THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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Using a factory method to create POJO object
By default, iPOJO calls the POJO constructor to create objects. This constructor can either has no argument or receive the bundle context. However sometimes, you may want a more advanced object creation policy.
iPOJO allows you describing a factory method called to create POJO objects instead of the constructor. So, every time that iPOJO needs to create an instance of your POJO class, this method will be called to obtain the object.
To use this feature you need to add the factory-method attribute in the Component element as illustrated below:
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{html} h1. Using a factory method to create POJO object _By default, iPOJO calls the POJO constructor to create objects. This constructor can either has no argument or receive the bundle context. However sometimes, you may want a more advanced object creation policy._ iPOJO allows you describing a factory method called to create POJO objects instead of the constructor. So, every time that iPOJO needs to create an instance of your POJO class, this method will be called to obtain the object. To use this feature you need to add the {{factory-method}} attribute in the Component element as illustrated below: {code:xml} <component className="org.apache.felix.ipojo.test.scenarios.component.FooProvider" factory-method="createProvider" > ... </component> {code} |
The
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specified
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method
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must
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be
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a
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static
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method
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of
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the
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implementation
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class
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returning
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an
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instance
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of
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this
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implementation
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class
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.
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The
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following
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code
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shows
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an
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example
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of
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usage:
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} public static FooProvider createProvider() { if (singleton == null) { singleton = new FooProvider(); } return singleton; } {code} |
This
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method
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must
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then
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call
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any
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valid
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constructor
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(potentially
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private)
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of
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the
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implementation
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class.
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However,
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be
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aware
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that
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if
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you
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create
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an
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instance
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by
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using
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a
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factory-method
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,
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the
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called
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constructor
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hasn't
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access
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to
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values
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injected
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by
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the
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iPOJO
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container.
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So,
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the
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called
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constructor
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must
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not
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try
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accessing
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to
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services,
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properties...
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These
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objects
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will
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be
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accessible
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when
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the
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constructor
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returns.
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As
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for
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"normal"
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constructor,
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the
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method-factory
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can
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receive
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the
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bundle
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context
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in
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argument,
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such
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as
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in:
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} public static FooProvider createProvider (BundleContext bc) { if (singleton == null) { singleton = new FooProvider(bc); } return singleton; } {code include |
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