/*
 * Copyright (c) 1997, 2018 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0, which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

/* FROM mail.jar */
package org.jvnet.mimepull;

import java.util.*;

Utilities to make it easier to get property values.
Properties can be strings or type-specific value objects.
Author:
Bill Shannon/**
 * Utilities to make it easier to get property values.
 * Properties can be strings or type-specific value objects.
 *
 * @author Bill Shannon
 */
final class PropUtil {

    // No one should instantiate this class.
    private PropUtil() {
    }

    
Get a boolean valued System property.
/**
     * Get a boolean valued System property.
     */
    public static boolean getBooleanSystemProperty(String name, boolean def) {
	try {
	    return getBoolean(getProp(System.getProperties(), name), def);
	} catch (SecurityException sex) {
	    // fall through...
	}

	/*
	 * If we can't get the entire System Properties object because
	 * of a SecurityException, just ask for the specific property.
	 */
	try {
	    String value = System.getProperty(name);
	    if (value == null) {
                return def;
            }
	    if (def) {
                return !value.equalsIgnoreCase("false");
            } else {
                return value.equalsIgnoreCase("true");
            }
	} catch (SecurityException sex) {
	    return def;
	}
    }

    
Get the value of the specified property.
If the "get" method returns null, use the getProperty method,
which might cascade to a default Properties object.
/**
     * Get the value of the specified property.
     * If the "get" method returns null, use the getProperty method,
     * which might cascade to a default Properties object.
     */
    private static Object getProp(Properties props, String name) {
	Object val = props.get(name);
	if (val != null) {
            return val;
        } else {
            return props.getProperty(name);
        }
    }

    
Interpret the value object as a boolean,
returning def if unable.
/**
     * Interpret the value object as a boolean,
     * returning def if unable.
     */
    private static boolean getBoolean(Object value, boolean def) {
	if (value == null) {
            return def;
        }
	if (value instanceof String) {
	    /*
	     * If the default is true, only "false" turns it off.
	     * If the default is false, only "true" turns it on.
	     */
	    if (def) {
                return !((String)value).equalsIgnoreCase("false");
            } else {
                return ((String)value).equalsIgnoreCase("true");
            }
	}
	if (value instanceof Boolean) {
            return ((Boolean)value).booleanValue();
        }
	return def;
    }
}