EventHandlerHolder.java

/**
 * ***************************************************************************
 * Copyright (c) 2010 Qcadoo Limited
 * Project: Qcadoo Framework
 * Version: 1.4
 *
 * This file is part of Qcadoo.
 *
 * Qcadoo is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published
 * by the Free Software Foundation; either version 3 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 * ***************************************************************************
 */
package com.qcadoo.view.internal.internal;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import com.google.common.collect.Maps;
import com.qcadoo.plugin.api.PluginUtils;
import com.qcadoo.view.api.ComponentState;
import com.qcadoo.view.api.ViewDefinitionState;
import com.qcadoo.view.internal.hooks.ViewEventListenerHook;

public final class EventHandlerHolder {

    private final ComponentState owner;

    public EventHandlerHolder(final ComponentState owner) {
        this.owner = owner;
    }

    private final Map<String, List<EventHandler>> eventHandlers = Maps.newHashMap();

    public void registerCustomEvent(final ViewEventListenerHook eventListenerHook) {
        registerEvent(eventListenerHook.getEventName(), eventListenerHook);
    }

    public void registerEvent(final String event, final Object obj, final String method) {
        registerEvent(event, new DefaultEventHandler(obj, method, null));
    }

    private void registerEvent(final String event, final EventHandler eventHandler) {
        if (!eventHandlers.containsKey(event)) {
            eventHandlers.put(event, new ArrayList<EventHandler>());
        }
        eventHandlers.get(event).add(eventHandler);
    }

    public void performEvent(final ViewDefinitionState viewDefinitionState, final String event, final String... args) {
        if (!eventHandlers.containsKey(event)) {
            return;
        }
        for (EventHandler eventHandler : eventHandlers.get(event)) {
            eventHandler.invokeEvent(viewDefinitionState, owner, args);
        }
    }

    public interface EventHandler {

        void invokeEvent(final ViewDefinitionState viewDefinitionState, final ComponentState eventPerformer, final String[] args);
    }

    private class DefaultEventHandler implements EventHandler {

        private final Method method;

        private final Object obj;

        private final String pluginIdentifier;

        public DefaultEventHandler(final Object obj, final String method, final String pluginIdentifier) {
            this.obj = obj;
            this.pluginIdentifier = pluginIdentifier;
            try {
                this.method = obj.getClass().getDeclaredMethod(method, String[].class);
            } catch (SecurityException e) {
                throw new IllegalStateException(e.getMessage(), e);
            } catch (NoSuchMethodException e) {
                throw new IllegalStateException(e.getMessage(), e);
            }
        }

        @Override
        public void invokeEvent(final ViewDefinitionState viewDefinitionState, final ComponentState eventPerformer,
                final String[] args) {
            if (pluginIdentifier != null && !PluginUtils.isEnabled(pluginIdentifier)) {
                return;
            }
            try {
                method.invoke(obj, new Object[] { args });
            } catch (IllegalArgumentException e) {
                throw new IllegalStateException(e.getMessage(), e);
            } catch (IllegalAccessException e) {
                throw new IllegalStateException(e.getMessage(), e);
            } catch (InvocationTargetException e) {
                throw new IllegalStateException(e.getMessage(), e);
            }
        }
    }

}