{{tag>Programmers_Reference IDocumentDataSource_Interface Example}}
[<10>]
===== Document Engine Example =====

The code snippet below represents essentially the full text of the document engine that handles the text document type in //**Aware IM**//:

Client side component

<code java>public class TextEngineClient implements IDocEngineClient
 {
    public TextEngineClient()
    {

    }
    /** 
    *@see IDocEngineClient#getTemplateType()
    */
    public StringgetTemplateType()
    {
        return CommonConstants.TEMPLATE_TEXT;
    }
    /**
     *@see IDocEngineClient#getEditCommand(String)
     */
    public FileToEditgetEditCommand(StringtemplateFilePath)
    {
        return Utils.isWindows()?
        new FileToEdit("cmd.exe /k","\""+templateFilePath+"\""):
        new FileToEdit("",templateFilePath);
    }
    /** 
     *@see IDocEngineClient#getTemplateFileType()
     */
    public StringgetTemplateFileType()
    {
        return "txt";
    }
    /**
     *@see IDocEngineClient#canHaveExternalResources()
     */
    public boolean canHaveExternalResources()
    {
        return false ;
    }
    /**
     *  @see IDocEngineClient#initialiseTemplate(DataPresentationTemplate,IDomainVersion)
     */
    public void initialiseTemplate(DataPresentationTemplatetdef,IDomainVersiondomainVersion)
    throws Exception
    {
        // determine attribute paths used
        Stringtext=getTemplateText(tdef);
        if (text!= null )
        {
            // find if there are any tags
            VectortaggedParams=Utils.extractParameters(text,“<<”, “>>”);
            if (taggedParams!= null &&taggedParams.size()>0)
                DocumentEngineUtils.setAttributePaths(taggedParams,tdef);
        }
    }
    /**
     * @see com.bas.shared.docengines.IDocEngineClient#elementsRenamed(com.bas.shared.domain.configuration.elements.DataPresentationTemplate,com.bas.shared.domain.configuration.misc.RenamedElements,com.bas.shared.ruleparser.INodeChangeHelper,IDomainVersion)
     */
    public DataPresentationTemplateelementsRenamed(
        DataPresentationTemplateoldTemplate,
        RenamedElementsrenamedElements,
        INodeChangeHelperhelper,
        IDomainVersiondomainVersion)
    {
        Stringtext=getTemplateText(oldTemplate);
        if (text== null )
            return null ;
            // extract all parameters, convert them to ASTTagStatement 
            // expressions, apply changes
            // and then replace parameters in the document
        VectortaggedParams=Utils.extractParameters(text,“<<”,“>>”);
        if (taggedParams== null ||taggedParams.size()==0)
            return null ;
        Vectormodified=DocumentEngineUtils.getModifiedParameters(taggedParams, renamedElements,helper);
        VectorwithTags=DocumentEngineUtils.appendTags(modified,"<<", ">>");
        StringnewText=Utils.replaceParameters (text,withTags,“<<”, “>>”); 
        if (newText.equals(text))
            return null ;
        DataPresentationTemplatenewTemplate = (DataPresentationTemplate)oldTemplate.deepCopy();
        try 
        {
            DocumentEngineUtils.setAttributePaths(modified, newTemplate);
            BinaryResourcebr= new BinaryResource
            (oldTemplate.getTemplate().getName(),newText.getBytes());
            newTemplate.setTemplate(br);
        }
        catch (Exception e)
        {
            return null ;
            } // shouldn't happen
            return newTemplate;
        }
        protected StringgetTemplateText(DataPresentationTemplatetemplate)
        {
            try 
            {
                BinaryResourcetemplData=template.getTemplate();
                if (templData== null )
                    return null ;
                byte []data=templData.getData();
                if (data== null )
                    return null ; 
                return new String(data);
            }
            catch (ResourceUnavailableExceptionre)
            {
                return null ;
            }
        }
    }

// Server side component
public class TextDocumentEngine implements IDocumentEngine
{
    public TextDocumentEngine()
    {
    }
    /**
    *@see IDocumentEngine#getClientEngine()
    */
    public IDocEngineClientgetClientEngine()
    {
        return new TextEngineClient();
    }
    /**
    *@see IDocumentEngine#fillWithData(String,Map,IDocumentDataSource,DataPresentationTemplate,IDocEngineHelper,IDomainVersion,int,boolean)
    */
    public BinaryResource[]fillWithData(Stringpath, Mapparams, IDocumentDataSourcedataSource, DataPresentationTemplatetdef, IDocEngineHelperhelper, DomainVersiondomainVersion, int outputFormat, boolean printResults)
    throws DocumentException
    {
        BinaryResourcetemplate=tdef.getLoadedTemplate();
        if (template== null )
            throw new DocumentException("No data in the presentation template");
        StringfileName=path+"/"+template.getName();
        try
        {
            FileinputFile= new File(fileName);
            Stringtext=FileUtils.readTextFile(fileName);
            // find if there are any tags
            VectortaggedParams= Utils.extractParameters(text);
            if (taggedParams== null || taggedParams.size()==0 || dataSource== null )
            {
                // just return the original template
                BinaryResource[]results= new BinaryResource[1];
                results[0]= new BinaryResource();
                results[0].setName(inputFile.getName());
                results[0].setData(FileUtils.readFile (fileName));
                return results;
            }
            if (dataSource== null )
                throw new DocumentException("Document template requires data, but the data source is not provided");
                // prepare the data source
            dataSource.reset();
            // for each group of records create resulting document 
            // and resolve tagged fields insidethe text
            Vectorresources= new Vector();
            while (dataSource.next())
            {
                VectortagValues= new Vector
                (taggedParams.size());
                for (Iteratoriter=taggedParams.iterator();
                    iter.hasNext();)
                {
                    StringtagContents=(String)iter.next();
                    Object o=dataSource.getExpressionValue (tagContents);
                    tagValues.add(o== null ?  null :o.toString());
                }
                StringnewText= Utils.replaceParameters(text, tagValues);
                if (printResults)
                    printText(newText);
                BinaryResourcebr= new BinaryResource();
                br.setData(newText.getBytes());
                br.setName(inputFile.getName());
                resources.add(br);
            }
            if (resources.size()==0)
                return null ;
            BinaryResource[]results= new BinaryResource [resources.size()];
            int i=0;
            for (Iteratoriter=resources.iterator();iter.hasNext();
                ++i) results[i]=(BinaryResource)iter.next();
            return results;
        }
        catch (DocumentException de)
        {
            throw de;
        }
        /** 
        *@see IDocumentEngine#printFile()
        */
        public void printFile(FilefileToPrint)
        throws DocumentException
        {
            try
            {
                Stringtext = FileUtils.readTextFile(fileToPrint.getPath());
                printText(text);
            }
            catch (Exception e)
            {
                throw new DocumentException(e.getMessage());
            }
        }
        protected void printText(Stringtext)
        throws DocumentException
        {
            try
            {
                PlainDocumentdoc= new PlainDocument();
                doc.insertString(0,text, null );
                TextDocumentPrintRendererprinter= new TextDocumentPrintRenderer();
                printer.print(doc, false );
            }
            catch (Exception e)
            {
                throw new DocumentException(e.getMessage());
            }
        }
    }
}
</code>