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                         Class driverClass = loadDriverClass(driverFile, className);
  28                         if (driverClass != null) {
  29                     try {
  30                         result = (Driver) driverClass.newInstance();
  31                     } catch (ClassCastException e) {
  32                     }
  33                 }
  34                 } catch (InstantiationException e) {
  35                 } catch (IllegalAccessException e) {
  36                 }
  37                 return result;
  38         }
  39
  40         public static Class loadDriverClass(String driverFile, String className) {
  41                 Class result = null;
  42                 if (driverFile != null && className != null) {
  43                         try {
  44                         File file = new File(driverFile);
  45                         if (file.exists() && file.isFile()) {
  46                                 URLClassLoader loader = getURLClassLoader(file);
  47                                 Class driverClass = loader.loadClass(className);
  48                                 result = Driver.class.isAssignableFrom(driverClass) ? driverClass : null;
  49                         }
  50                         } catch (MalformedURLException e) {
  51                         } catch (ClassNotFoundException e) {
  52                         }
  53                 }
  54                 return result;
  55         }
  56
  57         public static String[] getAllDriverNames(String driverFile) {
  58                 List list = new ArrayList();
  59                 try {
  60                         File file = new File(driverFile);
  61                         URLClassLoader loader = getURLClassLoader(file);
  62                         JarFile jar = new JarFile(file);
  63                         for (Enumeration e = jar.entries(); e.hasMoreElements(); ) {
  64                                 JarEntry entry = (JarEntry) e.nextElement();
  65                                 String className = getClassNameFromFileName(entry.getName());
  66                                 if (className != null) {
  67                                         try {
  68                                                 Class driverClass = loader.loadClass(className);
  69                                                 if (Driver.class.isAssignableFrom(driverClass)) {
  70                                                         list.add(className);
  71                                                 }
  72                                         } catch (ClassNotFoundException ex) {
  73                                         }
  74                                 }
  75                         }
  76                 } catch (IOException e) {
  77                 }
  78                 return (String[]) list.toArray(new String[list.size()]);
  79         }
  80
  81         private static String getClassNameFromFileName(String name) {
  82                 String result = null;
  83                 if (name.endsWith(".class")) {
  84                         result = name.substring(0, name.length()-6).replace('/', '.').replace('\\', '.' );
  85                 }
  86                 return result;
  87         }
  88
  89         /**
  90          * @param file
  91          * @return
  92          * @throws MalformedURLException
  93          */
  94         private static URLClassLoader getURLClassLoader(File file) throws MalformedURLException {
  95                 String driverFile = file.getAbsolutePath();
  96                 URLClassLoader loader =
  97                     (URLClassLoader) classLoaderCache.get(driverFile);
  98                 if (loader == null) {
  99                     URL urls[] = new URL[1];
 100                     urls[0] = file.toURL();
 101                     loader = new URLClassLoader(urls);
 102                     classLoaderCache.put(driverFile, loader);
 103                 }
 104                 return loader;
 105         }
 106 }