Accessing properties in Karaf cfg file from java? - osgi

Question

I am using cm:property-placeholder in blueprint to load config file:
<!-- External configuration -->
<cm:property-placeholder persistent-id="mubyndle" update-strategy="reload">
<cm:default-properties>
<cm:property name="schemaValidation" value="false"/>
</cm:default-properties>
</cm:property-placeholder>
<bean id="myBean" class="com.mybean">
<property name="abc" value="${abc}" />
</bean>
I can set values into beans, like ${abc}.
How can I access any other property of the config from java?
I am planning to add list of properties:
prop1=11
prop2=22
...
propn=nn
I cannot add all in blueprint as the number varies.
Thank you,
Viktor

Answer 1

Add reference to ConfigurationAdmin service in blueprint:
<reference id="configAdmin" interface="org.osgi.service.cm.ConfigurationAdmin" />
Set it to bean:
<bean id="myBean" class="com.mybean">
<property name="abc" value="${abc}" />
<property name="configAdmin" ref="configAdmin" />
</bean>
In bean:
private ConfigurationAdmin configAdmin;
public void setConfigAdmin(ConfigurationAdmin configAdmin) throws IOException {
this.configAdmin = configAdmin;
System.out.println(configAdmin);
System.out.println(configAdmin.getConfiguration("any-persistent-id").getProperties());
}

Answer 2

You can set org.apache.aries.blueprint.compendium.cm.CmPropertyPlaceholder into myBean as <property name="cmpp" ref="cmpp" /> after giving it id <cm:property-placeholder id="cmpp" ....
Then add setter in myBean for cmpp:
public void setProperties(CmPropertyPlaceholder properties) {
Configuration config = CmUtils.getConfiguration(properties.getConfigAdmin(), properties.getPersistentId());
if (config != null) {
Dictionary props = config.getProperties();
System.out.println(props);
}
The only problem is bundle org.apache.aries.blueprint.cm does not export package org.apache.aries.blueprint.compendium.cm, so I can't access CmPropertyPlaceholder in java. Is there any command in karaf that would additionally export a package of a bundle?
It is possible to access configuration through context, will look into that and post.

Answer 3

You better do this:
a) in blueprint.xml
<blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:ext="http://aries.apache.org/blueprint/xmlns/blueprint-ext/v1.1.0"
xmlns:cm="http://aries.apache.org/blueprint/xmlns/blueprint-cm/v1.1.0"
...
<cm:property-placeholder persistent-id="<name of cfg file>"
update-strategy="reload">
<cm:default-properties>
<cm:property name="<property name in file>" value="<value>" />
</cm:default-properties>
</cm:property-placeholder>
<bean id="<name of Bean>" class="<full name of class>" >
<property name="<property name in file>" value="${<value>}"></property>
</bean>
b) inside "bean"
define a public constructor (definition required by Spring)
define a variable and its Setter:
private <Type of> <name of variable>;
public <Constructor> (){} // no parameters
public void set<property name in file first upper letter>(<Type of> <property name in file>) {
<name of variable> = <property name A>;
}
c) add into '/etc' folder the configuration file:
<name of cfg file>.cfg
Obviously, within it, the property:
<Property name> = <value>