src/java.base/share/classes/sun/nio/fs/ExtendedOptions.java - master - githubmirror/jdk22

src/java.base/share/classes/sun/nio/fs/ExtendedOptions.java
145 строк5 KB
Lucy Lu
8164900: Add support for O_DIRECT
18 окт 2017, 02:51
18 окт 2017, 02:51ec1c3bc
/*
 * Copyright (c) 2016, 2017, 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 sun.nio.fs;

import java.nio.file.CopyOption;
import java.nio.file.OpenOption;
import java.nio.file.WatchEvent;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * Provides support for handling JDK-specific OpenOption, CopyOption and
 * WatchEvent.Modifier types.
 */

public final class ExtendedOptions {

    // maps InternalOption to ExternalOption
    private static final Map<InternalOption<?>, Wrapper<?>> internalToExternal
        = new ConcurrentHashMap<>();

    /**
     * Wraps an option or modifier.
     */
    private static final class Wrapper<T> {
        private final Object option;
        private final T param;

        Wrapper(Object option, T param) {
            this.option = option;
            this.param = param;
        }

        T parameter() {
            return param;
        }
    }

    /**
     * The internal version of a JDK-specific OpenOption, CopyOption or
     * WatchEvent.Modifier.
     */
    public static final class InternalOption<T> {

        InternalOption() { }

        private void registerInternal(Object option, T param) {
            Wrapper<T> wrapper = new Wrapper<T>(option, param);
            internalToExternal.put(this, wrapper);
        }

        /**
         * Register this internal option as a OpenOption.
         */
        public void register(OpenOption option) {
            registerInternal(option, null);
        }

        /**
         * Register this internal option as a CopyOption.
         */
        public void register(CopyOption option) {
            registerInternal(option, null);
        }

        /**
         * Register this internal option as a WatchEvent.Modifier.
         */
        public void register(WatchEvent.Modifier option) {
            registerInternal(option, null);
        }

        /**
         * Register this internal option as a WatchEvent.Modifier with the
         * given parameter.
         */
        public void register(WatchEvent.Modifier option, T param) {
            registerInternal(option, param);
        }

        /**
         * Returns true if the given option (or modifier) maps to this internal
         * option.
         */
        public boolean matches(Object option) {
            Wrapper <?> wrapper = internalToExternal.get(this);
            if (wrapper == null)
                return false;
            else
                return option == wrapper.option;
        }

        /**
         * Returns the parameter object associated with this internal option.
         */
        @SuppressWarnings("unchecked")
        public T parameter() {
            Wrapper<?> wrapper = internalToExternal.get(this);
            if (wrapper == null)
                return null;
            else
                return (T) wrapper.parameter();
        }
    }

    // Internal equivalents of the options and modifiers defined in
    // package com.sun.nio.file

    public static final InternalOption<Void> INTERRUPTIBLE = new InternalOption<>();

    public static final InternalOption<Void> NOSHARE_READ = new InternalOption<>();
    public static final InternalOption<Void> NOSHARE_WRITE = new InternalOption<>();
    public static final InternalOption<Void> NOSHARE_DELETE = new InternalOption<>();

    public static final InternalOption<Void> FILE_TREE = new InternalOption<>();

    public static final InternalOption<Void> DIRECT = new InternalOption<>();

    public static final InternalOption<Integer> SENSITIVITY_HIGH = new InternalOption<>();
    public static final InternalOption<Integer> SENSITIVITY_MEDIUM = new InternalOption<>();
    public static final InternalOption<Integer> SENSITIVITY_LOW = new InternalOption<>();
}