Groovy example source code file (CommandSupport.groovy)

This example Groovy source code file (CommandSupport.groovy) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Groovy tags/keywords

command, commandexception, commandsupport, commandsupport, groovyclassloader, history, list, list, messagesource, nullcompletor, shell, shell, string, string

The Groovy CommandSupport.groovy source code

/*
 * Copyright 2003-2007 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.codehaus.groovy.tools.shell

import jline.Completor
import jline.NullCompletor
import jline.ArgumentCompletor
import jline.History

import org.codehaus.groovy.tools.shell.util.MessageSource
import org.codehaus.groovy.tools.shell.util.Logger
import org.codehaus.groovy.tools.shell.util.SimpleCompletor

/**
 * Support for {@link Command} instances.
 *
 * @version $Id: CommandSupport.groovy 8806 2007-10-25 21:58:29Z user57 $
 * @author <a href="mailto:jason@planet57.com">Jason Dillon
 */
abstract class CommandSupport
    implements Command
{
    protected static final String NEWLINE = System.properties['line.separator']
    
    /** Instance logger for the command, initialized late to include the command name. */
    protected final Logger log

    /** i18n message source for the command. */
    protected final MessageSource messages = new MessageSource(this.class, CommandSupport.class)

    /** The name of the command. */
    final String name

    /** The shortcut switch */
    final String shortcut
    
    /** The owning shell. */
    protected final Shell shell

    /** The I/O container for the command to spit stuff out. */
    protected final IO io

    /** Provides the command instance with the registry, for aliasing support. */
    protected CommandRegistry registry
    
    /** Standard aliases for the command. */
    final List/*<CommandAlias>*/ aliases = []
    
    /** Flag to indicate if the command should be hidden or not. */
    boolean hidden = false
    
    protected CommandSupport(final Shell shell, final String name, final String shortcut) {
        assert shell
        assert name
        assert shortcut
        
        this.log = Logger.create(this.class, name)
        this.shell = shell
        this.io = shell.io
        this.name = name
        this.shortcut = shortcut
        
        //
        // NOTE: Registry will be added once registered.
        //
    }

    String getDescription() {
        return messages['command.description']
    }

    String getUsage() {
        return messages['command.usage']
    }

    String getHelp() {
        return messages['command.help']
    }

    /**
     * Override to provide custom completion semantics for the command.
     */
    protected List createCompletors() {
        return null
    }

    /**
     * Setup the completor for the command.
     */
    Completor getCompletor() {
        if (hidden) {
            return null
        }
        
        def list = [ new SimpleCompletor(name, shortcut) ]

        def completors = createCompletors()
        
        if (completors) {
            completors.each {
                if (it) {
                    list << it
                }
                else {
                    list << new NullCompletor()
                }
            }
        }
        else {
            list << new NullCompletor()
        }

        return new ArgumentCompletor(list)
    }
    
    //
    // Helpers
    //

    protected void alias(final String name, final String shortcut) {
        aliases << new CommandAlias(shell, name, shortcut, this.name)
    }

    protected void fail(final String msg) {
        throw new CommandException(this, msg)
    }
    
    protected void fail(final String msg, final Throwable cause) {
        throw new CommandException(this, msg, cause)
    }
    
    protected void assertNoArguments(final List args) {
        assert args != null
        
        if (args.size() > 0) {
            fail(messages.format('error.unexpected_args', args.join(' ')))
        }
    }
    
    //
    // Shell access helpers
    //

    protected BufferManager getBuffers() {
        return shell.buffers
    }

    protected List getBuffer() {
        return shell.buffers.current()
    }

    protected List getImports() {
        return shell.imports
    }
    
    protected Binding getBinding() {
        return shell.interp.context
    }
    
    protected Map getVariables() {
        return binding.variables
    }
    
    protected History getHistory() {
        return shell.history
    }
    
    protected GroovyClassLoader getClassLoader() {
        return shell.interp.classLoader
    }
}