com.jain.addon.i18N.I18NHelper.java Source code

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Here is the source code for com.jain.addon.i18N.I18NHelper.java

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/* 
 * Copyright 2012 Lokesh Jain.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.jain.addon.i18N;

import java.io.Serializable;

import com.jain.addon.i18N.component.I18NUI;
import com.vaadin.ui.Component;
import com.vaadin.ui.Field;
import com.vaadin.ui.UI;

/**
 * <code>I18NHelper<code> is a helper class for the i18N component handling.
 * This is also having couple of helping methods.
 * @author Lokesh Jain
 * @since Aug 27, 2012
 * @version 1.0.0
 */
@SuppressWarnings("serial")
public final class I18NHelper implements Serializable {
    private I18NHelper() {
    }

    /**
     * Method to get i18N caption for given component 
     * @param {@link Component}
     * @return i18NCaption
     */
    public static String getKey(Component component) {
        I18NChangeListener listener = findListener(component, false);
        if (listener != null)
            return listener.getI18NCaption(component);
        return component.getCaption();
    }

    /**
     * Method to get i18N caption for given component 
     * @param {@link Component}
     * @return i18NCaption
     */
    public static String getKey(Component component, Serializable serializable) {
        I18NChangeListener listener = findListener(component, false);
        if (listener != null)
            return listener.getI18NCaption(component, serializable);
        return component.getCaption();
    }

    /**
     * Register component for i18N handling.
     * @param {@link Component}
     * @param {@link UI}
     */
    public static void register(UI ui, Component component) {
        I18NChangeListener listener = findListener(ui, true);
        listener.registor(component);
    }

    /**
     * Remove registered component for i18N handling.
     * @param {@link Component}
     * @param {@link UI}
     */
    public static void deRegistor(UI ui, Component component) {
        I18NChangeListener listener = findListener(ui, true);
        listener.deRegistor(component);
    }

    /**
     * Method to add Value change listener for a locale drop down 
     * because complete i18N works with this listener.  
     * @param {@link UI}
     * @param {@link Field}
     */
    public static void addListener(UI ui, Field<?> field) {
        I18NChangeListener listener = findListener(ui, true);
        field.addValueChangeListener(listener);
    }

    /**
     * Method to find I18NChangeListener or create an instance if this is not available
     * @param component
     * @param create
     * @return {@link I18NChangeListener}
     */
    public static I18NChangeListener findListener(Component component, boolean create) {
        I18NChangeListener listener = null;

        if (component instanceof I18NUI) {
            listener = ((I18NUI) component).getLocalChangeListener();
            if (listener != null)
                return listener;
        }

        if (component.getUI() instanceof I18NUI) {
            listener = ((I18NUI) component.getUI()).getLocalChangeListener();
            if (listener != null)
                return listener;
        }

        if (create) {
            listener = new I18NChangeListener();
            return listener;
        }

        return listener;
    }
}