package test.at.gv.egovernment.moa.util;
import java.io.FileInputStream;
import java.io.InputStream;

import org.apache.xerces.parsers.DOMParser;
import org.apache.xerces.parsers.XMLGrammarPreparser;
import org.apache.xerces.util.SymbolTable;
import org.apache.xerces.util.XMLGrammarPoolImpl;
import org.apache.xerces.xni.grammars.Grammar;
import org.apache.xerces.xni.grammars.XMLGrammarDescription;
import org.apache.xerces.xni.parser.XMLInputSource;
import org.xml.sax.InputSource;

import test.at.gv.egovernment.moa.MOATestCase;

import at.gv.egovernment.moa.util.Constants;


/**
 * Experimentation with Xerces grammar caching.
 * 
 * Used the Xerces sample 'XMLGrammarBuilder' as a starting point. 
 * 
 * @author Patrick Peck
 * @version $Id$
 */
public class XMLGrammarBuilderTest extends MOATestCase {

  private static final String GRAMMAR_POOL =
    org.apache.xerces.impl.Constants.XERCES_PROPERTY_PREFIX
      + org.apache.xerces.impl.Constants.XMLGRAMMAR_POOL_PROPERTY;

  protected static final String NAMESPACES_FEATURE_ID =
    "http://xml.org/sax/features/namespaces";
  protected static final String VALIDATION_FEATURE_ID =
    "http://xml.org/sax/features/validation";
  protected static final String SCHEMA_VALIDATION_FEATURE_ID =
    "http://apache.org/xml/features/validation/schema";
  protected static final String SCHEMA_FULL_CHECKING_FEATURE_ID =
    "http://apache.org/xml/features/validation/schema-full-checking";

  private static final int BIG_PRIME = 2039;
  private SymbolTable symbolTable;
  private XMLGrammarPoolImpl grammarPool;

  /**
   * Constructor for XMLGrammarBuilderTest.
   * @param name
   */
  public XMLGrammarBuilderTest(String name) {
    super(name);
  }

  protected void setUp() throws Exception {
    XMLGrammarPreparser preparser;

    // set up symbol table and grammar pool
    symbolTable = new SymbolTable(BIG_PRIME);
    grammarPool = new XMLGrammarPoolImpl();
    preparser = new XMLGrammarPreparser(symbolTable);
    preparser.registerPreparser(XMLGrammarDescription.XML_SCHEMA, null);
    preparser.setProperty(GRAMMAR_POOL, grammarPool);
    preparser.setFeature(NAMESPACES_FEATURE_ID, true);
    preparser.setFeature(VALIDATION_FEATURE_ID, true);
    // now we can still do schema features just in case, 
    // so long as it's our configuraiton......
    preparser.setFeature(SCHEMA_VALIDATION_FEATURE_ID, true);
    preparseSchemaResource(
      preparser,
      Constants.DSIG_SCHEMA_LOCATION,
      "/resources/schemas/xmldsig-core-schema.xsd");
  }

  private static Grammar preparseSchemaResource(
    XMLGrammarPreparser preparser,
    String systemId,
    String resource)
    throws Exception {

    InputStream is = XMLGrammarBuilderTest.class.getResourceAsStream(resource);
    return preparser.preparseGrammar(
      XMLGrammarDescription.XML_SCHEMA,
      new XMLInputSource(null, systemId, null, is, null));
  }

  public void testParseValidating() throws Exception {
    DOMParser parser = new DOMParser(symbolTable, grammarPool);

    parser.setFeature(NAMESPACES_FEATURE_ID, true);
    parser.setFeature(VALIDATION_FEATURE_ID, true);
    parser.setFeature(SCHEMA_VALIDATION_FEATURE_ID, true);

    parser.parse(
      new InputSource(
        new FileInputStream(TESTDATA_ROOT + "xml/dsigTransform/base64.xml")));
    parser.getDocument();
  }

}