| Title: Configuring DataSources in tomee.xml |
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| <a name="ConfiguringDataSources-ConfiguringDataSourcesinopenejb.xml"></a> |
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| The *<Resource>* element is used to configure a *javax.sql.DataSource*. It |
| is also used to configure other resources like Timers, Topics, Queues. We |
| will see some examples of using <Resource> to configure a DataSource. |
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| The <Resource> element is designed after @Resource annotation and has |
| similar attributes. |
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| For example, this annotation in your bean: |
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| @Resource(name = "myDerbyDatasource", type = javax.sql.DataSource.class) |
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| Would map to a Resource declared in your openejb.xml as follows: |
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| <Resource id="myDerbyDatasource" type="javax.sql.DataSource"> |
| . . . . |
| <Resource> |
| |
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| Note that in the xml element, the _type_ value of _javax.sql.DataSource_ |
| can abbreviated to just _DataSource_ as follows: |
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| <Resource id="myDerbyDatasource" type="DataSource"> |
| . . . . |
| <Resource> |
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| It is also possible to specify the path to the driver jar file using a classpath attribute like so: |
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| <Resource id="myDerbyDatasource" type="DataSource" classpath="/path/to/driver.jar"> |
| . . . . |
| <Resource> |
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| ...Or in a [Maven](http://maven.apache.org/) environment like so: |
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| <Resource id="myDerbyDatasource" type="DataSource" classpath="mvn:org.apache.derby:derby:10.10.1.1"> |
| . . . . |
| <Resource> |
| |
| See [Containers and Resources](containers-and-resources.html) |
| for a complete list of supported DataSource properties. |
| |
| See [DataSource Password Encryption](datasource-password-encryption.html) |
| for information on specifying non-plain-text database passwords in your openejb.xml file. |
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| See [Common DataSource Configurations](common-datasource-configurations.html) |
| for a list of the commonly used databases and their driver configurations. |
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| See [DataSource Configuration by Creator](datasource-configuration-by-creator.html) |
| for a list of the different properties supported for each data source creator. |
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| You may also need data partitioning per customer or depending on any other |
| business criteria. That's also an available feature. See [Dynamic Datasource](dynamic-datasource.html) for more details. |
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| <a name="ConfiguringDataSources-JNDInamesforconfiguredDataSources"></a> |
| ## JNDI names for configured DataSources |
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| <a name="ConfiguringDataSources-Example1"></a> |
| ### Example 1 |
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| <Resource id="Default JDBC Database" type="DataSource"> |
| . . . . . |
| </Resource> |
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| The global jndi name would be *java:openejb/Resource/Default JDBC Database* |
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| <a name="ConfiguringDataSources-Example2"></a> |
| ### Example 2 |
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| <Resource id="Derby Database" type="DataSource"> |
| . . . . . |
| </Resource> |
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| The global jndi name would be *java:openejb/Resource/Derby Database* |
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| <a name="ConfiguringDataSources-ObtainingaDataSource"></a> |
| ## Obtaining a DataSource |
| |
| DataSource references in your ejb should get automatically mapped to the |
| Resource you declare. The shortest and easiest rule is that *if your |
| reference name matches a Resource in your openejb.xml, that's the one you |
| get*. Essentially, the rules for mapping are as follows. |
| |
| 1. Name Attribute Match - @Resource with a name attribute matching the |
| resource name gets that resource injected |
| 1. Injected Name Match - variable name matching the resource name gets that |
| resource injected |
| 1. No Match - nothing matches a resource name, so the first resource |
| available gets injected |
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| There are various ways one could obtain a DataSource now. Lets take an |
| example of Derby. |
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| With a Resource declaration in your openejb.xml like this: |
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| <Resource id="myDerbyDatabase" type="DataSource"> |
| . . . . . |
| </Resource> |
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| There are several possible ways to refer to it, as follows. |
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| *BY matching variable name to resource name* |
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| @Stateless |
| public class FooBean { |
| @Resource DataSource myDerbyDatabase; |
| } |
| |
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| *OR BY matching name* |
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| @Stateless |
| public class FooBean { |
| @Resource(name="myDerbyDatabase") |
| DataSource dataSource; |
| } |
| |
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| *OR BY JNDI lookup* |
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| @Resource(name="myDerbyDatabase", type=javax.sql.DataSource.class) |
| @Stateless |
| public class FooBean { |
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| public void setSessionContext(SessionContext sessionContext) { |
| DataSource dataSource = (DataSource) |
| sessionContext.lookup("myDerbyDatabase"); |
| } |
| |
| public void someOtherMethod() throws Exception { |
| InitialContext initialContext = new InitialContext(); |
| DataSource dataSource = (DataSource) |
| initialContext.lookup("java:comp/env/myDerbyDatabase"); |
| } |
| } |
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| *OR* |
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| <resource-ref> |
| <res-ref-name>myDerbyDatabase</res-ref-name> |
| <res-type>javax.sql.DataSource</res-type> |
| </resource-ref> |
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| *OR* |
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| <resource-ref> |
| <res-ref-name>jdbc/myDerbyDatabase</res-ref-name> |
| <res-type>javax.sql.DataSource</res-type> |
| </resource-ref> |
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| *OR* |
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| <resource-ref> |
| <res-ref-name>someOtherName</res-ref-name> |
| <res-type>javax.sql.DataSource</res-type> |
| <mapped-name>myDerbyDatabase</mapped-name> |
| </resource-ref> |
| |