Start a Java version of a daml engine. So far, just the identity transform.

Even for something so completely trivial, this was a pain to write,
because some stupid XML catalog was distributed with a DOCTYPE
referencing a broken URL which could not be replaced by a local file
because the catalog engine was bootstrapping; nor did Xerces provide a
way, in org.apache.xerces.util.XMLCatalogResolver, to provide a
bootstrap resolver: so I had to partially rewrite XMLCatalogResolver.

2 files changed, 204 insertions, 0 deletions

diff --git a/org/madore/damlengine/DamlEngine.java b/org/madore/damlengine/DamlEngine.java
new file mode 100644
index 0000000..8571319
--- /dev/null
+++ b/org/madore/damlengine/DamlEngine.java
@@ -0,0 +1,53 @@
+package org.madore.damlengine;
+
+import org.w3c.dom.DOMImplementation;
+import org.w3c.dom.ls.DOMImplementationLS;
+import org.w3c.dom.ls.LSParser;
+import org.w3c.dom.ls.LSSerializer;
+import org.w3c.dom.ls.LSInput;
+import org.w3c.dom.ls.LSOutput;
+import org.w3c.dom.Document;
+import org.apache.xerces.dom.DOMImplementationSourceImpl;
+
+public final class DamlEngine {
+
+    private static Document doc;
+
+    private DamlEngine() { }  // Forbid instantiation
+
+    public static void processDocument() {
+	// ...
+    }
+
+    public static void main(String[] args) {
+
+	final Resolver resolver = new Resolver();
+	final DOMImplementationSourceImpl source
+	    = new DOMImplementationSourceImpl();
+	final DOMImplementation impl
+	    = source.getDOMImplementation("XML 3.0 Core 3.0 LS 3.0");
+	final DOMImplementationLS implLS = (DOMImplementationLS)impl;
+	final LSParser parser
+	    = implLS.createLSParser(DOMImplementationLS.MODE_SYNCHRONOUS,
+				    null);
+	parser.getDomConfig().setParameter("resource-resolver", resolver);
+	final LSSerializer writer = implLS.createLSSerializer();
+
+	if ( args.length == 0 ) {
+	    System.err.println("expecting filename as argument");
+	}
+
+	for (String fname : args) {
+	    final LSInput in = implLS.createLSInput();
+	    in.setSystemId(fname);
+	    doc = parser.parse(in);
+	    processDocument();
+	    final LSOutput out = implLS.createLSOutput();
+	    out.setByteStream(System.out);
+	    writer.write(doc, out);
+	    System.out.println("");
+	}
+
+    }
+
+}
diff --git a/org/madore/damlengine/Resolver.java b/org/madore/damlengine/Resolver.java
new file mode 100644
index 0000000..80f8afb
--- /dev/null
+++ b/org/madore/damlengine/Resolver.java
@@ -0,0 +1,151 @@
+package org.madore.damlengine;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.MalformedURLException;
+import javax.xml.parsers.SAXParserFactory;
+import org.w3c.dom.ls.LSResourceResolver;
+import org.w3c.dom.ls.LSInput;
+import org.xml.sax.SAXException;
+import org.xml.sax.EntityResolver;
+import org.xml.sax.ext.EntityResolver2;
+import org.xml.sax.InputSource;
+import org.apache.xml.resolver.CatalogManager;
+import org.apache.xml.resolver.Catalog;
+import org.apache.xml.resolver.readers.SAXCatalogReader;
+import org.apache.xml.resolver.readers.OASISXMLCatalogReader;
+import org.apache.xerces.dom.DOMInputImpl;
+import org.apache.xerces.jaxp.SAXParserFactoryImpl;
+
+public final class Resolver
+    implements LSResourceResolver, EntityResolver, EntityResolver2 {
+
+    private static final String catalogFiles[] = { "/etc/xml/catalog" };
+
+    private CatalogManager catalogManager = null;
+    private Catalog catalog = null;
+
+    public static final class BootstrapResolver
+	extends org.apache.xml.resolver.helpers.BootstrapResolver {
+	public InputSource resolveEntity(String publicId, String systemId) {
+	    String resolved = null;
+	    if ( publicId.equals("-//GlobalTransCorp//DTD XML Catalogs "
+				 +"V1.0-Based Extension V1.0//EN") ) {
+		resolved
+		    = "file:///usr/share/xml/schema/xml-core/tr9401.dtd";
+	    }
+	    if ( resolved != null ) {
+		InputSource source = new InputSource(resolved);
+		source.setPublicId(publicId);
+		return source;
+	    }
+	    return super.resolveEntity(publicId, systemId);
+	}
+    }
+
+    public Resolver() {
+	catalogManager = new CatalogManager();
+	// catalogManager.setVerbosity(42);
+	catalogManager.setPreferPublic(true);
+	catalogManager.setRelativeCatalogs(false);
+	catalogManager.setBootstrapResolver(new BootstrapResolver());
+	catalog = new Catalog(catalogManager);
+        SAXParserFactory spf = new SAXParserFactoryImpl();
+        spf.setNamespaceAware(true);
+        spf.setValidating(false);
+        SAXCatalogReader saxReader = new SAXCatalogReader(spf);
+        saxReader.setCatalogParser(OASISXMLCatalogReader.namespaceName,
+				   "catalog", 
+				   "org.apache.xml.resolver.readers."
+				   +"OASISXMLCatalogReader");
+        catalog.addReader("application/xml", saxReader);
+	for ( String f : catalogFiles ) {
+	    try {
+		catalog.parseCatalog(f);
+	    } catch (MalformedURLException e) {
+	    } catch (IOException e) {
+	    }
+	}
+    }
+
+    public String resolvePublic(String publicId, String systemId) {
+	try {
+	    return catalog.resolvePublic(publicId, systemId);
+	} catch (MalformedURLException e) {
+	    return null;
+	} catch (IOException e) {
+	    return null;
+	}
+    }
+
+    public String resolveSystem(String systemId) {
+	try {
+	    return catalog.resolveSystem(systemId);
+	} catch (MalformedURLException e) {
+	    return null;
+	} catch (IOException e) {
+	    return null;
+	}
+    }
+
+    protected String resolve(String namespaceURI,
+			     String publicId,
+			     String systemId,
+			     String baseURI) {
+	String resolved;
+	if ( publicId != null )
+	    resolved = resolvePublic(publicId, systemId);
+	else
+	    resolved = resolveSystem(systemId);
+	if ( resolved != null )
+	    return resolved;
+	if ( baseURI != null ) {
+	    try {
+		URI u = new URI(baseURI);
+		URI v = u.resolve(systemId);
+		return v.toString();
+	    } catch ( URISyntaxException e ) {
+	    }
+	}
+	return systemId;
+    }
+
+    // Interface LSResourceResolver
+
+    public LSInput resolveResource(String type,
+				   String namespaceURI,
+				   String publicId,
+				   String systemId,
+				   String baseURI) {
+	String resolved = resolve(namespaceURI, publicId, systemId, baseURI);
+	return new DOMInputImpl(publicId, resolved, baseURI);
+    }
+
+    // Interface EntityResolver
+
+    public InputSource resolveEntity(String publicId, String systemId)
+	throws SAXException {
+	String resolved = resolve(null, publicId, systemId, null);
+	InputSource source = new InputSource(resolved);
+	source.setPublicId(publicId);
+	return source;
+    }
+
+    // Interface EntityResolver2
+
+    public InputSource resolveEntity(String name, String publicId,
+				     String baseURI, String systemId)
+	throws SAXException {
+	String resolved = resolve(null, publicId, systemId, baseURI);
+	InputSource source = new InputSource(resolved);
+	source.setPublicId(publicId);
+	return source;
+    }
+
+    public InputSource getExternalSubset(String name,
+					 String baseURI) {
+	return null;
+    }
+
+}