appl/util/GeneralUtil.java

package appl.util;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.URL;

import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;

import net.jini.loader.pref.PreferredClassLoader;

/**
 * General utility class. See method description for details.
 * 
 * @author Dominik Appl
 */
public class GeneralUtil {

        public static Logger LOG = LogManager.getLogger("appl.util.GeneralUtil");

        /**
         * Loads a class from the specified URL and returns an instance of this class.
         * @param location the URL of the rootDirectory/networkLocation
         * @param classname the fully qualified name of the class (the class must have a 
         * 
         * @return the instance of the class or <code>null</code> if loading fails
         */
        public static Object loadClassFromURL(URL location, String classname) {
                try {
                        URL[] locations = { location };
                        PreferredClassLoader classLoader = new PreferredClassLoader(
                                        locations, Thread.currentThread().getContextClassLoader(),
                                        null, false);
                        LOG.debug("Try to load " + classname.getClass().getName()
                                        + " from " + location);
                        Class classObject = classLoader.loadClass(classname);
                        return classObject.newInstance();
                } catch (Exception e) {
                        LOG.error("Could not load class for " + classname + " from "
                                        + location, e);
                        e.printStackTrace();
                }
                return null;
        }

        /**
         * Serializes the given object into the specified file. All exceptions are printed to console.
         * @param o the object
         * @param destFile the file to write to
         */
        public static void SerializeToFile(Object o, File destFile) {
                try {
                        destFile.createNewFile();
                        BufferedOutputStream fos = new BufferedOutputStream(
                                        new FileOutputStream(destFile));
                        ObjectOutputStream oos = new ObjectOutputStream(fos);
                        oos.writeObject(o);
                        oos.close();
                        fos.close();
                } catch (Exception e) {
                        e.printStackTrace();
                }
        }

        /**
         * Reads the first object out of the file
         * @param loadFile the file to read from
         * @return the object
         */
        public static Object readSerializedFrom(File loadFile) {
                Object loadedObject = null;
                try {
                        BufferedInputStream fis = new BufferedInputStream(
                                        new FileInputStream(loadFile));
                        ObjectInputStream ois = new ObjectInputStream(fis);
                        loadedObject = ois.readObject();
                        ois.close();
                        fis.close();
                        // remove File from Filesystem
                } catch (FileNotFoundException e) {
                        LOG.error(e);
                        e.printStackTrace();

                } catch (Exception e) {
                        LOG.error(e);
                        e.printStackTrace();
                }
                return loadedObject;
        }
}
1	mojays	2	package appl.util;
2
3			import java.io.BufferedInputStream;
4			import java.io.BufferedOutputStream;
5			import java.io.File;
6			import java.io.FileInputStream;
7			import java.io.FileNotFoundException;
8			import java.io.FileOutputStream;
9			import java.io.ObjectInputStream;
10			import java.io.ObjectOutputStream;
11			import java.net.URL;
12
13			import org.apache.log4j.LogManager;
14			import org.apache.log4j.Logger;
15
16			import net.jini.loader.pref.PreferredClassLoader;
17
18			/**
19			* General utility class. See method description for details.
20			*
21			* @author Dominik Appl
22			*/
23			public class GeneralUtil {
24
25			public static Logger LOG = LogManager.getLogger("appl.util.GeneralUtil");
26
27			/**
28			* Loads a class from the specified URL and returns an instance of this class.
29			* @param location the URL of the rootDirectory/networkLocation
30			* @param classname the fully qualified name of the class (the class must have a
31			*
32			* @return the instance of the class or <code>null</code> if loading fails
33			*/
34			public static Object loadClassFromURL(URL location, String classname) {
35			try {
36			URL[] locations = { location };
37			PreferredClassLoader classLoader = new PreferredClassLoader(
38			locations, Thread.currentThread().getContextClassLoader(),
39			null, false);
40			LOG.debug("Try to load " + classname.getClass().getName()
41			+ " from " + location);
42			Class classObject = classLoader.loadClass(classname);
43			return classObject.newInstance();
44			} catch (Exception e) {
45			LOG.error("Could not load class for " + classname + " from "
46			+ location, e);
47			e.printStackTrace();
48			}
49			return null;
50			}
51
52			/**
53			* Serializes the given object into the specified file. All exceptions are printed to console.
54			* @param o the object
55			* @param destFile the file to write to
56			*/
57			public static void SerializeToFile(Object o, File destFile) {
58			try {
59			destFile.createNewFile();
60			BufferedOutputStream fos = new BufferedOutputStream(
61			new FileOutputStream(destFile));
62			ObjectOutputStream oos = new ObjectOutputStream(fos);
63			oos.writeObject(o);
64			oos.close();
65			fos.close();
66			} catch (Exception e) {
67			e.printStackTrace();
68			}
69			}
70
71			/**
72			* Reads the first object out of the file
73			* @param loadFile the file to read from
74			* @return the object
75			*/
76			public static Object readSerializedFrom(File loadFile) {
77			Object loadedObject = null;
78			try {
79			BufferedInputStream fis = new BufferedInputStream(
80			new FileInputStream(loadFile));
81			ObjectInputStream ois = new ObjectInputStream(fis);
82			loadedObject = ois.readObject();
83			ois.close();
84			fis.close();
85			// remove File from Filesystem
86			} catch (FileNotFoundException e) {
87			LOG.error(e);
88			e.printStackTrace();
89
90			} catch (Exception e) {
91			LOG.error(e);
92			e.printStackTrace();
93			}
94			return loadedObject;
95			}
96			}