com.draagon.util.xml.XMLFileReader Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of utilities Show documentation

Draagon Utilities used by other Draagon projects

The newest version!

/*
 * Copyright 2003 Draagon Software LLC. All Rights Reserved.
 *
 * This software is the proprietary information of Draagon Software LLC.
 * Use is subject to license terms.
 */

package com.draagon.util.xml;

import java.io.IOException;
import java.io.InputStream;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.w3c.dom.Document;

/**
 * Meta Class loader for XML files
 */
public class XMLFileReader
{
  private static Log log = LogFactory.getLog( XMLFileReader.class );

  /**
   * Loads all the classes specified in the Filename
   */
  public static Document loadFromStream( InputStream is )
    throws IOException
  {
    Document d = null;

    // Try the JAXP Parser
    d = getPluginAndTryLoad( is, "com.draagon.util.xml.JAXPXMLPlugin" );
    if ( d != null ) return d;

    // If not Plugin worked, then error out
    throw new IOException( "No valid XML Plugin was found to load XML document" );
  }

  private static Document getPluginAndTryLoad( InputStream is, String className )
    throws IOException
  {
    XMLPlugin plugin = getPlugin( className );
    if ( plugin == null ) return null;

    //ystem.out.println( "TRYING PLUGIN: " + plugin );

    try {
      return plugin.loadFromStream( is );
    }
    catch( IOException e ) {
      throw e;
    }
    catch( Throwable e ) {
      //ystem.out.println( "ERROR: Cannot use [" + className + "]: " + e.getMessage() );
      log.debug( "Error attempting to use plugin [" + className + "]: " + e.getMessage() );
    }

    return null;
  }

  private static XMLPlugin getPlugin( String className )
  {
    try {
      Class c = Class.forName( className );
      return (XMLPlugin) c.newInstance();
    }
    catch( Throwable e ) {
      //ystem.out.println( "ERROR: Cannot load [" + className + "]: " + e.getMessage() );
      log.debug( "Unable to load XML Plugin [" + className + "]: " + e.getMessage() );
      return null;
    }
  }
}