Group items tagged

GDS (Global Distribution System)

Pegasus ODD (Online Distribution Database)

connects 100’s of Internet travel portals or OTA's (online travel agents) such as Orbitz, TravelNow, Expedia, and Hotwire

@Size(min = 3, max = 80)

@NotNull

LastName

extend AbstractBuilder

must implement the buildInternal() method:

Builder extends AbstractBuilder<Customer>

@Override protected Customer buildInternal()

Implementing the Builder Pattern using the Bean Validation API

variation of the Builder design pattern for instantiating objects with multiple optional attributes.

this pattern frees you from providing multiple constructors with the different optional attributes as parameters (hard to maintain and hard to read for clients)

or providing setter methods for the optional attributes

UserService

UserDao

FacebookWS

User u

UserService uses UserDAO and FacebookWS

but don’t know how those dependencies are instantiated

And you shouldn’t really care, all that is important is that UserService depends on dao and webservice object.

BDD template given-when-then) tests are easy to read

@Entity

public class User

calling new User(“someName”,”somePassowrd”, “someOtherName”, “someOtherPassword”) becomes hardly readable and maintainable

code duplication

Maintaining this code would turn into a nightmare in no time

running the code above will throw an exception by the JPA provider,

Joshua Blooch gives fine example of builder pattern.

Instead of making the desired object directly, the client calls a constructor (or static factory) with all of the required parameters and gets a builder object. Then the client calls setter-like methods on the builder object to set each optional parameter of interest. Finally, the client calls a parameterless build method to generate the object, which is immutable. The builder is a static member class of the class it builds.

Coffee

public static class Builder

Builder(CoffeeType type, int cupSize)

Builder withMilk()

Coffee build()

Coffee(this)

private Coffee(Builder builder)

Coffee coffee = new Coffee.Builder(CoffeeType.Expresso, 3).withMilk().build();2}

especially if most of those parameters are optional.

For all entity attributes I create private fields

those that are obligatory become parameters for the public constructor

parameter-less constructor, I create one, but I give him

protected access level

protected

map multiple properties as @Id properties

annotated the property as

map multiple properties as @Id properties and declare an external class to be the identifier type

declared on the entity via the @IdClass annotation

The identifier type must contain the same properties as the identifier properties of the entity: each property name must be the same, its type must be the same as well if the entity property is of a

last case is far from obvious

not responsible for the relationship

mappedBy

To use one of the target entity property as a key of the map, use

if the map key type is another entity

All entities marked as [Managed] are considered as corresponding to Hibernate/JPA managed entities on the server

It is highly recommended to use JPA optimistic locking in a multi-tier environment (@Version annotation

In conclusion, the recommended approach to avoid any kind of subtle problems is to have a real uid property which will be persisted in the database

Here all loaded collections of the Person object will be uninitialized so uperson contains only the minimum of data to correctly merge your changes in the server persistence context

Tide uses the client data tracking (the same used for dirty checking, see below) to determine which parts of the graph need to be sent.

Dirty Checking and Conflict Handling

Data Validation

Tide integrates with Hibernate Validator 3.x and the Bean Validation API (JSR 303) implementations, and propagate the server validation errors to the client UI components

Data Paging

In an EAV data model, each attribute-value pair is a fact describing an entity, and a row in an EAV table stores a single fact

EAV tables are often described as "long and skinny": "long" refers to the number of rows, "skinny" to the few columns

Data is recorded as three columns: The entity: the item being described. The attribute or parameter: a foreign key into a table of attribute definitions. At the very least, the attribute definitions table would contain the following columns: an attribute ID, attribute name, description, data type, and columns assisting input validation

The value of the attribute

Row modeling, where facts about something (in this case, a sales transaction) are recorded as multiple rows rather than multiple columns

differences between row modeling and EAV (which may be considered a generalization of row-modeling) are:

A row-modeled table is homogeneous in the facts that it describes

The data type of the value column/s in a row-modeled table is pre-determined by the nature of the facts it records. By contrast, in an EAV table, the conceptual data type of a value in a particular row depend on the attribute in that row

In the EAV table itself, this is just an attribute ID, a foreign key into an Attribute Definitions table

The Attribute

The Value

Coercing all values into strings

larger systems use separate EAV tables for each data type (including binary large objects, "BLOBS"), with the metadata for a given attribute identifying the EAV table in which its data will be stored

Where an EAV system is implemented through RDF, the RDF Schema language may conveniently be used to express such metadata

access to metadata must be restricted, and an audit trail of accesses and changes put into place to deal with situations where multiple individuals have metadata access

quality of the annotation and documentation within the metadata (i.e., the narrative/explanatory text in the descriptive columns of the metadata sub-schema) must be much higher, in order to facilitate understanding by various members of the development team.

Attribute metadata

Validation metadata include data type, range of permissible values or membership in a set of values, regular expression match, default value, and whether the value is permitted to be null

Presentation metadata: how the attribute is to be displayed to the user

Grouping metadata: Attributes are typically presented as part of a higher-order group, e.g., a specialty-specific form. Grouping metadata includes information such as the order in which attributes are presented

Advanced validation metadata Dependency metadata:

In general, JDBC Templates are a poor solution. They don’t have enough abstraction to work on different databases because you use plain SQL in queries. There is also no real ORM mapping which results in quite a lot of boilerplate code

SimpleJdbcTemplate(ds)

@InterceptorBinding

this annotation bypasses the management layer and as such it is recommended only for development and testing purposes

Defining a Managed DataSource

Installing a JDBC driver as a deployment

Installing the JDBC Driver

deployment or as a core module

managed by the application server (and thus take advantage of the management and connection pooling facilities it provides), you must perform two tasks.  First, you must make the JDBC driver available to the application server; then you can configure the data source itself.  Once you have performed these tasks you can use the data source via standard JNDI injection.

recommended way to install a JDBC driver into the application server is to simply deploy it as a regular JAR deployment.  The reason for this is that when you run your application server in domain mode, deployments are automatically propagated to all servers to which the deployment applies; thus distribution of the driver JAR is one less thing for administrators to worry about.

Note on MySQL driver and JDBC Type 4 compliance: while the MySQL driver (at least up to 5.1.18) is designed to be a Type 4 driver, its jdbcCompliant() method always return false. The reason is that the driver does not pass SQL 92 full compliance tests, says MySQL. Thus, you will need to install the MySQL JDBC driver as a module (see below).

Installing a JDBC driver as a module

<module xmlns="urn:jboss:module:1.0" name="com.mysql">  <resources>    <resource-root path="mysql-connector-java-5.1.15.jar"/>  </resources>  <dependencies>    <module name="javax.api"/>  </dependencies></module>

jboss-7.0.0.<release>/modules/com/mysql/main

define your module with a module.xml file, and the actual jar file that contains your database driver

content of the module.xml file

Under the root directory of the application server, is a directory called modules

module name, which in this example is com.mysql

where the implementation is, which is the resource-root tag with the path element

define any dependencies you might have.  In this case, as the case with all JDBC data sources, we would be dependent on the Java JDBC API's, which in this case in defined in another module called javax.api, which you can find under modules/javax/api/main as you would expect.

Defining the DataSource itself

   <datasource jndi-name="java:jboss/datasources/MySqlDS" pool-name="MySqlDS">      <connection-url>jdbc:mysql://localhost:3306/EJB3</connection-url>         <driver>com.mysql</driver>

    <drivers>      <driver name="com.mysql" module="com.mysql">        <xa-datasource-class>com.mysql.jdbc.jdbc2.optional.MysqlXADataSource</xa-datasource-class>      </driver>    </drivers>

jboss-7.0.0.<release>/domain/configuration/domain.xml or jboss-7.0.0.<release>/standalone/configuration/standalone.xml

Step 2 securing some content

create a database that will hold the list of the authorized users along with their password

Create a new directory “auth” and add a new JSP under it, let’s call it “BackOffice.jsp“

enable Shiro into our project by adding a ServletFilter into our Web.xml

 <filter-class>05            org.apache.shiro.web.servlet.IniShiroFilter06        </filter-class>

10    <filter-mapping>11         <filter-name>ShiroFilter</filter-name>12         <url-pattern>/*</url-pattern>13    </filter-mapping>

classpath:shiro.ini

shiro-core

shiro-web

create shiro.ini under resource dir

07ds.jdbcUrl=jdbc:derby://localhost:1527/shiro_schema08ds.username = APP09ds.password = APP

15/auth/** = authcBasic16/** = anon

jdbcRealm.authenticationQuery

jdbcRealm=org.apache.shiro.realm.jdbc.JdbcRealm

setup the jdbc realm, this is where Shiro will find the authorized users

map the URLs to be protected, all the url under /auth should be authenticated with basic HTTP authentication

All the other URLs should be accessed without authentication

Add a new directory under src let’s call it production we will create a new shiro configuration file compatible with MySQL

06ds.serverName = localhost07ds.user = ADM08ds.password = secret12309ds.databaseName = shiro_schema

jdbcRealm which use a MySQL driver

added the appropriate dependency to maven pom.xml

mysql-connector-java

environment.type

staging

13                <jdbc.user>APP</jdbc.user>14                <jdbc.passwd>APP</jdbc.passwd>15                <jdbc.url>jdbc:derby://localhost:1527/shiro_schema</jdbc.url>16                <jdbc.driver>org.apache.derby.jdbc.ClientDriver</jdbc.driver>

src/main/resources

derbyclient

production

environment.type

45                <jdbc.user>ADM</jdbc.user>46                <jdbc.passwd>secret123</jdbc.passwd>47                <jdbc.ds>com.mysql.jdbc.jdbc2.optional.MysqlDataSource</jdbc.ds>48                <jdbc.serverName>localhost</jdbc.serverName>49                <jdbc.databaseName>shiro_schema</jdbc.databaseName>

src/production/resources

To build and run for staging

To build for production

-Denvironment.type=prod