/**
* 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.util.component;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.camel.AsyncCallback;
import org.apache.camel.Exchange;
import org.apache.camel.RuntimeCamelException;
import org.apache.camel.impl.DefaultAsyncProducer;
import org.apache.camel.util.ObjectHelper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Base class for API based Producers
*/
public abstract class AbstractApiProducer<E extends Enum<E> & ApiName, T>
extends DefaultAsyncProducer implements PropertiesInterceptor, ResultInterceptor {
// API Endpoint
protected final AbstractApiEndpoint<E, T> endpoint;
// properties helper
protected final ApiMethodPropertiesHelper<T> propertiesHelper;
// method helper
protected final ApiMethodHelper<?> methodHelper;
// logger
private final transient Logger log = LoggerFactory.getLogger(getClass());
public AbstractApiProducer(AbstractApiEndpoint<E, T> endpoint, ApiMethodPropertiesHelper<T> propertiesHelper) {
super(endpoint);
this.propertiesHelper = propertiesHelper;
this.endpoint = endpoint;
this.methodHelper = endpoint.getMethodHelper();
}
@Override
public boolean process(final Exchange exchange, final AsyncCallback callback) {
// properties for method arguments
final Map<String, Object> properties = new HashMap<String, Object>();
properties.putAll(endpoint.getEndpointProperties());
propertiesHelper.getExchangeProperties(exchange, properties);
// let the endpoint and the Producer intercept properties
endpoint.interceptProperties(properties);
interceptProperties(properties);
// decide which method to invoke
final ApiMethod method = findMethod(exchange, properties);
if (method == null) {
// synchronous failure
callback.done(true);
return true;
}
// create a runnable invocation task to be submitted on a background thread pool
// this way we avoid blocking the current thread for long running methods
Runnable invocation = new Runnable() {
@Override
public void run() {
try {
if (log.isDebugEnabled()) {
log.debug("Invoking operation {} with {}", method.getName(), properties.keySet());
}
Object result = doInvokeMethod(method, properties);
// producer returns a single response, even for methods with List return types
exchange.getOut().setBody(result);
// copy headers
exchange.getOut().setHeaders(exchange.getIn().getHeaders());
interceptResult(result, exchange);
} catch (Throwable t) {
exchange.setException(ObjectHelper.wrapRuntimeCamelException(t));
} finally {
callback.done(false);
}
}
};
endpoint.getExecutorService().submit(invocation);
return false;
}
@Override
public void interceptProperties(Map<String, Object> properties) {
// do nothing by default
}
/**
* Invoke the API method. Derived classes can override, but MUST call super.doInvokeMethod().
* @param method API method to invoke.
* @param properties method arguments from endpoint properties and exchange In headers.
* @return API method invocation result.
* @throws RuntimeCamelException on error. Exceptions thrown by API method are wrapped.
*/
protected Object doInvokeMethod(ApiMethod method, Map<String, Object> properties) throws RuntimeCamelException {
return ApiMethodHelper.invokeMethod(endpoint.getApiProxy(method, properties), method, properties);
}
@Override
public final Object splitResult(Object result) {
// producer never splits results
return result;
}
@Override
public void interceptResult(Object methodResult, Exchange resultExchange) {
// do nothing by default
}
protected ApiMethod findMethod(Exchange exchange, Map<String, Object> properties) {
ApiMethod method = null;
final List<ApiMethod> candidates = endpoint.getCandidates();
if (processInBody(exchange, properties)) {
// filter candidates based on endpoint and exchange properties
final Set<String> argNames = properties.keySet();
final List<ApiMethod> filteredMethods = methodHelper.filterMethods(
candidates,
ApiMethodHelper.MatchType.SUPER_SET,
argNames);
// get the method to call
if (filteredMethods.isEmpty()) {
throw new RuntimeCamelException(String.format("Missing properties for %s, need one or more from %s",
endpoint.getMethodName(),
methodHelper.getMissingProperties(endpoint.getMethodName(), argNames))
);
} else if (filteredMethods.size() == 1) {
// found an exact match
method = filteredMethods.get(0);
} else {
method = ApiMethodHelper.getHighestPriorityMethod(filteredMethods);
log.warn("Calling highest priority operation {} from operations {}", method, filteredMethods);
}
}
return method;
}
// returns false on exception, which is set in exchange
private boolean processInBody(Exchange exchange, Map<String, Object> properties) {
final String inBodyProperty = endpoint.getInBody();
if (inBodyProperty != null) {
Object value = exchange.getIn().getBody();
if (value != null) {
try {
value = endpoint.getCamelContext().getTypeConverter().mandatoryConvertTo(
endpoint.getConfiguration().getClass().getDeclaredField(inBodyProperty).getType(),
exchange, value);
} catch (Exception e) {
exchange.setException(new RuntimeCamelException(String.format(
"Error converting value %s to property %s: %s", value, inBodyProperty, e.getMessage()), e));
return false;
}
} else {
// allow null values for inBody only if its a nullable option
if (!methodHelper.getNullableArguments().contains(inBodyProperty)) {
exchange.setException(new NullPointerException(inBodyProperty));
return false;
}
}
log.debug("Property [{}] has message body value {}", inBodyProperty, value);
properties.put(inBodyProperty, value);
}
return true;
}
}