package com.temp.client.foundation.util;

import java.util.Set;

import com.temp.shared.utils.StringUtils;
import com.temp.shared.utils.TemplateSource;

import com.google.gwt.i18n.client.Dictionary;

public class ExternalizedText implements TemplateSource {
    private static ExternalizedText instance;

    private final Dictionary dictionary;
    private final Set<String> keys;

    public static ExternalizedText getInstance() {
        if (instance == null) {
            instance = new ExternalizedText(Dictionary.getDictionary("ExternalTemplateText"));
        }
        return instance;
    }

    private ExternalizedText(Dictionary dictionary) {
        this.dictionary = dictionary;
        this.keys = dictionary.keySet();
    }

    private String safeGet(String key) {
        return keys.contains(key) ? dictionary.get(key) : null;
    }

    /**
     * Get the Template value associated with the key
     *
     * @param key
     *            Leading and trailing spaces are ignored
     *
     * @return null or the Template value associated with the key
     */
    public String get(String key) {
        key = StringUtils.noEmpty(key);
        return (key != null) ? StringUtils.noEmpty(safeGet(key)) : null;
    }

    /**
     * Get the Template value associated with the key or the defaultValue if the
     * key was not found or its value was empty
     *
     * @param key
     *            Leading and trailing spaces are ignored
     *
     * @return The Template value associated with the key or the defaultValue if
     *         the key was not found or its value was empty
     */
    public String get(String key, String defaultValue) {
        return StringUtils.deNull(get(key), defaultValue);
    }
}