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 * Copyright (c) 2018, 2020, 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
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package jdk.internal.util;

import java.util.Properties;

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  System#setProperty) or System.getProperties() is ignored. 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.
/**
 * 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;
    private static final String USER_HOME;
    private static final String USER_DIR;
    private static final String USER_NAME;
    private static final String JAVA_LIBRARY_PATH;
    private static final String SUN_BOOT_LIBRARY_PATH;
    private static final String JDK_SERIAL_FILTER;
    private static final String JAVA_IO_TMPDIR;

    private StaticProperty() {}

    static {
        Properties props = System.getProperties();
        JAVA_HOME = getProperty(props, "java.home");
        USER_HOME = getProperty(props, "user.home");
        USER_DIR  = getProperty(props, "user.dir");
        USER_NAME = getProperty(props, "user.name");
        JAVA_IO_TMPDIR = getProperty(props, "java.io.tmpdir");
        JAVA_LIBRARY_PATH = getProperty(props, "java.library.path", "");
        SUN_BOOT_LIBRARY_PATH = getProperty(props, "sun.boot.library.path", "");
        JDK_SERIAL_FILTER = getProperty(props, "jdk.serialFilter", null);
    }

    private static String getProperty(Properties props, String key) {
        String v = props.getProperty(key);
        if (v == null) {
            throw new InternalError("null property: " + key);
        }
        return v;
    }

    private static String getProperty(Properties props, String key,
                                      String defaultVal) {
        String v = props.getProperty(key);
        return (v == null) ? defaultVal : v;
    }

    
Return the java.home system property. 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.
Returns:
the java.home system property/**
     * 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 user.home system property. 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.
Returns:
the user.home system property/**
     * 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 user.dir system property. 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.
Returns:
the user.dir system property/**
     * 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 user.name system property. 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.
Returns:
the user.name system property/**
     * 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;
    }

    
Return the java.library.path system property. 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.
Returns:
the java.library.path system property/**
     * Return the {@code java.library.path} 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.library.path} system property
     */
    public static String javaLibraryPath() {
        return JAVA_LIBRARY_PATH;
    }

    
Return the java.io.tmpdir system property. 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.
Returns:
the java.io.tmpdir system property/**
     * Return the {@code java.io.tmpdir} 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.io.tmpdir} system property
     */
    public static String javaIoTmpDir() {
        return JAVA_IO_TMPDIR;
    }

    
Return the sun.boot.library.path system property. 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.
Returns:
the sun.boot.library.path system property/**
     * Return the {@code sun.boot.library.path} 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 sun.boot.library.path} system property
     */
    public static String sunBootLibraryPath() {
        return SUN_BOOT_LIBRARY_PATH;
    }


    
Return the jdk.serialFilter system property. 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.
Returns:
the user.name system property/**
     * Return the {@code jdk.serialFilter} 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 jdkSerialFilter() {
        return JDK_SERIAL_FILTER;
    }
}