001/*
002 * jPOS Project [http://jpos.org]
003 * Copyright (C) 2000-2026 jPOS Software SRL
004 *
005 * This program is free software: you can redistribute it and/or modify
006 * it under the terms of the GNU Affero General Public License as
007 * published by the Free Software Foundation, either version 3 of the
008 * License, or (at your option) any later version.
009 *
010 * This program is distributed in the hope that it will be useful,
011 * but WITHOUT ANY WARRANTY; without even the implied warranty of
012 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
013 * GNU Affero General Public License for more details.
014 *
015 * You should have received a copy of the GNU Affero General Public License
016 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
017 */
018
019package org.jpos.core;
020
021/** Provides environment variable values to the {@link org.jpos.core.Environment} resolver. */
022public interface EnvironmentProvider {
023    /**
024     * Returns the prefix identifying this provider.
025     * @return the prefix string (e.g. {@code "vault"}, {@code "env"})
026     */
027    String prefix();
028
029    /**
030     * Resolves the given configuration key using this provider.
031     * @param config the configuration key to resolve
032     * @return the resolved value, or null if not found
033     */
034    String get (String config);
035}