ClosedOutputStream.write(byte[], int, int) does not always throw

IOException

Author: garydgregory

src/changes/changes.xml

@@ -87,6 +87,7 @@ The <action> type attribute can be add,update,fix,remove.
       <action dev="ggregory" type="fix" due-to="Gary Gregory">Let subclasses of CountingInputStream.afterRead(int) throw IOException.</action>
       <action dev="ggregory" type="fix" issue="IO-807" due-to="Elliotte Rusty Harold, Gary Gregory">Characterization test for broken symlinks when copying directories #547.</action>
       <action dev="ggregory" type="fix" due-to="Gary Gregory">ClosedInputStream.read(byte[], int, int) does not always return -1.</action>
+      <action dev="ggregory" type="fix" due-to="Gary Gregory">ClosedOutputStream.write(byte[], int, int) does not always throw IOException.</action>
       <!-- Add -->
       <action dev="ggregory" type="add"                due-to="Gary Gregory">Add and use PathUtils.getFileName(Path, Function&lt;Path, R&gt;).</action>
       <action dev="ggregory" type="add"                due-to="Gary Gregory">Add and use PathUtils.getFileNameString().</action>

src/main/java/org/apache/commons/io/output/ClosedOutputStream.java

@@ -22,8 +22,8 @@
 /**
  * Throws an IOException on all attempts to write to the stream.
  * <p>
- * Typically uses of this class include testing for corner cases in methods that accept an output stream and acting as a
- * sentinel value instead of a {@code null} output stream.
+ * Typically uses of this class include testing for corner cases in methods that accept an output stream and acting as a sentinel value instead of a
+ * {@code null} output stream.
  * </p>
  *
  * @since 1.4
@@ -55,6 +55,19 @@ public void flush() throws IOException {
         throw new IOException("flush() failed: stream is closed");
     }
 
+    /**
+     * Throws an {@link IOException} to indicate that the stream is closed.
+     *
+     * @param b   ignored
+     * @param off ignored
+     * @param len ignored
+     * @throws IOException always thrown
+     */
+    @Override
+    public void write(final byte b[], final int off, final int len) throws IOException {
+        throw new IOException("write(byte[], int, int) failed: stream is closed");
+    }
+
     /**
      * Throws an {@link IOException} to indicate that the stream is closed.
      *
@@ -63,6 +76,6 @@ public void flush() throws IOException {
      */
     @Override
     public void write(final int b) throws IOException {
-        throw new IOException("write(" + b + ") failed: stream is closed");
+        throw new IOException("write(int) failed: stream is closed");
     }
 }

src/test/java/org/apache/commons/io/output/ClosedOutputStreamTest.java

@@ -33,7 +33,18 @@ public class ClosedOutputStreamTest {
     @Test
     public void testFlush() throws IOException {
         try (ClosedOutputStream cos = new ClosedOutputStream()) {
-            assertThrows(IOException.class, () -> cos.flush());
+            assertThrows(IOException.class, cos::flush);
+        }
+    }
+
+    @Test
+    public void testSingleton() throws IOException {
+        try (@SuppressWarnings("deprecation")
+        ClosedOutputStream cos = ClosedOutputStream.CLOSED_OUTPUT_STREAM) {
+            assertThrows(IOException.class, cos::flush);
+        }
+        try (ClosedOutputStream cos = ClosedOutputStream.INSTANCE) {
+            assertThrows(IOException.class, cos::flush);
         }
     }
 
@@ -47,4 +58,20 @@ public void testWrite() throws IOException {
         }
     }
 
+    @Test
+    public void testWriteArray() throws IOException {
+        try (ClosedOutputStream cos = new ClosedOutputStream()) {
+            assertThrows(IOException.class, () -> cos.write(new byte[0]));
+            assertThrows(IOException.class, () -> cos.write(new byte[10]));
+        }
+    }
+
+    @Test
+    public void testWriteArrayIndex() throws IOException {
+        try (ClosedOutputStream cos = new ClosedOutputStream()) {
+            assertThrows(IOException.class, () -> cos.write(new byte[0], 0, 0));
+            assertThrows(IOException.class, () -> cos.write(new byte[10], 0, 1));
+        }
+    }
+
 }