On Fri, Dec 18, 2009 at 11:20 AM, Claus Ibsen <claus.ib...@gmail.com> wrote: > Hi > > Actually the AtomicBoolean cannot safely be used for initializing code blocks? > > You can still have concurrent threads invoking the boolean and one > thread will see it as false and the other as true. > What it helps is that there are only one ever that sees it as false > and therefore only one thread that will initialize it. > > But in the mean time another thread could have seen it as true, but > its still not initialized because the first thread is currently doing > that. > e.g. there are no locks. > > You have to use the synchronized or a Lock object. > > See for example camel-jaxb and how it use the synchronized. > > Its not bad to use as synchronized is heavily optimized in JDK6. > > > A better idea would be to implements Service (extends ServiceSupport) > and do initialization in the start method. > I am pretty sure Camel will invoke these start/stop on data formats as > well. Could you try that? If not we should get that done. > Then all kind of initialization can be done using the Service interface. >
Ah yeah you need to do it at runtime sine you need access to CamelContext. I wonder if implementing CamelContextAware is sufficient? > > > > On Fri, Dec 18, 2009 at 10:54 AM, <ningji...@apache.org> wrote: >> Author: ningjiang >> Date: Fri Dec 18 09:54:30 2009 >> New Revision: 892199 >> >> URL: http://svn.apache.org/viewvc?rev=892199&view=rev >> Log: >> CAMEL-2148 using the ClassResolver from the CamelContext to load class >> >> Modified: >> >> camel/trunk/components/camel-protobuf/src/main/java/org/apache/camel/dataformat/protobuf/ProtobufDataFormat.java >> >> Modified: >> camel/trunk/components/camel-protobuf/src/main/java/org/apache/camel/dataformat/protobuf/ProtobufDataFormat.java >> URL: >> http://svn.apache.org/viewvc/camel/trunk/components/camel-protobuf/src/main/java/org/apache/camel/dataformat/protobuf/ProtobufDataFormat.java?rev=892199&r1=892198&r2=892199&view=diff >> ============================================================================== >> --- >> camel/trunk/components/camel-protobuf/src/main/java/org/apache/camel/dataformat/protobuf/ProtobufDataFormat.java >> (original) >> +++ >> camel/trunk/components/camel-protobuf/src/main/java/org/apache/camel/dataformat/protobuf/ProtobufDataFormat.java >> Fri Dec 18 09:54:30 2009 >> @@ -20,10 +20,12 @@ >> import java.io.InputStream; >> import java.io.OutputStream; >> import java.lang.reflect.Method; >> +import java.util.concurrent.atomic.AtomicBoolean; >> >> import com.google.protobuf.Message; >> import com.google.protobuf.Message.Builder; >> >> +import org.apache.camel.CamelContext; >> import org.apache.camel.CamelException; >> import org.apache.camel.Exchange; >> import org.apache.camel.InvalidPayloadException; >> @@ -34,6 +36,8 @@ >> public class ProtobufDataFormat implements DataFormat { >> >> private Message defaultInstance; >> + private String instanceClassName; >> + private AtomicBoolean setDefaultInstanceHasBeenCalled = new >> AtomicBoolean(false); >> >> /** >> * @param defaultInstance >> @@ -51,11 +55,15 @@ >> >> public void setInstanceClass(String className) throws Exception { >> ObjectHelper.notNull(className, "ProtobufDataFormat instaceClass"); >> - Class<?> instanceClass = ObjectHelper.loadClass(className); >> + instanceClassName = className; >> + } >> + >> + protected Message loadDefaultInstance(String className, CamelContext >> context) throws CamelException, ClassNotFoundException { >> + Class<?> instanceClass = >> context.getClassResolver().resolveMandatoryClass(className); >> if (Message.class.isAssignableFrom(instanceClass)) { >> try { >> Method method = >> instanceClass.getMethod("getDefaultInstance", new Class[0]); >> - defaultInstance = (Message) method.invoke(null, new >> Object[0]); >> + return (Message) method.invoke(null, new Object[0]); >> } catch (Exception ex) { >> throw new CamelException("Can't set the defaultInstance of >> ProtobufferDataFormat with " >> + className + ", caused by " + ex); >> @@ -64,7 +72,6 @@ >> throw new CamelException("Can't set the defaultInstance of >> ProtobufferDataFormat with " >> + className + ", as the class is not a subClass of >> com.google.protobuf.Message"); >> } >> - >> } >> >> /* >> @@ -82,8 +89,15 @@ >> * java.io.InputStream) >> */ >> public Object unmarshal(Exchange exchange, InputStream inputStream) >> throws Exception { >> + >> if (this.defaultInstance == null) { >> - throw new CamelException("There is not defaultInstance for >> protobuf unmarshaling"); >> + if (instanceClassName == null) { >> + throw new CamelException("There is not defaultInstance for >> protobuf unmarshaling"); >> + } else { >> + if (!setDefaultInstanceHasBeenCalled.getAndSet(true)) { >> + defaultInstance = >> loadDefaultInstance(instanceClassName, exchange.getContext()); >> + } >> + } >> } >> Builder builder = >> this.defaultInstance.newBuilderForType().mergeFrom(inputStream); >> if (!builder.isInitialized()) { >> >> >> > > > > -- > Claus Ibsen > Apache Camel Committer > > Author of Camel in Action: http://www.manning.com/ibsen/ > Open Source Integration: http://fusesource.com > Blog: http://davsclaus.blogspot.com/ > Twitter: http://twitter.com/davsclaus > -- Claus Ibsen Apache Camel Committer Author of Camel in Action: http://www.manning.com/ibsen/ Open Source Integration: http://fusesource.com Blog: http://davsclaus.blogspot.com/ Twitter: http://twitter.com/davsclaus
