001package com.pi4j.util;
002
003/*
004 * #%L
005 * **********************************************************************
006 * ORGANIZATION  :  Pi4J
007 * PROJECT       :  Pi4J :: Java Library (Core)
008 * FILENAME      :  ExecUtil.java
009 *
010 * This file is part of the Pi4J project. More information about
011 * this project can be found here:  https://www.pi4j.com/
012 * **********************************************************************
013 * %%
014 * Copyright (C) 2012 - 2019 Pi4J
015 * %%
016 * This program is free software: you can redistribute it and/or modify
017 * it under the terms of the GNU Lesser General Public License as
018 * published by the Free Software Foundation, either version 3 of the
019 * License, or (at your option) any later version.
020 *
021 * This program is distributed in the hope that it will be useful,
022 * but WITHOUT ANY WARRANTY; without even the implied warranty of
023 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
024 * GNU General Lesser Public License for more details.
025 *
026 * You should have received a copy of the GNU General Lesser Public
027 * License along with this program.  If not, see
028 * <http://www.gnu.org/licenses/lgpl-3.0.html>.
029 * #L%
030 */
031
032
033import java.io.BufferedReader;
034import java.io.IOException;
035import java.io.InputStreamReader;
036import java.util.ArrayList;
037import java.util.List;
038
039public class ExecUtil
040{
041    public static String[] execute(String command) throws IOException, InterruptedException {
042        return execute(command, null);
043    }
044
045    public static String[] execute(String command, String split) throws IOException, InterruptedException {
046        List<String> result = new ArrayList<>();
047
048        // create external process
049        Process p = Runtime.getRuntime().exec(command);
050
051        // wait for external process to complete
052        p.waitFor();
053
054        // if the external proess returns an error code (non-zero), then build out and return null
055        if(p.exitValue() != 0) {
056            p.destroy();
057            return null;
058        }
059
060        // using try-with-resources to ensure closure
061        try(InputStreamReader isr = new InputStreamReader(p.getInputStream());
062            BufferedReader reader = new BufferedReader(isr)) {
063            // read lines from buffered reader
064            String line = reader.readLine();
065            while (line != null) {
066                if (!line.isEmpty()) {
067                    if (split == null || split.isEmpty()) {
068                        result.add(line.trim());
069                    } else {
070                        String[] parts = line.trim().split(split);
071                        for(String part : parts) {
072                            if (part != null && !part.isEmpty()) {
073                                result.add(part.trim());
074                            }
075                        }
076                    }
077                }
078
079                // read next line
080                line = reader.readLine();
081            }
082        }
083
084        // destroy process
085        p.destroy();
086
087        // return result
088        if (result.size() > 0) {
089            return result.toArray(new String[result.size()]);
090        } else {
091            return new String[0];
092        }
093    }
094}