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'rapiddweller Common' is an open source Java library forked from Databene Commons by Volker Bergmann. It provides extensions to the Java core library by utility classes, abstract concepts and concrete implementations.
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/*
 * Copyright (C) 2004-2015 Volker Bergmann ([email protected]).
 * All rights reserved.
 *
 * 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 com.rapiddweller.common;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Writer;

/**
 * Executes shell commands and shell files.
 * Created at 05.08.2008 07:40:00
 *
 * @author Volker Bergmann
 * @since 0.4.5
 */
public class ShellUtil {

  private static final Logger logger = LogManager.getLogger(ShellUtil.class);

  /**
   * Run shell commands int.
   *
   * @param iterator     the iterator
   * @param outputWriter the output writer
   * @param errorHandler the error handler
   * @return the int
   */
  public static int runShellCommands(ReaderLineIterator iterator, Writer outputWriter, ErrorHandler errorHandler) {
    int result = 0;
    while (iterator.hasNext()) {
      String command = iterator.next().trim();
      if (command.length() > 0) {
        result = runShellCommand(command, outputWriter, errorHandler);
      }
    }
    return result;
  }

  /**
   * Run shell command int.
   *
   * @param command      the command
   * @param outputWriter the output writer
   * @param errorHandler the error handler
   * @return the int
   */
  public static int runShellCommand(String command, Writer outputWriter, ErrorHandler errorHandler) {
    return runShellCommand(command, outputWriter, new File(SystemInfo.getCurrentDir()), errorHandler);
  }

  /**
   * Run shell command int.
   *
   * @param command      the command
   * @param outputWriter the output writer
   * @param directory    the directory
   * @param errorHandler the error handler
   * @return the int
   */
  public static int runShellCommand(String command, Writer outputWriter, File directory, ErrorHandler errorHandler) {
    logger.debug(command);
    try {
      Process process = Runtime.getRuntime().exec(command, null, directory);
      return execute(process, command, outputWriter, errorHandler);
    } catch (FileNotFoundException e) {
      errorHandler.handleError("Error in shell invocation: " + command, e);
      return 2;
    } catch (Exception e) {
      errorHandler.handleError("Error in shell invocation: " + command, e);
      return 1;
    }
  }

  /**
   * Run shell command int.
   *
   * @param cmdArray     the cmd array
   * @param outputWriter the output writer
   * @param directory    the directory
   * @param errorHandler the error handler
   * @return the int
   */
  public static int runShellCommand(String[] cmdArray, Writer outputWriter, File directory, ErrorHandler errorHandler) {
    String description = renderCmdArray(cmdArray);
    if (logger.isDebugEnabled()) {
      logger.debug(description);
    }
    try {
      Process process = Runtime.getRuntime().exec(cmdArray, null, directory);
      return execute(process, description, outputWriter, errorHandler);
    } catch (Exception e) {
      errorHandler.handleError("Error in shell invocation: " + description, e);
      return -1;
    }
  }

  // private helpers ---------------------------------------------------------

  private static int execute(Process process, String description, Writer outputWriter, ErrorHandler errorHandler)
      throws IOException, InterruptedException {
    String lf = SystemInfo.getLineSeparator();
    BufferedReader stdIn = new BufferedReader(new InputStreamReader(process.getInputStream()));
    BufferedReader stdErr = new BufferedReader(new InputStreamReader(process.getErrorStream()));
    // read the output from the command
    boolean firstLine = true;
    String s;
    while ((s = stdIn.readLine()) != null) {
      if (outputWriter != null) {
        if (firstLine) {
          firstLine = false;
        } else {
          outputWriter.write(lf);
        }
        outputWriter.write(s);
      }
    }
    if (outputWriter != null) {
      outputWriter.flush();
    }
    // read any errors from the attempted command
    while ((s = stdErr.readLine()) != null) {
      errorHandler.handleError(s);
    }
    process.waitFor();
    int exitValue = process.exitValue();
    if (exitValue != 0) {
      errorHandler.handleError("Process (" + description + ") did not terminate normally: Return code " + exitValue);
    }
    return exitValue;
  }

  private static String renderCmdArray(String[] cmdArray) {
    return ArrayFormat.format(" ", cmdArray);
  }

}