Database Configuration for a Feed

This document describes how to create a feed configuration, adpater configuration and configure database settings.

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Contents

• Creating a Mapping File in iBATIS Format
• Creating an XML File with Database Connection Parameters for iBATIS
• Creating an Adapter Properties File
• Creating an Adapter Configuration Properties File
• Creating a Wrapper Config
• Creating a Feed Properties File

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Creating a Mapping File in iBATIS Format

In the conf/feedserver/sqlmap/ folder, create a mapping file for iBATIS to map Java objects to database queries and results on the table and view.

For example: contact.xml mapping file:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE sqlMap
    PUBLIC "-//ibatis.apache.org//DTD SQL Map 2.0//EN"
    "http://ibatis.apache.org/dtd/sql-map-2.dtd">

<sqlMap namespace="test">
  <resultMap id="result-map" class="java.util.HashMap">
    <result property="id" column="id"/>
     <result property="firstName" column="first_name"/>
     <result property="lastName" column="last_name"/>
    <result property="email" column="email"/>
    <result property="rating" column="rating"/>
  </resultMap>

  <select id="contact-get-feed" resultMap="result-map">
    select * from Contact
  </select>
 
  <select id="contact-get-entry" resultMap="result-map">
    select * from Contact where id = #value#
  </select>

  <delete id="contact-delete-entry" >
    delete from Contact where id = #value#
  </delete>
 
  <insert id="contact-insert-entry" parameterClass="map">
    insert into Contact (first_name,last_name,email,rating) values
        (#firstName#,#lastName#,#email#,#rating:NUMERIC#)
     <selectKey keyProperty="id" resultClass="long">
      <!-- For MySQL:   SELECT LAST_INSERT_ID()-->
      <!-- For Derby: --> values IDENTITY_VAL_LOCAL()
      <!-- For PostGRE SQL: SELECT currval('"contact_id_seq"')  -->
    </selectKey>
  </insert>

  <update id="contact-update-entry" parameterClass="map">
    update Contact set last_name = #lastName#, first_name = #firstName#,
        email = #email#, rating = #rating:NUMERIC# where id = #id#
  </update>
</sqlMap>

Note: All the id attributes in the previous XML file use the following naming conventions:

• To get a feed, id=<feedname>-get-feed
• To get an entry, id=<feedname>-get-entry
• To insert an entry, id=<feedname>-insert-entry
• To delete an entry, id=<feedname>-delete-entry
• To update an entry, id=<feedname>-update-entry

The name of the file should be <feedname> for easy mapping and understanding.

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Creating an XML File with Database Connection Parameters for iBATIS

The following example creates the sqlmap.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE sqlMapConfig     
    PUBLIC "-//ibatis.apache.org//DTD SQL Map Config 2.0//EN"     
    "http://ibatis.apache.org/dtd/sql-map-config-2.dtd">
<sqlMapConfig>
  <properties resource="database/dbConfig.properties"/>

  <typeHandler javaType="string" jdbcType="NUMERIC"
      callback="com.google.feedserver.ibatisCallbackHandlers.StringToNumericCallback" />

  <!-- Configure a built-in transaction manager.  If you're using an
       app server, you probably want to use its transaction manager
       and a managed datasource -->
  <transactionManager type="JDBC" commitRequired="false">
   
    <dataSource type="SIMPLE">
      <property name="JDBC.Driver" value="${JDBC.Driver}"/>
      <property name="JDBC.ConnectionURL" value="${JDBC.ConnectionURL}"/>
      <property name="JDBC.Username" value="${JDBC.Username}"/>
      <property name="JDBC.Password" value="${JDBC.Password}"/>
      <property name="Pool.MaximumActiveConnections" value="${Pool.MaximumActiveConnections}"/>
      <property name="Pool.MaximumIdleConnections" value="${Pool.MaximumIdleConnections}"/>
      <property name="Pool.MaximumCheckoutTime" value="${Pool.MaximumCheckoutTime}"/>
      <property name="Pool.TimeToWait" value="${Pool.TimeToWait}"/>
    </dataSource>
  </transactionManager>

</sqlMapConfig>

The database/dbConfig.properties file contains the actual values, which are also used by the Ant build script to create the database.

The reference to contact.xml is inserted by the wrapper at runtime as shown below:

<sqlMap resource="feedserver/sqlmap/contact.xml"/>

The value sqlmap/contact.xml is specified as part of feed configuration as explained in the following sections.

Creating an Adapter Properties File

Create an adapter properties file in conf/feedserver/{namespace}/Adapter/ dir.

For example: IBatisAdapter.properties

   className=com.google.feedserver.samples.adapters.IBatisCollectionAdapter
   isWrapper=false

   className is the fully qualified name of the adapter class that will interact with the datasource to perform CRUD operations
   isWrapper indicates whether the given adapter is a wrapper or simply an adapter

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Creating an Adapter Configuration Properties File

Create an adapter configuration properties file in the conf/feedserver/{namespace}/AdapterConfig/ folder.

For example: jdbcAdapterConfig.properties

   type=IBatisAdapter
   configValueType=xml
   configValue=@sqlmap.xml
   mixins=@IBatisAdapterWrapper

Attributes:

• type indicates the name of the target adapter stored under conf/feedserver/{namespace}/Adapter/ directory

• configValueType indicates the kind of content value that will be specified as configValue

• configValue is the configuration value used by the adapter class to interact with the datasource.

The content type (xml, text, etc) should be as specified by 'configValueType'.

If the value starts with '@', it implies that the value following '@' should be treated as the name of the file whose contents will be treated as configValue. The feed config store will have the responsibility of reading the file contents and setting them as the config value while loading the adapter config values.

• mixins is a pointer to the wrapper configurations to be applied over the target adapter

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Creating a Wrapper Config

Create an XML file under conf/feedserver/{namespace}/AdapterConfig/ directory

For example: IBatisAdapterWrapper.xml

   <?xml version="1.0" encoding="UTF-8"?>
   <mixin>
      <wrapperName>IBatisAdapterWrapper</wrapperName>
      <wrapperConfig></wrapperConfig>
   </mixin>

Attributes:

• wrapperName is the pointer to wrapper stored under conf/feedserver/{namespace}/Adapter/ directory

• wrapperConfig is any data that the wrapper will use

Create a IBatisAdapterWrapper.properties under conf/feedserver/{namespace}/Adapter/ directory having the wrapper details.

   className=com.google.feedserver.wrappers.IBatisAdapterWrapper
   configValue=""
   configType=XML
   isWrapper=true

Attributes:

• className is the fully qualified name of the wrapper class

• isWrapper=true identifies this adapter as wrapper

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Creating a Feed Properties File

Create a feed properties file in conf/feedserver/{namespace}/FeedConfig/ folder.

For example: contact.properties

   subUri=contact
   title=feed
   author=FeedServer
   adapterName=jdbcAdapterConfig
   configValue=@sqlmap/contact.xml

Attributes:

• adapterName is the name of the adapter configuration file.

This attribute acts as the link between the feed and adapter configurations.

The feed config store loads adapter values automatically for the specified adapter name while loading the feed configuration values.

• configValue is the value specific to the feed but will part of the adapter configValue.

If a value starts with '@', the value after '@' is the name of the file. The feed config store either adds the contents of file to the adapter 'configValue' or adds the name of the file.