org.crsh.shell.impl.command.spi.CommandInvoker Maven / Gradle / Ivy
/*
* Copyright (C) 2012 eXo Platform SAS.
*
* This 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 software 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 software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.crsh.shell.impl.command.spi;
import org.crsh.command.CommandContext;
import org.crsh.keyboard.KeyHandler;
import org.crsh.stream.Filter;
import org.crsh.text.ScreenContext;
import java.io.IOException;
/**
* A command invoker is a filter for a {@link org.crsh.command.CommandContext} kind of consumer.
*
* @param the consumed element generic type
* @param the produced element generic type
*/
public abstract class CommandInvoker implements Filter> {
/**
* Invoke the command.
*
* @param consumer the consumer for this invocation
* @throws IOException any io exception
* @throws CommandException anything command exception
*/
public final void invoke(CommandContext consumer) throws IOException, CommandException {
try {
open(consumer);
}
finally {
try {
flush();
}
finally {
close();
}
}
}
@Override
public abstract void flush() throws IOException;
@Override
public abstract void provide(C element) throws IOException, CommandException;
@Override
public abstract void open(CommandContext consumer) throws IOException, CommandException;
@Override
public abstract void close() throws IOException, CommandException;
/**
* Provide an opportunity for the command to implement screen context.
*
* @return the screen context
*/
public ScreenContext getScreenContext() {
return null;
}
/**
* Return the key handler or null if the invoker cannot handler key events.
*
* @return the key handler
*/
public KeyHandler getKeyHandler() {
return null;
}
}