package at.gv.egovernment.moa.util; import java.io.InputStream; import org.apache.xerces.util.URI; import org.apache.xerces.util.URI.MalformedURIException; import org.xml.sax.EntityResolver; import org.xml.sax.InputSource; import at.gv.egovernment.moa.logging.LogMsg; import at.gv.egovernment.moa.logging.Logger; /** * An <code>EntityResolver</code> that looks up entities stored as * local resources. * * <p>The following DTDs are mapped to local resources: * <ul> * <li>The XMLSchema.dtd</li> * <li>The datatypes.dtd</li> * </ul> * </p> * <p>For all other resources, an attempt is made to resolve them as resources, * either absolute or relative to <code>Constants.SCHEMA_ROOT</code>. * * @author Patrick Peck * @author Sven Aigner */ public class MOAEntityResolver implements EntityResolver { /** * Resolve an entity. * * The <code>systemId</code> parameter is used to perform the lookup of the * entity as a resource, either by interpreting the <code>systemId</code> as * an absolute resource path, or by appending the last path component of * <code>systemId</code> to <code>Constants.SCHEMA_ROOT</code>. * * @param publicId The public ID of the resource. * @param systemId The system ID of the resource. * @return An <code>InputSource</code> from which the entity can be read, or * <code>null</code>, if the entity could not be found. * @see org.xml.sax.EntityResolver#resolveEntity(java.lang.String, java.lang.String) */ public InputSource resolveEntity(String publicId, String systemId) { InputStream stream; int slashPos; if (Logger.isDebugEnabled()) { Logger.debug( new LogMsg("resolveEntity: p=" + publicId + " s=" + systemId)); } if (publicId != null) { // check if we can resolve some standard dtd's if (publicId.equalsIgnoreCase("-//W3C//DTD XMLSchema 200102//EN")) { return new InputSource( getClass().getResourceAsStream( Constants.SCHEMA_ROOT + "XMLSchema.dtd")); } else if (publicId.equalsIgnoreCase("datatypes")) { return new InputSource( getClass().getResourceAsStream( Constants.SCHEMA_ROOT + "datatypes.dtd")); } } else if (systemId != null) { // get the URI path try { URI uri = new URI(systemId); systemId = uri.getPath(); if (!"file".equals(uri.getScheme()) || "".equals(systemId.trim())) { return null; } } catch (MalformedURIException e) { return null; } // try to get the resource from the full path stream = getClass().getResourceAsStream(systemId); if (stream != null) { InputSource source = new InputSource(stream); source.setSystemId(systemId); return source; } // try to get the resource from the last path component slashPos = systemId.lastIndexOf('/'); if (slashPos >= 0 && systemId.length() > slashPos) { systemId = systemId.substring(slashPos + 1, systemId.length()); stream = getClass().getResourceAsStream(Constants.SCHEMA_ROOT + systemId); if (stream != null) { InputSource source = new InputSource(stream); source.setSystemId(systemId); return source; } } } return null; // nothing found - let the parser handle the entity } }