/**
 *   Copyright (C) 2011-2012 Typesafe Inc. <http://typesafe.com>
 */
package com.typesafe.config;


/**
 * Context provided to a {@link ConfigIncluder}; this interface is only useful
 * inside a {@code ConfigIncluder} implementation, and is not intended for apps
 * to implement.
 *
 * <p>
 * <em>Do not implement this interface</em>; it should only be implemented by
 * the config library. Arbitrary implementations will not work because the
 * library internals assume a specific concrete implementation. Also, this
 * interface is likely to grow new methods over time, so third-party
 * implementations will break.
 */
public interface ConfigIncludeContext {
    /**
     * Tries to find a name relative to whatever is doing the including, for
     * example in the same directory as the file doing the including. Returns
     * null if it can't meaningfully create a relative name. The returned
     * parseable may not exist; this function is not required to do any IO, just
     * compute what the name would be.
     *
     * The passed-in filename has to be a complete name (with extension), not
     * just a basename. (Include statements in config files are allowed to give
     * just a basename.)
     *
     * @param filename
     *            the name to make relative to the resource doing the including
     * @return parseable item relative to the resource doing the including, or
     *         null
     */
    ConfigParseable relativeTo(String filename);

    /**
     * Parse options to use (if you use another method to get a
     * {@link ConfigParseable} then use {@link ConfigParseable#options()}
     * instead though).
     *
     * @return the parse options
     */
    ConfigParseOptions parseOptions();
}
