Configuration config = new DatabaseConfiguration(dataSource, "app_config", "name", "value");
Using DatabaseConfiguration of Commons Configuration
TweetPosted on Sunday Feb 22, 2015 at 10:50PM in Technology
Commons Configuration is a very useful library which manages configurations of an application. it supported various data stores including RDBMS. I’ve done some test against RDBMS so leave this posting as a note. test was done against Commons Configuration 1.10. the project which used in test is can be obtained from my GitHub repository.
app_config Table
Assume now we have following data in a table named app_config.
| name | value |
|---|---|
anyJob.someProp1 |
abc |
anyJob.someProp2 |
def |
someJob.list |
1,2,3,4,5 |
someJob.someProp |
${anyJob.someProp1} |
Create Configuration instance
First, we need to create a DatabaseConfiguration instance with following procedure:
Obtain all of configuration
We can obtain all of configurations as follows:
// Obtain all of keys
for (Iterator<String> keys = config.getKeys(); keys.hasNext(); ) {
String key = keys.next();
Object value = config.getProperty(key);
System.out.println(key + "=" + value);
}
It produces:
anyJob.someProp1=abc
anyJob.someProp2=gef
someJob.list=[1, 2, 3, 4, 5]
someJob.someProp=${anyJob.someProp1}
Obtain keys with particular prefix
Sometimes we’d like to filter using prefixes. this time we get keys prefixed with someJob.
// Obtain keys with particular prefix
for (Iterator<String> keys = config.getKeys("someJob"); keys.hasNext(); ) {
String key = keys.next();
Object value = config.getProperty(key);
System.out.println(key + "=" + value);
}
It produces:
someJob.list=[1, 2, 3, 4, 5]
someJob.someProp=${anyJob.someProp1}
Obtain list
We can obtain comma-separated values as List as follows:
// Obtain list
System.out.println(config.getList("someJob.list")); // [1, 2, 3, 4, 5]
System.out.println(config.getString("someJob.list")); // 1
It produces:
[1, 2, 3, 4, 5] 1
Note that invocation of getString() returns only the first value.
Obtain referencing value
The value ${anyJob.someProp1} in the key someJob.someProp resolved as abc with getString() method as follows:
// Referencing a value of other key
System.out.println(config.getString("someJob.someProp")); // abc
It produces:
abc
Update
The library reflects a update of database immediately even after instantiation of DatabaseConfiguration. consider following procedure was executed after instantiation of the configuration instance.
// update value of a row
try (Connection cn = dataSource.getConnection()) {
try (Statement st = cn.createStatement()) {
st.executeUpdate("update app_config set value='hij' where name='anyJob.someProp1'");
}
}
// check updated value
System.out.println(config.getString("anyJob.someProp1")); // hij
System.out.println(config.getString("someJob.someProp")); // hij
It produces:
hij hij
Tags: commons
Using JSL Inheritance with JBeret
TweetPosted on Sunday Feb 22, 2015 at 06:28PM in Technology
In practical use, many boilerplate code will appear to Job definition XMLs of JSR352 batch such as definition of Listeners, Properties and attribute such as item-count of chunk element. to overcome this, there is the specification of JSL Inheritance but it deferred to next version of JBatch spec but JBeret supports this specification already. it’s very useful to eliminate annoying fragments appear repeatedly so I tested it. WildFly 8.2.0.Final was used for test.
Parent XML
Parent XML begins as follows:
<?xml version="1.0" encoding="UTF-8"?>
<job id="parent" abstract="true" version="1.0" xmlns="http://xmlns.jcp.org/xml/ns/javaee">
<properties>
<property name="someJobProp" value="someJobPropValue"/>
</properties>
<listeners>
<listener ref="myJobListener"/>
</listeners>
Declared property named someJobProp become visible from child XMLs. myJobListener will be included implicitly in child XMLs as well.
Parent XML has an abstract step element which will be referenced from child XMLs as follows. these properties and listeners for a step will be included implicitly too. we can override javax.transaction.global.timeout at there. it will be affected to all of child steps.
<step id="mySimpleStep" abstract="true">
<properties>
<property name="javax.transaction.global.timeout" value="1800"/>
</properties>
<listeners>
<listener ref="myStepListener"/>
</listeners>
</step>
It is the same for chunk based step. it can be used to eliminate defining item-count for all of chunk steps.
<step id="myChunkStep" abstract="true">
<properties>
<property name="javax.transaction.global.timeout" value="900"/>
<property name="jberet.local-tx" value="true"/>
</properties>
<listeners>
<listener ref="myStepListener"/>
<listener ref="myChunkListener"/>
</listeners>
<chunk item-count="3"/>
</step>
</job>
Child XML
Child XML became very simple thanks to inheritance as follows. you need to specify parent and jsl-name attributes to reference its parent. parent means the name of parent attribute. jsl-name means XML file name of referencing element.
<?xml version="1.0" encoding="UTF-8"?>
<job id="child" parent="parent" jsl-name="parent" version="1.0" xmlns="http://xmlns.jcp.org/xml/ns/javaee">
<step id="simpleStep" next="chunkStep" parent="mySimpleStep" jsl-name="parent">
<batchlet ref="myBatchlet"/>
</step>
<step id="chunkStep" parent="myChunkStep" jsl-name="parent">
<chunk>
<reader ref="myItemReader"/>
<writer ref="myItemWriter"/>
</chunk>
</step>
</job>
Launching example job
-
Clone the repository
-
Build the WAR and deploy it to your WildFly
-
Run a JUnit test class named JobTest. it invokes the job through remote EJB invocation.
Log
You can see Properties, Listeners and item-count attribute were inherited as expected.
(Batch Thread - 1) Job child starting
(Batch Thread - 1) Job child, Step simpleStep starting
(Batch Thread - 1) hello world!
(Batch Thread - 1) jobProps: {someJobProp=someJobPropValue}
(Batch Thread - 1) stepProps: {javax.transaction.global.timeout=1800}
(Batch Thread - 1) Job child, Step simpleStep done
(Batch Thread - 1) Job child, Step chunkStep starting
(Batch Thread - 1) jobProps: {someJobProp=someJobPropValue}
(Batch Thread - 1) stepProps: {jberet.local-tx=true, javax.transaction.global.timeout=900}
(Batch Thread - 1) Job child, Step chunkStep chunk starting
(Batch Thread - 1) write: [1, 2, 3]
(Batch Thread - 1) Job child, Step chunkStep chunk done
(Batch Thread - 1) Job child, Step chunkStep chunk starting
(Batch Thread - 1) write: [4, 5, 6]
(Batch Thread - 1) Job child, Step chunkStep chunk done
(Batch Thread - 1) Job child, Step chunkStep chunk starting
(Batch Thread - 1) write: [7, 8, 9]
(Batch Thread - 1) Job child, Step chunkStep chunk done
(Batch Thread - 1) Job child, Step chunkStep chunk starting
(Batch Thread - 1) write: [0]
(Batch Thread - 1) Job child, Step chunkStep chunk done
(Batch Thread - 1) Job child, Step chunkStep done
(Batch Thread - 1) Job child done
