I18nObject.java

/**
 * Licensed under the GNU LGPL v.2.1 or later.
 */

package info.freelibrary.util;

import java.io.File;
import java.util.ResourceBundle;

/**
 * A generic object with baked-in "default Locale" I18N support. It wraps an {@link XMLResourceBundle} and
 * provides an easy way to get access to internationalized strings. It doesn't support dynamically passed in locales,
 * but just the one that the system is configured to use as its default locale.
 *
 * @author <a href="mailto:ksclarke@ksclarke.io">Kevin S. Clarke</a>
 */
public abstract class I18nObject {

    private final XMLResourceBundle BUNDLE;

    /**
     * Empty constructor for an I18nObject.
     */
    I18nObject() {
        BUNDLE = null;
    }

    /**
     * Constructor for an I18nObject that takes a {@link ResourceBundle} name as an argument. The name should be
     * something specific to the package that's extending the <code>I18nObject</code>... for instance:
     * <code>freelib-utils_messages</code> or <code>freelib-djatoka_messages</code>.
     *
     * @param aBundleName The name of a {@link ResourceBundle} that gets lower cased automatically
     */
    public I18nObject(final String aBundleName) {
        BUNDLE = (XMLResourceBundle) ResourceBundle.getBundle(aBundleName.toLowerCase(), new XMLBundleControl());
    }

    /**
     * Gets the internationalized value for the supplied message key.
     *
     * @param aMessageKey A message key
     * @return An internationalized value
     */
    protected String getI18n(final String aMessageKey) {
        return StringUtils.normalizeWS(BUNDLE.get(aMessageKey));
    }

    /**
     * Gets the internationalized value for the supplied message key, using a long as additional information.
     *
     * @param aMessageKey A message key
     * @param aLongDetail Additional details for the message
     * @return The internationalized message
     */
    protected String getI18n(final String aMessageKey, final long aLongDetail) {
        return StringUtils.normalizeWS(BUNDLE.get(aMessageKey, Long.toString(aLongDetail)));
    }

    /**
     * Gets the internationalized value for the supplied message key, using an int as additional information.
     *
     * @param aMessageKey A message key
     * @param aIntDetail Additional details for the message
     * @return The internationalized message
     */
    protected String getI18n(final String aMessageKey, final int aIntDetail) {
        return StringUtils.normalizeWS(BUNDLE.get(aMessageKey, Integer.toString(aIntDetail)));
    }

    /**
     * Gets the internationalized value for the supplied message key, using a string as additional information.
     *
     * @param aMessageKey A message key
     * @param aDetail Additional details for the message
     * @return The internationalized message
     */
    protected String getI18n(final String aMessageKey, final String aDetail) {
        return StringUtils.normalizeWS(BUNDLE.get(aMessageKey, aDetail));
    }

    /**
     * Gets the internationalized value for the supplied message key, using a string array as additional information.
     *
     * @param aMessageKey A message key
     * @param aDetailsArray Additional details for the message
     * @return The internationalized message
     */
    protected String getI18n(final String aMessageKey, final String... aDetailsArray) {
        return StringUtils.normalizeWS(BUNDLE.get(aMessageKey, aDetailsArray));
    }

    /**
     * Gets the internationalized value for the supplied message key, using an exception as additional information.
     *
     * @param aMessageKey A message key
     * @param aException Additional details for the message
     * @return The internationalized message
     */
    protected String getI18n(final String aMessageKey, final Exception aException) {
        return StringUtils.normalizeWS(BUNDLE.get(aMessageKey, aException.getMessage()));
    }

    /**
     * Gets the internationalized value for the supplied message key, using a file as additional information.
     *
     * @param aMessageKey A message key
     * @param aFile Additional details for the message
     * @return The internationalized message
     */
    protected String getI18n(final String aMessageKey, final File aFile) {
        return StringUtils.normalizeWS(BUNDLE.get(aMessageKey, aFile.getAbsolutePath()));
    }

    /**
     * Gets the internationalized value for the supplied message key, using a file array as additional information.
     *
     * @param aMessageKey A message key
     * @param aFileArray Additional details for the message
     * @return The internationalized message
     */
    protected String getI18n(final String aMessageKey, final File... aFileArray) {
        final String[] fileNames = new String[aFileArray.length];

        for (int index = 0; index < fileNames.length; index++) {
            fileNames[index] = aFileArray[index].getAbsolutePath();
        }

        return StringUtils.normalizeWS(BUNDLE.get(aMessageKey, fileNames));
    }

    /**
     * Gets the internationalized value for the supplied message key, using an object array as additional information.
     *
     * @param aMessageKey A message key
     * @param aObjArray Additional details for the message
     * @return The internationalized message
     */
    protected String getI18n(final String aMessageKey, final Object... aObjArray) {
        final String[] strings = new String[aObjArray.length];

        for (int index = 0; index < aObjArray.length; index++) {
            if (aObjArray[index] instanceof File) {
                strings[index] = ((File) aObjArray[index]).getAbsolutePath();
            } else {
                strings[index] = aObjArray[index].toString();
            }
        }

        return StringUtils.normalizeWS(BUNDLE.get(aMessageKey, strings));
    }

    /**
     * Returns true if this I18N object contains the requested I18N key; else, false.
     *
     * @param aMessageKey A key to check to see if it exists
     * @return True if the key exists; else, false
     */
    protected boolean hasI18nKey(final String aMessageKey) {
        return BUNDLE != null && BUNDLE.containsKey(aMessageKey);
    }
}