Groovy example source code file (HistoryCommand.groovy)

This example Groovy source code file (HistoryCommand.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

can, complexcommandsupport, history, history, historycommand, historycommand, invalid, list, object, object, recalling, shell, shell, simplecompletor

The Groovy HistoryCommand.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.commands

import org.codehaus.groovy.tools.shell.ComplexCommandSupport
import org.codehaus.groovy.tools.shell.Shell

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

/**
 * The 'history' command.
 *
 * @version $Id: HistoryCommand.groovy 21580 2011-02-17 20:06:49Z glaforge $
 * @author <a href="mailto:jason@planet57.com">Jason Dillon
 */
class HistoryCommand
    extends ComplexCommandSupport
{
    HistoryCommand(final Shell shell) {
        super(shell, 'history', '\\H')
        
        this.functions = [ 'show', 'clear', 'flush', 'recall' ]
        
        this.defaultFunction = 'show'
    }
    
    protected List createCompletors() {
        def loader = {
            def list = []
            
            functions.each { list << it }
            
            return list
        }
        
        return [
            new SimpleCompletor(loader),
            null
        ]
    }
    
    Object execute(List args) {
        if (!history) {
            fail("Shell does not appear to be interactive; Can not query history")
        }
        
        super.execute(args)

        // Don't return anything
        return null
    }
    
    def do_show = {
        history.historyList.eachWithIndex { item, i ->
            i = i.toString().padLeft(3, ' ')
            
            io.out.println(" @|bold $i|@  $item")
        }
    }
    
    def do_clear = {
        history.clear()
        
        if (io.verbose) {
            io.out.println('History cleared')
        }
    }
    
    def do_flush = {
        history.flushBuffer()
        
        if (io.verbose) {
            io.out.println('History flushed')
        }
    }
    
    def do_recall = { args ->
        def line
        
        if (args.size() != 1) {
            fail("History recall requires a single history identifer")
        }
        
        def id = args[0]

        //
        // FIXME: This won't work as desired because the history shifts when we run recall and could internally shift more from alias redirection
        //
        
        try {
            id = Integer.parseInt(id)
            if (shell.historyFull) {
                // if history was full before execution of the command, then the recall command itself
                // has been added to history before it actually gets executed
                // so we need to shift by one
                id--
            };
            line = id<0?shell.evictedLine:history.historyList[id]
        }
        catch (Exception e) {
            fail("Invalid history identifier: $id", e)
        }
        
        log.debug("Recalling history item #$id: $line")
        
        return shell.execute(line)
    }
}