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Overview of the Provider API and Desktop Servlet
See the Javadocs for more information on the methods in this interface.
PropertiesFilter
The PropertiesFilter abstract class, when extended, can describe a specific filter
criteria. To implement a specific filter, one must minimally implement the
getCondition() and match() methods in the PropertiesFilter abstract class.
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The getCondition() method must return the condition on which the
PropertiesFilter should operate.
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The getValue() method must return the value that corresponds to the given
condition.
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The isRequired() method can be implemented to specify whether you want
this to be a required filter or not. A conditional property lookup involves one
or more property filters. If a filter in the filter list is required, then it must
match for the overall conditional lookup to succeed. If a filter is not required,
then it can fail to match without causing the overall lookup to fail.
A chain of non-required filters can be used to implement a progressively
less-specific filter lookup, similar to the semantics of Java resource bundle
lookup. For instance, an optional filter would be useful in a case where a locale
lookup is followed by a date lookup. Given the filter {locale=en, locale=US,
date=03/03/2003}, you can get it to successfully match a property with the
qualifier {locale=en; date=03/03/2003} even though it does not exactly match
the filter specification. This can be accomplished by setting the locale filter to
be optional. The locale property type is deprecated.
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The match() method returns true if this filter object agrees with or matches the
condition and value that are passed in, given the information that was used to
create the object.
Out of the box, the Portal Server software includes filters based on locale and client.
The locale and client filter extend the PropertiesFilter abstract class and includes an
implementation of the getCondition() and match() methods in the
PropertiesFilter class. See the Javadoc for more details.
Exceptions
The Desktop expects a provider to only throw ProviderException or a subclass of
the ProviderException. For correct operation, a provider must only throw expected
exception type. That is:
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Minor exceptions can be managed internally, for example, log a debug
message.
Chapter
2
Using Provider API (PAPI)
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