DataRetriever

Description

The element DataRetriever allows to define a helper function.

GreenVulcano^® ESB configuration

The DataRetriever elements define helper functions used in data transformations for enriching XML products. Might contain placeholders.

It is defined by the following parameters:

Attribute	Type	Description
cacheable	optional	If true the calculated function value, for the given parameters set, is cached for future access during the service processing. The cache is cancelled at service end. Default false.
method	required	Helper function name.
signature	optional	Comma-separated list of parameters name to be substituted in the function.

Examples of GenericRetriever functions

Configuration examples.

<RetrieverConfig>
    <GenericRetriever class="it.greenvulcano.gvesb.datahandling.utils.GenericRetriever"
                        type="retriever">

        <DataRetriever cacheable="true" method="getCityID" signature="NAME">
            select ID from CITY
            where NAME='@{{NAME}}'
        </DataRetriever>

        <DataRetriever cacheable="true" method="getCityName" signature="ID">
            select NAME from CITY
            where ID=@{{ID}}
        </DataRetriever>

        <DataRetriever method="getPersonID" signature="NAME,CITY">
            select ID from PERSON
            where NAME='@{{NAME}}'
            and ID_CITY=(select ID from CITY where NAME='@{{CITY}}')
        </DataRetriever>

        <DataRetriever cacheable="true" method="getCardID" signature="NUMBER,ID_OWNER">
            select ID from CREDIT_CARD
            where CNUMBER='@{{NUMBER}}'
            and ID_OWNER=@{{ID_OWNER}}
        </DataRetriever>

        <DataRetriever method="getSeqVal">
            select SEQ_PERSON_ID.nextval from dual
        </DataRetriever>
    </GenericRetriever>
</RetrieverConfig>

Function description.

Function	Parameters	Cacheable	Description
getCityID	NAME	true	Returns the ID field of the first record of table CITY with field NAME equals to the passed parameter. The parameter is cacheable so, for the given parameter value, the subsequent call returns the same value.
getCityName	ID	true	Returns the NAME field of the first record of table CITY with field ID equals to the passed parameter. The parameter is cacheable so, for the given parameter value, the subsequent call returns the same value.
getPersonID	NAME,CITY	false	Returns the ID field of a record of table PERSON with field NAME equals to the first passed parameter and with an external reference to a record of table CITY with field NAME equals to the second passed parameter.
getCardID	NUMBER,ID_OWNER	true	Returns the ID field of the first record of table CREDIT_CARD with field CNUMBER equals to the first passed parameter and the field ID_OWNER equals to the second passed parameter. The parameter is cacheable so, for the given parameters value, the subsequent call returns the same value.
getSeqVal		false	Returns the next sequence value.

Usage examples in XSL transformation. The examples use the calling procedure of Java classes of Xalan-J XSLT Engine.

    <!-- from gvdte/datasource/xsl/DataHandler/CREDIT/CreditUpdate.xsl -->
    <xsl:variable name="name" select="/PersonsData/PersonData/Name"/>
    <xsl:variable name="city" select="/PersonsData/PersonData/City"/>
    <xsl:element name="col">
        <xsl:value-of   
          select="java:it.greenvulcano.gvesb.datahandling.utils.GenericRetriever.getData
                       ('getPersonID',concat($name,',',$city))"/>
    </xsl:element>

    <!-- from gvdte/datasource/xsl/DataHandler/CREDIT/PersonInsertFull.xsl -->
    <xsl:template match="PersonData">
        <xsl:variable name="PersonId"  
          select="java:it.greenvulcano.gvesb.datahandling.utils.GenericRetriever.getData
                 ('getPersonID', concat(Name, ',', City))"/>
        <xsl:variable name="CityId"
          select="java:it.greenvulcano.gvesb.datahandling.utils.GenericRetriever.getData
                 ('getCityID', City)"/>
    .....
        <xsl:variable name="PersonId"  
          select="java:it.greenvulcano.gvesb.datahandling.utils.GenericRetriever.getData
                 ('getSeqVal', '')"/>
    .....
    <xsl:template match="CardData">
        <xsl:param name="OwnerId"/>
        <xsl:variable name="CardId" 
          select="java:it.greenvulcano.gvesb.datahandling.utils.GenericRetriever.getData
                 ('getCardID', concat(Number, ',', $OwnerId))"/>

From 3.4.0.9 version the getData method can accept 3 parameters, in order to specify the DataRetriever's actual parameters value separator, useful if some parameter value contains a comma.

    <!-- from gvdte/datasource/xsl/DataHandler/CREDIT/CreditUpdate.xsl -->
    <xsl:variable name="name" select="/PersonsData/PersonData/Name"/>
    <xsl:variable name="city" select="/PersonsData/PersonData/City"/>
    <xsl:element name="col">
        <xsl:value-of   
          select="java:it.greenvulcano.gvesb.datahandling.utils.GenericRetriever.getData
                       ('getPersonID',concat($name,'$',$city), '$')"/>
    </xsl:element>

    <!-- from gvdte/datasource/xsl/DataHandler/CREDIT/PersonInsertFull.xsl -->
    <xsl:template match="PersonData">
        <xsl:variable name="PersonId"  
          select="java:it.greenvulcano.gvesb.datahandling.utils.GenericRetriever.getData
                 ('getPersonID', concat(Name, '#', City), '#')"/>
    .....
    <xsl:template match="CardData">
        <xsl:param name="OwnerId"/>
        <xsl:variable name="CardId" 
          select="java:it.greenvulcano.gvesb.datahandling.utils.GenericRetriever.getData
                 ('getCardID', concat(Number, '-', $OwnerId), '-')"/>