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/*
* Tentackle - https://tentackle.org
*
* 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.tentackle.app;
import org.tentackle.common.TentackleRuntimeException;
import org.tentackle.misc.CommandLine;
import org.tentackle.misc.Identifiable;
import org.tentackle.misc.VolatileHolder;
import org.tentackle.pdo.DomainContext;
import org.tentackle.pdo.DomainContextProvider;
import org.tentackle.session.SessionInfo;
import org.tentackle.session.SessionProvider;
import java.util.Properties;
interface ApplicationHolder {
VolatileHolder HOLDER = new VolatileHolder<>();
}
/**
* Tentackle application.
*/
public interface Application extends SessionProvider, DomainContextProvider {
/**
* Gets the application instance currently running.
*
* @return the application singleton, null if no application running yet
*/
static Application getInstance() {
// no synchronized necessary due to VolatileHolder
return ApplicationHolder.HOLDER.get();
}
/**
* Registers this application.
* Makes sure that only one application is running at a time.
*
* Throws TentackleRuntimeException if another application is already running.
*/
default void register() {
synchronized(ApplicationHolder.class) {
Application running = getInstance();
if (running != null && running != this) {
throw new TentackleRuntimeException("application '" + running + "' already registered");
}
ApplicationHolder.HOLDER.accept(this);
}
}
/**
* Unregisters this application.
*
* Throws TentackleRuntimeException if no application is running at all or another application is still running.
*/
default void unregister() {
synchronized(ApplicationHolder.class) {
Application running = getInstance();
if (running != this) {
if (running == null) {
throw new TentackleRuntimeException("no application registered at all");
}
throw new TentackleRuntimeException("application '" + this + "' cannot override already registered application '" + running + "'");
}
ApplicationHolder.HOLDER.accept(null);
}
}
/**
* Gets the application name.
*
* @return the name
*/
String getName();
/**
* Gets the application version.
*
* @return the version
*/
String getVersion();
/**
* Gets the creation time in epochal milliseconds.
*
* @return the creation time of this application
*/
long getCreationTime();
/**
* Gets the command line.
*
* @return the commandline, null if not started
*/
CommandLine getCommandLine();
/**
* Gets the session info.
*
* @return the session info
*/
SessionInfo getSessionInfo();
/**
* Gets an application property.
*
* @param key the property's name
* @return the value of the key, null if no such property, the empty string if no value for this property
*/
String getProperty(String key);
/**
* Gets an application property case-insensitive.
*
* @param key the property's name
* @return the value of the key, null if no such property, the empty string if no value for this property
*/
String getPropertyIgnoreCase(String key);
/**
* Gets an application property as a character array.
* Useful for passwords and alike.
*
* @param key the property's name
* @return the value of the key, null if no such property, the empty array if no value for this property
*/
char[] getPropertyAsChars(String key);
/**
* Gets an application property as a character array, case-insensitive.
* Useful for passwords and alike.
*
* @param key the property's name
* @return the value of the key, null if no such property, the empty array if no value for this property
*/
char[] getPropertyAsCharsIgnoreCase(String key);
/**
* Applies further application properties.
* If the given properties are different from the application properties, they will be copied to
* the application properties.
*
* @param properties the properties, null if none
*/
void applyProperties(Properties properties);
/**
* Gets the identifiable corresponding to the ID of a user.
*
* @param the user type
* @param context the domain context
* @param userId the user id
* @return the user object, null if unknown
*/
U getUser(DomainContext context, long userId);
/**
* Returns whether the running application is a server.
*
* @return true if server, false if not a server or no application running at all
*/
boolean isServer();
/**
* Returns whether the running application is interactive.
*
* @return true if interaction with user, false if server, daemon or whatever
*/
boolean isInteractive();
/**
* Starts the application.
*
* @param args the arguments (usually from commandline), null or empty if none
*/
void start(String[] args);
/**
* Starts the application without further arguments.
*/
default void start() {
start(null);
}
/**
* Terminates the application with optional error handling.
*
* @param exitValue the stop value for System.exit()
* @param exitThrowable an exception causing the termination, null if none
*/
void stop(int exitValue, Throwable exitThrowable);
/**
* Gracefully terminates the application.
*/
default void stop() {
stop(0, null);
}
}