uk.co.q3c.v7.i18n.AnnotationI18NInterpreter.java Source code

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Here is the source code for uk.co.q3c.v7.i18n.AnnotationI18NInterpreter.java

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/*
 * Copyright (C) 2013 David Sowerby
 * 
 * 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 uk.co.q3c.v7.i18n;

import java.lang.reflect.Field;
import java.util.Locale;

import javax.inject.Inject;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.vaadin.data.Property;
import com.vaadin.ui.AbstractComponent;

/**
 * Utility class to manipulate Vaadin component settings to reflect locale changes. {@link I18N} field annotations
 * specify the keys to use, and this class then looks up the key values and sets caption, description and value
 * properties of the component. All the annotation parameters are optional, and any which are not provided are just
 * ignored, and the associated component property is unchanged.
 * <p>
 * The value parameter is only relevant to things like Vaadin Labels, which implement the
 * {@link com.vaadin.data.Property} interface
 * <p>
 * The locale of all components with an {@link I18N} annotation is always updated to {@link CurrentLocale#getLocale()}
 * 
 * @author David Sowerby 8 Feb 2013
 * 
 */
public class AnnotationI18NInterpreter implements I18NInterpreter {
    private static Logger log = LoggerFactory.getLogger(AnnotationI18NInterpreter.class);
    private final Locale locale;

    @Inject
    protected AnnotationI18NInterpreter(CurrentLocale currentLocale) {
        super();
        locale = currentLocale.getLocale();
    }

    /** 
     * @see uk.co.q3c.v7.i18n.I18NInterpreter#interpret(uk.co.q3c.v7.i18n.I18NListener)
     */
    @Override
    public void interpret(I18NListener listener) {
        Class<?> clazz = listener.getClass();
        Field[] fields = clazz.getDeclaredFields();
        for (Field field : fields) {
            if (AbstractComponent.class.isAssignableFrom(field.getType())) {
                processComponent(listener, field);
            }

        }
    }

    private void processComponent(I18NListener listener, Field field) {
        if (field.isAnnotationPresent(I18N.class)) {
            I18N annotation = field.getAnnotation(I18N.class);
            LabelKeys captionKey = annotation.caption();
            DescriptionKeys descriptionKey = annotation.description();
            DescriptionKeys valueKey = annotation.value();

            String captionValue = captionKey.equals(LabelKeys._notdefined_) ? null : captionKey.getValue(locale);
            String descriptionValue = descriptionKey.equals(DescriptionKeys._notdefined_) ? null
                    : descriptionKey.getValue(locale);

            field.setAccessible(true);
            try {
                AbstractComponent c = (AbstractComponent) field.get(listener);
                if (captionValue != null) {
                    c.setCaption(captionValue);
                }
                if (descriptionValue != null) {
                    c.setDescription(descriptionValue);
                }
                c.setLocale(locale);
            } catch (IllegalArgumentException | IllegalAccessException e) {
                log.error("Unable to set I18N caption or description for " + field.getName(), e);
            }

            // These components have a value. Usually I18N would only be used for Label values. If no key is provided
            // the component value is left unchanged
            if (valueKey != null) {
                if (Property.class.isAssignableFrom(field.getType())) {
                    try {
                        @SuppressWarnings("unchecked")
                        Property<String> c = (Property<String>) field.get(listener);
                        String valueValue = valueKey.equals(DescriptionKeys._notdefined_) ? null
                                : valueKey.getValue(locale);
                        if (valueValue != null) {
                            c.setValue(valueValue);
                        }
                    } catch (Exception e) {
                        log.error("Unable to set I18N value for " + field.getName(), e);

                    }
                }
            }

        }

    }

    /** 
     * @see uk.co.q3c.v7.i18n.I18NInterpreter#getLocale()
     */
    @Override
    public Locale getLocale() {
        return locale;
    }

}