/*
 * Copyright 2002-2020 the original author or authors.
 *
 * 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
 *
 *      https://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 org.springframework.core.env;

import java.util.List;

import org.springframework.lang.Nullable;
import org.springframework.util.StringUtils;

CommandLinePropertySource implementation backed by a simple String array. 
Purpose
This CommandLinePropertySource implementation aims to provide the simplest possible approach to parsing command line arguments. As with all 
CommandLinePropertySource implementations, command line arguments are broken into two distinct groups: option arguments and non-option arguments, as
described below (some sections copied from Javadoc for SimpleCommandLineArgsParser):
Working with option arguments
Option arguments must adhere to the exact syntax:
--optName[=optValue]
That is, options must be prefixed with "--" and may or may not specify a value. If a value is specified, the name and value must be separated without spaces by an equals sign ("="). The value may optionally be
an empty string.
Valid examples of option arguments
--foo
--foo=
--foo=""
--foo=bar
--foo="bar then baz"
--foo=bar,baz,biz
Invalid examples of option arguments
-foo
--foo bar
--foo = bar
--foo=bar --foo=baz --foo=biz
Working with non-option arguments
Any and all arguments specified at the command line without the "--" option prefix will be considered as "non-option arguments" and made available through the CommandLineArgs.getNonOptionArgs() method. 
Typical usage
public static void main(String[] args) {
    PropertySource ps = new SimpleCommandLinePropertySource(args);
    // ...
}
 See CommandLinePropertySource for complete general usage examples. 
Beyond the basics
When more fully-featured command line parsing is necessary, consider using the provided JOptCommandLinePropertySource, or implement your own CommandLinePropertySource against the command line parsing library of your choice. 
Author:
Chris Beams
See Also:
CommandLinePropertySource
JOptCommandLinePropertySource
Since:
3.1/**
 * {@link CommandLinePropertySource} implementation backed by a simple String array.
 *
 * <h3>Purpose</h3>
 * <p>This {@code CommandLinePropertySource} implementation aims to provide the simplest
 * possible approach to parsing command line arguments. As with all {@code
 * CommandLinePropertySource} implementations, command line arguments are broken into two
 * distinct groups: <em>option arguments</em> and <em>non-option arguments</em>, as
 * described below <em>(some sections copied from Javadoc for
 * {@link SimpleCommandLineArgsParser})</em>:
 *
 * <h3>Working with option arguments</h3>
 * <p>Option arguments must adhere to the exact syntax:
 *
 * <pre class="code">--optName[=optValue]</pre>
 *
 * <p>That is, options must be prefixed with "{@code --}" and may or may not
 * specify a value. If a value is specified, the name and value must be separated
 * <em>without spaces</em> by an equals sign ("="). The value may optionally be
 * an empty string.
 *
 * <h4>Valid examples of option arguments</h4>
 * <pre class="code">
 * --foo
 * --foo=
 * --foo=""
 * --foo=bar
 * --foo="bar then baz"
 * --foo=bar,baz,biz</pre>
 *
 * <h4>Invalid examples of option arguments</h4>
 * <pre class="code">
 * -foo
 * --foo bar
 * --foo = bar
 * --foo=bar --foo=baz --foo=biz</pre>
 *
 * <h3>Working with non-option arguments</h3>
 * <p>Any and all arguments specified at the command line without the "{@code --}"
 * option prefix will be considered as "non-option arguments" and made available
 * through the {@link CommandLineArgs#getNonOptionArgs()} method.
 *
 * <h3>Typical usage</h3>
 * <pre class="code">
 * public static void main(String[] args) {
 *     PropertySource<?> ps = new SimpleCommandLinePropertySource(args);
 *     // ...
 * }</pre>
 *
 * See {@link CommandLinePropertySource} for complete general usage examples.
 *
 * <h3>Beyond the basics</h3>
 *
 * <p>When more fully-featured command line parsing is necessary, consider using
 * the provided {@link JOptCommandLinePropertySource}, or implement your own
 * {@code CommandLinePropertySource} against the command line parsing library of your
 * choice.
 *
 * @author Chris Beams
 * @since 3.1
 * @see CommandLinePropertySource
 * @see JOptCommandLinePropertySource
 */
public class SimpleCommandLinePropertySource extends CommandLinePropertySource<CommandLineArgs> {

	
Create a new SimpleCommandLinePropertySource having the default name and backed by the given String[] of command line arguments. 
See Also:
CommandLinePropertySource.COMMAND_LINE_PROPERTY_SOURCE_NAME
CommandLinePropertySource(Object)/**
	 * Create a new {@code SimpleCommandLinePropertySource} having the default name
	 * and backed by the given {@code String[]} of command line arguments.
	 * @see CommandLinePropertySource#COMMAND_LINE_PROPERTY_SOURCE_NAME
	 * @see CommandLinePropertySource#CommandLinePropertySource(Object)
	 */
	public SimpleCommandLinePropertySource(String... args) {
		super(new SimpleCommandLineArgsParser().parse(args));
	}

	
Create a new SimpleCommandLinePropertySource having the given name and backed by the given String[] of command line arguments. /**
	 * Create a new {@code SimpleCommandLinePropertySource} having the given name
	 * and backed by the given {@code String[]} of command line arguments.
	 */
	public SimpleCommandLinePropertySource(String name, String[] args) {
		super(name, new SimpleCommandLineArgsParser().parse(args));
	}

	
Get the property names for the option arguments.
/**
	 * Get the property names for the option arguments.
	 */
	@Override
	public String[] getPropertyNames() {
		return StringUtils.toStringArray(this.source.getOptionNames());
	}

	@Override
	protected boolean containsOption(String name) {
		return this.source.containsOption(name);
	}

	@Override
	@Nullable
	protected List<String> getOptionValues(String name) {
		return this.source.getOptionValues(name);
	}

	@Override
	protected List<String> getNonOptionArgs() {
		return this.source.getNonOptionArgs();
	}

}