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MyViewObjectImpl:
Programmatic View Object
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The class inherits
basic ADF behavior from oracle.jbo.server.ViewObjectImpl class and is
responsible for managing programmatic data collection.
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For that, it
overrides data source methods, they are:
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-
executeQueryForCollection()
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-
hasNextForCollection()
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-
createRowFromResultSet()
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-
getQueryHitCount()
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1st method -
executeQueryForCollection() - is the most important, because it performs all
actions needed for receiving results of the query by mean of WSDS client.
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Preparing request to
WSDS client, the method takes from ADF all necessary properties that define
the expected rowset. Here are the request parameters and appropriate ADF
methods used:
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- query SQL
statement
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is constructed from getQuery(),
getWhereClause(), getOrderByClause() mtds
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- query parameters - are taken from the method arguments
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- number of rows in
range - returned by getMaxFetchSize()
method
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- jdbc fetch size
for WSDS - the value from
getFetchSize()
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In return, the
method gets from WSDS client:
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- total count of
rows in the query
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- two-dimensional
array of values representing requested rowset used as new programmatic data
collection
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For further
fulfilling its model functions, the new class overrides row manipulation
methods - insertRow() and removeCurrentRow() - which results should be
reflected in programmatic data collection.
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ADF Developer's
Guide contains detailed description for programmatic view object in the
chapter "27.8 Using Programmatic View Objects for Alternative Data
Sources".
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