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src/java.base/share/classes/java/io/InputStream.java
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@@ -52,10 +52,103 @@
private static final int MAX_SKIP_BUFFER_SIZE = 2048;
private static final int DEFAULT_BUFFER_SIZE = 8192;
/**
+ * Returns a new {@code InputStream} that contains no bytes. The returned
+ * stream is initially open. The stream is closed by calling the
+ * {@code close()} method. Subsequent calls to {@code close()} have no
+ * effect.
+ *
+ * <p> While the stream is open, the {@code available()}, {@code read()},
+ * {@code read(byte[])}, {@code read(byte[], int, int)},
+ * {@code readAllBytes()}, {@code readNBytes()}, {@code skip()}, and
+ * {@code transferTo()} methods all behave as if end of stream has been
+ * reached. After the stream has been closed, these methods all throw
+ * {@code IOException}.
+ *
+ * <p> The {@code markSupported()} method returns {@code false}. The
+ * {@code mark()} method does nothing, and the {@code reset()} method
+ * throws {@code IOException}.
+ *
+ * @return an {@code InputStream} which contains no bytes
+ *
+ * @since 10
+ */
+ public static InputStream nullStream() {
+ return new InputStream() {
+ private volatile boolean closed;
+
+ private void ensureOpen() throws IOException {
+ if (closed) {
+ throw new IOException("Stream closed");
+ }
+ }
+
+ @Override
+ public int available () throws IOException {
+ ensureOpen();
+ return 0;
+ }
+
+ @Override
+ public int read() throws IOException {
+ ensureOpen();
+ return -1;
+ }
+
+ @Override
+ public int read(byte[] b, int off, int len) throws IOException {
+ Objects.requireNonNull(b);
+ Objects.checkFromIndexSize(off, len, b.length);
+ if (len == 0) {
+ return 0;
+ }
+ ensureOpen();
+ return -1;
+ }
+
+ @Override
+ // overridden for efficiency
+ public byte[] readAllBytes() throws IOException {
+ ensureOpen();
+ return new byte[0];
+ }
+
+ @Override
+ // overridden for efficiency
+ public int readNBytes(byte[] b, int off, int len)
+ throws IOException {
+ Objects.requireNonNull(b);
+ Objects.checkFromIndexSize(off, len, b.length);
+ ensureOpen();
+ return 0;
+ }
+
+ @Override
+ // overridden for efficiency
+ public long skip(long n) throws IOException {
+ ensureOpen();
+ return 0L;
+ }
+
+ @Override
+ // overridden for efficiency
+ public long transferTo(OutputStream out) throws IOException {
+ Objects.requireNonNull(out);
+ ensureOpen();
+ return 0L;
+ }
+
+ @Override
+ public void close() throws IOException {
+ closed = true;
+ }
+ };
+ }
+
+ /**
* Reads the next byte of data from the input stream. The value byte is
* returned as an <code>int</code> in the range <code>0</code> to
* <code>255</code>. If no byte is available because the end of the stream
* has been reached, the value <code>-1</code> is returned. This method
* blocks until input data is available, the end of the stream is detected,
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