/*

 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.internal.util;

/**

 * System Property access for internal use only.

 * Read-only access to System property values initialized during Phase 1

 * are cached.  Setting, clearing, or modifying the value using

 * {@link System#setProperty) or {@link System#getProperties()} is ignored.

 * <strong>{@link SecurityManager#checkPropertyAccess} is NOT checked

 * in these access methods. The caller of these methods should take care to ensure

 * that the returned property is not made accessible to untrusted code.</strong>

 */

public final class StaticProperty {

    // The class static initialization is triggered to initialize these final

    // fields during init Phase 1 and before a security manager is set.

    private static final String JAVA_HOME = initProperty("java.home");

    private static final String USER_HOME = initProperty("user.home");

    private static final String USER_DIR  = initProperty("user.dir");

    private static final String USER_NAME = initProperty("user.name");

    private StaticProperty() {}

    private static String initProperty(String key) {

        String v = System.getProperty(key);

        if (v == null) {

            throw new InternalError("null property: " + key);

        }

        return v;

    }

    /**

     * Return the {@code java.home} system property.

     *

     * <strong>{@link SecurityManager#checkPropertyAccess} is NOT checked

     * in this method. The caller of this method should take care to ensure

     * that the returned property is not made accessible to untrusted code.</strong>

     *

     * @return the {@code java.home} system property

     */

    public static String javaHome() {

        return JAVA_HOME;

    }

    /**

     * Return the {@code user.home} system property.

     *

     * <strong>{@link SecurityManager#checkPropertyAccess} is NOT checked

     * in this method. The caller of this method should take care to ensure

     * that the returned property is not made accessible to untrusted code.</strong>

     *

     * @return the {@code user.home} system property

     */

    public static String userHome() {

        return USER_HOME;

    }

    /**

     * Return the {@code user.dir} system property.

     *

     * <strong>{@link SecurityManager#checkPropertyAccess} is NOT checked

     * in this method. The caller of this method should take care to ensure

     * that the returned property is not made accessible to untrusted code.</strong>

     *

     * @return the {@code user.dir} system property

     */

    public static String userDir() {

        return USER_DIR;

    }

    /**

     * Return the {@code user.name} system property.

     *

     * <strong>{@link SecurityManager#checkPropertyAccess} is NOT checked

     * in this method. The caller of this method should take care to ensure

     * that the returned property is not made accessible to untrusted code.</strong>

     *

     * @return the {@code user.name} system property

     */

    public static String userName() {

        return USER_NAME;

    }

}