dotnet core barcode generator

.net core barcode

.net core barcode generator

.net core barcode

dotnet core barcode generator,

.net core barcode,
dotnet core barcode generator,

dotnet core barcode generator,

.net core barcode,
.net core barcode,
.net core barcode,
dotnet core barcode generator,
.net core barcode generator,

.net core barcode generator,
.net core barcode,
.net core barcode generator,
.net core barcode generator,
dotnet core barcode generator,
dotnet core barcode generator,
.net core barcode,
dotnet core barcode generator,
.net core barcode,
.net core barcode generator,
dotnet core barcode generator,
dotnet core barcode generator,
.net core barcode generator,
.net core barcode,
.net core barcode generator,
dotnet core barcode generator,
.net core barcode generator,
dotnet core barcode generator,
.net core barcode,
dotnet core barcode generator,
.net core barcode,

.net core barcode generator,
.net core barcode generator,
.net core barcode generator,
.net core barcode,
.net core barcode generator,
dotnet core barcode generator,
dotnet core barcode generator,
dotnet core barcode generator,
.net core barcode generator,
dotnet core barcode generator,
.net core barcode,
.net core barcode,
dotnet core barcode generator,
dotnet core barcode generator,
.net core barcode generator,
.net core barcode generator,
.net core barcode,
.net core barcode generator,
.net core barcode,
.net core barcode generator,
dotnet core barcode generator,
.net core barcode,
.net core barcode generator,
dotnet core barcode generator,
.net core barcode generator,
dotnet core barcode generator,
.net core barcode generator,
.net core barcode,
.net core barcode generator,
.net core barcode,
dotnet core barcode generator,
.net core barcode generator,
.net core barcode,
.net core barcode generator,
.net core barcode generator,
.net core barcode,
dotnet core barcode generator,
.net core barcode,
.net core barcode generator,
dotnet core barcode generator,
.net core barcode generator,
.net core barcode generator,
dotnet core barcode generator,
.net core barcode generator,
dotnet core barcode generator,
.net core barcode,
.net core barcode generator,
.net core barcode generator,
.net core barcode generator,

Since onMessage will not complete normally, the container will be forced to roll back the transaction and put the message back on the queue instead of acknowledging it (in fact, since a runtime exception is thrown, the bean instance will be removed from the pool). The problem is, since we are still listening on the queue, the same message will be delivered to us again and we will be stuck in the accept/ die loop indefinitely! Messages that cause this all-too-common scenario are called poison messages. The good news is that many MOMs and EJB containers provide mechanisms that deal with poison messages, including redelivery counts and dead message queues. If you set up the redelivery count and dead message queue for the shipping request destination, the message delivery will be attempted for the specified number of times. After the redelivery count is exceeded, the message will be moved to a specially designated queue for poison messages called the dead message queue. The bad news is that these mechanisms are not standardized and are vendor specific. Configure MDB pool size. Most EJB containers let you specify the maximum number of instances of a particular MDB the container can create. In effect, this controls the level of concurrency. If there are five concurrent messages to process and the pool size is set to three, the container will wait until the first three

Summary

/* * Generated file - Do not edit! */ package ch2; import java.util.*; /** * Value object for ItemBean. * */ public class ItemBeanValue extends java.lang.Object implements java.io.Serializable { private java.lang.String iD; private boolean iDHasBeenSet = false; private java.lang.String type; private boolean typeHasBeenSet = false; private ch2.ItemBeanPK pk; public ItemBeanValue() { pk = new ch2.ItemBeanPK();

Gang of Four, 149 GaugeMonitor monitor type MBeanServer component, 193 get joinpoint type, AspectJ, 36, 42 getAliases method, BeanFactory class Spring AOP, 117 getArgs method, JoinPoint interface org.aspectj.lang, 34 getDate method, Calendar class mix-in mechanism, JBoss AOP 104 , getDetails method, AccountBean class, 234

messages are processed before assigning any more instances. This is a doubleedged sword and requires careful handling. If you set your MDB pool size too small, messages will be processed slowly. At the same time, it is desirable to place reasonable limits on the MDB pool size so that many concurrent MDB instances do not choke the machine. Unfortunately, at the time of this writing, setting MDB pool sizes is not standardized and is provider specific.

4.5 Summary

} public ItemBeanValue( java.lang.String iD, java.lang.String type ) { this.iD = iD; iDHasBeenSet = true; this.type = type; typeHasBeenSet = true; pk = new ch2.ItemBeanPK(this.getID()); } //TODO Cloneable is better than this ! public ItemBeanValue( ItemBeanValue otherValue ) { this.iD = otherValue.iD; iDHasBeenSet = true; this.type = otherValue.type; typeHasBeenSet = true; pk = new ch2.ItemBeanPK(this.getID()); } public ch2.ItemBeanPK getPrimaryKey() { return pk; } public void setPrimaryKey( ch2.ItemBeanPK pk ) { // it's also nice to update PK object - just in case // somebody would ask for it later... this.pk = pk; } public java.lang.String getID() { return this.iD; } public java.lang.String getType() { return this.type; }

In this chapter, we covered basic messaging concepts, JMS, and MDBs. Messaging is an extremely powerful technology for the enterprise, and it helps build loosely coupled systems. JMS allows you to use message-oriented middleware (MOM) from enterprise Java applications. Using the JMS API to build a message consumer application can be time consuming, and MDBs make using MOM in a standardized manner through Java EE extremely easy. Note, however, that messaging and MDBs are not right for all circumstances and can be overused. One such case is using the request/reply model (discussed in the sidebar The request-reply model ), which entails a lot of extra complexity compared to simple PTP or pub-sub messaging. If you find yourself using this model extensively and in ways very close to synchronous messaging, it might be worth thinking about switching to a synchronous technology such as RMI, SOAP, or remote session bean calls. A few major EJB features we touched on in this chapter are dependency injection, interceptors, timers, transaction, and security. As you ve seen, EJB 3 largely relieves us from these system-level concerns while providing extremely robust and flexible functionality. We ll discuss dependency injection, timers, and interceptors in the next chapter.

getDetails method, AccountPOJO class, 245 getEntityId method, AccountPOJO class, 244 getInstance method Singleton pattern, 151 getInterceptors method, InvocationBase class joinpoint introspection, JBoss AOP 101 , getInterfaces method InterceptionIntroductionAdvisor interface, Spring AOP, 130 getKind method, JoinPoint interface org.aspectj.lang, 34 getName method, Interceptor interface implementing preconditions, 176 JBoss AOP interceptors, 92, 100 getNextTxId method resolving object references, 250 getNextTxId method, DBUtil class, 252 getPrice method, Catalog Class, AspectJ, 25 getServiceFacade method business delegate implementation for bank application, 273 getSignature method, JoinPoint interface org.aspectj.lang, 34 getSourceLocation method, JoinPoint interface org.aspectj.lang, 34 getTarget method, JoinPoint interface call and execution joinpoint types, AspectJ, 36 org.aspectj.lang, 34 getTargetObject method, InvocationBase class joinpoint introspection, JBoss AOP 101 , GETTERS method-type operators, JAC, 70, 71 getThis method, JoinPoint interface org.aspectj.lang, 34 global shared variables transforming a class into a singleton, 157 GNU regexp library, 69 see also regular expressions goto instruction demise of, 2 granularity creating manageable resource with an aspect, 202 grouping parameters aspect-configuration files, JAC, 77 78 GUI aspect, JAC, 81 82 GUI parameter, Jac class, 88 GuiAC aspect, JAC, 82

EJB internals Dependency injection of the @Resource annotation Crosscutting concerns with interceptors Task scheduling with the EJB timer