private static final Logger LOG = LoggerFactory.getLogger(TransactedDefinition.class);
@XmlTransient
protected Class type = TransactedPolicy.class;
@XmlAttribute
protected String ref;
@XmlTransient
private Policy policy;
public TransactedDefinition() {
}
public TransactedDefinition(Policy policy) {
this.policy = policy;
}
@Override
public String toString() {
return "Transacted[" + description() + "]";
}
protected String description() {
if (ref != null) {
return "ref:" + ref;
} else if (policy != null) {
return policy.toString();
} else {
return "";
}
}
@Override
public String getLabel() {
return "transacted[" + description() + "]";
}
@Override
public boolean isAbstract() {
return true;
}
@Override
public boolean isTopLevelOnly() {
// transacted is top level as we only allow have it configured once per route
return true;
}
public String getRef() {
return ref;
}
public void setRef(String ref) {
this.ref = ref;
}
/**
* Sets a policy type that this definition should scope within.
*
* Is used for convention over configuration situations where the policy
* should be automatic looked up in the registry and it should be based
* on this type. For instance a {@link org.apache.camel.spi.TransactedPolicy}
* can be set as type for easy transaction configuration.
*
* Will by default scope to the wide {@link Policy}
*
* @param type the policy type
*/
public void setType(Class type) {
this.type = type;
}
/**
* Sets a reference to use for lookup the policy in the registry.
*
* @param ref the reference
* @return the builder
*/
public TransactedDefinition ref(String ref) {
setRef(ref);
return this;
}
@Override
public Processor createProcessor(RouteContext routeContext) throws Exception {
Policy policy = resolvePolicy(routeContext);
ObjectHelper.notNull(policy, "policy", this);
// before wrap
policy.beforeWrap(routeContext, this);
// create processor after the before wrap
Processor childProcessor = this.createChildProcessor(routeContext, true);
// wrap
Processor target = policy.wrap(routeContext, childProcessor);
if (!(target instanceof Service)) {
// wrap the target so it becomes a service and we can manage its lifecycle
target = new WrapProcessor(target, childProcessor);
}
return target;
}
protected Policy resolvePolicy(RouteContext routeContext) {
if (policy != null) {
return policy;
}
return doResolvePolicy(routeContext, getRef(), type);
}
protected static Policy doResolvePolicy(RouteContext routeContext, String ref, Class type) {
// explicit ref given so lookup by it
if (ObjectHelper.isNotEmpty(ref)) {
return CamelContextHelper.mandatoryLookup(routeContext.getCamelContext(), ref, Policy.class);
}
// no explicit reference given from user so we can use some convention over configuration here
// try to lookup by scoped type
Policy answer = null;
if (type != null) {
// try find by type, note that this method is not supported by all registry
Map types = routeContext.lookupByType(type);
if (types.size() == 1) {
// only one policy defined so use it
Object found = types.values().iterator().next();
if (type.isInstance(found)) {
return type.cast(found);
}
}
}
// for transacted routing try the default REQUIRED name
if (type == TransactedPolicy.class) {
// still not found try with the default name PROPAGATION_REQUIRED
answer = routeContext.lookup(PROPAGATION_REQUIRED, TransactedPolicy.class);
}
// this logic only applies if we are a transacted policy
// still no policy found then try lookup the platform transaction manager and use it as policy
if (answer == null && type == TransactedPolicy.class) {
Class tmClazz = routeContext.getCamelContext().getClassResolver().resolveClass("org.springframework.transaction.PlatformTransactionManager");
if (tmClazz != null) {
// see if we can find the platform transaction manager in the registry
Map maps = routeContext.lookupByType(tmClazz);
if (maps.size() == 1) {
// only one platform manager then use it as default and create a transacted
// policy with it and default to required
// as we do not want dependency on spring jars in the camel-core we use
// reflection to lookup classes and create new objects and call methods
// as this is only done during route building it does not matter that we
// use reflection as performance is no a concern during route building
Object transactionManager = maps.values().iterator().next();
LOG.debug("One instance of PlatformTransactionManager found in registry: {}", transactionManager);
Class txClazz = routeContext.getCamelContext().getClassResolver().resolveClass("org.apache.camel.spring.spi.SpringTransactionPolicy");
if (txClazz != null) {
LOG.debug("Creating a new temporary SpringTransactionPolicy using the PlatformTransactionManager: {}", transactionManager);
TransactedPolicy txPolicy = ObjectHelper.newInstance(txClazz, TransactedPolicy.class);
Method method;
try {
method = txClazz.getMethod("setTransactionManager", tmClazz);
} catch (NoSuchMethodException e) {
throw new RuntimeCamelException("Cannot get method setTransactionManager(PlatformTransactionManager) on class: " + txClazz);
}
ObjectHelper.invokeMethod(method, txPolicy, transactionManager);
return txPolicy;
} else {
// camel-spring is missing on the classpath
throw new RuntimeCamelException("Cannot create a transacted policy as camel-spring.jar is not on the classpath!");
}
} else {
if (maps.isEmpty()) {
throw new NoSuchBeanException(null, "PlatformTransactionManager");
} else {
throw new IllegalArgumentException("Found " + maps.size() + " PlatformTransactionManager in registry. "
+ "Cannot determine which one to use. Please configure a TransactionTemplate on the transacted policy.");
}
}
}
}
return answer;
}
}