Hi,
On 17.06.2010, at 16:46, Joel Schuster wrote:
> As a continued question in this vein...
>
> What would the be 'appropriate' way to convert from a *.cfg property to an
> Enum?
>
> In this example I use a set method instead of just the member itself:
>
> import gnu.io.SerialPort;
>
> public enum ParityEnum {
> EVEN, MARK, NONE, ODD, SPACE;
> public static int value(ParityEnum pe) {
> switch (pe) {
> case EVEN: {
> return SerialPort.PARITY_EVEN;
> }
> case MARK: {
> return SerialPort.PARITY_MARK;
> }
> case NONE: {
> return SerialPort.PARITY_NONE;
> }
> case ODD: {
> return SerialPort.PARITY_ODD;
> }
> case SPACE: {
> return SerialPort.PARITY_SPACE;
> }
> default: {
> return -1;
> }
> }
> }
> };
>
> @Property(name = "parity", value = "NONE")
> public void setParity(String parity) throws CommunicationsException {
> try {
> this.parityEnum = ParityEnum.valueOf(parity);
> } catch (IllegalArgumentException iae) {
> /* ... */
> }
> }
>
> protected ParityEnum parityEnum = ParityEnum.NONE;
>
> What is the order in this case? Does the method get called before the
> constructor here too? (I'm not sure how that would happen.)
No, this is a 'set' method.
Those methods are called just after the constructor.
The callbacks order is described here :
http://felix.apache.org/site/ipojo-faq.html#iPOJOFAQ-Callbacksorder.
Your method will be called in third position : constructor, bind methods,
properties. This also mean that you can't use this.parityEnum inside the
constructor. If the configuration does not contains 'parity', iPOJO call
setParity("NONE").
Regards,
Clement
>
> -----Original Message-----
> From: Clement Escoffier [mailto:[email protected]]
> Sent: Thursday, June 17, 2010 4:56 AM
> To: [email protected]
> Subject: Re: Problems with iPOJO / File Install
>
> Hello,
>
> On 17.06.2010, at 11:21, Bengt Rodehav wrote:
>
>> Hello!
>>
>> I use iPOJO (1.4.0) and File Install (3.0.0) deployed on Karaf (1.6.0).
>>
>> I use the service factory pattern in OSGi to instantiate services from
>> configuration files picked up by File Install. Howrver, there seems to be a
>> startup problem. When the service is originally started, not all properties
>> (in my newly instantiated service have received their values from the
>> configuration file). Using Felix web console (the Configuration tab) the
>> property values are correct. However, when I look under the iPOJO tab on the
>> created instances the values are wrong. If I do any change in my
>> configuration file (e g add some whitspace) and save it, File Install picks
>> up the change and the iPOJO instance is now configured with the correct
>> value.
>>
>> I've seen a pattern regarding this. It seems like properties that are not
>> given a default value in my code (initialised to null) will get their
>> configuration set properly but the properties that are initialised to
>> another value than null will not get their proper value until I later
>> re-save my configuration file (which I guess is the next time File Install
>> will propagate configuration changes).
>>
>> Given the following code in my iPOJO service:
>>
>> ...
>> @Property(name = "toUri", mandatory = false)
>> private String mToUri;
>>
>> @Property(name = "delay", mandatory = false)
>> private long mDelay = 1000;
>> ...
>>
>> The "toUri" property will be initialised properly when the service is
>> started but the "delay" property will be initialised to 1000 regardless of
>> what value I put in the configuration file. When I later re-save the
>> configuration file, the proper value of the "delay" property will be
>> propagated.
>
> Your instance receives the configuration from the config admin before that an
> 'object' is created. So iPOJO associates mDelay to the correct value (from
> the configuration). However, then, an object is created (and so the
> constructor is called), and it executes an implicit constructor doing:
> mDelay = 1000;
>
> This overrides the value received by the configuration. If the configuration
> is updated, the instance receives the new value overriding the 1000.
>
> So to avoid such behavior, just do:
> @Property(name="delay", mandatory=false, value="1000")
> private long mDelay; // No value here
>
> This will inject 1000 if the property is not set in the configuration, or
> inject the value from the configuration.
>
> Regards,
>
> Clement
>
>
>
>
>>
>> How can I have a default value but still have it overridden properly?
>>
>> /Bengt
>
>
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