/**
*
* @title IndexSearcher
* @author James McElvenny
*
* This class opens the index file, processes it and then searches the entry path for index items.
*
*/

import javax.swing.DefaultListModel;

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

import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;

import org.w3c.dom.Document;
import org.xml.sax.SAXException;

import java.io.IOException;

public class IndexSearcher
{
	private String server;
	private String indexFile;
	private String entryPath;

	private DocumentBuilder builder;
	private XPath path;
	
	/**
	*
	* The constructor sets up all instance variables and the XML parser.
	*
	*/
	public IndexSearcher(String passedServer, String passedIndexFile, String passedEntryPath) 
		throws ParserConfigurationException
	{
		server = passedServer;
		indexFile = passedIndexFile;
		entryPath = passedEntryPath;
		
		DocumentBuilderFactory dbfactory = DocumentBuilderFactory.newInstance();
		
		builder = dbfactory.newDocumentBuilder();
		
		XPathFactory xpfactory = XPathFactory.newInstance();
		path = xpfactory.newXPath();
	}
	
	/**
	*
	* The searchIndex method searches through the passed path for strings that match the searchString.
	*
	*/	
	public void searchIndex(String index, String searchString, DefaultListModel outputTarget)
		throws SAXException, IOException, XPathExpressionException
	{
		String inputFile = server + indexFile;
		Document indexDoc = builder.parse(inputFile);
		
		int entryCount = Integer.parseInt(path.evaluate("count("+entryPath+")", indexDoc));
				
		for(int i = 1; i <= entryCount; i++)
		{
			String indexItem = path.evaluate(entryPath+"["+i+"]/"+index, indexDoc);
			
			String indexLink = path.evaluate(entryPath+"["+i+"]/link", indexDoc);
			
			if(indexItem.equals(searchString)) 
			{
				outputTarget.addElement(indexLink);
			}
		}
		if(outputTarget.isEmpty())
			outputTarget.addElement(DictSearch.ERROR_MESSAGE);
	}
}