Scala example source code file (Configuration.java)

This example Scala source code file (Configuration.java) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Scala source code examples by using tags.

All credit for the original source code belongs to scala-lang.org; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Scala tags/keywords

boolean, configuration, file, inputstream, ioexception, jline_rc, loaded, properties, string, unable

The Configuration.java Scala example source code

/*
 * 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 scala.tools.jline.internal;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

/**
 * Provides access to configuration values.
 *
 * @author <a href="mailto:jason@planet57.com">Jason Dillon</a>
 * @since 2.4
 */
public final class Configuration
{
    public static final String JLINE_RC = ".jline.rc";

    private static final Properties userprops;

    static {
        Properties props = new Properties();

        File file = new File(getUserHome(), JLINE_RC);
        if (file.exists() && file.canRead()) {
            try {
                InputStream input = new BufferedInputStream(new FileInputStream(file));
                try {
                    props.load(input);
                    Log.debug("Loaded user configuration: ", file);
                }
                finally {
                    input.close();
                }
            }
            catch (IOException e) {
                Log.warn("Unable to read user configuration: ", file, e);
            }
        }
        else {
            Log.trace("User configuration file missing or unreadable: ", file);
        }

        userprops = props;
    }

    private static boolean isEmpty(final String value) {
        return value == null || value.trim().length() == 0;
    }

    public static String getString(final String name, final String defaultValue) {
        assert name != null;

        String value;

        // Check sysprops first, it always wins
        value = System.getProperty(name);

        if (isEmpty(value)) {
            // Next try userprops
            value = userprops.getProperty(name);

            if (isEmpty(value)) {
                // else use the default
                value = defaultValue;
            }
        }

        return value;
    }

    public static String getString(final String name) {
        return getString(name, null);
    }

    public static Boolean getBoolean(final String name, final Boolean defaultValue) {
        String value = getString(name);
        if (isEmpty(value)) {
            return defaultValue;
        }
        return Boolean.valueOf(value);
    }

    public static Boolean getBoolean(final String name) {
        return getBoolean(name, null);
    }

    //
    // System property helpers
    //

    public static File getUserHome() {
        return new File(System.getProperty("user.home"));
    }

    public static String getOsName() {
        return System.getProperty("os.name").toLowerCase();
    }

    public static String getFileEncoding() {
        return System.getProperty("file.encoding");
    }

    public static String getInputEncoding() {
        return System.getProperty("input.encoding", "UTF-8");
    }
}