/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
* PluginManager.java
* Copyright (C) 2011 University of Waikato, Hamilton, New Zealand
*
*/
package weka.gui.beans;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
/**
* Class that manages a global map of plugins. The knowledge flow
* uses this to manage plugins other than step components and
* perspectives. Is general purpose, so can be used by other Weka
* components. Provides static methods for registering and instantiating
* plugins.
*
* @author Mark Hall (mhall{[at]}pentaho{[dot]}com)
* @version $Revision: 7643 $
*/
public class PluginManager {
/**
* Global map that is keyed by plugin base class/interface type. The inner
* Map then stores individual plugin instances of the interface type, keyed
* by plugin name/short title with values the actual fully qualified class
* name
*/
protected static Map<String, Map<String, String>> PLUGINS =
new HashMap<String, Map<String, String>>();
/**
* Get a set of names of plugins that implement the supplied interface.
*
* @param interfaceName the fully qualified name of the interface to list
* plugins for
*
* @return a set of names of plugins
*/
public static Set<String> getPluginNamesOfType(String interfaceName) {
if (PLUGINS.get(interfaceName) != null) {
return PLUGINS.get(interfaceName).keySet();
}
return null;
}
/**
* Add a plugin.
*
* @param interfaceName the fully qualified interface name that the
* plugin implements
*
* @param name the name/short description of the plugin
* @param concreteType the fully qualified class name of the actual
* concrete implementation
*/
public static void addPlugin(String interfaceName, String name,
String concreteType) {
if (PLUGINS.get(interfaceName) == null) {
Map<String, String> pluginsOfInterfaceType =
new TreeMap<String, String>();
pluginsOfInterfaceType.put(name, concreteType);
PLUGINS.put(interfaceName, pluginsOfInterfaceType);
} else {
PLUGINS.get(interfaceName).put(name, concreteType);
}
}
/**
* Get an instance of a concrete implementation of a plugin type
*
* @param interfaceType the fully qualified interface name of the
* plugin type
* @param name the name/short description of the plugin to get
* @return the concrete plugin
* @throws Exception if the plugin can't be found or instantiated
*/
public static Object getPluginInstance(String interfaceType, String name)
throws Exception {
if (PLUGINS.get(interfaceType) == null ||
PLUGINS.get(interfaceType).size() == 0) {
throw new Exception("No plugins of interface type: " + interfaceType
+ " available!!");
}
Map<String, String> pluginsOfInterfaceType =
PLUGINS.get(interfaceType);
if (pluginsOfInterfaceType.get(name) == null) {
throw new Exception("Can't find named plugin '" + name + "' of type '" +
interfaceType + "'!");
}
String concreteImpl = pluginsOfInterfaceType.get(name);
Object plugin = Class.forName(concreteImpl).newInstance();
return plugin;
}
}