Configuration config = new DatabaseConfiguration(dataSource, "app_config", "name", "value");
Entries tagged [commons]
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