org.xnap.commons.i18n.I18n Maven / Gradle / Ivy
Show all versions of gettext-commons Show documentation
/*
* Gettext Commons
*
* Copyright (C) 2005 Felix Berger
* Copyright (C) 2005 Steffen Pingel
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package org.xnap.commons.i18n;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.text.MessageFormat;
import java.util.Locale;
import java.util.MissingResourceException;
import java.util.ResourceBundle;
/**
* Provides methods for internationalization.
*
* To learn how message strings wrapped in one of the tr*()
* methods can be extracted and localized, see this tutorial.
*
* @author Steffen Pingel
* @author Felix Berger
* @author Tammo van Lessen
* @since 0.9
*/
public class I18n {
private static final String CONTEXT_GLUE = "\u0004";
/**
* Reference to the current localization bundles.
*/
private volatile ResourceBundle bundle;
/**
* The locale of the strings used in the source code.
*
* @see #trc(String, String)
*/
private volatile Locale sourceCodeLocale = Locale.ENGLISH;
private String baseName;
private ClassLoader loader;
private volatile Locale locale;
/**
* Constructs an I18n object for a resource bundle.
*
* @param bundle
* must not be null
* @throws NullPointerException
* if bundle is null
* @since 0.9
*/
public I18n(ResourceBundle bundle)
{
setResources(bundle);
}
/**
* Constructs an I18n object by calling {@link #setResources(String, Locale,
* ClassLoader)}.
*
* @throws MissingResourceException
* if the resource bundle could not be loaded
* @throws NullPointerException
* if one of the arguments is null
* @since 0.9
*/
public I18n(String baseName, Locale locale, ClassLoader loader)
{
setResources(baseName, locale, loader);
}
/**
* Returns the current resource bundle.
*
* @since 0.9
*/
public ResourceBundle getResources()
{
return bundle;
}
/**
* Returns the locale this instance was created with. This can be different
* from the locale of the resource bundle returned by
* {@link #getResources()}.
*
* @return the locale or null, if this instance was directly created from a
* resource bundle
* @since 0.9
*/
public Locale getLocale()
{
return locale;
}
/**
* Sets a resource bundle to be used for message translations.
*
* If this is called, the possibly previously specified class loader and
* baseName are invalidated, since the bundle might be from a different
* context. Subsequent calls to {@link #setLocale(Locale)} won't have any
* effect.
*
* @since 0.9
*/
public synchronized void setResources(ResourceBundle bundle)
{
if (bundle == null) {
throw new NullPointerException();
}
this.bundle = bundle;
this.baseName = null;
this.locale = bundle.getLocale();
this.loader = null;
}
/**
* Tries to load a resource bundle using {@link
* ResourceBundle#getBundle(java.lang.String, java.util.Locale,
* java.lang.ClassLoader)}.
*
* @throws MissingResourceException
* if the bundle could not be loaded
* @throws NullPointerException
* if one of the arguments is null
* @since 0.9
*/
public synchronized void setResources(String baseName, Locale locale, ClassLoader loader)
{
this.bundle = ResourceBundle.getBundle(baseName, locale, loader);
this.baseName = baseName;
this.locale = locale;
this.loader = loader;
}
/**
* Marks text to be translated, but doesn't return the
* translation but text itself.
*
* @since 0.9
*/
public static final String marktr(String text)
{
return text;
}
/**
* Tries to load a resource bundle for the locale.
*
* The resource bundle is then used for message translations. Note, you have
* to retrieve all messages anew after a locale change in order for them to
* be translated to the language specified by the new locale.
*
*
* @return false if there is not enough information for loading a new
* resource bundle, see {@link #setResources(ResourceBundle)}.
* @throws MissingResourceException
* if the resource bundle for locale could not be
* found
* @throws NullPointerException
* if locale is null
* @since 0.9
*/
public synchronized boolean setLocale(Locale locale)
{
if (baseName != null && loader != null) {
setResources(baseName, locale, loader);
return true;
}
else {
this.locale = locale;
}
return false;
}
/**
* Sets the locale of the text in the source code.
*
* Only languages that have one singular and one plural form can be used as
* source code locales, since {@link #trn(String, String, long)} takes
* exactly these two forms as parameters.
*
* @param locale
* the locale
* @throws NullPointerException
* if locale is null
* @see #trc(String, String)
* @since 0.9
*/
public void setSourceCodeLocale(Locale locale)
{
if (locale == null) {
throw new NullPointerException("locale must not be null");
}
sourceCodeLocale = locale;
}
/**
* Returns text translated into the currently selected
* language. Every user-visible string in the program must be wrapped into
* this function.
*
* @param text
* text to translate
* @return the translation
* @since 0.9
*/
public final String tr(String text)
{
try {
return bundle.getString(text);
}
catch (MissingResourceException e) {
return text;
}
}
/**
* Returns text translated into the currently selected
* language.
*
* Occurrences of {number} placeholders in text are replaced by
* objects.
*
* Invokes
* {@link MessageFormat#format(java.lang.String, java.lang.Object[])}.
*
* @param text
* text to translate
* @param objects
* arguments to MessageFormat.format()
* @return the translated text
* @since 0.9
*/
public final String tr(String text, Object[] objects)
{
return MessageFormat.format(tr(text), objects);
}
/**
* Convenience method that invokes {@link #tr(String, Object[])}.
*
* @since 0.9
*/
public final String tr(String text, Object o1)
{
return tr(text, new Object[]{ o1 });
}
/**
* Convenience method that invokes {@link #tr(String, Object[])}.
*
* @since 0.9
*/
public final String tr(String text, Object o1, Object o2)
{
return tr(text, new Object[]{ o1, o2 });
}
/**
* Convenience method that invokes {@link #tr(String, Object[])}.
*
* @since 0.9
*/
public final String tr(String text, Object o1, Object o2, Object o3)
{
return tr(text, new Object[]{ o1, o2, o3 });
}
/**
* Convenience method that invokes {@link #tr(String, Object[])}.
*
* @since 0.9
*/
public final String tr(String text, Object o1, Object o2, Object o3, Object o4)
{
return tr(text, new Object[]{ o1, o2, o3, o4 });
}
/**
* Returns the plural form for n of the translation of
* text.
*
* @param text
* the key string to be translated.
* @param pluralText
* the plural form of text.
* @param n
* value that determines the plural form
* @return the translated text
* @since 0.9
*/
public final String trn(String text, String pluralText, long n)
{
try {
return trnInternal(bundle, text, pluralText, n);
}
catch (MissingResourceException e) {
return (n == 1) ? text : pluralText;
}
}
/**
* Returns the plural form for n of the translation of
* text.
*
* @param text
* the key string to be translated.
* @param pluralText
* the plural form of text.
* @param n
* value that determines the plural form
* @param objects
* object args to be formatted and substituted.
* @return the translated text
* @since 0.9
*/
public final String trn(String text, String pluralText, long n, Object[] objects)
{
return MessageFormat.format(trn(text, pluralText, n), objects);
}
/**
* Overloaded method that invokes
* {@link #trn(String, String, long, Object[])} passing Object
* arguments as an array.
*
* @since 0.9
*/
public final String trn(String text, String pluralText, long n, Object o1)
{
return trn(text, pluralText, n, new Object[]{ o1 });
}
/**
* Overloaded method that invokes
* {@link #trn(String, String, long, Object[])} passing Object
* arguments as an array.
*
* @since 0.9
*/
public final String trn(String text, String pluralText, long n, Object o1, Object o2)
{
return trn(text, pluralText, n, new Object[]{ o1, o2 });
}
/**
* Overloaded method that invokes
* {@link #trn(String, String, long, Object[])} passing Object
* arguments as an array.
*
* @since 0.9
*/
public final String trn(String text, String pluralText, long n, Object o1, Object o2, Object o3)
{
return trn(text, pluralText, n, new Object[]{ o1, o2, o3 });
}
/**
* Overloaded method that invokes
* {@link #trn(String, String, long, Object[])} passing Object
* arguments as an array.
*
* @since 0.9
*/
public final String trn(String text, String pluralText, long n, Object o1, Object o2, Object o3, Object o4)
{
return trn(text, pluralText, n, new Object[]{ o1, o2, o3, o4 });
}
/**
* Returns the plural form for n of the translation of ???
*
* Based on GettextResource.java that is part of GNU gettext for Java
* Copyright (C) 2001 Free Software Foundation, Inc.
*
* @param bundle a ResourceBundle
* @param text the key string to be translated, an ASCII string
* @param pluralText its English plural form
* @return the translation of text depending on n,
* or text or pluralText if none is found
*/
private static String trnInternal(ResourceBundle orgBundle, String text, String pluralText, long n)
{
ResourceBundle bundle = orgBundle;
do {
boolean isGetTextBundle = false;
boolean hasPluralHandling = false;
Method handleGetObjectMethod = null;
Method getParentMethod = null;
Method lookupMethod = null;
Method pluralEvalMethod = null;
try {
handleGetObjectMethod = bundle.getClass().getMethod("handleGetObject", new Class[]{ String.class });
getParentMethod = bundle.getClass().getMethod("getParent", new Class[0]);
isGetTextBundle = Modifier.isPublic(handleGetObjectMethod.getModifiers());
lookupMethod = bundle.getClass().getMethod("lookup", new Class[]{ String.class });
pluralEvalMethod = bundle.getClass().getMethod("pluralEval", new Class[]{ Long.TYPE });
hasPluralHandling = true;
}
catch (Exception e) {}
if (isGetTextBundle) {
// GNU gettext generated bundle
if (hasPluralHandling) {
// GNU gettext generated bundle w/ plural handling
try {
Object localValue = lookupMethod.invoke(bundle, new Object[]{ text });
if (localValue.getClass().isArray()) {
String[] pluralforms = (String[])localValue;
long index = 0;
try {
index = ((Long)pluralEvalMethod.invoke(bundle, new Object[]{ new Long(n) }))
.longValue();
if (!(index >= 0 && index < pluralforms.length)) {
index = 0;
}
}
catch (IllegalAccessException e) {}
return pluralforms[(int)index];
}
else {
// Found the value. It doesn't depend on n in this
// case.
return (String)localValue;
}
}
catch (Exception e) {}
}
else {
// GNU gettext generated bundle w/o plural handling
try {
Object localValue = handleGetObjectMethod.invoke(bundle, new Object[]{ text });
if (localValue != null) {
return (String)localValue;
}
}
catch (Exception e) {}
}
bundle = null;
try {
bundle = (ResourceBundle)getParentMethod.invoke(bundle, new Object[0]);
}
catch (Exception e) {}
}
else {
return bundle.getString(text);
}
}
while (bundle != null);
throw new MissingResourceException("Can not find resource for key " + text + " in bundle "
+ orgBundle.getClass().getName(), orgBundle.getClass().getName(), text);
}
/**
* Disambiguates translation keys.
*
* @param context
* the context of the text to be translated
* @param text
* the ambiguous key message in the source locale
* @return text if the locale of the underlying resource
* bundle equals the source code locale, the disambiguated
* translation of text otherwise
*
* @see #setSourceCodeLocale(Locale)
* @since 0.9
*/
public final String trc(String context, String text)
{
if (sourceCodeLocale.equals(getResources().getLocale())) {
return text;
} else {
String key = context + CONTEXT_GLUE + text;
String translated = tr(key);
// if no translation was found return text in source locale
return translated == key ? text : translated;
}
}
/**
* Returns the plural form for n of the translation of
* text.
*
* @param context
* the context of the message to disambiguate it when translating
* @param singularText
* the key string to be translated.
* @param pluralText
* the plural form of text.
* @param n
* value that determines the plural form
* @return the translated text
* @since 0.9.5
*/
public final String trnc(String context, String singularText, String pluralText, long n) {
try {
return trnInternal(bundle, context + CONTEXT_GLUE + singularText, pluralText, n);
}
catch (MissingResourceException e) {
return (n == 1) ? singularText : pluralText;
}
}
/**
* Returns the plural form for n of the translation of
* text.
*
* @param context
* the context of the message to disambiguate it when translating
* @param singularText
* the key string to be translated.
* @param pluralText
* the plural form of text.
* @param n
* value that determines the plural form
* @param objects
* object args to be formatted and substituted.
* @return the translated text
* @since 0.9
*/
public final String trnc(String context, String singularText, String pluralText, long n, Object[] objects) {
return MessageFormat.format(trnc(context, singularText, pluralText, n), objects);
}
/**
* Overloaded method that invokes
* {@link #trnc(String, String, String, long, Object[])} passing obj
* arguments as an array.
*
* @since 0.9.5
*/
public final String trnc(String comment, String singularText, String pluralText, long n, Object obj) {
return MessageFormat.format(trnc(comment, singularText, pluralText, n), new Object[] { obj });
}
/**
* Overloaded method that invokes
* {@link #trnc(String, String, String, long, Object[])} passing obj1 and obj2
* arguments as an array.
*
* @since 0.9.5
*/
public final String trnc(String comment, String singularText, String pluralText, long n, Object obj1, Object obj2) {
return MessageFormat.format(trnc(comment, singularText, pluralText, n), new Object[] { obj1, obj2 });
}
/**
* Overloaded method that invokes
* {@link #trnc(String, String, String, long, Object[])} passing obj1, obj2 and obj3
* arguments as an array.
*
* @since 0.9.5
*/
public final String trnc(String comment, String singularText, String pluralText, long n, Object obj1, Object obj2, Object obj3) {
return MessageFormat.format(trnc(comment, singularText, pluralText, n), new Object[] { obj1, obj2, obj3 });
}
/**
* Overloaded method that invokes
* {@link #trnc(String, String, String, long, Object[])} passing obj1, obj2, obj3 and obj4
* arguments as an array.
*
* @since 0.9.5
*/
public final String trnc(String comment, String singularText, String pluralText, long n, Object obj1, Object obj2, Object obj3, Object obj4) {
return MessageFormat.format(trnc(comment, singularText, pluralText, n), new Object[] { obj1, obj2, obj3, obj4 });
}
}