package org.apache.xerces.util;

import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import org.apache.xerces.xni.XMLResourceIdentifier;
import org.apache.xerces.xni.XNIException;
import org.apache.xerces.xni.parser.XMLEntityResolver;
import org.apache.xerces.xni.parser.XMLInputSource;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

public class EntityResolverWrapper implements XMLEntityResolver {
  protected EntityResolver fEntityResolver;
  
  public EntityResolverWrapper() {}
  
  public EntityResolverWrapper(EntityResolver entityResolver) {
    setEntityResolver(entityResolver);
  }
  
  public void setEntityResolver(EntityResolver entityResolver) {
    this.fEntityResolver = entityResolver;
  }
  
  public EntityResolver getEntityResolver() {
    return this.fEntityResolver;
  }
  
  public XMLInputSource resolveEntity(XMLResourceIdentifier resourceIdentifier) throws XNIException, IOException {
    String pubId = resourceIdentifier.getPublicId();
    String sysId = resourceIdentifier.getExpandedSystemId();
    if (pubId == null && sysId == null)
      return null; 
    if (this.fEntityResolver != null && resourceIdentifier != null)
      try {
        InputSource inputSource = this.fEntityResolver.resolveEntity(pubId, sysId);
        if (inputSource != null) {
          String publicId = inputSource.getPublicId();
          String systemId = inputSource.getSystemId();
          String baseSystemId = resourceIdentifier.getBaseSystemId();
          InputStream byteStream = inputSource.getByteStream();
          Reader charStream = inputSource.getCharacterStream();
          String encoding = inputSource.getEncoding();
          XMLInputSource xmlInputSource = new XMLInputSource(publicId, systemId, baseSystemId);
          xmlInputSource.setByteStream(byteStream);
          xmlInputSource.setCharacterStream(charStream);
          xmlInputSource.setEncoding(encoding);
          return xmlInputSource;
        } 
      } catch (SAXException e) {
        Exception ex = e.getException();
        if (ex == null)
          ex = e; 
        throw new XNIException(ex);
      }  
    return null;
  }
}