Birt：从beforeFactory访问数据集的内容

Question

Im trying (desperately) to access the content of a dataset by script in the beforeFactory.

The task at hand is to create design elements from a linked library and place them in a certain cell of a grid. Everything works fine except for the "place them in a certain cell of a grid"-part.

The information about which element is to be created and where it is to be placed is available in a dataset (dsDesignInformation), which contains three columns: targetRow, targetColumn, targetContent. targetContent contains a string, which is used to find an element in the library.

For example: There is a grid placed on the body (grdMasterGrid), with two rows and two columns. If the dsDesignInformation would contain a row like (1,1,"testObjectName"), I want to create the element "testObject" from a linked library and place it in the intersection of row 1 and column 1 of my grdMasterGrid.

The code for creating and placing the element:

importPackage(org.eclipse.birt.report.model.api);

var myLibraryHandle = reportContext.getDesignHandle().getLibrary("myLibraryName");
var myElementFactory = reportContext.getDesignHandle().getElementFactory();

// should be the objectname as defined in the dsDesignInformation 
var myTargetElementHandle = myLibraryHandle.findElement("testObjectName");
var myCreatedElementHandle = myElementFactory.newElementFrom(myTargetElementHandle , "someUniqueElementName");

var myMasterGridHandle = reportContext.getDesignHandle().findElement("grdMasterGrid");
// should be target coordinates as defined in dsDesignInformation 
var myTargetCellHandle= myMasterGridHandle.getCell(1,1);
myTargeCellHandle.getContent().add(myCreatedElementHandle);

This works like a charm when used with hard coded target-information and placed in the beforeFactory of the report design.

I do however need to access the contents of dsDesignInformation and pass them on to the script above. So far (4 days in) I had zero (as in null) success.

I would be glad for any help or ideas on the topic.

Regards, maggutz

Answer 1

It is possible to do this, but with some severe restrictions.

The main restriction is: You cannot use your DataSource and your DataSet directly. Instead, you'll have to copy them and work with the copy. Don't ask my why this is, because I don't know. But I learned it the hard way during hours and days of trying...

The next restriction is: You cannot access report parameter values, unfortunately. This is not a problem if your query works without parameters. Otherwise, you'll have to find a way to access the parameter value anyhow. Depending on how your report is integrated into the app, you could try writing the value into the appContext before calling BIRT, for example.

Here is a fragment of working code (in the beforeFactory event) to show you how to workaround this limitation:

importPackage( Packages.org.eclipse.birt.report.model.api );
importPackage(Packages.org.eclipse.birt.data.engine.api);
importPackage(Packages.org.eclipse.birt.report.model.api);
importPackage(Packages.org.eclipse.birt.data.engine.api.querydefn);
importPackage(Packages.org.eclipse.birt.data.engine.core);
importPackage( Packages.org.eclipse.birt.report.model.api );

var myconfig = reportContext.getReportRunnable().getReportEngine().getConfig();
var de = DataEngine.newDataEngine( myconfig, null );

var dsrc = reportContext.getDesignHandle().findDataSource("lisa");
// This is the existing data source.

var odaDataSource = new OdaDataSourceDesign( "Test Data Source" );
// We create a new DataSource which is only to be used in this event

// Now we copy the relevant properties from the existing DataSource to the new one.
var dbUrl = dsrc.getProperty("odaURL").toString();
var dbUsr = dsrc.getProperty("odaUser").toString();
var dbPwd = dsrc.getProperty("odaPassword").toString();
var dbDrv = dsrc.getProperty("odaDriverClass").toString();
odaDataSource.setExtensionID( "org.eclipse.birt.report.data.oda.jdbc" );
odaDataSource.addPublicProperty( "odaURL", dbUrl );
odaDataSource.addPublicProperty( "odaDriverClass", dbDrv);
odaDataSource.addPublicProperty( "odaUser", dbUsr );
odaDataSource.addPublicProperty( "odaPassword", dbPwd );        

// log.info("odaURL=" + dbUrl); // Only if you have a logging framework at hand

// Now create a new DataSet and set its query etc.
// I suppose that it is possible to copy the properties from an existing DataSet instead.
//  However, I didn't try that.
var odaDataSet = new OdaDataSetDesign( "Test Data Set" );
odaDataSet.setDataSource( odaDataSource.getName() );
odaDataSet.setExtensionID( "org.eclipse.birt.report.data.oda.jdbc.JdbcSelectDataSet" );

// This is the SQL query (in my application).
// You'll have to modify this as needed.
odaDataSet.setQueryText( " select STEDA.TEDA_ID, STBST.LANGTEXT" +
                     " from STEDA, STBST" +
                     " where STEDA.ZUSATZ_1 = 'MATRIX'" +
                     " and STBST.TBST_ID = STEDA.TEDA_ID"); 

// Tell the DataEngine about the new objects.
de.defineDataSource( odaDataSource );
de.defineDataSet( odaDataSet );

// Now execute the query:
// This seems overly complicated, but hey: it works.
var queryDefinition = new QueryDefinition( );
queryDefinition.setDataSetName( odaDataSet.getName() );
queryDefinition.setAutoBinding(true);
var pq = de.prepare( queryDefinition );
var qr = pq.execute( null );

rowcount=0;     
var elementFactory = reportContext.getDesignHandle().getElementFactory()
var ri = qr.getResultIterator( );       

// Our application is using the query to generate a layout structure 
// into an (already existing) placeholder element "Layout MATRIX".
var containerGrid = reportContext.getDesignHandle().findElement("Layout MATRIX");

// Iterate through the query results
while (  ri.next( ) )
{
    // get the actual values of the query output columns
    var tedaId = ri.getString("TEDA_ID");
    var langtext = ri.getString("LANGTEXT");
    // log.info("langtext: " + langtext);
    rowcount++;

    // Do something with the current result row.
    ... myModifyLayout(containerGrid, tedaId, langtext); ...
}

// Cleanup
ri.close( );
qr.close( );
de.shutdown( );

// You may want to save the modified design file while developing.
// That way you can check the mresults in the Report Designer.
if (false) {
    reportContext.getDesignHandle().saveAs("c:/temp/modified.rptdesign");
}