de.highbyte_le.weberknecht.request.actions.DynamicActionFactory.java Source code

Introduction

Here is the source code for de.highbyte_le.weberknecht.request.actions.DynamicActionFactory.java

Source

/*
 * DynamicActionFactory.java
 *
 * Copyright 2008-2013 Patrick Mairif.
 * The program is distributed under the terms of the Apache License (ALv2).
 * 
 * tabstop=4, charset=UTF-8
 */
package de.highbyte_le.weberknecht.request.actions;

import java.util.HashMap;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * create actions by name
 * @author pmairif
 */
@SuppressWarnings("nls")
public class DynamicActionFactory implements ActionFactory {

    private Map<String, Class<? extends ExecutableAction>> actionMap = new HashMap<String, Class<? extends ExecutableAction>>();

    /**
     * Logger for this class
     */
    private final Log log = LogFactory.getLog(DynamicActionFactory.class);

    /**
     * creates new instance for requested action 
     * @param actionName
     * @return new instance of action
     */
    @Override
    public ExecutableAction createAction(String actionName) throws ActionInstantiationException {
        try {
            Class<? extends ExecutableAction> actionClass = actionMap.get(actionName);
            if (actionClass != null)
                return actionClass.newInstance();
        } catch (IllegalAccessException e) {
            log.error("createAction() - IllegalAccessException: " + e.getMessage(), e);
        } catch (InstantiationException e) {
            log.error("createAction() - InstantiationException: " + e.getMessage(), e);
        } catch (Exception e) {
            throw new ActionInstantiationException(e.getMessage(), e);
        }

        return null;
    }

    /* (non-Javadoc)
     * @see de.highbyte_le.weberknecht.request.actions.ActionFactory#hasAction(java.lang.String)
     */
    @Override
    public boolean knowsAction(String actionName) {
        return actionMap.containsKey(actionName);
    }

    @SuppressWarnings({ "unchecked" })
    @Override
    public void registerAction(String name, String className) throws ActionInstantiationException {
        try {

            Class<?> c = Class.forName(className);
            Object o = c.newInstance();

            if (o instanceof ExecutableAction) {
                actionMap.put(name, (Class<ExecutableAction>) c);
            } else {
                throw new ActionInstantiationException(className + " is not a valid action.");
            }

        } catch (Exception e) {
            throw new ActionInstantiationException("problems instantiating " + className + ": " + e.getMessage(),
                    e);
        }
    }
}