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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.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.TreeMap;
import java.util.concurrent.TimeUnit;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlTransient;
import org.apache.camel.CamelContext;
import org.apache.camel.Endpoint;
import org.apache.camel.Expression;
import org.apache.camel.Processor;
import org.apache.camel.RuntimeCamelException;
import org.apache.camel.processor.saga.SagaProcessorBuilder;
import org.apache.camel.saga.CamelSagaService;
import org.apache.camel.saga.CamelSagaStep;
import org.apache.camel.spi.Metadata;
import org.apache.camel.spi.RouteContext;
import org.apache.camel.util.CamelContextHelper;
import org.apache.camel.util.ObjectHelper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Enables sagas on the route
*
* @version
*/
@Metadata(label = "eip,routing")
@XmlRootElement(name = "saga")
@XmlAccessorType(XmlAccessType.FIELD)
public class SagaDefinition extends OutputDefinition {
private static final Logger LOG = LoggerFactory.getLogger(SagaDefinition.class);
@XmlAttribute
@Metadata(defaultValue = "REQUIRED")
private SagaPropagation propagation;
@XmlAttribute
@Metadata(defaultValue = "AUTO")
private SagaCompletionMode completionMode;
@XmlAttribute
private Long timeoutInMilliseconds;
@XmlElement
private SagaActionUriDefinition compensation;
@XmlElement
private SagaActionUriDefinition completion;
@XmlElement(name = "option")
private List options;
@XmlTransient
private CamelSagaService sagaService; // TODO add ref for xml configuration
public SagaDefinition() {
}
@Override
public Processor createProcessor(RouteContext routeContext) throws Exception {
Optional compensationEndpoint = Optional.ofNullable(this.compensation)
.map(SagaActionUriDefinition::getUri)
.map(routeContext::resolveEndpoint);
Optional completionEndpoint = Optional.ofNullable(this.completion)
.map(SagaActionUriDefinition::getUri)
.map(routeContext::resolveEndpoint);
Map optionsMap = new TreeMap<>();
if (this.options != null) {
for (SagaOptionDefinition optionDef : this.options) {
String optionName = optionDef.getOptionName();
Expression expr = optionDef.getExpression();
optionsMap.put(optionName, expr);
}
}
CamelSagaStep step = new CamelSagaStep(compensationEndpoint, completionEndpoint, optionsMap, Optional.ofNullable(timeoutInMilliseconds));
SagaPropagation propagation = this.propagation;
if (propagation == null) {
// default propagation mode
propagation = SagaPropagation.REQUIRED;
}
SagaCompletionMode completionMode = this.completionMode;
if (completionMode == null) {
// default completion mode
completionMode = SagaCompletionMode.defaultCompletionMode();
}
Processor childProcessor = this.createChildProcessor(routeContext, true);
CamelSagaService camelSagaService = findSagaService(routeContext.getCamelContext());
camelSagaService.registerStep(step);
return new SagaProcessorBuilder()
.camelContext(routeContext.getCamelContext())
.childProcessor(childProcessor)
.sagaService(camelSagaService)
.step(step)
.propagation(propagation)
.completionMode(completionMode)
.build();
}
@Override
public boolean isAbstract() {
return true;
}
@Override
public boolean isTopLevelOnly() {
return true;
}
@Override
public boolean isWrappingEntireOutput() {
return true;
}
@Override
public String getLabel() {
String desc = description();
if (ObjectHelper.isEmpty(desc)) {
return "saga";
} else {
return "saga[" + desc + "]";
}
}
@Override
public String toString() {
String desc = description();
if (ObjectHelper.isEmpty(desc)) {
return "Saga -> [" + outputs + "]";
} else {
return "Saga[" + desc + "] -> [" + outputs + "]";
}
}
// Properties
public SagaActionUriDefinition getCompensation() {
return compensation;
}
/**
* The compensation endpoint URI that must be called to compensate all changes done in the route.
* The route corresponding to the compensation URI must perform compensation and complete without error.
*
* If errors occur during compensation, the saga service may call again the compensation URI to retry.
*/
public void setCompensation(SagaActionUriDefinition compensation) {
this.compensation = compensation;
}
public SagaActionUriDefinition getCompletion() {
return completion;
}
/**
* The completion endpoint URI that will be called when the Saga is completed successfully.
* The route corresponding to the completion URI must perform completion tasks and terminate without error.
*
* If errors occur during completion, the saga service may call again the completion URI to retry.
*/
public void setCompletion(SagaActionUriDefinition completion) {
this.completion = completion;
}
public SagaPropagation getPropagation() {
return propagation;
}
/**
* Set the Saga propagation mode (REQUIRED, REQUIRES_NEW, MANDATORY, SUPPORTS, NOT_SUPPORTED, NEVER).
*/
public void setPropagation(SagaPropagation propagation) {
this.propagation = propagation;
}
public SagaCompletionMode getCompletionMode() {
return completionMode;
}
/**
* Determine how the saga should be considered complete. When set to AUTO, the saga is completed when the exchange that
* initiates the saga is processed successfully, or compensated when it completes exceptionally.
*
* When set to MANUAL, the user must complete or compensate the saga using the "saga:complete" or "saga:compensate" endpoints.
*/
public void setCompletionMode(SagaCompletionMode completionMode) {
this.completionMode = completionMode;
}
public CamelSagaService getSagaService() {
return sagaService;
}
public void setSagaService(CamelSagaService sagaService) {
this.sagaService = sagaService;
}
public List getOptions() {
return options;
}
/**
* Allows to save properties of the current exchange in order to re-use them in a compensation/completion callback route.
* Options are usually helpful e.g. to store and retrieve identifiers of objects that should be deleted in compensating actions.
*
* Option values will be transformed into input headers of the compensation/completion exchange.
*/
public void setOptions(List options) {
this.options = options;
}
public Long getTimeoutInMilliseconds() {
return timeoutInMilliseconds;
}
/**
* Set the maximum amount of time for the Saga. After the timeout is expired, the saga will be compensated
* automatically (unless a different decision has been taken in the meantime).
*/
public void setTimeoutInMilliseconds(Long timeoutInMilliseconds) {
this.timeoutInMilliseconds = timeoutInMilliseconds;
}
private void addOption(String option, Expression expression) {
if (this.options == null) {
this.options = new ArrayList<>();
}
this.options.add(new SagaOptionDefinition(option, expression));
}
// Builders
public SagaDefinition compensation(String compensation) {
if (this.compensation != null) {
throw new IllegalStateException("Compensation has already been set");
}
this.compensation = new SagaActionUriDefinition(compensation);
return this;
}
public SagaDefinition completion(String completion) {
if (this.completion != null) {
throw new IllegalStateException("Completion has already been set");
}
this.completion = new SagaActionUriDefinition(completion);
return this;
}
public SagaDefinition propagation(SagaPropagation propagation) {
setPropagation(propagation);
return this;
}
public SagaDefinition sagaService(CamelSagaService sagaService) {
setSagaService(sagaService);
return this;
}
public SagaDefinition completionMode(SagaCompletionMode completionMode) {
setCompletionMode(completionMode);
return this;
}
public SagaDefinition option(String option, Expression expression) {
addOption(option, expression);
return this;
}
public SagaDefinition timeout(long timeout, TimeUnit unit) {
setTimeoutInMilliseconds(unit.toMillis(timeout));
return this;
}
// Utils
protected CamelSagaService findSagaService(CamelContext context) {
CamelSagaService sagaService = getSagaService();
if (sagaService != null) {
return sagaService;
}
sagaService = context.hasService(CamelSagaService.class);
if (sagaService != null) {
return sagaService;
}
sagaService = CamelContextHelper.findByType(context, CamelSagaService.class);
if (sagaService != null) {
return sagaService;
}
throw new RuntimeCamelException("Cannot find a CamelSagaService");
}
protected String description() {
StringBuilder desc = new StringBuilder();
addField(desc, "compensation", compensation);
addField(desc, "completion", completion);
addField(desc, "propagation", propagation);
return desc.toString();
}
private void addField(StringBuilder builder, String key, Object value) {
if (value == null) {
return;
}
if (builder.length() > 0) {
builder.append(',');
}
builder.append(key).append(':').append(value);
}
}