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kuni katsuya

Why you should never use getSingleResult() in JPA | Sysout.be - 0 views

  • The only use for getSingleResult() is when we are
  • executing a scalar (count, sum, avg) query
  • query wich will
  • ...8 more annotations...
  • alway
  • return a row
  • 3 ways to do this
  • EntityManger.find()
  • returns a typed instance of the entity when it is found, null when it is not found
  • But what if the row isn’t in the database (anymore)?
  • We get an unchecked exception: NoResultException
  • We never know for sure what we can expect from our database, so throwing an unchecked exception seems the wrong choice for this use-case
    • kuni katsuya
       
      thinking defensively, in a pathological scenario, the data and/or schema of the database could be corrupt eg. using a named query that should return a single entity based on a unique constraint of a table: - what if the unique constraint was implemented incorrectly in the ddl? (too relaxed or too strict) - what if the data became inconsistent as a result of some external process? => should always code defensively, especially at integration points to anything external to the jvm 
kuni katsuya

Refactoring Databases - Evolutionary Database Design - 1 views

  • Evolutionary Database Design
  • Refactoring Databases : Evolutionary Database Design
  • Recipes for Continuous Database Integration
kuni katsuya

Session Management | Apache Shiro - 0 views

  • available in any application,
  • regardless of container.
  • even if you deploy your application in a Servlet or EJB container, there are still compelling reasons to use Shiro's Session support instead of the container's
  • ...40 more annotations...
  • Easy Custom Session Storage
  • POJO/J2SE based (IoC friendly)
  • Container-Independent Clustering!
  • Heterogeneous Client Access
  • Event Listeners
  • listen to lifecycle events during a session's lifetime
  • Host Address Retention
  • retain the IP address or host name of the host from where the session was initiated
  • Inactivity/Expiration Support
  • can be prolonged via a touch() method to keep them 'alive' if desired
  • Transparent Web Use
  • can use Shiro sessions in existing web applications and you
  • don't need to change any of your existing web cod
  • Can be used for SSO
  • easily stored in any data source
  • can be
  • 'shared'
  • across applications if needed
  • 'poor man's SSO'
  • simple sign-on experience since the shared session can retain authentication state
  • interface-based and implemented with POJOs
  • allows you to easily configure all session components with any JavaBeans-compatible configuration format, like JSON, YAML
  • easily extend
  • customize session management functionality
  • session data can be easily stored in any number of data sources
  • easily clustered using any of the readily-available networked caching products
  • no matter what container you deploy to, your sessions will be clustered the same way
  • No need for container-specific configuration!
  • Shiro sessions can be 'shared' across various client technologies
  • listen for these events and react to them for custom application behavior
  • SecurityUtils.getSubject()
  • currentUser.getSession()
  • If the Subject already has a Session, the boolean argument is ignored and the Session is returned immediately
  • If the Subject does not yet have a Session and the create boolean argument is true,
  • a new session will be created
  • and returned.
  • If the Subject does not yet have a Session and the create boolean argument is false, a new session will not be created and null is returned.
  • Suject.getSession(boolean create)
  • method functions the same way as the
  • HttpServletRequest.getSession(boolean create) method:
    • kuni katsuya
kuni katsuya

HttpServletRequest (Java EE 6 ) - 0 views

  •  
    "getSession(boolean create)"
kuni katsuya

Subject | Apache Shiro - 0 views

  • Understanding Subjects in Apache Shiro
  • 'Subject'
  • is just a security term that means a
  • ...8 more annotations...
  • security-specific 'view'
  • of an application user
  • Subject instance represents both security state and operations for
  • a single application user
  • in the security world, the term 'Subject' is actually the recognized nomenclature
  • Subject currentUser = SecurityUtils.getSubject();
  • obtain the currently executing Subject by using org.apache.shiro.SecurityUtils:
  • Subject based on user data associated with current thread or incoming request.
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