001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.hbtop.screen.help;
019
020import org.apache.hadoop.hbase.hbtop.screen.AbstractScreenView;
021import org.apache.hadoop.hbase.hbtop.screen.Screen;
022import org.apache.hadoop.hbase.hbtop.screen.ScreenView;
023import org.apache.hadoop.hbase.hbtop.terminal.KeyPress;
024import org.apache.hadoop.hbase.hbtop.terminal.Terminal;
025import org.apache.hadoop.hbase.hbtop.terminal.TerminalPrinter;
026import org.apache.yetus.audience.InterfaceAudience;
027
028
029/**
030 * The help screen.
031 */
032@InterfaceAudience.Private
033public class HelpScreenView extends AbstractScreenView {
034
035  private static final int SCREEN_DESCRIPTION_START_ROW = 0;
036  private static final int COMMAND_DESCRIPTION_START_ROW = 3;
037
038  private final HelpScreenPresenter helpScreenPresenter;
039
040  public HelpScreenView(Screen screen, Terminal terminal, long refreshDelay,
041    ScreenView nextScreenView) {
042    super(screen, terminal);
043    this.helpScreenPresenter = new HelpScreenPresenter(this, refreshDelay, nextScreenView);
044  }
045
046  @Override
047  public void init() {
048    helpScreenPresenter.init();
049  }
050
051  @Override
052  public ScreenView handleKeyPress(KeyPress keyPress) {
053    return helpScreenPresenter.transitionToNextScreen();
054  }
055
056  public void showHelpScreen(long refreshDelay, CommandDescription[] commandDescriptions) {
057    showScreenDescription(refreshDelay);
058
059    TerminalPrinter printer = getTerminalPrinter(COMMAND_DESCRIPTION_START_ROW);
060    for (CommandDescription commandDescription : commandDescriptions) {
061      showCommandDescription(printer, commandDescription);
062    }
063
064    printer.endOfLine();
065    printer.print("Press any key to continue").endOfLine();
066  }
067
068  private void showScreenDescription(long refreshDelay) {
069    TerminalPrinter printer = getTerminalPrinter(SCREEN_DESCRIPTION_START_ROW);
070    printer.startBold().print("Help for Interactive Commands").stopBold().endOfLine();
071    printer.print("Refresh delay: ").startBold()
072      .print((double) refreshDelay / 1000).stopBold().endOfLine();
073  }
074
075  private void showCommandDescription(TerminalPrinter terminalPrinter,
076    CommandDescription commandDescription) {
077    terminalPrinter.print("  ");
078    boolean first = true;
079    for (String key : commandDescription.getKeys()) {
080      if (first) {
081        first = false;
082      } else {
083        terminalPrinter.print(",");
084      }
085      terminalPrinter.startBold().print(key).stopBold();
086    }
087
088    terminalPrinter.printFormat(": %s", commandDescription.getDescription()).endOfLine();
089  }
090}