/* GNU gettext for Java
* Copyright (C) 2001, 2007, 2015 Free Software Foundation, Inc.
*
* This program 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 program 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 program. If not, see <http://www.gnu.org/licenses/>.
*/
package gnu.gettext;
import java.lang.reflect.*;
import java.util.*;
/**
* This class implements the main GNU libintl functions in Java.
* <P>
* Using the GNU gettext approach, compiled message catalogs are normal
* Java ResourceBundle classes and are thus interoperable with standard
* ResourceBundle based code.
* <P>
* The main differences between the Sun ResourceBundle approach and the
* GNU gettext approach are:
* <UL>
* <LI>In the Sun approach, the keys are abstract textual shortcuts.
* In the GNU gettext approach, the keys are the English/ASCII version
* of the messages.
* <LI>In the Sun approach, the translation files are called
* "<VAR>Resource</VAR>_<VAR>locale</VAR>.properties" and have non-ASCII
* characters encoded in the Java
* <CODE>\</CODE><CODE>u<VAR>nnnn</VAR></CODE> syntax. Very few editors
* can natively display international characters in this format. In the
* GNU gettext approach, the translation files are called
* "<VAR>Resource</VAR>.<VAR>locale</VAR>.po"
* and are in the encoding the translator has chosen. Many editors
* can be used. There are at least three GUI translating tools
* (Emacs PO mode, KDE KBabel, GNOME gtranslator).
* <LI>In the Sun approach, the function
* <CODE>ResourceBundle.getString</CODE> throws a
* <CODE>MissingResourceException</CODE> when no translation is found.
* In the GNU gettext approach, the <CODE>gettext</CODE> function
* returns the (English) message key in that case.
* <LI>In the Sun approach, there is no support for plural handling.
* Even the most elaborate MessageFormat strings cannot provide decent
* plural handling. In the GNU gettext approach, we have the
* <CODE>ngettext</CODE> function.
* </UL>
* <P>
* To compile GNU gettext message catalogs into Java ResourceBundle classes,
* the <CODE>msgfmt</CODE> program can be used.
*
* @author Bruno Haible
*/
public abstract class GettextResource extends ResourceBundle {
public static boolean verbose = false;
/**
* Like gettext(catalog,msgid), except that it returns <CODE>null</CODE>
* when no translation was found.
*/
private static String gettextnull (ResourceBundle catalog, String msgid) {
try {
return (String)catalog.getObject(msgid);
} catch (MissingResourceException e) {
return null;
}
}
/**
* Returns the translation of <VAR>msgid</VAR>.
* @param catalog a ResourceBundle
* @param msgid the key string to be translated, an ASCII string
* @return the translation of <VAR>msgid</VAR>, or <VAR>msgid</VAR> if
* none is found
*/
public static String gettext (ResourceBundle catalog, String msgid) {
String result = gettextnull(catalog,msgid);
if (result != null)
return result;
return msgid;
}
/**
* Like ngettext(catalog,msgid,msgid_plural,n), except that it returns
* <CODE>null</CODE> when no translation was found.
*/
private static String ngettextnull (ResourceBundle catalog, String msgid, long n) {
// The reason why we use so many reflective API calls instead of letting
// the GNU gettext generated ResourceBundles implement some interface,
// is that we want the generated ResourceBundles to be completely
// standalone, so that migration from the Sun approach to the GNU gettext
// approach (without use of plurals) is as straightforward as possible.
ResourceBundle origCatalog = catalog;
do {
// Try catalog itself.
if (verbose)
System.out.println("ngettext on "+catalog);
Method handleGetObjectMethod = null;
Method getParentMethod = null;
try {
handleGetObjectMethod = catalog.getClass().getMethod("handleGetObject", new Class[] { java.lang.String.class });
getParentMethod = catalog.getClass().getMethod("getParent", new Class[0]);
} catch (NoSuchMethodException e) {
} catch (SecurityException e) {
}
if (verbose)
System.out.println("handleGetObject = "+(handleGetObjectMethod!=null)+", getParent = "+(getParentMethod!=null));
if (handleGetObjectMethod != null
&& Modifier.isPublic(handleGetObjectMethod.getModifiers())
&& getParentMethod != null) {
// A GNU gettext created class.
Method lookupMethod = null;
Method pluralEvalMethod = null;
try {
lookupMethod = catalog.getClass().getMethod("lookup", new Class[] { java.lang.String.class });
pluralEvalMethod = catalog.getClass().getMethod("pluralEval", new Class[] { Long.TYPE });
} catch (NoSuchMethodException e) {
} catch (SecurityException e) {
}
if (verbose)
System.out.println("lookup = "+(lookupMethod!=null)+", pluralEval = "+(pluralEvalMethod!=null));
if (lookupMethod != null && pluralEvalMethod != null) {
// A GNU gettext created class with plural handling.
Object localValue = null;
try {
localValue = lookupMethod.invoke(catalog, new Object[] { msgid });
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.getTargetException().printStackTrace();
}
if (localValue != null) {
if (verbose)
System.out.println("localValue = "+localValue);
if (localValue instanceof String)
// Found the value. It doesn't depend on n in this case.
return (String)localValue;
else {
String[] pluralforms = (String[])localValue;
long i = 0;
try {
i = ((Long) pluralEvalMethod.invoke(catalog, new Object[] { new Long(n) })).longValue();
if (!(i >= 0 && i < pluralforms.length))
i = 0;
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.getTargetException().printStackTrace();
}
return pluralforms[(int)i];
}
}
} else {
// A GNU gettext created class without plural handling.
Object localValue = null;
try {
localValue = handleGetObjectMethod.invoke(catalog, new Object[] { msgid });
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.getTargetException().printStackTrace();
}
if (localValue != null) {
// Found the value. It doesn't depend on n in this case.
if (verbose)
System.out.println("localValue = "+localValue);
return (String)localValue;
}
}
Object parentCatalog = catalog;
try {
parentCatalog = getParentMethod.invoke(catalog, new Object[0]);
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.getTargetException().printStackTrace();
}
if (parentCatalog != catalog)
catalog = (ResourceBundle)parentCatalog;
else
break;
} else
// Not a GNU gettext created class.
break;
} while (catalog != null);
// The end of chain of GNU gettext ResourceBundles is reached.
if (catalog != null) {
// For a non-GNU ResourceBundle we cannot access 'parent' and
// 'handleGetObject', so make a single call to catalog and all
// its parent catalogs at once.
Object value;
try {
value = catalog.getObject(msgid);
} catch (MissingResourceException e) {
value = null;
}
if (value != null)
// Found the value. It doesn't depend on n in this case.
return (String)value;
}
// Default: null.
return null;
}
/**
* Returns the plural form for <VAR>n</VAR> of the translation of
* <VAR>msgid</VAR>.
* @param catalog a ResourceBundle
* @param msgid the key string to be translated, an ASCII string
* @param msgid_plural its English plural form
* @return the translation of <VAR>msgid</VAR> depending on <VAR>n</VAR>,
* or <VAR>msgid</VAR> or <VAR>msgid_plural</VAR> if none is found
*/
public static String ngettext (ResourceBundle catalog, String msgid, String msgid_plural, long n) {
String result = ngettextnull(catalog,msgid,n);
if (result != null)
return result;
// Default: English strings and Germanic plural rule.
return (n != 1 ? msgid_plural : msgid);
}
/* The separator between msgctxt and msgid. */
private static final String CONTEXT_GLUE = "\u0004";
/**
* Returns the translation of <VAR>msgid</VAR> in the context of
* <VAR>msgctxt</VAR>.
* @param catalog a ResourceBundle
* @param msgctxt the context for the key string, an ASCII string
* @param msgid the key string to be translated, an ASCII string
* @return the translation of <VAR>msgid</VAR>, or <VAR>msgid</VAR> if
* none is found
*/
public static String pgettext (ResourceBundle catalog, String msgctxt, String msgid) {
String result = gettextnull(catalog,msgctxt+CONTEXT_GLUE+msgid);
if (result != null)
return result;
return msgid;
}
/**
* Returns the plural form for <VAR>n</VAR> of the translation of
* <VAR>msgid</VAR> in the context of <VAR>msgctxt</VAR>.
* @param catalog a ResourceBundle
* @param msgctxt the context for the key string, an ASCII string
* @param msgid the key string to be translated, an ASCII string
* @param msgid_plural its English plural form
* @return the translation of <VAR>msgid</VAR> depending on <VAR>n</VAR>,
* or <VAR>msgid</VAR> or <VAR>msgid_plural</VAR> if none is found
*/
public static String npgettext (ResourceBundle catalog, String msgctxt, String msgid, String msgid_plural, long n) {
String result = ngettextnull(catalog,msgctxt+CONTEXT_GLUE+msgid,n);
if (result != null)
return result;
// Default: English strings and Germanic plural rule.
return (n != 1 ? msgid_plural : msgid);
}
}