src/java.base/share/classes/java/io/InputStream.java

rev 48211 : imported patch 4358774-nullISAndOS.01
rev 48210 : 4358774: Add null InputStream and OutputStream
Reviewed-by: reinhapa
rev 47920 : 8191516: OutputStream.write(byte[],int,int) could have fewer parameter bounds checks
Summary: Reduce parameter bounds checks from five to three as in InputStream::read
Reviewed-by: psandoz
rev 47216 : 8187443: Forest Consolidation: Move files to unified layout
Reviewed-by: darcy, ihse

*** 52,61 ****
--- 52,162 ----
      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 {
+                 if (b == null) {
+                     throw new NullPointerException();
+                 } else if (off < 0 || len < 0 || len > b.length - off) {
+                     throw new IndexOutOfBoundsException();
+                 }
+                 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 {
+                 if (b == null) {
+                     throw new NullPointerException();
+                 } else if (off < 0 || len < 0 || len > b.length - off) {
+                     throw new IndexOutOfBoundsException();
+                 }
+                 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 {
+                 if (out == null) {
+                     throw new NullPointerException();
+                 }
+                 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,