source: josm/src/org/openstreetmap/josm/plugins/PluginInformation.java@ 157

package org.openstreetmap.josm.plugins;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.jar.JarInputStream;
import java.util.jar.Manifest;

/**
 * Encapsulate general information about a plugin. This information is available
 * without the need of loading any class from the plugin jar file.
 *
 * @author imi
 */
public class PluginInformation {
        public final File file;
        public final String name;
        public final String className;
        public final String description;

        public PluginInformation(File file) {
                this.file = file;
                name = file.getName().substring(0, file.getName().length()-4);
                try {
                JarInputStream jar = new JarInputStream(new FileInputStream(file));
                Manifest manifest = jar.getManifest();
                className = manifest.getMainAttributes().getValue("Plugin-Class");
                description = manifest.getMainAttributes().getValue("Plugin-Description");
                jar.close();
        } catch (IOException e) {
                throw new PluginException(null, name, e);
        }
    }

        /**
         * Load and instantiate the plugin
         */
        public PluginProxy load() {
                try {
                        ClassLoader loader = URLClassLoader.newInstance(
                                        new URL[]{new URL(getURLString())},
                                        getClass().getClassLoader());
                        Object plugin = Class.forName(className, true, loader).newInstance();
                        return new PluginProxy(plugin, this);
                } catch (Exception e) {
                        throw new PluginException(null, name, e);
                }
        }

        private String getURLString() {
                if (System.getProperty("os.name").startsWith("Windows"))
                        return "file:/"+file.getAbsolutePath();
                return "file://"+file.getAbsolutePath();
    }
}