Since lots of config in grails were placed at grailsApplication.config, lets say if i have a secure management page for managing and updating properties. Should i directly modify those configuration properties directly? Is it a good practice to do so? Im taking this into consideration:
the app should be scalable. Multiple instance of the same app will be deployed.
i will use an application servlet to deploy my app, e.g. wildfly
i will use hazelcast for session, etc
Can you guys share your experience in this?
I'm working on a webapp running on Tomcat which using spring-data to connect to a neo4j graph in embedded mode.
I would like to use neo4j server instead of the embedded mode and I am looking for some help to be sure about how to do that.
Some of my application services are quite difficult and combine, in a single transaction, the result of several cypher requests in a dto sent back to the user.
First I thought that I have to create a server unmanaged extension and I think I should follow these following steps.
- Keep my webapp with springMVC and spring security to hold and secure users sessions.
- Regroup all my transactional services in a specific jar my-app.jar
- Use Jax-RS to add a REST access point on each of my service of my-app.jar
- use something like spring restTemplate from my spring controller to call services from my-app.jar
First question : is this way of doing things is the good way ?
Second question : I have many spring injection in my services layer. How can I keep them working (how can I add dependencies in the server extension ?
Then I discovered graphAware and I wonder if I should use it instead.
And finally I just read this post http://jexp.de/blog/2014/12/spring-data-neo4j-improving-remoting-performance/ and it seems that I should use
the SpringCypherRestGraphDatabase (as explain in the bold text at the end of the article).
Well, I'm a little bit lost and I would appreciate any help to use neo4j server instead the embedded mode for my application which contain some complexe transactions.
You have a number of options here and you are on the right track with your thinking.
Option 1:
If your use cases are business-logic-heavy, and your question suggests that they are, going the unmanaged extension route is one option.
Essentially, you can then combine the most performant Java API and Cypher (if you wish) to perform your use case. I wouldn't use SDN here by the way, so you have to do your mapping manually, but is there really any mapping? Maybe you just want to execute traversals / Cypher queries for each one of your use cases.
Each use case then exposes a simple REST API, which is consumed by your Spring-powered application running Spring MVC, Spring Security, and all that. You can use the RestTemplate from Spring in your app's Controllers.
To add a twist to all that, you can use the GraphAware Framework to develop the "unmanaged extension" using Spring MVC as well. That would be my preferred option, knowing nothing about your domain/app.
Option 2:
Use the new version of SDN (v4) as Michael suggests. This allows you to run your application with annotated domain objects, Spring MVC, Security, et al. Operations (CRUD and other) are automatically translated to Cypher and sent across the wire to Neo4j running in server mode (no extensions needed). Results are then marshalled back to Java objects.
We're about to release Milestone 1 of SDN v4. It shouldn't take more than a week. That said, it is still going to be a Milestone release, thus not ready for production. A GA release is expected in May (ish).
You can already try SDN v4 yourself. Clone this repo: https://github.com/spring-projects/spring-data-neo4j, make sure you're on the 4.0 branch, and do an mvn clean install on it. Here's a sample app, built using Angular JS and Spring Boot.
Please do get in touch with feedback / questions / problems (best by email info at graphaware dot com). Cheers!
I suggest you wait a bit until SDN4 Milestone 1 comes out (developed by GraphAware) this was written from scratch for Neo4j-Server.
I would like to share the data access portion of my grails app (Grails domain classes and services) with another grails app. One is a standard client facing web app, the other (not yet written) will be for periodic background tasks such as reminder emails and such using the Quartz plugin or similar, where the UI will just be for statistics/control for internal users.
I do not want this all bundled in one Grails application because I want to be able to scale them and run them on different machines. What is the proper way to do this? I have accomplished this in the past in more legacy Java web applications by bundling the shared data access classes into a .jar and including them where needed in multiple apps, but I'm not sure if this is the right approach for Grails.
I've considered a full blown service oriented architecture where a third grails application is responsible for all data access and the two described do all their data access through REST calls to this service app, but this is out of scope for the short term since the client facing webapp is already written.
Usually this is done via plugins. Create your domain classes, services, controllers and even default gsp's that you want to share among apps and create them as a plugin. That way you can install them in any Grails app that requires that behavior.
I've done this with some generic accounting type behavior that is fairly common among apps I write like receivables, payables, etc.
One great thing is that you can write the plugin and test separately with a test data source and then when you install it into a Grails app it will use the apps data source. And it will have default gsp's and controllers that give you a basic set of behavior that you can override in the actual app.
What is JNDI?
What is its basic use?
When is it used?
What is JNDI ?
It stands for Java Naming and Directory Interface.
What is its basic use?
JNDI allows distributed applications to look up services in an abstract, resource-independent way.
When it is used?
The most common use case is to set up a database connection pool on a Java EE application server. Any application that's deployed on that server can gain access to the connections they need using the JNDI name java:comp/env/FooBarPool without having to know the details about the connection.
This has several advantages:
If you have a deployment sequence where apps move from devl->int->test->prod environments, you can use the same JNDI name in each environment and hide the actual database being used. Applications don't have to change as they migrate between environments.
You can minimize the number of folks who need to know the credentials for accessing a production database. Only the Java EE app server needs to know if you use JNDI.
What is JNDI ?
The Java Naming and Directory InterfaceTM (JNDI) is an application programming interface (API) that provides naming and directory functionality to applications written using the JavaTM programming language. It is defined to be independent of any specific directory service implementation. Thus a variety of directories(new, emerging, and already deployed) can be accessed in a common way.
What is its basic use?
Most of it is covered in the above answer but I would like to provide architecture here so that above will make more sense.
To use the JNDI, you must have the JNDI classes and one or more service providers. The Java 2 SDK, v1.3 includes three service providers for the following naming/directory services:
Lightweight Directory Access Protocol (LDAP)
Common Object Request Broker Architecture (CORBA) Common Object Services (COS) name service
Java Remote Method Invocation (RMI) Registry
So basically you create objects and register them on the directory services which you can later do lookup and execute operation on.
JNDI in layman's terms is basically an Interface for being able to get instances of internal/External resources such as
javax.sql.DataSource,
javax.jms.Connection-Factory,
javax.jms.QueueConnectionFactory,
javax.jms.TopicConnectionFactory,
javax.mail.Session, java.net.URL,
javax.resource.cci.ConnectionFactory,
or any other type defined by a JCA resource adapter.
It provides a syntax in being able to create access whether they are internal or external. i.e (comp/env in this instance means where component/environment, there are lots of other syntax):
jndiContext.lookup("java:comp/env/persistence/customerDB");
JNDI Overview
JNDI is an API specified in Java
technology that provides naming and
directory functionality to
applications written in the Java
programming language. It is designed
especially for the Java platform using
Java's object model. Using JNDI,
applications based on Java technology
can store and retrieve named Java
objects of any type. In addition, JNDI
provides methods for performing
standard directory operations, such as
associating attributes with objects
and searching for objects using their
attributes.
JNDI is also defined independent of
any specific naming or directory
service implementation. It enables
applications to access different,
possibly multiple, naming and
directory services using a common API.
Different naming and directory service
providers can be plugged in seamlessly
behind this common API. This enables
Java technology-based applications to
take advantage of information in a
variety of existing naming and
directory services, such as LDAP, NDS,
DNS, and NIS(YP), as well as enabling
the applications to coexist with
legacy software and systems.
Using JNDI as a tool, you can build
new powerful and portable applications
that not only take advantage of Java's
object model but are also
well-integrated with the environment
in which they are deployed.
Reference
What is JNDI ?
JNDI stands for Java Naming and Directory Interface. It comes standard with J2EE.
What is its basic use?
With this API, you can access many types of data, like objects, devices, files of naming and directory services, eg. it is used by EJB to find remote objects. JNDI is designed to provide a common interface to access existing services like DNS, NDS, LDAP, CORBA and RMI.
When it is used?
You can use the JNDI to perform naming operations, including read operations and operations for updating the namespace. The following operations are described here.
I will use one example to explain how JNDI can be used to configure database without any application developer knowing username and password of the database.
1) We have configured the data source in JBoss server's standalone-full.xml. Additionally, we can configure pool details also.
<datasource jta="false" jndi-name="java:/DEV.DS" pool-name="DEV" enabled="true" use-ccm="false">
<connection-url>jdbc:oracle:thin:#<IP>:1521:DEV</connection-url>
<driver-class>oracle.jdbc.OracleDriver</driver-class>
<driver>oracle</driver>
<security>
<user-name>usname</user-name>
<password>pass</password>
</security>
<security>
<security-domain>encryptedSecurityDomain</security-domain>
</security>
<validation>
<validate-on-match>false</validate-on-match>
<background-validation>false</background-validation>
<background-validation-millis>1</background-validation-millis>
</validation>
<statement>
<prepared-statement-cache-size>0</prepared-statement-cache-size>
<share-prepared-statements>false</share-prepared-statements>
<pool>
<min-pool-size>5</min-pool-size>
<max-pool-size>10</max-pool-size>
</pool>
</statement>
</datasource>
Now, this jndi-name and its associated datasource object will be available for our application.application.
2) We can retrieve this datasource object using JndiDataSourceLookup class.
Spring will instantiate the datasource bean, after we provide the jndi-name.
Now, we can change the pool size, user name or password as per our environment or requirement, but it will not impact the application.
Note : encryptedSecurityDomain, we need to configure it separately in JBoss server like
<security-domain name="encryptedSecurityDomain" cache-type="default">
<authentication>
<login-module code="org.picketbox.datasource.security.SecureIdentityLoginModule" flag="required">
<module-option name="username" value="<usernamefordb>"/>
<module-option name="password" value="894c8a6aegc8d028ce169c596d67afd0"/>
</login-module>
</authentication>
</security-domain>
This is one of the use cases. Hope it clarifies.
A naming service associates names with objects and finds objects based on their given names.(RMI registry is a good example of a naming service.) JNDI provides a common interface to many existing naming services, such as LDAP, DNS.
Without JNDI, the location or access information of remote resources would have to be hard-coded in applications or made available in a configuration. Maintaining this information is quite tedious and error prone.
The best explanation to me is given here
What is JNDI
It is an API to providing access to a directory service, that is, a service mapping name (strings) with objects, reference to remote objects or simple data. This is called
binding. The set of bindings is called the context. Applications use the JNDI interface to access resources.
To put it very simply, it is like a hashmap with a String key and Object values representing resources on the web.
What Issues Does JNDI Solve
Without JNDI, the location or access information of remote resources would have to be hard-coded in applications or made available in a configuration. Maintaining this information is quite tedious and error prone.
If a resources has been relocated on another server, with another IP address, for example, all applications using this resource would have to be updated with this new information. With JNDI, this is not necessary. Only the corresponding resource binding has to be updated. Applications can still access it with its name and the relocation is transparent.
I am just curious why the official docs are so ignored which elaborate the details meticulously already.
But if you'd like to understand the cases, please refer to duffymo's answer.
The Java Naming and Directory InterfaceTM (JNDI) is an application programming interface (API) that provides naming and directory functionality to applications written using the JavaTM programming language. It is defined to be independent of any specific directory service implementation. Thus a variety of directories--new, emerging, and already deployed--can be accessed in a common way.
And its architecture
And normally how you use it.
The Java Naming and Directory InterfaceTM (JNDI) is an application programming interface (API) that provides naming and directory functionality to applications written using the JavaTM programming language. It is defined to be independent of any specific directory service implementation. Thus a variety of directories--new, emerging, and already deployed--can be accessed in a common way.
While JNDI plays less of a role in lightweight, containerized Java applications such as Spring Boot, there are other uses. Three Java technologies that still use JNDI are JDBC, EJB, and JMS. All have a wide array of uses across Java enterprise applications.
For example, a separate DevOps team may manage environment variables such as username and password for a sensitive database connection in all environments. A JNDI resource can be created in the web application container, with JNDI used as a layer of consistent abstraction that works in all environments.
This setup allows developers to create and control a local definition for development purposes while connecting to sensitive resources in a production environment through the same JNDI name.
reference :
https://docs.oracle.com/javase/tutorial/jndi/overview/index.html
I'm thinking about possible alternatives for our EJB based service layer and wondered if it would make sense to use just the service and database layer of Grails together with the Remoting Plugin or is this using a sledgehammer to crack a nut?
Speaking of the Remoting Plugin: is there a standard way of generating a JAR file, that contains the necessary classes to make a remote call to a Grails service from a non-Spring Java application?
Interesting idea. I don't think it'd be overkill at all. The nice thing is that your service would be very portable across protocols and deployment options (e.g. put a controller layer on top and it's instantly embedded). This gives you the benefits of EJB's (persistence) + the ability to use Groovy and GORM.
FWIW, we're using Grails as our service tier; in come cases we use it embedded (as a plugin), in others we expose the services (via controllers) as JSON or SOAP; I see exposing as RMI as a variation of what we're doing (without the controller layer).