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Scala example source code file (TerminalLineSettings.java)

This example Scala source code file (TerminalLineSettings.java) 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 - Scala tags/keywords

bytearrayoutputstream, closeable, closeable, default_sh, default_stty, exception, inputstream, interruptedexception, interruptedexception, io, ioexception, ioexception, regex, string, string, terminallinesettings, text

The Scala TerminalLineSettings.java source code

/*
 * Copyright (c) 2002-2007, Marc Prud'hommeaux. All rights reserved.
 *
 * This software is distributable under the BSD license. See the terms of the
 * BSD license in the documentation provided with this software.
 */

package scala.tools.jline.internal;

import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.text.MessageFormat;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Provides access to terminal line settings via <tt>stty.
 *
 * @author <a href="mailto:mwp1@cornell.edu">Marc Prud'hommeaux
 * @author <a href="mailto:dwkemp@gmail.com">Dale Kemp
 * @author <a href="mailto:jason@planet57.com">Jason Dillon
 * @author <a href="mailto:jbonofre@apache.org">Jean-Baptiste Onofré
 * @since 2.0
 */
public final class TerminalLineSettings
{
    public static final String JLINE_STTY = "jline.stty";

    public static final String DEFAULT_STTY = "stty";

    public static final String JLINE_SH = "jline.sh";

    public static final String DEFAULT_SH = "sh";

    private static String sttyCommand = Configuration.getString(JLINE_STTY, DEFAULT_STTY);

    private static String shCommand = Configuration.getString(JLINE_SH, DEFAULT_SH);

    private String config;

    private long configLastFetched;

    public TerminalLineSettings() throws IOException, InterruptedException {
        config = get("-a");
        configLastFetched = System.currentTimeMillis();

        Log.debug("Config: ", config);

        // sanity check
        if (config.length() == 0) {
            throw new IOException(MessageFormat.format("Unrecognized stty code: {0}", config));
        }
    }

    public String getConfig() {
        return config;
    }

    public void restore() throws IOException, InterruptedException {
        set("sane");
    }

    public String get(final String args) throws IOException, InterruptedException {
        return stty(args);
    }

    public void set(final String args) throws IOException, InterruptedException {
        stty(args);
    }

    /**
     * <p>
     * Get the value of a stty property, including the management of a cache.
     * </p>
     *
     * @param name the stty property.
     * @return the stty property value.                        
     */
    public int getProperty(String name) {
        assert name != null;
        try {
            // tty properties are cached so we don't have to worry too much about getting term widht/height
            if (config == null || System.currentTimeMillis() - configLastFetched > 1000 ) {
                config = get("-a");
                configLastFetched = System.currentTimeMillis();
            }
            return this.getProperty(name, config);
        } catch (Exception e) {
            Log.warn("Failed to query stty ", name, e);            
            return -1;
        }
    }

    /**
     * <p>
     * Parses a stty output (provided by stty -a) and return the value of a given property.
     * </p>
     *
     * @param name property name.
     * @param stty string resulting of stty -a execution.
     * @return value of the given property.
     */
    protected int getProperty(String name, String stty) {
        // try the first kind of regex
        Pattern pattern = Pattern.compile(name + "\\s+=\\s+([^;]*)[;\\n\\r]");
        Matcher matcher = pattern.matcher(stty);
        if (!matcher.find()) {
            // try a second kind of regex
            pattern = Pattern.compile(name + "\\s+([^;]*)[;\\n\\r]");
            matcher = pattern.matcher(stty);
            if (!matcher.find()) {
                // try a second try of regex
                pattern = Pattern.compile("(\\S*)\\s+" + name);
                matcher = pattern.matcher(stty);
                if (!matcher.find()) {
                    return -1;
                }
            }
        }
        return parseControlChar(matcher.group(1));
    }

    private int parseControlChar(String str) {
        // under
        if ("<undef>".equals(str)) {
            return -1;
        }
        // octal
        if (str.charAt(0) == '0') {
            return Integer.parseInt(str, 8);
        }
        // decimal
        if (str.charAt(0) >= '1' && str.charAt(0) <= '9') {
            return Integer.parseInt(str, 10);
        }
        // control char
        if (str.charAt(0) == '^') {
            if (str.charAt(1) == '?') {
                return 127;
            } else {
                return str.charAt(1) - 64;
            }
        } else if (str.charAt(0) == 'M' && str.charAt(1) == '-') {
            if (str.charAt(2) == '^') {
                if (str.charAt(3) == '?') {
                    return 127 + 128;
                } else {
                    return str.charAt(3) - 64 + 128;
                }
            } else {
                return str.charAt(2) + 128;
            }
        } else {
            return str.charAt(0);
        }
    }

    private static String stty(final String args) throws IOException, InterruptedException {
        assert args != null;
        return exec(String.format("%s %s < /dev/tty", sttyCommand, args));
    }

    private static String exec(final String cmd) throws IOException, InterruptedException {
        assert cmd != null;
        return exec(shCommand, "-c", cmd);
    }

    private static String exec(final String... cmd) throws IOException, InterruptedException {
        assert cmd != null;

        ByteArrayOutputStream bout = new ByteArrayOutputStream();

        Log.trace("Running: ", cmd);

        Process p = Runtime.getRuntime().exec(cmd);

        InputStream in = null;
        InputStream err = null;
        OutputStream out = null;
        try {
            int c;
            in = p.getInputStream();
            while ((c = in.read()) != -1) {
                bout.write(c);
            }
            err = p.getErrorStream();
            while ((c = err.read()) != -1) {
                bout.write(c);
            }
            out = p.getOutputStream();
            p.waitFor();
        }
        finally {
            close(in, out, err);
        }

        String result = bout.toString();

        Log.trace("Result: ", result);

        return result;
    }

    private static void close(final Closeable... closeables) {
        for (Closeable c : closeables) {
            try {
                c.close();
            }
            catch (Exception e) {
                // Ignore
            }
        }
    }
}

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