java-topology/test/jdk/java/nio/channels/Channels/TransferTo.java

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import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.channels.Channels;
import java.nio.channels.FileChannel;
import java.nio.channels.IllegalBlockingModeException;
import java.nio.channels.Pipe;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.SelectableChannel;
import java.nio.channels.WritableByteChannel;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.stream.Stream;

import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.Arguments;
import org.junit.jupiter.params.provider.MethodSource;

import static org.junit.jupiter.api.Assertions.assertThrows;

/*
 * @test
 * @library /test/lib
 * @build jdk.test.lib.RandomFactory
 * @run junit/othervm/timeout=720 TransferTo
 * @bug 8265891
 * @summary Tests whether sun.nio.ChannelInputStream.transferTo conforms to the
 *          InputStream.transferTo specification
 * @key randomness
 */
public class TransferTo extends TransferToBase {

    /*
     * Provides test scenarios, i.e., combinations of input and output streams
     * to be tested.
     */
    public static Stream<Arguments> streamCombinations() {
        return Stream.of
            (// tests FileChannel.transferTo(FileChannel) optimized case
             Arguments.of(fileChannelInput(), fileChannelOutput()),

             // tests FileChannel.transferTo(SelectableChannelOutput)
             // optimized case
             Arguments.of(fileChannelInput(), selectableChannelOutput()),

             // tests FileChannel.transferTo(WritableByteChannelOutput)
             // optimized case
             Arguments.of(fileChannelInput(), writableByteChannelOutput()),

             // tests InputStream.transferTo(OutputStream) default case
             Arguments.of(readableByteChannelInput(), defaultOutput()));
    }

    /*
     * Input streams to be tested.
     */
    public static Stream<Arguments> inputStreamProviders() {
        return Stream.of(Arguments.of(fileChannelInput()),
                         Arguments.of(readableByteChannelInput()));
    }

    /*
     * Testing API compliance: input stream must throw NullPointerException
     * when parameter "out" is null.
     */
    @ParameterizedTest
    @MethodSource("inputStreamProviders")
    public void testNullPointerException(InputStreamProvider inputStreamProvider) {
        assertNullPointerException(inputStreamProvider);
    }

    /*
     * Testing API compliance: complete content of input stream must be
     * transferred to output stream.
     */
    @ParameterizedTest
    @MethodSource("streamCombinations")
    public void testStreamContents(InputStreamProvider inputStreamProvider,
            OutputStreamProvider outputStreamProvider) throws Exception {
        assertStreamContents(inputStreamProvider, outputStreamProvider);
    }

    /*
     * Special test whether selectable channel based transfer throws blocking mode exception.
     */
    @Test
    public void testIllegalBlockingMode() throws IOException {
        Pipe pipe = Pipe.open();
        try {
            // testing arbitrary input (here: empty file) to non-blocking
            // selectable output
            try (FileChannel fc = FileChannel.open(Files.createTempFile(CWD, "testIllegalBlockingMode", null));
                InputStream is = Channels.newInputStream(fc);
                SelectableChannel sc = pipe.sink().configureBlocking(false);
                OutputStream os = Channels.newOutputStream((WritableByteChannel) sc)) {

                // IllegalBlockingMode must be thrown when trying to perform
                // a transfer
                assertThrows(IllegalBlockingModeException.class, () -> is.transferTo(os));
            }

            // testing non-blocking selectable input to arbitrary output
            // (here: byte array)
            try (SelectableChannel sc = pipe.source().configureBlocking(false);
                InputStream is = Channels.newInputStream((ReadableByteChannel) sc);
                OutputStream os = new ByteArrayOutputStream()) {

                // IllegalBlockingMode must be thrown when trying to perform
                // a transfer
                assertThrows(IllegalBlockingModeException.class, () -> is.transferTo(os));
            }
        } finally {
            pipe.source().close();
            pipe.sink().close();
        }
    }

    /*
     * Creates a provider for an output stream which does not wrap a channel
     */
    private static OutputStreamProvider defaultOutput() {
        return spy -> {
            ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
            spy.accept(outputStream::toByteArray);
            return outputStream;
        };
    }

    /*
     * Creates a provider for an input stream which wraps a file channel
     */
    private static InputStreamProvider fileChannelInput() {
        return bytes -> {
            Path path = Files.createTempFile(CWD, "fileChannelInput", null);
            Files.write(path, bytes);
            FileChannel fileChannel = FileChannel.open(path);
            return Channels.newInputStream(fileChannel);
        };
    }

    /*
     * Creates a provider for an output stream which wraps a selectable channel
     */
    private static OutputStreamProvider selectableChannelOutput() {
        return spy -> {
            Pipe pipe = Pipe.open();
            Future<byte[]> bytes = CompletableFuture.supplyAsync(() -> {
                try {
                    InputStream is = Channels.newInputStream(pipe.source());
                    return is.readAllBytes();
                } catch (IOException e) {
                    throw new AssertionError("Exception while asserting content", e);
                }
            });
            final OutputStream os = Channels.newOutputStream(pipe.sink());
            spy.accept(() -> {
                try {
                    os.close();
                    return bytes.get();
                } catch (IOException | InterruptedException | ExecutionException e) {
                    throw new AssertionError("Exception while asserting content", e);
                }
            });
            return os;
        };
    }

    /*
     * Creates a provider for an output stream which wraps a writable byte channel but is not a file channel
     */
    private static OutputStreamProvider writableByteChannelOutput() {
        return spy -> {
            ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
            spy.accept(outputStream::toByteArray);
            return Channels.newOutputStream(Channels.newChannel(outputStream));
        };
    }

}