/**
* 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.component.olingo2;
import java.util.concurrent.CountDownLatch;
import org.apache.camel.RuntimeCamelException;
import org.apache.camel.component.olingo2.api.Olingo2App;
import org.apache.camel.component.olingo2.api.Olingo2ResponseHandler;
import org.apache.camel.util.ObjectHelper;
import org.apache.olingo.odata2.api.edm.Edm;
/**
* Holder class for {@link org.apache.camel.component.olingo2.api.Olingo2App}
* and its lazily read {@link org.apache.olingo.odata2.api.edm.Edm}.
*/
public class Olingo2AppWrapper {
private final Olingo2App olingo2App;
private volatile Edm edm;
public Olingo2AppWrapper(Olingo2App olingo2App) {
ObjectHelper.notNull(olingo2App, "olingo2App");
this.olingo2App = olingo2App;
}
public Olingo2App getOlingo2App() {
return olingo2App;
}
public void close() {
olingo2App.close();
}
// double checked locking based singleton Edm reader
public Edm getEdm() throws RuntimeCamelException {
Edm localEdm = edm;
if (localEdm == null) {
synchronized (this) {
localEdm = edm;
if (localEdm == null) {
final CountDownLatch latch = new CountDownLatch(1);
final Exception[] error = new Exception[1];
olingo2App.read(null, "$metadata", null, new Olingo2ResponseHandler<Edm>() {
@Override
public void onResponse(Edm response) {
edm = response;
latch.countDown();
}
@Override
public void onException(Exception ex) {
error[0] = ex;
latch.countDown();
}
@Override
public void onCanceled() {
error[0] = new RuntimeCamelException("OData HTTP request cancelled!");
latch.countDown();
}
});
try {
// wait until response or timeout
latch.await();
final Exception ex = error[0];
if (ex != null) {
if (ex instanceof RuntimeCamelException) {
throw (RuntimeCamelException) ex;
} else {
final String message = ex.getMessage() != null
? ex.getMessage() : ex.getClass().getName();
throw new RuntimeCamelException("Error reading EDM: " + message, ex);
}
}
} catch (InterruptedException e) {
throw new RuntimeCamelException(e.getMessage(), e);
}
localEdm = edm;
}
}
}
return localEdm;
}
}