org.apache.accumulo.shell.commands.ClearCommand Maven / Gradle / Ivy

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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.apache.accumulo.shell.commands;

import java.io.IOException;

import org.apache.accumulo.shell.Shell;
import org.apache.accumulo.shell.Shell.Command;
import org.apache.commons.cli.CommandLine;

public class ClearCommand extends Command {
  @Override
  public String description() {
    return "clears the screen";
  }

  @Override
  public int execute(final String fullCommand, final CommandLine cl, final Shell shellState) throws IOException {
    // custom clear screen, so I don't have to redraw the prompt twice
    if (!shellState.getReader().getTerminal().isAnsiSupported()) {
      throw new IOException("Terminal does not support ANSI commands");
    }
    // send the ANSI code to clear the screen
    shellState.getReader().print(((char) 27) + "[2J");
    shellState.getReader().flush();

    // then send the ANSI code to go to position 1,1
    shellState.getReader().print(((char) 27) + "[1;1H");
    shellState.getReader().flush();

    return 0;
  }

  @Override
  public int numArgs() {
    return 0;
  }
}