/*
    * Copyright 2006 the original author or authors.
    *
    * Licensed 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.springframework.xml.stream;
  
  import javax.xml.stream.Location;
  import javax.xml.stream.XMLStreamException;
  
  import org.xml.sax.ContentHandler;
  import org.xml.sax.InputSource;
  import org.xml.sax.Locator;
  import org.xml.sax.SAXException;
  import org.xml.sax.SAXNotRecognizedException;
  import org.xml.sax.SAXNotSupportedException;
  import org.xml.sax.SAXParseException;
  
  import org.springframework.xml.sax.AbstractXmlReader;
  
  /**
   * Abstract base class for SAX <code>XMLReader</code> implementations that use StAX as a basis.
   *
   * @author Arjen Poutsma
   * @see #setContentHandler(org.xml.sax.ContentHandler)
   * @see #setDTDHandler(org.xml.sax.DTDHandler)
   * @see #setEntityResolver(org.xml.sax.EntityResolver)
   * @see #setErrorHandler(org.xml.sax.ErrorHandler)
   * @since 1.0.0
   */
  public abstract class AbstractStaxXmlReader extends AbstractXmlReader {
  
      private static final String NAMESPACES_FEATURE_NAME = "http://xml.org/sax/features/namespaces";
  
      private static final String NAMESPACE_PREFIXES_FEATURE_NAME = "http://xml.org/sax/features/namespace-prefixes";
  
      private static final String IS_STANDALONE_FEATURE_NAME = "http://xml.org/sax/features/is-standalone";
  
      private boolean namespacesFeature = true;
  
      private boolean namespacePrefixesFeature = false;
  
      private Boolean isStandalone;
  
      public boolean getFeature(String name) throws SAXNotRecognizedException, SAXNotSupportedException {
          if (NAMESPACES_FEATURE_NAME.equals(name)) {
              return namespacesFeature;
          }
          else if (NAMESPACE_PREFIXES_FEATURE_NAME.equals(name)) {
              return namespacePrefixesFeature;
          }
          else if (IS_STANDALONE_FEATURE_NAME.equals(name)) {
              if (isStandalone != null) {
                  return isStandalone.booleanValue();
              }
              else {
                  throw new SAXNotSupportedException("startDocument() callback not completed yet");
              }
          }
          else {
              return super.getFeature(name);
          }
      }
  
      public void setFeature(String name, boolean value) throws SAXNotRecognizedException, SAXNotSupportedException {
          if (NAMESPACES_FEATURE_NAME.equals(name)) {
              this.namespacesFeature = value;
          }
          else if (NAMESPACE_PREFIXES_FEATURE_NAME.equals(name)) {
              this.namespacePrefixesFeature = value;
          }
          else {
              super.setFeature(name, value);
          }
      }
  
      /** Indicates whether the SAX feature <code>http://xml.org/sax/features/namespaces</code>" target="alexandria_uri">http://xml.org/sax/features/namespaces</code> is turned on. */
      protected boolean hasNamespacesFeature() {
          return namespacesFeature;
      }
  
      /** Indicates whether the SAX feature <code>http://xml.org/sax/features/namespaces-prefixes</code>" target="alexandria_uri">http://xml.org/sax/features/namespaces-prefixes</code> is turned on. */
      protected boolean hasNamespacePrefixesFeature() {
          return namespacePrefixesFeature;
      }
  
      protected void setStandalone(boolean standalone) {
          isStandalone = (standalone) ? Boolean.TRUE : Boolean.FALSE;
     }
 
     /**
      * Parses the StAX XML reader passed at construction-time.
      * <p/>
      * <strong>Note</strong> that the given <code>InputSource</code> is not read, but ignored.
      *
      * @param ignored is ignored
      * @throws SAXException A SAX exception, possibly wrapping a <code>XMLStreamException</code>
      */
     public final void parse(InputSource ignored) throws SAXException {
         parse();
     }
 
     /**
      * Parses the StAX XML reader passed at construction-time.
      * <p/>
      * <strong>Note</strong> that the given system identifier is not read, but ignored.
      *
      * @param ignored is ignored
      * @throws SAXException A SAX exception, possibly wrapping a <code>XMLStreamException</code>
      */
     public final void parse(String ignored) throws SAXException {
         parse();
     }
 
     private void parse() throws SAXException {
         try {
             parseInternal();
         }
         catch (XMLStreamException ex) {
             Locator locator = null;
             if (ex.getLocation() != null) {
                 locator = new StaxLocator(ex.getLocation());
             }
             SAXParseException saxException = new SAXParseException(ex.getMessage(), locator, ex);
             if (getErrorHandler() != null) {
                 getErrorHandler().fatalError(saxException);
             }
             else {
                 throw saxException;
             }
         }
     }
 
     /**
      * Sets the SAX <code>Locator</code> based on the given StAX <code>Location</code>.
      *
      * @param location the location
      * @see ContentHandler#setDocumentLocator(org.xml.sax.Locator)
      */
     protected void setLocator(Location location) {
         if (getContentHandler() != null) {
             getContentHandler().setDocumentLocator(new StaxLocator(location));
         }
     }
 
     /** Template-method that parses the StAX reader passed at construction-time. */
     protected abstract void parseInternal() throws SAXException, XMLStreamException;
 
     /**
      * Implementation of the <code>Locator</code> interface that is based on a StAX <code>Location</code>.
      *
      * @see Locator
      * @see Location
      */
     private static class StaxLocator implements Locator {
 
         private Location location;
 
         protected StaxLocator(Location location) {
             this.location = location;
         }
 
         public String getPublicId() {
             return location.getPublicId();
         }
 
         public String getSystemId() {
             return location.getSystemId();
         }
 
         public int getLineNumber() {
             return location.getLineNumber();
         }
 
         public int getColumnNumber() {
             return location.getColumnNumber();
         }
     }
 }