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Groovy: A powerful, dynamic language for the JVM
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/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you 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.console.completer.Completer
import jline.console.completer.NullCompleter
import jline.console.completer.StringsCompleter
import jline.console.history.FileHistory
import org.codehaus.groovy.tools.shell.completion.StricterArgumentCompleter
import org.codehaus.groovy.tools.shell.util.Logger
import org.codehaus.groovy.tools.shell.util.MessageSource

/**
 * Support for {@link Command} instances.
 *
 * @author 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)

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

    /** The shortcut switch */
    final String shortcut

    /** The owning shell. */
    protected final Groovysh 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/**/ aliases = []

    /** Flag to indicate if the command should be hidden or not. */
    boolean hidden = false

    protected CommandSupport(final Groovysh shell, final String name, final String shortcut) {
        assert shell != null
        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.
        //
    }

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

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

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

    @Override
    boolean getHidden() {
        return hidden
    }

    @Override
    List getAliases() {
        return aliases
    }

    @Override
    String getShortcut() {
        return shortcut
    }

    @Override
    String getName() {
        return name
    }
/**
     * Override to provide custom completion semantics for the command.
     */
    protected List createCompleters() {
        return []
    }

    /**
     * Setup the Completer for the command.
     */
    @Override
    Completer getCompleter() {
        if (hidden) {
            return null
        }

        List list = new ArrayList()
        list << new StringsCompleter(name, shortcut)

        List completers = createCompleters()

        if (completers) {
            completers.each {Completer it ->
                if (it) {
                    list << it
                }
                else {
                    list << new NullCompleter()
                }
            }
        }
        else {
            list << new NullCompleter()
        }

        return new StricterArgumentCompleter(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 FileHistory getHistory() {
        return shell.history
    }

    protected GroovyClassLoader getClassLoader() {
        return shell.interp.classLoader
    }
}