src/java.base/share/classes/jdk/internal/util/StaticProperty.java

/*
 * Copyright (c) 2018, 2024, 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
 * {@link System#setProperty} or {@link System#getProperties()} is ignored.
 */
public final class StaticProperty {

    // The class static initialization is triggered to initialize these final
    // fields during init Phase 1.
    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 JDK_SERIAL_FILTER_FACTORY;
    private static final String JAVA_IO_TMPDIR;
    private static final String NATIVE_ENCODING;
    private static final String FILE_ENCODING;
    private static final String JAVA_PROPERTIES_DATE;
    private static final String SUN_JNU_ENCODING;
    private static final String JAVA_LOCALE_USE_OLD_ISO_CODES;
    private static final String OS_NAME;
    private static final String OS_ARCH;
    private static final String OS_VERSION;
    public static final String USER_LANGUAGE;
    public static final String USER_LANGUAGE_DISPLAY;
    public static final String USER_LANGUAGE_FORMAT;
    public static final String USER_SCRIPT;
    public static final String USER_SCRIPT_DISPLAY;
    public static final String USER_SCRIPT_FORMAT;
    public static final String USER_COUNTRY;
    public static final String USER_COUNTRY_DISPLAY;
    public static final String USER_COUNTRY_FORMAT;
    public static final String USER_VARIANT;
    public static final String USER_VARIANT_DISPLAY;
    public static final String USER_VARIANT_FORMAT;
    public static final String USER_EXTENSIONS;
    public static final String USER_EXTENSIONS_DISPLAY;
    public static final String USER_EXTENSIONS_FORMAT;
    public static final String USER_REGION;

    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);
        JDK_SERIAL_FILTER_FACTORY = getProperty(props, "jdk.serialFilterFactory", null);
        NATIVE_ENCODING = getProperty(props, "native.encoding");
        FILE_ENCODING = getProperty(props, "file.encoding");
        JAVA_PROPERTIES_DATE = getProperty(props, "java.properties.date", null);
        SUN_JNU_ENCODING = getProperty(props, "sun.jnu.encoding");
        JAVA_LOCALE_USE_OLD_ISO_CODES = getProperty(props, "java.locale.useOldISOCodes", "");
        OS_NAME = getProperty(props, "os.name");
        OS_ARCH = getProperty(props, "os.arch");
        OS_VERSION = getProperty(props, "os.version");
        USER_LANGUAGE = getProperty(props, "user.language", "en");
        USER_LANGUAGE_DISPLAY = getProperty(props, "user.language.display", USER_LANGUAGE);
        USER_LANGUAGE_FORMAT = getProperty(props, "user.language.format", USER_LANGUAGE);
        // for compatibility, check for old user.region property
        USER_REGION = getProperty(props, "user.region", "");
        if (!USER_REGION.isEmpty()) {
            // region can be of form country, country_variant, or _variant
            int i = USER_REGION.indexOf('_');
            if (i >= 0) {
                USER_COUNTRY = USER_REGION.substring(0, i);
                USER_VARIANT = USER_REGION.substring(i + 1);
            } else {
                USER_COUNTRY = USER_REGION;
                USER_VARIANT = "";
            }
            USER_SCRIPT = "";
        } else {
            USER_SCRIPT = getProperty(props, "user.script", "");
            USER_COUNTRY = getProperty(props, "user.country", "");
            USER_VARIANT = getProperty(props, "user.variant", "");
        }
        USER_SCRIPT_DISPLAY = getProperty(props, "user.script.display", USER_SCRIPT);
        USER_SCRIPT_FORMAT = getProperty(props, "user.script.format", USER_SCRIPT);
        USER_COUNTRY_DISPLAY = getProperty(props, "user.country.display", USER_COUNTRY);
        USER_COUNTRY_FORMAT = getProperty(props, "user.country.format", USER_COUNTRY);
        USER_VARIANT_DISPLAY = getProperty(props, "user.variant.display", USER_VARIANT);
        USER_VARIANT_FORMAT = getProperty(props, "user.variant.format", USER_VARIANT);
        USER_EXTENSIONS = getProperty(props, "user.extensions", "");
        USER_EXTENSIONS_DISPLAY = getProperty(props, "user.extensions.display", USER_EXTENSIONS);
        USER_EXTENSIONS_FORMAT = getProperty(props, "user.extensions.format", USER_EXTENSIONS);
    }

    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 {@code java.home} system property}
     */
    public static String javaHome() {
        return JAVA_HOME;
    }

    /**
     * {@return the {@code user.home} system property}
     */
    public static String userHome() {
        return USER_HOME;
    }

    /**
     * {@return the {@code user.dir} system property}
     */
    public static String userDir() {
        return USER_DIR;
    }

    /**
     * {@return the {@code user.name} system property}
     */
    public static String userName() {
        return USER_NAME;
    }

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

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

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


    /**
     * {@return the {@code jdk.serialFilter} system property}
     */
    public static String jdkSerialFilter() {
        return JDK_SERIAL_FILTER;
    }


    /**
     * {@return the {@code jdk.serialFilterFactory} system property}
     */
    public static String jdkSerialFilterFactory() {
        return JDK_SERIAL_FILTER_FACTORY;
    }

    /**
     * {@return the {@code native.encoding} system property}
     */
    public static String nativeEncoding() {
        return NATIVE_ENCODING;
    }

    /**
     * {@return the {@code file.encoding} system property}
     */
    public static String fileEncoding() {
        return FILE_ENCODING;
    }

    /**
     * {@return the {@code java.properties.date} system property}
     */
    public static String javaPropertiesDate() {
        return JAVA_PROPERTIES_DATE;
    }

    /**
     * {@return the {@code sun.jnu.encoding} system property}
     */
    public static String jnuEncoding() {
        return SUN_JNU_ENCODING;
    }

    /**
     * {@return the {@code java.locale.useOldISOCodes} system property}
     */
    public static String javaLocaleUseOldISOCodes() {
        return JAVA_LOCALE_USE_OLD_ISO_CODES;
    }

     /**
      * {@return the {@code os.name} system property}
      */
     public static String osName() {
         return OS_NAME;
     }

     /**
      * {@return the {@code os.arch} system property}
      */
     public static String osArch() {
         return OS_ARCH;
     }

     /**
      * {@return the {@code os.version} system property}
      */
     public static String osVersion() {
         return OS_VERSION;
     }
}