import java.io.IOException;
import java.io.StringReader;
import java.util.Hashtable;
import java.util.Iterator;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.w3c.dom.Node;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;



public class XMLParser {

	public XMLParser()
	{
		// default constructor
	}
	
	protected Document makeDOM( String pstr_xml ) 
    throws makeDOMException
	{	
		try {
			DocumentBuilderFactory ldbf_factory = 
                DocumentBuilderFactory.newInstance();
			DocumentBuilder ldb_builder = ldbf_factory.newDocumentBuilder();
			
			Document ldom_document = 
                ldb_builder.parse( 
                    new InputSource( new StringReader( pstr_xml.trim() ) ) );
			
			return ldom_document;
						
		} catch( SAXException sxe ){
			// parser failed
			Exception x = sxe;
			if( sxe.getException() != null )
				x = sxe.getException();
			//x.printStackTrace();
			throw new makeDOMException( sxe.getLocalizedMessage() );
			
		} catch( ParserConfigurationException pce ){
			// user setup parser wrong
			//pce.printStackTrace();
		    throw new makeDOMException( pce.getLocalizedMessage() );
			
		} catch( IOException ioe ){
		    throw new makeDOMException( ioe.getLocalizedMessage() );
						
		}
		
		//return null;
	}
	

	
    /**
     * This function converts node lists of the form 
     * <FOO>
     *  <BAR>
     *      <FUD>value</FUD>
     *  </BAR>
     * </FOO>
     * 
     * into hash tables with key => value pairs like
     * 
     * FOO.BAR.FUD => value
     * 
     * 
     * @param pnl_nodes         Input
     * @param phsh_hashtable    The key->values pairs will be stored here.
     * @param pstr_prefix       The prefix that created the dotted form.
     * @param pstr_attribute    The name of a particular attribute to look for.  
     *                          If the attribute exists, it add's it's value to the prefix.
     */
    protected void nodeListTree2Hash( NodeList pnl_nodes, 
            Hashtable phsh_hashtable, 
            String pstr_prefix, 
            String pstr_attribute 
            )
    {
        String lstr_dot = ".";
        try{
            for( int i=0; i < pnl_nodes.getLength(); i++ ){
                if( pnl_nodes.item(i).hasChildNodes() ){
                    // if the prefix is blank, don't put a dot in front
                    if( pstr_prefix.length() < 1 ){   
                        lstr_dot = "";
                    }
                    if( pnl_nodes.item(i).getAttributes().getNamedItem( 
                            pstr_attribute ) != null 
                    ){
                        nodeListTree2Hash( 
                            pnl_nodes.item(i).getChildNodes(), 
                            phsh_hashtable,
                            pstr_prefix + lstr_dot + pnl_nodes.item(i).getNodeName() + 
                            pnl_nodes.item(i).getAttributes().getNamedItem( pstr_attribute ).getNodeValue().trim(),
                            pstr_attribute
                        );
                    } else {
                        nodeListTree2Hash( 
                            pnl_nodes.item(i).getChildNodes(), 
                            phsh_hashtable,
                            pstr_prefix + lstr_dot + pnl_nodes.item(i).getNodeName(),
                            pstr_attribute
                            );
                    }
                } else {
                    if( pnl_nodes.item(i).getNodeValue() != null
                        && pnl_nodes.item(i).getNodeValue().trim().length() > 0 
                    ){
                        phsh_hashtable.put( 
                            pstr_prefix, 
                            pnl_nodes.item(i).getNodeValue().trim() + "" );
                        lstr_dot = ".";
                    }
                }
            }  // end for
        } catch( NullPointerException e ){
            // do nothing
            //System.out.println( "error " + e.getLocalizedMessage() );
            //e.printStackTrace();
        }
    }
    
    /**
     * This version of nodeListTree2Hash will add the value of the first attribute to the prefix.
     * 
     * @param pnl_nodes
     * @param phsh_hashtable
     * @param pstr_prefix
     */
	protected void nodeListTree2Hash( 
            NodeList pnl_nodes, 
            Hashtable phsh_hashtable, 
            String pstr_prefix 
    ) {
	    String lstr_dot = ".";
	    try{
			for( int i=0; i < pnl_nodes.getLength(); i++ ){
				if( pnl_nodes.item(i).hasChildNodes() ){
				    if( pstr_prefix.length() < 1 ){   // if the prefix is blank, don't put a dot in front
				        lstr_dot = "";
				    }
				    if( pnl_nodes.item(i).hasAttributes() ){
				        nodeListTree2Hash( 
						        pnl_nodes.item(i).getChildNodes(), 
						        phsh_hashtable,
						        pstr_prefix + lstr_dot + pnl_nodes.item(i).getNodeName() + 
						        	pnl_nodes.item(i).getAttributes().toString().trim()
						        );
				    } else {
					    nodeListTree2Hash( 
						        pnl_nodes.item(i).getChildNodes(), 
						        phsh_hashtable,
						        pstr_prefix + lstr_dot + pnl_nodes.item(i).getNodeName()
						        );
				    }
				} else {
					if( pnl_nodes.item(i).getNodeValue() != null
					        && pnl_nodes.item(i).getNodeValue().trim().length() > 0 ){
						phsh_hashtable.put( 
								pstr_prefix, 
								pnl_nodes.item(i).getNodeValue().trim() + "" );
						lstr_dot = ".";
					}
				}
			}  // end for
	    } catch( NullPointerException e ){
	        // do nothing
	    }
	} 
    
    /** Just a convenience method */
    protected void nodeListTree2Hash( NodeList pnl_nodes, Hashtable phsh_hashtable )
    {
        nodeListTree2Hash( pnl_nodes, phsh_hashtable, "" );
    }
	
    /**
     * Much like NodeListTree2Hash, but it prints the result in a nicely human readable form.
     * You could also use printHash( nodeListTree2Hash( hashtable ) ), but this prints more cleanly.
     * 
     * @param pnl_nodes
     * @param pstr_prefix
     */
	protected void printNodeListTree( NodeList pnl_nodes, String pstr_prefix )
	{
	    String lstr_dot = ".";
	    try{
			for( int i=0; i < pnl_nodes.getLength(); i++ ){
				if( pnl_nodes.item(i).hasChildNodes() ){
				    if( pstr_prefix.length() < 1 ){   // if the prefix is blank, don't put a dot in front
				        lstr_dot = "";
				    }
				    if( pnl_nodes.item(i).hasAttributes() ){
						printNodeListTree( 
						        pnl_nodes.item(i).getChildNodes(), 
						        pstr_prefix + lstr_dot + pnl_nodes.item(i).getNodeName()  
						        	//+ pnl_nodes.item(i).getAttributes().toString().trim()
						        	+ pnl_nodes.item(i).getAttributes().item(0).getNodeValue()
						        );
				    } else {
						printNodeListTree( 
						        pnl_nodes.item(i).getChildNodes(), 
						        pstr_prefix + lstr_dot + pnl_nodes.item(i).getNodeName()
						        );
				    }
				} else {
					if( pnl_nodes.item(i).getNodeValue() != null
					        && pnl_nodes.item(i).getNodeValue().trim().length() > 0 ){
					    
					    System.out.println( pstr_prefix + "" + 
					            "\t" + pnl_nodes.item(i).getNodeValue().trim() + "" 
					            );
					    lstr_dot = ".";
					}
				}
			}
	    } catch( NullPointerException e ){
	        // do nothing
	        System.out.println( pstr_prefix + " Same error" );
	        e.printStackTrace();
	    }
	}
	
    
    protected String getFromHash( Hashtable phsh_hash, String pstr_key )
    {
        if( phsh_hash.containsKey( pstr_key ) ){
            return phsh_hash.get(pstr_key).toString();
        } else {
            return null;
        }
    }
    
	public static String hash2String( Hashtable phsh_hashtable )
	{
		Object lobj_key;
		String tmp = "";
			
		Iterator litr_valueIter = phsh_hashtable.values().iterator();
		Iterator litr_keyIter = phsh_hashtable.keySet().iterator();
			
		while( litr_keyIter.hasNext() ){
		    tmp += litr_keyIter.next() + "\t\t" + litr_valueIter.next() + "\n";
		}
		
		return tmp;
	}
    
    public static void printHash( Hashtable phsh_hashtable )
    {
        System.out.println( hash2String(phsh_hashtable) );
    }
	
	// EXCEPTIONS
	protected class makeDOMException extends Exception
	{
	    /* (non-Javadoc)
         * @see java.lang.Throwable#getLocalizedMessage()
         */
	    private String gstr_message = "Error Creating DOM";
	    
	    public makeDOMException(){}
	    public makeDOMException( String pstr_message )
	    {
	        gstr_message = pstr_message;
	    }
        public String getLocalizedMessage() {
            return gstr_message;
        }
	}
}