/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.uima.util.impl;

import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.apache.uima.UIMAFramework;
import org.apache.uima.UIMA_IllegalArgumentException;
import org.apache.uima.UIMA_IllegalStateException;
import org.apache.uima.analysis_engine.AnalysisEngineDescription;
import org.apache.uima.analysis_engine.ResultSpecification;
import org.apache.uima.analysis_engine.TaeDescription;
import org.apache.uima.collection.CasConsumerDescription;
import org.apache.uima.collection.CasInitializerDescription;
import org.apache.uima.collection.CollectionReaderDescription;
import org.apache.uima.collection.metadata.CpeDescription;
import org.apache.uima.flow.FlowControllerDescription;
import org.apache.uima.internal.util.XMLUtils;
import org.apache.uima.resource.CustomResourceSpecifier;
import org.apache.uima.resource.PearSpecifier;
import org.apache.uima.resource.ResourceSpecifier;
import org.apache.uima.resource.URISpecifier;
import org.apache.uima.resource.metadata.FsIndexCollection;
import org.apache.uima.resource.metadata.ResourceManagerConfiguration;
import org.apache.uima.resource.metadata.ResourceMetaData;
import org.apache.uima.resource.metadata.TypePriorities;
import org.apache.uima.resource.metadata.TypeSystemDescription;
import org.apache.uima.resource.metadata.impl.MetaDataObject_impl;
import org.apache.uima.search.IndexBuildSpecification;
import org.apache.uima.util.InvalidXMLException;
import org.apache.uima.util.Level;
import org.apache.uima.util.SaxDeserializer;
import org.apache.uima.util.XMLInputSource;
import org.apache.uima.util.XMLParser;
import org.apache.uima.util.XMLizable;
import org.w3c.dom.Element;
import org.xml.sax.InputSource;
import org.xml.sax.SAXNotRecognizedException;
import org.xml.sax.SAXParseException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;

/**
 * Reference implementation of {@link XMLParser}.
 * 
 * 
 */
public class XMLParser_impl implements XMLParser {

  /**
   * resource bundle for log messages
   */
  private static final String LOG_RESOURCE_BUNDLE = "org.apache.uima.impl.log_messages";

  /**
   * current class
   */
  private static final Class<XMLParser_impl> CLASS_NAME = XMLParser_impl.class;

  /**
   * The URL to the Resource Specifier XML Schema file
   */
  private static final URL SCHEMA_URL;
  
  static {
    URL schemaURL = XMLParser_impl.class.getResource(RESOURCE_SPECIFIER_SCHEMA_NAME);
    if (schemaURL == null) {
      UIMAFramework.getLogger(CLASS_NAME).logrb(Level.WARNING, CLASS_NAME.getName(), "getSchemaURL",
          LOG_RESOURCE_BUNDLE, "UIMA_resource_specifier_schema_not_found__WARNING");
    } else {
      String urlString = schemaURL.toString().replaceAll(" ", "%20");
      try {
        schemaURL = new URL(urlString);
      } catch (MalformedURLException e) {
      }
    }
    SCHEMA_URL = schemaURL;
  }

  
  /**
   * Map from XML element names to Class objects.
   */
  protected Map<String, Class<? extends XMLizable>> mElementToClassMap = Collections.synchronizedMap(
		  new HashMap<String, Class<? extends XMLizable>>());

  /**
   * Whether schema validation is enabled.
   */
  protected boolean mSchemaValidationEnabled = false;

  protected static final ParsingOptions DEFAULT_PARSING_OPTIONS = new ParsingOptions(true);

  /**
   * Creates a new XMLParser_impl.
   * 
   * @throws ParserConfigurationException
   *           if the underlying XML parser could not be constructed
   */
  public XMLParser_impl() throws ParserConfigurationException {
  }

  /**
   * @see org.apache.uima.util.XMLParser#enableSchemaValidation(boolean)
   */
  public void enableSchemaValidation(boolean aEnable) {
    mSchemaValidationEnabled = aEnable;
  }

  /**
   * Parses an XML input stream and produces an object.
   * 
   * @param aInput
   *          the input source from which to read the XML document
   * @param aNamespaceForSchema
   *          XML namespace for elements to be validated against XML schema. If null, no schema will
   *          be used.
   * @param aSchemaUrl
   *          URL to XML schema that will be used to validate the XML document. If null, no schema
   *          will be used.
   * 
   * @return an <code>XMLizable</code> object constructed from the XML document
   * 
   * @throws InvalidXMLException
   *           if the input XML is not valid or does not specify a valid object
   */
  public XMLizable parse(XMLInputSource aInput, String aNamespaceForSchema, URL aSchemaUrl,
          XMLParser.ParsingOptions aOptions) throws InvalidXMLException {
    URL urlToParse = aInput.getURL();
    try {
      SAXParserFactory factory = XMLUtils.createSAXParserFactory();

      // Turn on namespace support
      factory.setNamespaceAware(true);        
      SAXParser parser = factory.newSAXParser();  // unless multi-threaded, in the future, if performance issue, can save this , and reuse with reset()
        
      XMLReader reader = parser.getXMLReader();
      reader.setFeature("http://xml.org/sax/features/namespace-prefixes", true);
      // reader.setFeature("http://xml.org/sax/features/namespaces", true);  // Is this needed?

      // enable validation if requested
      if (mSchemaValidationEnabled && aNamespaceForSchema != null && aSchemaUrl != null) {
        try {
          reader.setFeature("http://apache.org/xml/features/validation/schema", true);
          reader.setProperty("http://apache.org/xml/properties/schema/external-schemaLocation",
                aNamespaceForSchema + " " + aSchemaUrl);
          reader.setFeature("http://xml.org/sax/features/validation", true);
        }
        catch(SAXNotRecognizedException e) {
          UIMAFramework.getLogger().log(Level.INFO, "The installed XML Parser does not support schema validation.  No validation will occur.");
        }
      }

      // set up InputSource
      InputSource input = new InputSource();
      input.setByteStream(aInput.getInputStream());
      String systemId;
      if (urlToParse != null) {
        systemId = urlToParse.toString();
      } else {
        systemId = new File(System.getProperty("user.dir")).toURL().toString();
      }
      input.setSystemId(systemId);

      // set up error handler to catch validation errors\
      ParseErrorHandler errorHandler = new ParseErrorHandler();
      reader.setErrorHandler(errorHandler);

      // Parse with SaxDeserializer
      SaxDeserializer deser = new SaxDeserializer_impl(this, aOptions);
      reader.setContentHandler(deser);
      if (aOptions.preserveComments) {
        reader.setProperty ("http://xml.org/sax/properties/lexical-handler", deser);
      }
      reader.parse(input);

      // if there was an exception, throw it
      if (errorHandler.getException() != null) {
        throw errorHandler.getException();
      }

      // otherwise build the UIMA XMLizable object and return it
      XMLizable result = deser.getObject();

      if (result instanceof MetaDataObject_impl) {
        // set Source URL (needed to later resolve descriptor-relative paths)
        ((MetaDataObject_impl) result).setSourceUrl(urlToParse);
      }
      return result;
    } catch (Exception e) {
      String sourceFile = urlToParse != null ? urlToParse.toString() : "<unknown source>";
      throw new InvalidXMLException(InvalidXMLException.INVALID_DESCRIPTOR_FILE,
              new Object[] { sourceFile }, e);
    }
  }

  /**
   * Parses an XML input stream and produces an object.
   * 
   * @param aInput
   *          the input source from which to read the XML document
   * @param aNamespaceForSchema
   *          XML namespace for elements to be validated against XML schema. If null, no schema will
   *          be used.
   * @param aSchemaUrl
   *          URL to XML schema that will be used to validate the XML document. If null, no schema
   *          will be used.
   * 
   * @return an <code>XMLizable</code> object constructed from the XML document
   * 
   * @throws InvalidXMLException
   *           if the input XML is not valid or does not specify a valid object
   */
  public XMLizable parse(XMLInputSource aInput, String aNamespaceForSchema, URL aSchemaUrl)
          throws InvalidXMLException {
    return parse(aInput, aNamespaceForSchema, aSchemaUrl, DEFAULT_PARSING_OPTIONS);
  }

  /**
   * Parses an XML input stream and produces an object. No schema validation will be done.
   * 
   * @param aInput
   *          the input source from which to read the XML document
   * 
   * @return an <code>XMLizable</code> object constructed from the XML document
   * 
   * @throws InvalidXMLException
   *           if the input XML is not valid or does not specify a valid object
   */
  public XMLizable parse(XMLInputSource aInput) throws InvalidXMLException {
    return parse(aInput, null, null, DEFAULT_PARSING_OPTIONS);
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.apache.uima.util.XMLParser#parse(org.apache.uima.util.XMLInputSource,
   *      org.apache.uima.util.XMLParser.ParsingOptions)
   */
  public XMLizable parse(XMLInputSource aInput, ParsingOptions aOptions) throws InvalidXMLException {
    return parse(aInput, null, null, aOptions);
  }

  /**
   * Builds an object from its XML DOM representation.
   * 
   * @param aElement
   *          a DOM Element
   * 
   * @return an <code>XMLizable</code> object constructed from the DOM element
   * 
   * @throws InvalidXMLException
   *           if the XML element does not specify a valid object
   */
  public XMLizable buildObject(Element aElement) throws InvalidXMLException {
    return buildObject(aElement, new ParsingOptions(true));
  }

  /**
   * Builds an object from its XML DOM representation.
   * 
   * @param aElement
   *          a DOM Element
   * 
   * @return an <code>XMLizable</code> object constructed from the DOM element
   * 
   * @throws InvalidXMLException
   *           if the XML element does not specify a valid object
   */
  public XMLizable buildObject(Element aElement, ParsingOptions aOptions)
          throws InvalidXMLException {
    // attempt to locate a Class that can be built from the element
    Class<? extends XMLizable> cls = mElementToClassMap.get(aElement.getTagName());
    if (cls == null) {
      throw new InvalidXMLException(InvalidXMLException.UNKNOWN_ELEMENT, new Object[] { aElement
              .getTagName() });
    }

    // resolve the class name and instantiate the class
    XMLizable object;
    try {
      object = cls.newInstance();
    } catch (Exception e) {
      throw new UIMA_IllegalStateException(
              UIMA_IllegalStateException.COULD_NOT_INSTANTIATE_XMLIZABLE, new Object[] { cls
                      .getName() }, e);
    }
    
    callBuildFromXMLElement(aElement, object, aOptions);

    return object;
  }
  
  private void callBuildFromXMLElement(Element aElement, XMLizable object, ParsingOptions aOptions) 
                   throws InvalidXMLException {
    if (aOptions.preserveComments && (object instanceof MetaDataObject_impl)) {
      ((MetaDataObject_impl)object).setInfoset(aElement);
    }

    object.buildFromXMLElement(aElement, this, aOptions);
    
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.apache.uima.util.XMLParser#buildObjectOrPrimitive(Element, ParsingOptions)
   */
  public Object buildObjectOrPrimitive(Element aElement, ParsingOptions aOptions)
          throws InvalidXMLException {
    // attempt to locate a Class that can be built from the element
    Class<? extends XMLizable> cls = mElementToClassMap.get(aElement.getTagName());
    if (cls == null) {
      // attempt to parse as primitive
      Object primObj = XMLUtils.readPrimitiveValue(aElement);
      if (primObj != null) {
        return primObj;
      }

      // unknown element - throw exception
      throw new InvalidXMLException(InvalidXMLException.UNKNOWN_ELEMENT, new Object[] { aElement
              .getTagName() });
    }

    // resolve the class name and instantiate the class
    XMLizable object;
    try {
      object = cls.newInstance();
    } catch (Exception e) {
      throw new UIMA_IllegalStateException(
              UIMA_IllegalStateException.COULD_NOT_INSTANTIATE_XMLIZABLE, new Object[] { cls
                      .getName() }, e);
    }

    // construct the XMLizable object from the XML element
    callBuildFromXMLElement(aElement, object, aOptions);
    return object;
  }

  /**
   * Parses a ResourceSpecifier from an XML input stream. XML schema validation will be done against
   * the {@link #RESOURCE_SPECIFIER_SCHEMA_NAME} if it can be found in the classpath.
   * 
   * @param aInput
   *          the input source from which to read the XML document
   * 
   * @return a <code>ResourceSpecifier</code> object constructed from the XML document
   * 
   * @throws InvalidXMLException
   *           if the input XML is not valid or does not specify a valid ResourceSpecifier
   */
  public ResourceSpecifier parseResourceSpecifier(XMLInputSource aInput) throws InvalidXMLException {
    return parseResourceSpecifier(aInput, DEFAULT_PARSING_OPTIONS);
  }

  /**
   * Parses a ResourceSpecifier from an XML input stream. XML schema validation will be done against
   * the {@link #RESOURCE_SPECIFIER_SCHEMA_NAME} if it can be found in the classpath.
   * 
   * @param aInput
   *          the input source from which to read the XML document
   * 
   * @return a <code>ResourceSpecifier</code> object constructed from the XML document
   * 
   * @throws InvalidXMLException
   *           if the input XML is not valid or does not specify a valid ResourceSpecifier
   */
  public ResourceSpecifier parseResourceSpecifier(XMLInputSource aInput, ParsingOptions aOptions)
          throws InvalidXMLException {
    // attempt to locate resource specifier schema
    XMLizable object = parse(aInput, RESOURCE_SPECIFIER_NAMESPACE, SCHEMA_URL, aOptions);
    if (object instanceof ResourceSpecifier) {
      return (ResourceSpecifier) object;
    } else {
      throw new InvalidXMLException(InvalidXMLException.INVALID_CLASS, new Object[] {
          ResourceSpecifier.class.getName(), object.getClass().getName() });
    }
  }

  /**
   * Parses a ResourceMetaData object from an XML input stream. XML schema validation will be done
   * against the {@link #RESOURCE_SPECIFIER_SCHEMA_NAME} if it can be found in the classpath.
   * 
   * @param aInput
   *          the input source from which to read the XML document
   * 
   * @return a <code>ResourceMetaData</code> object constructed from the XML document
   * 
   * @throws InvalidXMLException
   *           if the input XML is not valid or does not specify a valid ResourceSpecifier
   */
  public ResourceMetaData parseResourceMetaData(XMLInputSource aInput) throws InvalidXMLException {
    return parseResourceMetaData(aInput, DEFAULT_PARSING_OPTIONS);
  }

  /**
   * Parses a ResourceMetaData object from an XML input stream. XML schema validation will be done
   * against the {@link #RESOURCE_SPECIFIER_SCHEMA_NAME} if it can be found in the classpath.
   * 
   * @param aInput
   *          the input source from which to read the XML document
   * 
   * @return a <code>ResourceMetaData</code> object constructed from the XML document
   * 
   * @throws InvalidXMLException
   *           if the input XML is not valid or does not specify a valid ResourceSpecifier
   */
  public ResourceMetaData parseResourceMetaData(XMLInputSource aInput, ParsingOptions aOptions)
          throws InvalidXMLException {
    // attempt to locate resource specifier schema
    XMLizable object = parse(aInput, RESOURCE_SPECIFIER_NAMESPACE, SCHEMA_URL, aOptions);

    if (object instanceof ResourceMetaData) {
      return (ResourceMetaData) object;
    } else {
      throw new InvalidXMLException(InvalidXMLException.INVALID_CLASS, new Object[] {
          ResourceMetaData.class.getName(), object.getClass().getName() });
    }
  }

  /**
   * Parses a URISpecifier from an XML input stream. XML schema validation will be done against the
   * {@link #RESOURCE_SPECIFIER_SCHEMA_NAME} if it can be found in the classpath.
   * 
   * @param aInput
   *          the input source from which to read the XML document
   * 
   * @return a <code>URISpecifier</code> object constructed from the XML document
   * 
   * @throws InvalidXMLException
   *           if the input XML is not valid or does not specify a valid URISpecifier
   */
  public URISpecifier parseURISpecifier(XMLInputSource aInput) throws InvalidXMLException {
    return parseURISpecifier(aInput, DEFAULT_PARSING_OPTIONS);
  }

  /**
   * Parses a URISpecifier from an XML input stream. XML schema validation will be done against the
   * {@link #RESOURCE_SPECIFIER_SCHEMA_NAME} if it can be found in the classpath.
   * 
   * @param aInput
   *          the input source from which to read the XML document
   * 
   * @return a <code>URISpecifier</code> object constructed from the XML document
   * 
   * @throws InvalidXMLException
   *           if the input XML is not valid or does not specify a valid URISpecifier
   */
  public URISpecifier parseURISpecifier(XMLInputSource aInput, ParsingOptions aOptions)
          throws InvalidXMLException {
    // attempt to locate resource specifier schema
    XMLizable object = parse(aInput, RESOURCE_SPECIFIER_NAMESPACE, SCHEMA_URL, aOptions);

    if (object instanceof URISpecifier) {
      return (URISpecifier) object;
    } else {
      throw new InvalidXMLException(InvalidXMLException.INVALID_CLASS, new Object[] {
          URISpecifier.class.getName(), object.getClass().getName() });
    }
  }

  /**
   * Parses a AnalysisEngineDescription from an XML input stream. XML schema validation will be done
   * against the {@link #RESOURCE_SPECIFIER_SCHEMA_NAME} if it can be found in the classpath.
   * 
   * @param aInput
   *          the input source from which to read the XML document
   * 
   * @return a <code>AnalysisEngineDescription</code> object constructed from the XML document
   * 
   * @throws InvalidXMLException
   *           if the input XML is not valid or does not specify a valid AnalysisEngineDescription
   */
  public AnalysisEngineDescription parseAnalysisEngineDescription(XMLInputSource aInput)
          throws InvalidXMLException {
    return parseAnalysisEngineDescription(aInput, DEFAULT_PARSING_OPTIONS);
  }

  /**
   * Parses a AnalysisEngineDescription from an XML input stream. XML schema validation will be done
   * against the {@link #RESOURCE_SPECIFIER_SCHEMA_NAME} if it can be found in the classpath.
   * 
   * @param aInput
   *          the input source from which to read the XML document
   * 
   * @return a <code>AnalysisEngineDescription</code> object constructed from the XML document
   * 
   * @throws InvalidXMLException
   *           if the input XML is not valid or does not specify a valid AnalysisEngineDescription
   */
  public AnalysisEngineDescription parseAnalysisEngineDescription(XMLInputSource aInput,
          ParsingOptions aOptions) throws InvalidXMLException {
    // attempt to locate resource specifier schema
    XMLizable object = parse(aInput, RESOURCE_SPECIFIER_NAMESPACE, SCHEMA_URL, aOptions);

    if (object instanceof AnalysisEngineDescription) {
      return (AnalysisEngineDescription) object;
    } else {
      throw new InvalidXMLException(InvalidXMLException.INVALID_CLASS, new Object[] {
          AnalysisEngineDescription.class.getName(), object.getClass().getName() });
    }
  }

  /**
   * Parses a TaeDescription from an XML input stream. XML schema validation will be done against
   * the {@link #RESOURCE_SPECIFIER_SCHEMA_NAME} if it can be found in the classpath.
   * 
   * @param aInput
   *          the input source from which to read the XML document
   * 
   * @return a <code>TaeDescription</code> object constructed from the XML document
   * 
   * @throws InvalidXMLException
   *           if the input XML is not valid or does not specify a valid TaeDescription
   * 
   * @deprecated since v2.0
   */
  @Deprecated
  public TaeDescription parseTaeDescription(XMLInputSource aInput) throws InvalidXMLException {
    return parseTaeDescription(aInput, DEFAULT_PARSING_OPTIONS);
  }

  /**
   * Parses a TaeDescription from an XML input stream. XML schema validation will be done against
   * the {@link #RESOURCE_SPECIFIER_SCHEMA_NAME} if it can be found in the classpath.
   * 
   * @param aInput
   *          the input source from which to read the XML document
   * 
   * @return a <code>TaeDescription</code> object constructed from the XML document
   * 
   * @throws InvalidXMLException
   *           if the input XML is not valid or does not specify a valid TaeDescription
   * 
   * @deprecated since v2.0
   */
  @Deprecated
  public TaeDescription parseTaeDescription(XMLInputSource aInput, ParsingOptions aOptions)
          throws InvalidXMLException {
    // attempt to locate resource specifier schema
    XMLizable object = parse(aInput, RESOURCE_SPECIFIER_NAMESPACE, SCHEMA_URL, aOptions);

    if (object instanceof TaeDescription) {
      return (TaeDescription) object;
    } else {
      throw new InvalidXMLException(InvalidXMLException.INVALID_CLASS, new Object[] {
          TaeDescription.class.getName(), object.getClass().getName() });
    }
  }

  /**
   * @see org.apache.uima.util.XMLParser#parseResultSpecification(org.apache.uima.util.XMLInputSource)
   */
  public ResultSpecification parseResultSpecification(XMLInputSource aInput)
          throws InvalidXMLException {
    return parseResultSpecification(aInput, DEFAULT_PARSING_OPTIONS);
  }

  /**
   * @see org.apache.uima.util.XMLParser#parseResultSpecification(org.apache.uima.util.XMLInputSource)
   */
  public ResultSpecification parseResultSpecification(XMLInputSource aInput, ParsingOptions aOptions)
          throws InvalidXMLException {
    XMLizable object = parse(aInput, RESOURCE_SPECIFIER_NAMESPACE, null, aOptions);

    if (object instanceof ResultSpecification) {
      return (ResultSpecification) object;
    } else {
      throw new InvalidXMLException(InvalidXMLException.INVALID_CLASS, new Object[] {
          ResultSpecification.class.getName(), object.getClass().getName() });
    }
  }

  /**
   * @see org.apache.uima.util.XMLParser#parseCasConsumerDescription(org.apache.uima.util.XMLInputSource)
   */
  public CasConsumerDescription parseCasConsumerDescription(XMLInputSource aInput)
          throws InvalidXMLException {
    return parseCasConsumerDescription(aInput, DEFAULT_PARSING_OPTIONS);
  }

  /**
   * @see org.apache.uima.util.XMLParser#parseCasConsumerDescription(org.apache.uima.util.XMLInputSource)
   */
  public CasConsumerDescription parseCasConsumerDescription(XMLInputSource aInput,
          ParsingOptions aOptions) throws InvalidXMLException {
    // attempt to locate resource specifier schema
    XMLizable object = parse(aInput, RESOURCE_SPECIFIER_NAMESPACE, SCHEMA_URL, aOptions);

    if (object instanceof CasConsumerDescription) {
      return (CasConsumerDescription) object;
    } else {
      throw new InvalidXMLException(InvalidXMLException.INVALID_CLASS, new Object[] {
          CasConsumerDescription.class.getName(), object.getClass().getName() });
    }
  }

  @Deprecated
  public CasInitializerDescription parseCasInitializerDescription(XMLInputSource aInput)
          throws InvalidXMLException {
    return parseCasInitializerDescription(aInput, DEFAULT_PARSING_OPTIONS);
  }

  @Deprecated
  public CasInitializerDescription parseCasInitializerDescription(XMLInputSource aInput,
          ParsingOptions aOptions) throws InvalidXMLException {
    // attempt to locate resource specifier schema
    XMLizable object = parse(aInput, RESOURCE_SPECIFIER_NAMESPACE, SCHEMA_URL, aOptions);

    if (object instanceof CasInitializerDescription) {
      return (CasInitializerDescription) object;
    } else {
      throw new InvalidXMLException(InvalidXMLException.INVALID_CLASS, new Object[] {
          CasInitializerDescription.class.getName(), object.getClass().getName() });
    }
  }

  public CollectionReaderDescription parseCollectionReaderDescription(XMLInputSource aInput)
          throws InvalidXMLException {
    return parseCollectionReaderDescription(aInput, DEFAULT_PARSING_OPTIONS);
  }

  public CollectionReaderDescription parseCollectionReaderDescription(XMLInputSource aInput,
          ParsingOptions aOptions) throws InvalidXMLException {
    // attempt to locate resource specifier schema
    XMLizable object = parse(aInput, RESOURCE_SPECIFIER_NAMESPACE, SCHEMA_URL, aOptions);

    if (object instanceof CollectionReaderDescription) {
      return (CollectionReaderDescription) object;
    } else {
      throw new InvalidXMLException(InvalidXMLException.INVALID_CLASS, new Object[] {
          CollectionReaderDescription.class.getName(), object.getClass().getName() });
    }
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.apache.uima.util.XMLParser#parseCpeDescription(org.apache.uima.util.XMLInputSource)
   */
  public CpeDescription parseCpeDescription(XMLInputSource aInput) throws InvalidXMLException {
    XMLizable object = parse(aInput);

    if (object instanceof CpeDescription) {
      return (CpeDescription) object;
    } else {
      throw new InvalidXMLException(InvalidXMLException.INVALID_CLASS, new Object[] {
          CpeDescription.class.getName(), object.getClass().getName() });
    }
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.apache.uima.util.XMLParser#parseTypePriorities(org.apache.uima.util.XMLInputSource)
   */
  public TypePriorities parseTypePriorities(XMLInputSource aInput) throws InvalidXMLException {
    return parseTypePriorities(aInput, DEFAULT_PARSING_OPTIONS);
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.apache.uima.util.XMLParser#parseTypePriorities(org.apache.uima.util.XMLInputSource)
   */
  public TypePriorities parseTypePriorities(XMLInputSource aInput, ParsingOptions aOptions)
          throws InvalidXMLException {
    // attempt to locate resource specifier schema
    XMLizable object = parse(aInput, RESOURCE_SPECIFIER_NAMESPACE, SCHEMA_URL, aOptions);

    if (object instanceof TypePriorities) {
      return (TypePriorities) object;
    } else {
      throw new InvalidXMLException(InvalidXMLException.INVALID_CLASS, new Object[] {
          TypePriorities.class.getName(), object.getClass().getName() });
    }
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.apache.uima.util.XMLParser#parseTypeSystemDescription(org.apache.uima.util.XMLInputSource)
   */
  public TypeSystemDescription parseTypeSystemDescription(XMLInputSource aInput)
          throws InvalidXMLException {
    return parseTypeSystemDescription(aInput, DEFAULT_PARSING_OPTIONS);
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.apache.uima.util.XMLParser#parseTypeSystemDescription(org.apache.uima.util.XMLInputSource)
   */
  public TypeSystemDescription parseTypeSystemDescription(XMLInputSource aInput,
          ParsingOptions aOptions) throws InvalidXMLException {
    // attempt to locate resource specifier schema
    XMLizable object = parse(aInput, RESOURCE_SPECIFIER_NAMESPACE, SCHEMA_URL, aOptions);

    if (object instanceof TypeSystemDescription) {
      return (TypeSystemDescription) object;
    } else {
      throw new InvalidXMLException(InvalidXMLException.INVALID_CLASS, new Object[] {
          TypeSystemDescription.class.getName(), object.getClass().getName() });
    }
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.apache.uima.util.XMLParser#parseFsIndexCollection(org.apache.uima.util.XMLInputSource)
   */
  public FsIndexCollection parseFsIndexCollection(XMLInputSource aInput) throws InvalidXMLException {
    return parseFsIndexCollection(aInput, DEFAULT_PARSING_OPTIONS);
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.apache.uima.util.XMLParser#parseFsIndexCollection(org.apache.uima.util.XMLInputSource)
   */
  public FsIndexCollection parseFsIndexCollection(XMLInputSource aInput, ParsingOptions aOptions)
          throws InvalidXMLException {
    // attempt to locate resource specifier schema
    XMLizable object = parse(aInput, RESOURCE_SPECIFIER_NAMESPACE, SCHEMA_URL, aOptions);

    if (object instanceof FsIndexCollection) {
      return (FsIndexCollection) object;
    } else {
      throw new InvalidXMLException(InvalidXMLException.INVALID_CLASS, new Object[] {
          FsIndexCollection.class.getName(), object.getClass().getName() });
    }
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.apache.uima.util.XMLParser#parseResourceManagerConfiguration(org.apache.uima.util.XMLInputSource)
   */
  public ResourceManagerConfiguration parseResourceManagerConfiguration(XMLInputSource aInput)
          throws InvalidXMLException {
    return parseResourceManagerConfiguration(aInput, DEFAULT_PARSING_OPTIONS);
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.apache.uima.util.XMLParser#parseResourceManagerConfiguration(org.apache.uima.util.XMLInputSource)
   */
  public ResourceManagerConfiguration parseResourceManagerConfiguration(XMLInputSource aInput,
          ParsingOptions aOptions) throws InvalidXMLException {
    // attempt to locate resource specifier schema
    XMLizable object = parse(aInput, RESOURCE_SPECIFIER_NAMESPACE, SCHEMA_URL, aOptions);

    if (object instanceof ResourceManagerConfiguration) {
      return (ResourceManagerConfiguration) object;
    } else {
      throw new InvalidXMLException(InvalidXMLException.INVALID_CLASS, new Object[] {
          ResourceManagerConfiguration.class.getName(), object.getClass().getName() });
    }
  }

  /* (non-Javadoc)
   * @see org.apache.uima.util.XMLParser#parseFlowControllerDescription(org.apache.uima.util.XMLInputSource)
   */
  public FlowControllerDescription parseFlowControllerDescription(XMLInputSource aInput) throws InvalidXMLException {
    return parseFlowControllerDescription(aInput, DEFAULT_PARSING_OPTIONS);
  }

  /* (non-Javadoc)
   * @see org.apache.uima.util.XMLParser#parseFlowControllerDescription(org.apache.uima.util.XMLInputSource, org.apache.uima.util.XMLParser.ParsingOptions)
   */
  public FlowControllerDescription parseFlowControllerDescription(XMLInputSource aInput, ParsingOptions aOptions) throws InvalidXMLException {
    // attempt to locate resource specifier schema
    XMLizable object = parse(aInput, RESOURCE_SPECIFIER_NAMESPACE, SCHEMA_URL, aOptions);

    if (object instanceof FlowControllerDescription) {
      return (FlowControllerDescription) object;
    } else {
      throw new InvalidXMLException(InvalidXMLException.INVALID_CLASS, new Object[] {
              FlowControllerDescription.class.getName(), object.getClass().getName() });
    }
  }

  /* (non-Javadoc)
   * @see org.apache.uima.util.XMLParser#parseCustomResourceSpecifier(org.apache.uima.util.XMLInputSource)
   */
  public CustomResourceSpecifier parseCustomResourceSpecifier(XMLInputSource aInput) throws InvalidXMLException {
    return parseCustomResourceSpecifier(aInput, DEFAULT_PARSING_OPTIONS);
  }

  /* (non-Javadoc)
   * @see org.apache.uima.util.XMLParser#parseCustomResourceSpecifier(org.apache.uima.util.XMLInputSource, org.apache.uima.util.XMLParser.ParsingOptions)
   */
  public CustomResourceSpecifier parseCustomResourceSpecifier(XMLInputSource aInput, ParsingOptions aOptions) throws InvalidXMLException {
    // attempt to locate resource specifier schema
    XMLizable object = parse(aInput, RESOURCE_SPECIFIER_NAMESPACE, SCHEMA_URL, aOptions);

    if (object instanceof CustomResourceSpecifier) {
      return (CustomResourceSpecifier) object;
    } else {
      throw new InvalidXMLException(InvalidXMLException.INVALID_CLASS, new Object[] {
              CustomResourceSpecifier.class.getName(), object.getClass().getName() });
    }
  }
  
  /* (non-Javadoc)
   * @see org.apache.uima.util.XMLParser#parsePearSpecifier(org.apache.uima.util.XMLInputSource)
   */
  public PearSpecifier parsePearSpecifier(XMLInputSource aInput) throws InvalidXMLException {
    return parsePearSpecifier(aInput, DEFAULT_PARSING_OPTIONS);
  }

  /* (non-Javadoc)
   * @see org.apache.uima.util.XMLParser#parsePearSpecifier(org.apache.uima.util.XMLInputSource, org.apache.uima.util.XMLParser.ParsingOptions)
   */
  public PearSpecifier parsePearSpecifier(XMLInputSource aInput, ParsingOptions aOptions) throws InvalidXMLException {
    // attempt to locate resource specifier schema
    XMLizable object = parse(aInput, RESOURCE_SPECIFIER_NAMESPACE, SCHEMA_URL, aOptions);

    if (object instanceof PearSpecifier) {
      return (PearSpecifier) object;
    } else {
      throw new InvalidXMLException(InvalidXMLException.INVALID_CLASS, new Object[] {
              PearSpecifier.class.getName(), object.getClass().getName() });
    }
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.apache.uima.util.XMLParser#parseIndexBuildSpecification(org.apache.uima.util.XMLInputSource)
   */
  public IndexBuildSpecification parseIndexBuildSpecification(XMLInputSource aInput)
          throws InvalidXMLException {
    return parseIndexBuildSpecification(aInput, DEFAULT_PARSING_OPTIONS);
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.apache.uima.util.XMLParser#parseIndexBuildSpecification(org.apache.uima.util.XMLInputSource,
   *      org.apache.uima.util.XMLParser.ParsingOptions)
   */
  public IndexBuildSpecification parseIndexBuildSpecification(XMLInputSource aInput,
          ParsingOptions aOptions) throws InvalidXMLException {
    XMLizable object = parse(aInput, aOptions);

    if (object instanceof IndexBuildSpecification) {
      return (IndexBuildSpecification) object;
    } else {
      throw new InvalidXMLException(InvalidXMLException.INVALID_CLASS, new Object[] {
          IndexBuildSpecification.class.getName(), object.getClass().getName() });
    }
  }

  /**
   * Configures this XMLParser by registering a mapping between the name of an XML element and the
   * Class of object to be built from elements with that name.
   * Ignores entries with no name, i.e. are not configured via XML
   * 
   * @param aElementName
   *          the name of an XML element
   * @param aClassName
   *          the name of a Class of object to be built. This class must implement {@link XMLizable}
   *          and have a zero-argument constructor.
   * 
   * @throws ClassNotFoundException
   *           if the class named by <code>aClassName</code> could not be found
   * @throws UIMA_IllegalArgumentException
   *           if the class named by <code>aClassName</code> does not implement
   * <code>XMLIzable</code>. @
   */
  @SuppressWarnings("unchecked")
  public void addMapping(String aElementName, String aClassName) throws ClassNotFoundException {
    if (aElementName == null) {
      return;
    }
    // resolve the class name and ensure that it implements XMLizable
    Class<? extends XMLizable> cls = (Class<? extends XMLizable>) Class.forName(aClassName);
    if (XMLizable.class.isAssignableFrom(cls)) {
      // add to the map
      mElementToClassMap.put(aElementName, cls);
    } else {
      throw new UIMA_IllegalArgumentException(
              UIMA_IllegalArgumentException.MUST_IMPLEMENT_XMLIZABLE, new Object[] { aClassName });
    }
  }

  /**
   * @see org.apache.uima.util.XMLParser#newSaxDeserializer()
   */
  public SaxDeserializer newSaxDeserializer() {
    return new SaxDeserializer_impl(this, new XMLParser.ParsingOptions(true));
  }

  /**
   * @see org.apache.uima.util.XMLParser#newSaxDeserializer(org.apache.uima.util.XMLParser.ParsingOptions)
   */
  public SaxDeserializer newSaxDeserializer(XMLParser.ParsingOptions aOptions) {
    return new SaxDeserializer_impl(this, aOptions);
  }

  /**
   * Error handler for XML parsing. Stores first error in <code>exception</code> field for later
   * retrieval.
   */
  static class ParseErrorHandler extends DefaultHandler {
    private SAXParseException mException = null;

    public void error(SAXParseException aError) {
      if (mException == null)
        mException = aError;
    }

    public void fatalError(SAXParseException aError) {
      if (mException == null)
        mException = aError;
    }

    public void warning(SAXParseException aWarning) {
      System.err.println("XML Warning: " + aWarning.getMessage());
    }

    public SAXParseException getException() {
      return mException;
    }

    public void clear() {
      mException = null;
    }
  }
}
