archive/net.sourceforge.phpeclipse.quantum.sql/src/com/quantum/util/JarUtil.java

   1 package com.quantum.util;
   2
   3 import java.io.File;
   4 import java.io.IOException;
   5 import java.net.MalformedURLException;
   6 import java.net.URL;
   7 import java.net.URLClassLoader;
   8 import java.sql.Driver;
   9 import java.util.ArrayList;
  10 import java.util.Enumeration;
  11 import java.util.Hashtable;
  12 import java.util.List;
  13 import java.util.jar.JarEntry;
  14 import java.util.jar.JarFile;
  15
  16
  17 /**
  18  * @author BC Holmes
  19  */
  20 public class JarUtil {
  21
  22     private static Hashtable classLoaderCache = new Hashtable();
  23
  24         public static Driver loadDriver(String driverFile, String className) {
  25                 Driver result = null;
  26                 try {
  27                 File file = new File(driverFile);
  28                 if (file.exists() && file.isFile()) {
  29                         URLClassLoader loader = getURLClassLoader(file);
  30                         Class driverClass = loader.loadClass(className);
  31                     try {
  32                         result = (Driver) driverClass.newInstance();
  33                     } catch (ClassCastException e) {
  34                     }
  35                 }
  36                 } catch (MalformedURLException e) {
  37                 } catch (ClassNotFoundException e) {
  38                 } catch (InstantiationException e) {
  39                 } catch (IllegalAccessException e) {
  40                 }
  41                 return result;
  42         }
  43
  44         public static String[] getAllDriverNames(String driverFile) {
  45                 List list = new ArrayList();
  46                 try {
  47                         File file = new File(driverFile);
  48                         URLClassLoader loader = getURLClassLoader(file);
  49                         JarFile jar = new JarFile(file);
  50                         for (Enumeration e = jar.entries(); e.hasMoreElements(); ) {
  51                                 JarEntry entry = (JarEntry) e.nextElement();
  52                                 String className = getClassNameFromFileName(entry.getName());
  53                                 if (className != null) {
  54                                         try {
  55                                                 Class driverClass = loader.loadClass(className);
  56                                                 if (Driver.class.isAssignableFrom(driverClass)) {
  57                                                         list.add(className);
  58                                                 }
  59                                         } catch (ClassNotFoundException ex) {
  60                                         }
  61                                 }
  62                         }
  63                 } catch (IOException e) {
  64                 }
  65                 return (String[]) list.toArray(new String[list.size()]);
  66         }
  67
  68         private static String getClassNameFromFileName(String name) {
  69                 String result = null;
  70                 if (name.endsWith(".class")) {
  71                         result = name.substring(0, name.length()-6).replace('/', '.').replace('\\', '.' );
  72                 }
  73                 return result;
  74         }
  75
  76         /**
  77          * @param file
  78          * @return
  79          * @throws MalformedURLException
  80          */
  81         private static URLClassLoader getURLClassLoader(File file) throws MalformedURLException {
  82                 String driverFile = file.getAbsolutePath();
  83                 URLClassLoader loader =
  84                     (URLClassLoader) classLoaderCache.get(driverFile);
  85                 if (loader == null) {
  86                     URL urls[] = new URL[1];
  87                     urls[0] = file.toURL();
  88                     loader = new URLClassLoader(urls);
  89                     classLoaderCache.put(driverFile, loader);
  90                 }
  91                 return loader;
  92         }
  93 }