Changeset 25445 for main

Timestamp:

2012-04-19T22:09:50+12:00 (12 years ago)

Author:

ak19

Message:

Error reporting is now improved again, much better than in previous commit: no longer just writes out the XSLT stylesheet to the log file, but follows Dr Bainbridge and Sam's suggestion of performing the transformation that failed again with physical files instead of in-memory as before. This points out the exact line location of errors.

Location:

main/trunk/greenstone3/src/java/org/greenstone/gsdl3

Files:

• core/TransformingReceptionist.java (modified) (2 diffs)
• util/GSXML.java (modified) (2 diffs)
• util/XMLTransformer.java (modified) (15 diffs)

main/trunk/greenstone3/src/java/org/greenstone/gsdl3/core/TransformingReceptionist.java

@@ -593 +593 @@
         Document skinAndLibraryXsl = null;
         Document skinAndLibraryDoc = converter.newDOM();
-        try
+        
+        // Applying the preprocessing XSLT - in its own block {} to allow use of non-unique variable names
         {
 
@@ -615 +616 @@
             //In other words, apply the preProcess.xsl to 'skinAndLibraryXsl' in order to
             //expand all GS-Lib statements into complete XSL statements and also to create
-            //a valid  xsl style sheet document.
-
-            Transformer preProcessor = transformerFactory.newTransformer(new DOMSource(preprocessingXsl));
-            preProcessor.setErrorListener(new XMLTransformer.TransformErrorListener(preprocessingXsl));
-            DOMResult result = new DOMResult();
-            result.setNode(skinAndLibraryDoc);
-            preProcessor.transform(new DOMSource(skinAndLibraryXsl), result);
-            //System.out.println("GS-Lib statements are now expanded") ;        
-
-        }
-        catch (TransformerException e)
-        {
-            e.printStackTrace();
-            System.out.println("TransformerException while preprocessing the skin xslt");
-            return XMLTransformer.constructErrorXHTMLPage(e.getMessage());
-        }
-        catch (Exception e)
-        {
-            e.printStackTrace();
-            System.out.println("Error while preprocessing the skin xslt");
-            return XMLTransformer.constructErrorXHTMLPage(e.getMessage());
-        }
+            //a valid xsl style sheet document.
+
+            XMLTransformer preProcessor = new XMLTransformer();
+            // Perform the transformation, by passing in:
+            // preprocess-stylesheet, source-xsl (skinAndLibraryXsl), and the node that should 
+            // be in the result (skinAndLibraryDoc)
+            preProcessor.transform_withResultNode(preprocessingXsl, skinAndLibraryXsl, skinAndLibraryDoc);
+            //System.out.println("GS-Lib statements are now expanded") ;
+        }
+    
 
         //The following code is to be uncommented if we need to append the extracted GSF statements

main/trunk/greenstone3/src/java/org/greenstone/gsdl3/util/GSXML.java

@@ -1244 +1244 @@
     public static String elementToString(Element e, boolean indent)
     {
-        String str = "**********START*************\n";
         try {
         TransformerFactory tf = TransformerFactory.newInstance();
@@ -1261 +1260 @@
         } 
         finally {
-        str += "\n***********************\n";
         return str;
         }

main/trunk/greenstone3/src/java/org/greenstone/gsdl3/util/XMLTransformer.java

@@ -19 +19 @@
 package org.greenstone.gsdl3.util;
 
+import org.greenstone.util.GlobalProperties;
+
 // XML classes
 import javax.xml.transform.Transformer;
@@ -28 +30 @@
 import javax.xml.transform.stream.StreamSource;
 import javax.xml.transform.dom.DOMSource;
+import javax.xml.transform.Source;
 import javax.xml.transform.stream.StreamResult;
 import javax.xml.transform.dom.DOMResult;
@@ -44 +47 @@
 import java.io.BufferedReader;
 import java.io.FileReader;
+import java.io.FileWriter;
 import java.io.File;
 import java.util.HashMap;
@@ -62 +66 @@
  */
 public class XMLTransformer {
+    private static int debugFileCount = 0; // for unique filenames when debugging XML transformations with physical files
 
     static Logger logger = Logger.getLogger(org.greenstone.gsdl3.util.XMLTransformer.class.getName());
@@ -118 +123 @@
         // Use the TransformerFactory to process the stylesheet Source and generate a Transformer.
         Transformer transformer = this.t_factory.newTransformer(new StreamSource(stylesheet));
-        transformer.setErrorListener(new TransformErrorListener(stylesheet));
 
         // Use the Transformer to transform an XML Source and send the output to a Result object.
         StringWriter output = new StringWriter();
-
-        transformer.transform(new StreamSource(new StringReader(xml_in)), new StreamResult(output));
+        StreamSource streamSource = new StreamSource(new StringReader(xml_in));
+        transformer.setErrorListener(new TransformErrorListener(stylesheet, streamSource));
+        transformer.transform(streamSource, new StreamResult(output));
         return output.toString();
     } catch (TransformerConfigurationException e) {
@@ -139 +144 @@
     }
     
+
     public String transformToString(Document stylesheet, Document source, HashMap parameters) {
     
@@ -144 +150 @@
         // Use the TransformerFactory to process the stylesheet Source and generate a Transformer.
         Transformer transformer = this.t_factory.newTransformer(new DOMSource(stylesheet));
-        transformer.setErrorListener(new TransformErrorListener(stylesheet));
         if (parameters != null) {
         Set params = parameters.entrySet();
@@ -158 +163 @@
         // Use the Transformer to transform an XML Source and send the output to a Result object.
         StringWriter output = new StringWriter();
-        
-        transformer.transform(new DOMSource(source), new StreamResult(output));
+        DOMSource domSource = new DOMSource(source);
+
+        transformer.setErrorListener(new TransformErrorListener(stylesheet, domSource));
+        transformer.transform(domSource, new StreamResult(output));
         return output.toString();
     } catch (TransformerConfigurationException e) {
@@ -171 +178 @@
     }
 
+    
+
+    /**
+     * Transform an XML document using a XSLT stylesheet, 
+     * but using a DOMResult whose node should be set to the Document donated by resultNode
+     */
+    public Node transform_withResultNode(Document stylesheet, Document source, Document resultNode) {
+        return transform(stylesheet, source, null, null, resultNode);
+    }
+
     public Node transform(Document stylesheet, Document source) {
-        return transform(stylesheet, source, null, null);
+        return transform(stylesheet, source, null, null, null);
     }
     
     public Node transform(Document stylesheet, Document source, HashMap parameters) {
-        return transform(stylesheet, source, parameters, null);
+        return transform(stylesheet, source, parameters, null, null);
     }
 
     public Node transform(Document stylesheet, Document source, HashMap parameters, Document docDocType) {
+    return transform(stylesheet, source, parameters, docDocType, null);
+    }
+
+    protected Node transform(Document stylesheet, Document source, HashMap parameters, Document docDocType, Document resultNode) {
         try {
             // Use the TransformerFactory to process the stylesheet Source and generate a Transformer.
             Transformer transformer = this.t_factory.newTransformer(new DOMSource(stylesheet));
             logger.info("XMLTransformer transformer is " + transformer);
-            transformer.setErrorListener(new TransformErrorListener(stylesheet));
             if (parameters != null) {
                 Set params = parameters.entrySet();
@@ -200 +220 @@
             // that does not contain any doctype (like we use to do before).
             DOMResult result = docDocType == null ? new DOMResult() : new DOMResult(docDocType);
-            transformer.transform(new DOMSource(source), result);
+            if(resultNode != null) {
+                result.setNode(resultNode);
+            }
+            DOMSource domSource = new DOMSource(source);
+            transformer.setErrorListener(new TransformErrorListener(stylesheet, domSource));
+            transformer.transform(domSource, result);
             return result.getNode(); // pass the entire document
         } 
@@ -214 +239 @@
 
     public Node transform(File stylesheet, File source) {
+    return transform(stylesheet, source, null);
+    }
+
+    // debugAsFile is only to be set to true when either the stylesheet or source parameters 
+    // are not objects of type File. The debugAsFile variable is passed into the 
+    // TransformErrorListener. When set to true, the TransformErrorListener will itself create
+    // two files containing the stylesheet and source XML, and try to transform the new source
+    // file with the stylesheet file for debugging purposes.
+    protected Node transform(File stylesheet, File source, Document docDocType) {
     try {
         Transformer transformer = this.t_factory.newTransformer(new StreamSource(stylesheet));
-        transformer.setErrorListener(new TransformErrorListener(stylesheet));
-        DOMResult result = new DOMResult();
-        transformer.transform(new StreamSource(source), result);
+        DOMResult result = (docDocType == null) ? new DOMResult() : new DOMResult(docDocType);
+        StreamSource streamSource = new StreamSource(source);
+
+        transformer.setErrorListener(new TransformErrorListener(stylesheet, streamSource));
+
+        transformer.transform(streamSource, result);
         return result.getNode().getFirstChild();
     } catch (TransformerConfigurationException e) {
@@ -230 +267 @@
                 + stylesheet + "\n" + source, e);
     }   
- }
- 
-    public Node transform(File stylesheet, File source, Document docDocType) {
-        try {
-            Transformer transformer = this.t_factory.newTransformer(new StreamSource(stylesheet));
-            transformer.setErrorListener(new TransformErrorListener(stylesheet));
-            DOMResult result = new DOMResult(docDocType);
-            transformer.transform(new StreamSource(source), result);
-            return result.getNode().getFirstChild();
-        } catch (TransformerConfigurationException e) {
-            return transformError("XMLTransformer.transform(File, File, Doc)"
-                + "\ncouldn't create transformer object for files\n" 
-                + stylesheet + "\n" + source, e);
-        } 
-        catch (TransformerException e) {
-            return transformError("XMLTransformer.transform(File, File, Doc)"
-                + "\ncouldn't transform the source for files\n" 
-                + stylesheet + "\n" + source, e);
-        }   
-    }
-    
+    }
+     
     // Given a heading string on the sort of transformation error that occurred and the exception object itself, 
     // this method prints the exception to the tomcat window (system.err) and the greenstone log and then returns
@@ -317 +335 @@
     }
     
-    // ErrorListener class that can be used to register a handler for any fatal errors, errors and warnings that may
-    // occur when transforming an xml file with an xslt stylesheet. The errors are printed both to the greenstone.log and 
-    // to the tomcat console (System.err), and the error message is stored in the errorMessage variable so that it can
-    // be retrieved and be used to generate an xhtml error page.
-    static public class TransformErrorListener implements ErrorListener {
+    // ErrorListener class that can be used to register a handler for any fatal errors, errors and warnings
+    // that may occur when transforming an xml file with an xslt stylesheet using the XMLTransformer. 
+        // The errors are printed both to the greenstone.log and to the tomcat console (System.err), and the
+    // error message is stored in the errorMessage variable so that it can be retrieved and be used to
+    // generate an xhtml error page.
+    public class TransformErrorListener implements ErrorListener {
         protected String errorMessage = null;
         protected String stylesheet = null;
-        protected String file = null;
+        protected Source source = null; // can be DOMSource or StreamSource
+        protected boolean debugAsFile = true; // true if xslt or source are not real physical files
         
-        public TransformErrorListener(String xslt) { 
+        public TransformErrorListener(String xslt, Source source) { 
         this.stylesheet = xslt; 
-        }
-
-        public TransformErrorListener(Document xslt) { 
-        //this.stylesheet = GSXML.xmlNodeToString(xslt); 
+        this.source = source;
+        XMLTransformer.debugFileCount++;
+        }
+
+        public TransformErrorListener(Document xslt, Source source) {       
         this.stylesheet = GSXML.elementToString(xslt.getDocumentElement(), true);
-        }
-
-        public TransformErrorListener(File xslt) { 
-        stylesheet = "";        
-        file = xslt.getAbsolutePath();
-        String error = "Can't locate stylesheet file: " + xslt;
-
-        if(!xslt.exists()) {
-            stylesheet = error;
-            System.err.println("@@@@@@@ " + error);
-            return;
-        }
-        try {
-            BufferedReader in = new BufferedReader(new FileReader(xslt));
-            String line = "";
-            while((line = in.readLine()) != null) {
-            stylesheet = stylesheet + line + "\n";
-            }
-            in.close();
-            in = null;
-        } catch(Exception e) {
-            stylesheet = error;
-            System.err.println("Exception reading file: " + xslt.getAbsolutePath());
-            e.printStackTrace();
-        }
+        this.source = source;
+        XMLTransformer.debugFileCount++;
+        }
+
+        public TransformErrorListener(File xslt, Source source) {
+        this.debugAsFile = false; // if this constructor is called, we're dealing with physical files for both xslt and source
+        this.source = source;
+        this.stylesheet = xslt.getAbsolutePath(); // not necessary to get the string from the file
+                   // all we were going to do with it *on error* was write it out to a file anyway      
         }
 
@@ -383 +388 @@
         }
         
-        // clears the errorPage variable after first call to this method
+        // clears the errorPage variable after the first call to this method
         public String getErrorMessage() {
         String errMsg = this.errorMessage;
@@ -395 +400 @@
         // and writes the errorMessage to the logger and tomcat's System.err
         protected void handleError(String errorType, TransformerException exception) {
-        this.errorMessage = errorType + toString(exception); 
-        if(file != null) { 
-            this.errorMessage = this.errorMessage + "\nfilename: " + file;
-        }
-        this.errorMessage += "\nException CAUSE:\n" + exception.getCause();
-        System.err.println("\n****Error transforming xml:\n" + this.errorMessage + "\n****\n");
-        System.err.println("Stylesheet was:\n" + this.stylesheet + "\n\n");
-        logger.error(this.errorMessage);
+
+        this.errorMessage = errorType + toString(exception);
+
+        // If either the stylesheet or the source to be transformed with it were not files,
+        // so that the transformation was performed in-memory, then the "location" information
+        // during the error handling (if any) wouldn't have been helpful.
+        // To allow proper debugging, we write both stylesheet and source out as physical files
+        // and perform the same transformation again, so that when a transformation error does 
+        // occur, the files are not in-memory but can be viewed, and any location information
+        // for the error given by the ErrorListener will be sensible (instead of the unhelpful
+        // "line#0 column#0 in file://somewhere/dummy.xsl").
+        // Note that if the stylesheet and the source it is to transform were both physical 
+        // files to start off with, we will not need to perform the same transformation again
+        // since the error reporting would have provided accurate locations for those.
+        if(debugAsFile) {
+            
+            performTransformWithPhysicalFiles(); // will give accurate line numbers
+        
+            // No need to print out the current error message (seen in the Else statement below), 
+            // as the recursive call to XMLTransformer.transform(File, File, false) in method
+            // performTransformWithPhysicalFiles() will do this for us.
+        }
+        else { 
+            // printing out the error message
+            // since !debugAsFile, we are dealing with physical files, 
+            // variable stylesheet would have stored the filename instead of contents
+            this.errorMessage = this.errorMessage + "\nstylesheet filename: " + stylesheet;
+            
+            this.errorMessage += "\nException CAUSE:\n" + exception.getCause();
+            System.err.println("\n****Error transforming xml:\n" + this.errorMessage + "\n****\n");
+            //System.err.println("Stylesheet was:\n + this.stylesheet + "************END STYLESHEET***********\n\n");           
+            
+            logger.error(this.errorMessage);
+            
+            // now print out the source to a file, and run the stylesheet on it using a transform()
+            // then any error will be referring to one of these two input files.
+        }
+        }
+
+        // This method will redo the transformation that went wrong with *real* files: 
+        // it writes out the stylesheet and source XML to files first, then performs the transformation
+        // to get the actual line location of where things went wrong (instead of "line#0 column#0 in dummy.xsl")
+        protected void performTransformWithPhysicalFiles() {
+        File webLogsTmpFolder = new File(GlobalProperties.getGSDL3Home() + File.separator + "logs" + File.separator + "tmp");
+        File styleFile = new File(webLogsTmpFolder + File.separator + "stylesheet" + XMLTransformer.debugFileCount + ".xml");
+        File sourceFile = new File(webLogsTmpFolder + File.separator + "source" + XMLTransformer.debugFileCount + ".xml");
+        
+        try {
+            // write stylesheet to a file called stylesheet_systemID in tmp
+            FileWriter styleSheetWriter = new FileWriter(styleFile);
+            styleSheetWriter.write(stylesheet, 0, stylesheet.length());
+            styleSheetWriter.flush();
+            styleSheetWriter.close();
+        } catch(Exception e) {
+            System.err.println("*** Exception when trying to write out stylesheet to " + styleFile.getAbsolutePath());
+        }       
+        
+        try {
+            FileWriter srcWriter = new FileWriter(sourceFile);
+            String contents = "";
+            if(source instanceof DOMSource) {
+            DOMSource domSource = (DOMSource)source;
+            Document doc = (Document)domSource.getNode();
+            contents = GSXML.elementToString(doc.getDocumentElement(), true);
+            //contents = GSXML.xmlNodeToXMLString(domSource.getNode());
+            } else if (source instanceof StreamSource) {
+            StreamSource streamSource = (StreamSource)source;
+            BufferedReader reader = new BufferedReader(streamSource.getReader());
+            String line = "";
+            while((line = reader.readLine()) != null) {
+                contents = contents + line + "\n";
+            }           
+            }
+            srcWriter.write(contents, 0, contents.length());
+            srcWriter.flush();
+            srcWriter.close();      
+        } catch(Exception e) {
+            System.err.println("*** Exception when trying to write out stylesheet to " + sourceFile.getAbsolutePath());
+        }
+        
+        System.err.println("*****************************************");
+        System.err.println("Look for stylesheet in: " + styleFile.getAbsolutePath());
+        System.err.println("Look for source XML in: " + sourceFile.getAbsolutePath());
+        
+        // now perform the transform again, which will assign another TransformErrorListener
+        // but since debuggingAsFile is turned off, we won't recurse into this section of
+        // handling the error again
+        XMLTransformer.this.transform(styleFile, sourceFile); // calls the File, File version, so debugAsFile will be false     
+        
         }
     }