VersionedCatalogLoader.java

/*
 * Copyright 2010-2011 Ning, Inc.
 *
 * Ning licenses this file to you 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 com.ning.billing.catalog.io;

import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

import javax.xml.bind.JAXBException;

import org.xml.sax.SAXException;

import com.ning.billing.catalog.Catalog;
import com.ning.billing.catalog.VersionedCatalog;
import com.ning.billing.catalog.api.InvalidConfigException;

public class VersionedCatalogLoader {
	private static final String XML_EXTENSION = ".xml";
	private static final String HREF_LOW_START = "href=\""; 
	private static final String HREF_CAPS_START = "HREF=\""; 
	private static final String HREF_SEARCH_END = "\"";
		
	public static VersionedCatalog load(URL url) throws IOException, SAXException, InvalidConfigException, JAXBException {
		String directoryContents = pullContentsFrom(url);
		List<URL> xmlURLs = findXmlReferences(directoryContents, url);
		VersionedCatalog result = new VersionedCatalog();
		for(URL u : xmlURLs) {
			Catalog catalog = XMLReader.getCatalogFromName(u);
			result.add(catalog);
		}
		return result;
	}
	
	protected static List<URL> findXmlReferences(String directoryContents, URL url) throws MalformedURLException {
		if(url.getProtocol().equals("file")) {
			return findXmlFileReferences(directoryContents, url);
		} 
		return findXmlUrlReferences(directoryContents, url);
	}

	protected static List<URL> findXmlUrlReferences(String directoryContents, URL url) throws MalformedURLException {
		List<URL> results = new ArrayList<URL>();
		List<String> urlFragments = extractHrefs(directoryContents);
		for(String u : urlFragments) {
			if(u.endsWith(XML_EXTENSION)) { //points to xml
				if(u.startsWith("/")) { //absolute path need to add the protocol
					results.add(new URL(url.getProtocol() + ":" + u));
				} else if (u.startsWith("http:")) { // full url
					results.add(new URL(u));
				} else { // relative url stick the name on the end
					results.add(appendToURL(url,u));
				}
			}
		}
		return results;
	}

	protected static List<String> extractHrefs(String directoryContents) {
		List<String> results = new ArrayList<String>();
		int start = 0;
		int end = 0;
		while(start >= 0) {
			start = directoryContents.indexOf(HREF_LOW_START, end);
			if (start > 0) start = start + HREF_LOW_START.length();
					
			end = directoryContents.indexOf(HREF_SEARCH_END, start);
			if(start >= 0) { // We found something
				results.add(directoryContents.substring(start, end));
			}
		}
		
		start = 0;
		end = 0;
		while(start >= 0) {
			start = directoryContents.indexOf(HREF_CAPS_START, end);
			if (start > 0) start =+ HREF_LOW_START.length();
			
			end = directoryContents.indexOf(HREF_SEARCH_END, start);
			if(start >= 0) { // We found something
				results.add(directoryContents.substring(start, end));
			}
		}
		return results;
	}

	protected static List<URL> findXmlFileReferences(String directoryContents, URL url) throws MalformedURLException {
		List<URL> results = new ArrayList<URL>();
		String[] filenames = directoryContents.split("\\n");
		for(String filename : filenames) {
			if(filename.endsWith(XML_EXTENSION)) {
				results.add(appendToURL(url,filename));
			}
		}
		return results;
	}

	protected static URL appendToURL(final URL url, final String filename) throws MalformedURLException {
		String f = filename;
		if (!url.toString().endsWith("/")) {
			f = "/" + filename;
		}
		return new URL(url.toString() + f);
	}

	protected static String pullContentsFrom(final URL url) throws IOException {
		URLConnection connection = url.openConnection();
		InputStream content = connection.getInputStream();
		return new Scanner(content).useDelimiter("\\A").next();
	}
	
	public static void main (String[] args) throws Exception {		
		//new VersionedCatalog().initialize(new URL("http://gepo.ningops.net/config/trunk/xno/viking/master/viking-core/"));
		new VersionedCatalogLoader().load(new URL("file:///Users/mwesthead/work/killbill/catalog/src/test/resources/"));
	}
}