appextensions.java

JRemoteControl is a simple Java&#8482 driven bluetooth remote control.It allows you to initiate virt

/*
 * JRemCntl - Copyright (C) 2007 Filippo Di Vattimo <[e-mail]>
 * See COPYING
 */

package fildiv.jremcntl.server.core;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.jar.Attributes;
import java.util.jar.JarFile;
import java.util.jar.Manifest;

import fildiv.jremcntl.common.core.Logger;
import fildiv.jremcntl.common.util.JRemUtils;
import fildiv.jremcntl.server.utils.JRemServerUtils.ExtFileFilter;

public class AppExtensions {

	private Environment env;
	private Logger logger;

	private Map extsMap;
	
	protected AppExtensions() {
		this.env = JRemEnv.getInstance();
		this.logger = env.getLogger();
		
		try {
			readExtensionsInfo();
		} catch(Exception e) {
			logger.error("Unable to load extension");
			logger.error(e);
		}
	}
	
	protected void readExtensionsInfo() {

		extsMap = new Hashtable();
		
		if (env.isLogEnabled())
			logger.info("Reading extensions from " + env.getExtDirPath());
		
		File extDir = new File(env.getExtDirPath());
		
		ExtFileFilter ff = new ExtFileFilter(".jar");

		File[] files = extDir.listFiles(ff);
		for (int index = 0; index < files.length; ++index) {
			File f = files[index];
			
			List extsList = readExtensionInfo(f);
			if (extsList != null) {
			
				for (Iterator i = extsList.iterator(); i.hasNext(); ) {
					AppExtension appExt = (AppExtension) i.next();
					
					extsMap.put(appExt.getID(), appExt);
				}				
			}
		}

		if (env.isLogEnabled())
			logger.info("Done ...");
	}

	protected List readExtensionInfo(File f) {
		
		logger.info("Reading file : " + f.getAbsolutePath());
		
		JarFile jf = null;
		
		try {
			jf = new JarFile(f);
		} catch (IOException e) {
			logger.error("Error reading " + f.getAbsolutePath());
			logger.error(e);
			
			return null;
		}

		Manifest m = null;
		
		try {
			m = jf.getManifest();
		} catch (IOException e) {
			logger.error("Error reading manifest from " + f.getAbsolutePath());
			logger.error(e);
			
			return null;
		}
		
		Attributes attrs = m.getAttributes(ExtensionConst.MANIFEST_SECTION);
		
		List infos = null;
		
		try {
			infos = readExtensionInfo(attrs, f);
		} catch(Exception e) {
			logger.error("Error reading extension information from " + f.getAbsolutePath());
			logger.error(e);
			return null;
		}
		
		return infos;
	}
	
	protected List readExtensionInfo(Attributes attrs, File f) {
		
		List extList = new ArrayList();
		
		int index = 1;
		
		while (true) {
		
			String shortName = getAttrValue(attrs, ExtensionConst.MANIFEST_SHORT_NAME, index);
			if (shortName == null) {
				if (index == 1)
					logger.error(ExtensionConst.MANIFEST_SHORT_NAME + 
							" was not found in MANIFEST (" + f.getAbsolutePath() + ")");

				return extList;
			}
			
			String id = getAttrValue(attrs, ExtensionConst.MANIFEST_EXT_ID, index);
			if (id == null) {
				if (index == 1)
					logger.error(ExtensionConst.MANIFEST_EXT_ID + 
							" was not found in MANIFEST (" + f.getAbsolutePath() + ")");

				return extList;
			}

			String className = getAttrValue(attrs, ExtensionConst.MANIFEST_CLASS_NAME, index);
			if (className == null) {
				if (index == 1)
					logger.error(ExtensionConst.MANIFEST_CLASS_NAME + 
							" was not found in MANIFEST (" + f.getAbsolutePath() + ")");

				return extList;
			}
			
			if (env.isLogEnabled())
				logger.info("found : " + shortName + "[" + id + "]");
			
			AppExtension ext = new AppExtension(id, shortName, 
					className, f.getAbsolutePath());
			extList.add(ext);
			
			index++;
		}
	}
	
	protected String getAttrValue(Attributes attrs, String attrName, int index) {
		attrName = attrName + "-" + index;

		String attrValue = attrs.getValue(attrName);
		return attrValue;
	}
	
	public AppExtension getExtension(String id) {
		
		if (JRemUtils.isEmptyString(id))
			throw new IllegalArgumentException("id cannot be null");
		
		return (AppExtension) extsMap.get(id);
	}
	
	public List asList() {
		return Collections.unmodifiableList( new ArrayList(extsMap.values())) ;
	}

	public AppExtension getDefault() {
		return getExtension(ExtensionConst.DEFAULT_EXT_ID) ;
	}
	
}