Eliminate use of DocumentBuilder (use DOM LS everywhere) + use validation to catch undefined entities.

There seems to be no way to catch the undefined entity error (when it
is considered a validation error, e.g., when the document has an
external subset) other than by turning on validation.  So we register
an error handler to throw away useless validation errors.

3 files changed, 67 insertions, 41 deletions

diff --git a/org/madore/damlengine/DamlEngine.java b/org/madore/damlengine/DamlEngine.java
index c0010b6..7bc81bd 100644
--- a/org/madore/damlengine/DamlEngine.java
+++ b/org/madore/damlengine/DamlEngine.java
@@ -1,5 +1,6 @@
 package org.madore.damlengine;
 
+import java.util.MissingResourceException;
 import java.util.regex.Pattern;
 import java.util.regex.Matcher;
 import java.io.InputStream;
@@ -12,12 +13,13 @@ import java.io.BufferedReader;
 import java.io.PrintStream;
 import javax.xml.XMLConstants;
 import javax.xml.namespace.NamespaceContext;
-import javax.xml.parsers.DocumentBuilderFactory;
-import javax.xml.parsers.DocumentBuilder;
-import javax.xml.parsers.ParserConfigurationException;
-import org.w3c.dom.Document;
-// import org.xml.sax.EntityResolver;
-import org.apache.xerces.jaxp.DocumentBuilderFactoryImpl;
+import org.w3c.dom.*;
+import org.w3c.dom.ls.DOMImplementationLS;
+import org.w3c.dom.ls.LSParser;
+import org.w3c.dom.ls.LSInput;
+import org.apache.xerces.dom.DOMImplementationSourceImpl;
+import org.apache.xerces.xni.parser.XMLErrorHandler;
+import org.apache.xerces.xni.parser.XMLParseException;
 
 public final class DamlEngine {
 
@@ -54,19 +56,37 @@ public final class DamlEngine {
 	}
     }
 
-    public static final class GetDocumentBuilder {
-	static final DocumentBuilder db;
-	static {
-	    final Resolver resolver = new Resolver();
-	    final DocumentBuilderFactory dbf = new DocumentBuilderFactoryImpl();
-	    dbf.setNamespaceAware(true);
-	    dbf.setValidating(false);
-	    try {
-		db = dbf.newDocumentBuilder();
-	    } catch (ParserConfigurationException e) {
-		throw new RuntimeException(e);
+    public static class SelectiveErrorHandler implements XMLErrorHandler {
+    	public void warning(String domain, String key, XMLParseException exc) {
+    	    System.err.println("warning: line "+exc.getLineNumber()
+			       +": "+exc.getMessage());
+    	}
+    	public void error(String domain, String key, XMLParseException exc) {
+	    if ( domain.equals("http://www.w3.org/TR/1998/REC-xml-19980210")
+		 && key.equals("MSG_ELEMENT_NOT_DECLARED") )
+		return;
+    	    System.err.println("error: line "+exc.getLineNumber()
+			       +": "+exc.getMessage());
+    	}
+    	public void fatalError(String domain, String key, XMLParseException exc) {
+    	    System.err.println("fatal error: line "+exc.getLineNumber()
+			       +": "+exc.getMessage());
+    	    throw exc;
+    	}
+    }
+
+    public static final class IncantDOM {
+	static DOMImplementation domi;
+	public static DOMImplementation getDOMI() {
+	    if ( domi == null ) {
+		DOMImplementationSource source
+		    = new DOMImplementationSourceImpl();
+		domi = source.getDOMImplementation("XML 3.0 Core 3.0 LS 3.0");
+		if ( domi == null )
+		    throw new MissingResourceException("failed to obtain DOM implementation",
+						       "org.w3c.dom.ls.DOMImplementationLS", "");
 	    }
-	    db.setEntityResolver(resolver);
+	    return domi;
 	}
     }
 
@@ -103,9 +123,17 @@ public final class DamlEngine {
 				   Context.WeblogSelectionContext wsc)
 	throws Exception {
 
-	final DocumentBuilder db = GetDocumentBuilder.db;
-
-	Document doc = db.parse(in);
+	final DOMImplementationLS domils
+	    = (DOMImplementationLS)(IncantDOM.getDOMI());
+	LSParser par
+	    = domils.createLSParser(DOMImplementationLS.MODE_SYNCHRONOUS, null);
+	par.getDomConfig().setParameter("resource-resolver", new Resolver());
+	par.getDomConfig().setParameter("http://xml.org/sax/features/validation", true);
+	par.getDomConfig().setParameter("http://xml.org/sax/features/namespaces", true);
+	par.getDomConfig().setParameter("http://apache.org/xml/properties/internal/error-handler", new SelectiveErrorHandler());
+	LSInput input = domils.createLSInput();
+	input.setByteStream(in);
+	Document doc = par.parse(input);
 	processDocument(doc, wsc);
 	doc.normalizeDocument();
 	Unparser unparser
diff --git a/org/madore/damlengine/WeblogPopulate.java b/org/madore/damlengine/WeblogPopulate.java
index 56e51ac..16c7ea0 100644
--- a/org/madore/damlengine/WeblogPopulate.java
+++ b/org/madore/damlengine/WeblogPopulate.java
@@ -6,12 +6,12 @@ import java.security.MessageDigest;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
-import javax.xml.parsers.DocumentBuilder;
 import javax.xml.xpath.*;
 import org.w3c.dom.*;
 import org.w3c.dom.ls.DOMImplementationLS;
+import org.w3c.dom.ls.LSParser;
 import org.w3c.dom.ls.LSSerializer;
-// import org.xml.sax.EntityResolver;
+import org.w3c.dom.ls.LSInput;
 
 public final class WeblogPopulate {
 
@@ -29,12 +29,11 @@ public final class WeblogPopulate {
     public static void populate(InputStream in)
 	throws Exception {
 
-	final DocumentBuilder db = DamlEngine.GetDocumentBuilder.db;
-
-	final DOMImplementationLS domi
-	    = (DOMImplementationLS)(db.getDOMImplementation());
-	LSSerializer ser = domi.createLSSerializer();
+	final DOMImplementationLS domils
+	    = (DOMImplementationLS)(DamlEngine.IncantDOM.getDOMI());
+	LSSerializer ser = domils.createLSSerializer();
 	ser.getDomConfig().setParameter("xml-declaration", false);
+	LSParser par = domils.createLSParser(DOMImplementationLS.MODE_SYNCHRONOUS, null);
 
 	MessageDigest sha1 = MessageDigest.getInstance("SHA-1");
 
@@ -53,7 +52,9 @@ public final class WeblogPopulate {
 	final PreparedStatement setCatSt
 	    = conn.prepareStatement("INSERT INTO incat(id,code) VALUES (?,?)");
 
-	Document doc = db.parse(in);
+	LSInput input = domils.createLSInput();
+	input.setByteStream(in);
+	Document doc = par.parse(input);
 	XPathFactory xpf = XPathFactory.newInstance();
 	XPath xp = xpf.newXPath();
 	xp.setNamespaceContext(new DamlEngine.DamlNSMapping());
diff --git a/org/madore/damlengine/WeblogRSS.java b/org/madore/damlengine/WeblogRSS.java
index 5d918b8..3bf6489 100644
--- a/org/madore/damlengine/WeblogRSS.java
+++ b/org/madore/damlengine/WeblogRSS.java
@@ -6,7 +6,6 @@ import java.io.OutputStream;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
-import javax.xml.parsers.DocumentBuilder;
 import org.w3c.dom.*;
 import org.w3c.dom.ls.DOMImplementationLS;
 import org.w3c.dom.ls.LSParser;
@@ -32,21 +31,19 @@ public final class WeblogRSS {
 
 	final ResultSet selRes = selSt.executeQuery();
 
-	final DocumentBuilder db = DamlEngine.GetDocumentBuilder.db;
-
-	final DOMImplementationLS domi
-	    = (DOMImplementationLS)(db.getDOMImplementation());
-	LSSerializer ser = domi.createLSSerializer();
+	final DOMImplementation domi
+	    = (DamlEngine.IncantDOM.getDOMI());
+	final DOMImplementationLS domils = (DOMImplementationLS)(domi);
+	LSSerializer ser = domils.createLSSerializer();
 	ser.getDomConfig().setParameter("xml-declaration", true);
-	LSParser par = domi.createLSParser(DOMImplementationLS.MODE_SYNCHRONOUS, null);
+	LSParser par = domils.createLSParser(DOMImplementationLS.MODE_SYNCHRONOUS, null);
 
-	final LSOutput lsout = domi.createLSOutput();
+	final LSOutput lsout = domils.createLSOutput();
 	lsout.setByteStream(out);
 	lsout.setEncoding("UTF-8");
 
-	Document rssDoc = db.newDocument();
-	Element rssRoot = rssDoc.createElementNS(DamlEngine.RDF_NS, "rdf:RDF");
-	rssDoc.appendChild(rssRoot);
+	Document rssDoc = domi.createDocument(DamlEngine.RDF_NS, "rdf:RDF", null);
+	Element rssRoot = rssDoc.getDocumentElement();
 	// rssDoc.appendChild(rssDoc.createTextNode("\n"));
 
 	rssRoot.setAttributeNS(DamlEngine.XMLNS_NS, "xmlns:rdf", DamlEngine.RDF_NS);
@@ -138,7 +135,7 @@ public final class WeblogRSS {
 	    item.appendChild(itemDate);
 	    item.appendChild(rssDoc.createTextNode("\n"));
 	    itemDate.appendChild(rssDoc.createTextNode(cdate));
-	    LSInput input = domi.createLSInput();
+	    LSInput input = domils.createLSInput();
 	    input.setStringData(contentXml);
 	    Document temp = par.parse(input);
 	    String contentStr = temp.getDocumentElement().getTextContent();