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Java example source code file (CustomOptions.java)

This example Java source code file (CustomOptions.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

customoptions, fileattribute, ignore, ioexception, map, mycustomprovider, net, network, nullpointerexception, openoption, path, runtimeexception, seekablebytechannel, set, unsupportedoperationexception, uri, util

The CustomOptions.java Java example source code

/*
 * Copyright (c) 2011, 2012, 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.
 *
 * 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.
 */

/*
 * @test
 * @bug     7087549
 * @summary Test custom options with newInputStream.
 * @author  Brandon Passanisi
 * @library ..
 * @build   CustomOptions PassThroughFileSystem
 * @run main CustomOptions
 */

import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.nio.file.*;
import java.nio.file.attribute.FileAttribute;
import java.nio.file.spi.FileSystemProvider;
import java.nio.channels.SeekableByteChannel;
import java.util.Collections;
import java.util.Set;
import java.util.Map;

public class CustomOptions {

    // Create a custom option
    static enum CustomOption implements OpenOption {
        IGNORE,
    }

    // number of times that IGNORE option is observed
    static int ignoreCount;

    // A pass through provider that supports a custom open option
    static class MyCustomProvider extends PassThroughFileSystem.PassThroughProvider {
        public MyCustomProvider() { }

        @Override
        public SeekableByteChannel newByteChannel(Path path,
                                                  Set<? extends OpenOption> options,
                                                  FileAttribute<?>... attrs)
            throws IOException
        {
            if (options.contains(CustomOption.IGNORE)) {
                ignoreCount++;
                options.remove(CustomOption.IGNORE);
            }
            return super.newByteChannel(path, options, attrs);
        }
    }

    public static void main(String[] args) throws Exception {
        FileSystemProvider provider = new MyCustomProvider();
        Map<String,?> env = Collections.emptyMap();
        URI uri = URI.create("pass:///");
        FileSystem fs = provider.newFileSystem(uri, env);

        // Create temp dir for testing
        Path dir = TestUtil.createTemporaryDirectory();
        try {

            // Create temp file for testing
            Path path = fs.getPath(dir.resolve("foo").toString());
            Files.createFile(path);

            // Test custom option
            Files.newInputStream(path, CustomOption.IGNORE).close();
            if (ignoreCount != 1)
                throw new RuntimeException("IGNORE option not passed through");

            // Test null option
            try {
                Files.newInputStream(path, new OpenOption[] { null }).close();
                throw new RuntimeException("NullPointerException expected");
            } catch (NullPointerException ignore) { }

            // Test unsupported options
            try {
                Files.newInputStream(path, StandardOpenOption.WRITE).close();
                throw new RuntimeException("UnsupportedOperationException expected");
            } catch (UnsupportedOperationException uoe) { }
            try {
                Files.newInputStream(path, StandardOpenOption.APPEND).close();
                throw new RuntimeException("UnsupportedOperationException expected");
            } catch (UnsupportedOperationException uoe) { }

        } finally {
            // Cleanup
            TestUtil.removeAll(dir);
        }
    }
}

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