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Domino Design Code Injection - Part 2

In Part 1 I introduced the approach to code injection and some sample LotusScript Code to pull a design element, transform it and push it back. Missing there was the function that actually implemented that method. I'm using a Java class to do that, which I wrap into LS2J. The LotusScript function looks like this: 
 


  Option Public Option Declare Uselsx "*javacon"

  Use "CodeInjector"

  Function injectCode
  
  (rawDXL
  
  As
  
  String
  
  , xPath
  
  As
  
  String
  
  , codeSnippet
  
  As
  
  String
  
  )
  
  As
  
  String

  'Dummy doesn't do anything

  Dim jSession
  
  As
  
  JAVASESSION

  Dim injectorClass
  
  As
  
  JAVACLASS

  Dim injector
  
  As
  
  JavaObject

  Set jSession
  
  =
  
  New
  
  JAVASESSION
 injectCode
  
  = rawDXL

  Set injectorClass
  
  = jSession
  
  .GetClass
  
  (
  
  "DominoXPathInjector"
  
  )

  Set injector
  
  = injectorClass
  
  .
  
  CreateObject

  'Now set the document

  Call injector
  
  .setDocument
  
  (rawDXL
  
  )

  'and execute the function 
 injectCode
  
  = injector
  
  .injectCode
  
  (codeSnippet
  
  , xPath
  
  , 4
  
  )

  End
  
  Function
This LotusScript was converted to HTML using the ls2html routine,
provided by Julian Robichaux at nsftools.com.
Now let us have a quick look at the Java class./**
* Sample Code without warranty, use at your own risk
* (C) 2008, stephan@wissel.net
* Proper error handling omitted for clarity
*/

import java.io.ByteArrayOutputStream;
import java.io.StringReader;

import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.*;
import javax.xml.transform.stream.*;
import javax.xml.xpath.*;

import org.w3c.dom.*;
import org.xml.sax.InputSource;

public class XPathInjector {
  public static final int IMPORT_BEFORE = 0;
  public static final int IMPORT_AFTER = 1;
  public static final int IMPORT_REPLACE = 2;
  public static final int IMPORT_FIRSTCHILD = 3;
  public static final int IMPORT_LASTCHILD = 4;
  Document doc;

  private DocumentBuilder getDocumentBuilder() throws ParserConfigurationException {
    DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
    documentBuilderFactory.setValidating(false);
    documentBuilderFactory.setSchema(null);
    documentBuilderFactory.setNamespaceAware(false);
    documentBuilderFactory.setIgnoringComments(false);
    documentBuilderFactory.setIgnoringElementContentWhitespace(false);
    documentBuilderFactory.setXIncludeAware(false);
    DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
    return documentBuilder;
  }

  private NodeList getMachingNodes(String xPathString) {
    XPathFactory factory = XPathFactory.newInstance();
    XPath xpath = factory.newXPath();
    XPathExpression expr;
    try {
      expr = xpath.compile(xPathString);
      Object result = expr.evaluate(doc, XPathConstants.NODESET);
      return (NodeList) result;
    } catch (Exception e) {
      e.printStackTrace();
    }
    return null;
  }

  private Node getNodeFromString(String codeFragment) {
    String workString = "<wrapper>" + codeFragment + "</wrapper>";
    InputSource in = new InputSource(new StringReader(workString));
    try {
      DocumentBuilder documentBuilder = this.getDocumentBuilder();
      Document miniDoc = documentBuilder.parse(in);
      Node wrapper = doc.importNode(miniDoc.getDocumentElement(), true);
      return wrapper;
    } catch (Exception e) {
      e.printStackTrace();
    }
    return null;
  }

  public String injectCode(String codeFragment, String xPath, int importOption) {
    Node codeToInsert = this.getNodeFromString(codeFragment);
    NodeList replaceCandidates = this.getMachingNodes(xPath);
    boolean appendToNode = true;
    if (replaceCandidates != null) {
      for (int i = 0, size = replaceCandidates.getLength(); i < size; i++) {
        Node curNode = replaceCandidates.item(i);
        Node referenceNode = null;
        if (importOption == XPathInjector.IMPORT_BEFORE) {
          appendToNode = false;
          referenceNode = curNode;
        } else if (importOption == XPathInjector.IMPORT_AFTER) {
          if (curNode.getNextSibling() == null) {
            referenceNode = curNode.getParentNode();
            appendToNode = true;
          } else {
            referenceNode = curNode.getNextSibling();
            appendToNode = false;
          }
        } else if (importOption == XPathInjector.IMPORT_FIRSTCHILD) {
          if (curNode.getFirstChild() == null) {
            referenceNode = curNode;
            appendToNode = true;
          } else {
            referenceNode = curNode.getFirstChild();
            appendToNode = false;
          }
        } else if (importOption == XPathInjector.IMPORT_LASTCHILD) {
          referenceNode = curNode;
          appendToNode = true;
        } else if (importOption == XPathInjector.IMPORT_REPLACE) {
          if (curNode.getNextSibling() == null) {
            referenceNode = curNode.getParentNode();
            appendToNode = true;
          } else {
            referenceNode = curNode.getNextSibling();
            appendToNode = false;
          }
          curNode.getParentNode().removeChild(curNode);
        } else {
          return this.toString();
        }
        NodeList newNodes = codeToInsert.getChildNodes();
        for (int k = 0, insertSize = newNodes.getLength(); k < insertSize; k++) {
          if (appendToNode) {
            referenceNode.appendChild(newNodes.item(k));
          } else {
            referenceNode.getParentNode().insertBefore(newNodes.item(i), referenceNode);
          }
        }
      }
    }
    return this.toString();
  }

  public void setDocument(String docString) {

    InputSource in = new InputSource(new StringReader(docString));
    try {
      DocumentBuilder documentBuilder = this.getDocumentBuilder();
      this.doc = documentBuilder.parse(in);
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
  @Override
  public String toString() {
    try {
      StreamResult result = null;
      ByteArrayOutputStream byteResult = new ByteArrayOutputStream();
      TransformerFactory tFactory = TransformerFactory.newInstance();
      Transformer transformer = tFactory.newTransformer();
      DOMSource source = new DOMSource(doc);
      result = new StreamResult(byteResult);
      transformer.transform(source, result);
      return byteResult.toString();
    } catch (Exception e) {
      e.printStackTrace();
    }
    return null;
  }
}

Posted by on 21 March 2008 | Comments (0) | categories: Show-N-Tell Thursday

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