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Modified things to make handling of message resource bundles easier. We

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now have an actual application class that's used by dispatched
applications. The message manager provides an easy interface into
localizing messages and MsgTool has a way to get at the message manager in
effect for whatever application is handling a request.


git-svn-id: https://samskivert.googlecode.com/svn/trunk@88 6335cc39-0255-0410-8fd6-9bcaacd3b74c
This commit is contained in:
mdb
2001-03-04 06:15:39 +00:00
parent f96b4cc237
commit 81710f70ec
4 changed files with 360 additions and 181 deletions
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projects/samskivert/src/java/com/samskivert/servlet/MessageManager.java
+145
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@@ -0,0 +1,145 @@
//
// $Id: MessageManager.java,v 1.1 2001/03/04 06:15:39 mdb Exp $
package com.samskivert.servlet;
import java.text.MessageFormat;
import java.util.*;
import javax.servlet.http.HttpServletRequest;
import com.samskivert.Log;
/**
* The message manager handles the translation messages for a web
* application. The webapp should construct the message manager with the
* name of its message properties file and it can then make use of the
* message manager to generate locale specific messages for a request.
*/
public class MessageManager
{
/**
* Constructs a message manager with the specified bundle path. The
* message manager will be instantiating a <code>ResourceBundle</code>
* with the supplied path, so it should conform to the naming
* conventions defined by that class.
*
* @see java.util.ResourceBundle
*/
public MessageManager (String bundlePath)
{
// keep this for later
_bundlePath = bundlePath;
}
/**
* Looks up the message with the specified path in the resource bundle
* most appropriate for the locales described as preferred by the
* request.
*/
public String getMessage (HttpServletRequest req, String path)
{
try {
// use the locale preferred by the client if possible
ResourceBundle bundle = resolveBundle(req);
if (bundle != null) {
return bundle.getString(path);
}
// if we couldn't find a bundle, things are way wacked out,
// but we've already complained about it so we just fall
// through and return the path back to the caller
} catch (MissingResourceException mre) {
// if there's no translation for this path, complain about it
Log.warning("Missing translation message [path=" + path + "].");
}
return path;
}
/**
* Looks up the message with the specified path in the resource bundle
* most appropriate for the locales described as preferred by the
* request, then substitutes the supplied arguments into that message
* using a <code>MessageFormat</code> object.
*
* @see java.text.MessageFormat
*/
public String getMessage (HttpServletRequest req, String path,
Object[] args)
{
try {
// use the locale preferred by the client if possible
ResourceBundle bundle = resolveBundle(req);
if (bundle != null) {
String msg = bundle.getString(path);
// we may cache message formatters later, but for now just
// use the static convenience function
return MessageFormat.format(msg, args);
}
// if we couldn't find a bundle, things are way wacked out,
// but we've already complained about it so we just fall
// through and return the path back to the caller
} catch (MissingResourceException mre) {
// if there's no translation for this path, complain about it
Log.warning("Missing translation message [path=" + path + "].");
}
return path;
}
/**
* Finds the closest matching resource bundle for the locales
* specified as preferred by the client in the supplied http request.
*/
protected ResourceBundle resolveBundle (HttpServletRequest req)
throws MissingResourceException
{
Enumeration locales = req.getLocales();
while (locales.hasMoreElements()) {
Locale locale = (Locale)locales.nextElement();
try {
// java caches resource bundles, so we don't need to
// reinvent the wheel here. however, java also falls back
// from a specific bundle to a more general one if it
// can't find a specific bundle. that's real nice of it,
// but we want first to see whether or not we have exact
// matches on any of the preferred locales specified by
// the client. if we don't, then we can rely on java's
// fallback mechanisms
ResourceBundle bundle =
ResourceBundle.getBundle(_bundlePath, locale);
// if it's an exact match, off we go
if (bundle.getLocale().equals(locale)) {
return bundle;
}
} catch (MissingResourceException mre) {
// no need to freak out quite yet, see if we have
// something for one of the other preferred locales
}
}
try {
// if we were unable to find an exact match for any of the
// user's preferred locales, take their most preferred and let
// java perform it's fallback logic on that one
return ResourceBundle.getBundle(_bundlePath, req.getLocale());
} catch (MissingResourceException mre) {
// if we were unable even to find a default bundle, we've got
// real problems. time to freak out
Log.warning("Unable to resolve any message bundle " +
"[bundlePath=" + _bundlePath +
", locale=" + req.getLocale() + "].");
return null;
}
}
protected String _bundlePath;
}
projects/samskivert/src/java/com/samskivert/webmacro/Application.java
+103
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@@ -0,0 +1,103 @@
//
// $Id: Application.java,v 1.1 2001/03/04 06:15:39 mdb Exp $
package com.samskivert.webmacro;
import javax.servlet.ServletContext;
import com.samskivert.servlet.MessageManager;
import com.samskivert.util.StringUtil;
/**
* The servlet API defines the concept of a web application and associates
* certain attributes with it like document root and so on. This
* application class extends that concept by providing a base class that
* represents the web application. The application class is responsible
* for initializing services that will be used by the application's logic
* objects as well as cleaning them up when the application is shut down.
*/
public class Application
{
/**
* This should be overridden by the application implementation to
* perform any necessary initialization.
*/
public void init (ServletContext context)
{
}
/**
* This should be overridden by the application implementation to
* perform any necessary cleanup.
*/
public void shutdown ()
{
}
/**
* If an application wishes to make use of the translation facilities
* provided by the message manager, it can instantiate one and make it
* available through this member function. This allows framework
* components like the <code>MsgTool</code> to make use of the
* application's message bundles.
*/
public MessageManager getMessageManager ()
{
return null;
}
/**
* The default application implementation takes the base URI and base
* package as defined in the application declaration in the servlet
* configuration and uses those to determine whether or not a given
* URI maps to this application.
*/
public void setConfig (String baseURI, String basePkg)
{
// remove any trailing slash
if (baseURI.endsWith("/")) {
_baseURI = baseURI.substring(0, baseURI.length()-1);
} else {
_baseURI = baseURI;
}
// remove any trailing dot
if (basePkg.endsWith(".")) {
_basePkg = basePkg.substring(0, basePkg.length()-1);
} else {
_basePkg = basePkg;
}
}
/**
* Returns true if the supplied URI should be handled by this
* application.
*/
public boolean matches (String uri)
{
return uri.startsWith(_baseURI);
}
/**
* Given a request URI this generates the classname of the logic class
* that should handle the request.
*/
public String generateClass (String uri)
{
// remove the base URI
uri = uri.substring(_baseURI.length());
// convert slashes to dots
uri = StringUtil.replace(uri, "/", ".");
// remove the trailing file extension
uri = uri.substring(0, uri.length() - FILE_EXTENSION.length());
// prepend the base package and we're all set
return _basePkg + uri;
}
protected String _baseURI;
protected String _basePkg;
/**
* This is the default file extension.
*/
protected static final String FILE_EXTENSION = ".wm";
}
projects/samskivert/src/java/com/samskivert/webmacro/DispatcherServlet.java
+73 -141
View File
@@ -1,5 +1,5 @@
//
// $Id: DispatcherServlet.java,v 1.6 2001/03/03 21:20:13 mdb Exp $
// $Id: DispatcherServlet.java,v 1.7 2001/03/04 06:15:39 mdb Exp $
package com.samskivert.webmacro;
@@ -17,7 +17,9 @@ import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import org.webmacro.*;
import org.webmacro.servlet.*;
import org.webmacro.servlet.HandlerException;
import org.webmacro.servlet.WMServlet;
import org.webmacro.servlet.WebContext;
import com.samskivert.Log;
import com.samskivert.servlet.RedirectException;
@@ -169,14 +171,31 @@ public class DispatcherServlet extends WMServlet
continue;
}
Application app = new Application(baseURI, basePkg);
// if an application class was specified, initialize it
// instantiate the specified application class
Application app;
try {
// if a custom application class was specified,
// instantiate one of those. otherwise use the default
if (appcl != null) {
app.init(appcl, getServletContext());
Class appclass = Class.forName(appcl);
app = (Application)appclass.newInstance();
} else {
app = new Application();
}
// construct an application object and add it to our list
// now initialize the applicaiton
app.setConfig(baseURI, basePkg);
app.init(getServletContext());
// finally add it to our list
_apps.add(app);
} catch (Throwable t) {
Log.warning("Error instantiating custom application " +
"[class=" + appcl + "].");
Log.logStackTrace(t);
}
}
}
}
@@ -205,24 +224,33 @@ public class DispatcherServlet extends WMServlet
// then we populate the context with data
try {
Logic logic = selectLogic(ctx);
// if no logic is matched, we simply execute the template
// directly with the default information in the context (tools
// and other WebMacro services can be used by the template to
// do their WebMacro thing)
String path = cleanupURI(ctx.getRequest().getRequestURI());
// select the proper application for the request
Application app = selectApplication(path);
if (app != null) {
// insert the application into the web context in case the
// logic or a tool wishes to make use of it
ctx.put(APPLICATION_KEY, app);
// resolve the appropriate logic class for this URI and
// execute it if it exists
Logic logic = resolveLogic(app, path);
if (logic != null) {
logic.invoke(ctx);
}
}
} catch (RedirectException re) {
try {
ctx.getResponse().sendRedirect(re.getRedirectURL());
return null;
} catch (IOException ioe) {
throw new HandlerException("Unable to send redirect: " + ioe);
}
} catch (DataValidationException dve) {
ctx.put(DV_ERROR_KEY, ExceptionMap.getMessage(dve));
} catch (FriendlyException fe) {
ctx.put(ERROR_KEY, fe.getMessage());
} catch (Exception e) {
ctx.put(ERROR_KEY, ExceptionMap.getMessage(e));
@@ -232,6 +260,18 @@ public class DispatcherServlet extends WMServlet
return tmpl;
}
/**
* Returns the reference to the application that is handling this
* request.
*
* @return The application in effect for this request or null if no
* application was selected to handle the request.
*/
public static Application getApplication (WebContext context)
{
return (Application)context.get(APPLICATION_KEY);
}
/**
* This method is called to select the appropriate template for this
* request. The default implementation simply loads the template using
@@ -252,39 +292,37 @@ public class DispatcherServlet extends WMServlet
}
/**
* This method is called to select the appropriate logic for this
* request. The dispatcher configuration described in this class's
* documentation is consulted to map the URI to a logic class which is
* then instantiated and a single instance used to process all
* matching requests.
* Selects and returns the matching application for this request.
*
* @param ctx The context of this request.
*
* @return The logic to be used in generating the response or null if
* no logic could be matched.
* @return the application that should handle this request or null if
* no matching application could be found.
*/
protected Logic selectLogic (WebContext ctx)
protected Application selectApplication (String path)
{
String path = cleanupURI(ctx.getRequest().getRequestURI());
String lclass = null;
// Log.info("Loading logic [path=" + path + "].");
// try to locate an application that matches this URI
for (int i = 0; i < _apps.size(); i++) {
Application app = (Application)_apps.get(i);
if (app.matches(path)) {
lclass = app.generateClass(path);
break;
return app;
}
}
// if we didn't find a matching application, we can stop now
if (lclass == null) {
return null;
}
// otherwise look for a cached logic instance
/**
* This method is called to select the appropriate logic for this
* request URI.
*
* @return The logic to be used in generating the response or null if
* no logic could be matched.
*/
protected Logic resolveLogic (Application app, String path)
{
// look for a cached logic instance
String lclass = app.generateClass(path);
Logic logic = (Logic)_logic.get(lclass);
if (logic == null) {
try {
Class pcl = Class.forName(lclass);
@@ -337,107 +375,6 @@ public class DispatcherServlet extends WMServlet
System.out.println(cleanupURI("//samskivert.com/is/this/even/legal"));
}
protected static class Application
{
public Application (String baseURI, String basePkg)
{
// remove any trailing slash
if (baseURI.endsWith("/")) {
_baseURI = baseURI.substring(0, baseURI.length()-1);
} else {
_baseURI = baseURI;
}
// remove any trailing dot
if (basePkg.endsWith(".")) {
_basePkg = basePkg.substring(0, basePkg.length()-1);
} else {
_basePkg = basePkg;
}
}
public boolean matches (String uri)
{
return uri.startsWith(_baseURI);
}
public String generateClass (String uri)
{
// remove the base URI
uri = uri.substring(_baseURI.length());
// convert slashes to dots
uri = StringUtil.replace(uri, "/", ".");
// remove the trailing file extension
uri = uri.substring(0, uri.length() - FILE_EXTENSION.length());
// prepend the base package and we're all set
return _basePkg + uri;
}
public void init (String appclass, ServletContext context)
{
// keep track of this for later
_appclass = appclass;
try {
// get the application class
Class appcl = Class.forName(appclass);
// look up the init method
Class[] ptypes = new Class[] { ServletContext.class };
Method initmeth = appcl.getDeclaredMethod("init", ptypes);
// make sure it's static
if ((initmeth.getModifiers() & Modifier.STATIC) == 0) {
Log.warning("Application init() method not static " +
"[app=" + appclass + "].");
return;
}
// look up the shutdown method
_shutdownMethod =
appcl.getDeclaredMethod("shutdown", new Class[0]);
// make sure it's static
if ((_shutdownMethod.getModifiers() & Modifier.STATIC) == 0) {
Log.warning("Application shutdown() method not static " +
"[app=" + appclass + "].");
return;
}
// invoke the init method
Object[] args = new Object[] { context };
initmeth.invoke(null, args);
} catch (NoSuchMethodError nsme) {
Log.warning("Application class missing init() method " +
"[app=" + appclass + "].");
} catch (Throwable t) {
Log.warning("Error initializing application [app=" + appclass +
", error=" + t + "].");
}
}
public void shutdown ()
{
if (_shutdownMethod != null) {
try {
_shutdownMethod.invoke(null, null);
} catch (Throwable t) {
Log.warning("Error shutting down application " +
"[app=" + _appclass + ", error=" + t + "].");
Log.logStackTrace(t);
}
}
}
protected String _baseURI;
protected String _basePkg;
protected String _appclass;
protected Method _shutdownMethod;
}
protected ArrayList _apps = new ArrayList();
protected HashMap _logic = new HashMap();
@@ -445,13 +382,8 @@ public class DispatcherServlet extends WMServlet
protected static final String ERROR_KEY = "error";
/**
* This is the key used in the context for data validation error
* messages.
* This is the key used to store a reference back to the dispatcher
* servlet in our web context.
*/
protected static final String DV_ERROR_KEY = "invalid_data";
/**
* This is the default file extension.
*/
protected static final String FILE_EXTENSION = ".wm";
protected static final String APPLICATION_KEY = "%_app_%";
}
projects/samskivert/src/java/com/samskivert/webmacro/MsgTool.java
+31 -32
View File
@@ -1,18 +1,15 @@
//
// $Id: MsgTool.java,v 1.1 2001/03/03 21:21:28 mdb Exp $
// $Id: MsgTool.java,v 1.2 2001/03/04 06:15:39 mdb Exp $
package com.samskivert.webmacro;
import java.text.MessageFormat;
import java.util.MissingResourceException;
import java.util.ResourceBundle;
import org.webmacro.*;
import org.webmacro.servlet.WebContext;
import org.webmacro.util.PropertyObject;
import org.webmacro.util.PropertyMethod;
import com.samskivert.Log;
import com.samskivert.servlet.MessageManager;
/**
* The message tool maps a set of appliation messages (translation
@@ -30,19 +27,27 @@ public class MsgTool implements ContextTool
try {
WebContext wctx = (WebContext)ctx;
// first fetch our messages resource bundle
final ResourceBundle messages =
ResourceBundle.getBundle(MESSAGE_FILE_NAME);
// get a handle on the application in effect for this request
Application app = DispatcherServlet.getApplication(wctx);
if (app == null) {
String err = "No application in effect for this request. " +
"Can't resolve messages without an application.";
throw new InvalidContextException(err);
}
// get the message manager from the application
MessageManager msgmgr = app.getMessageManager();
if (msgmgr == null) {
String err = "Application did not provide a message " +
"manager. Can't resolve messages without one.";
throw new InvalidContextException(err);
}
// then create a wrapper that allows webmacro to access it
return new Wrapper(messages);
} catch (MissingResourceException mre) {
Log.warning("Unable to load message bundle: " + mre);
return new Wrapper(null);
return new Wrapper(msgmgr);
} catch (ClassCastException cce) {
throw new InvalidContextException("error.requires_webcontext");
throw new InvalidContextException("MsgTool requires a WebContext");
}
}
@@ -53,9 +58,9 @@ public class MsgTool implements ContextTool
public static class Wrapper implements PropertyObject
{
public Wrapper (ResourceBundle bundle)
public Wrapper (MessageManager msgmgr)
{
_bundle = bundle;
_msgmgr = msgmgr;
}
public Object getProperty (Context context, Object[] names, int offset)
@@ -64,6 +69,7 @@ public class MsgTool implements ContextTool
StringBuffer path = new StringBuffer();
boolean bogus = false;
int lastidx = names.length-1;
WebContext wctx = (WebContext)context;
// reconstruct the path to the property
for (int i = offset; i < names.length; i++) {
@@ -95,21 +101,20 @@ public class MsgTool implements ContextTool
"path: " + path);
}
// look up the translated message
String msg = _bundle.getString(path.toString());
// if the last component is a property method, we want to
// substitute it's arguments into the returned string using a
// message formatter
// if the last component is a property method, we want to use
// it's arguments when looking up the message
if (names[lastidx] instanceof PropertyMethod) {
PropertyMethod pm = (PropertyMethod)names[lastidx];
// we may cache message formatters later, but for now just
// use the static convenience function
Object[] args = pm.getArguments(context);
msg = MessageFormat.format(msg, args);
}
return _msgmgr.getMessage(wctx.getRequest(),
path.toString(), args);
return msg;
} else {
// otherwise just look up the path
return _msgmgr.getMessage(wctx.getRequest(), path.toString());
}
}
public boolean setProperty (Context context, Object[] names, int offset,
@@ -120,12 +125,6 @@ public class MsgTool implements ContextTool
"is not supported!");
}
protected ResourceBundle _bundle;
protected MessageManager _msgmgr;
}
/**
* The file name of the resource file that contains our translation
* strings.
*/
protected static final String MESSAGE_FILE_NAME = "messages";
}