[IO-353] Add API IOUtils.copy(InputStream, OutputStream, int).

garydgregory · garydgregory · commit 03027d8ff289 · 2012-10-25T19:15:57.000Z
git-svn-id: https://svn.apache.org/repos/asf/commons/proper/io/trunk@1402280 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/changes/changes.xml b/src/changes/changes.xml
@@ -47,6 +47,9 @@ The <action> type attribute can be add,update,fix,remove.
   <body>
     <!-- The release date is the date RC is cut -->
     <release version="2.5" date="201?-??-??" description="New features and bug fixes.">
+      <action issue="IO-353" dev="ggregory" type="add" due-to="ggregory">
+        Add API IOUtils.copy(InputStream, OutputStream, int)
+      </action>            
       <action issue="IO-349" dev="ggregory" type="add" due-to="scop">
         Add API with array offset and length argument to FileUtils.writeByteArrayToFile.
       </action>            
diff --git a/src/main/java/org/apache/commons/io/IOUtils.java b/src/main/java/org/apache/commons/io/IOUtils.java
@@ -1748,6 +1748,30 @@ public static int copy(InputStream input, OutputStream output) throws IOExceptio
         return (int) count;
     }
 
+    /**
+     * Copy bytes from an <code>InputStream</code> to an <code>OutputStream</code> using an internal buffer of the
+     * given size.
+     * <p>
+     * This method buffers the input internally, so there is no need to use a <code>BufferedInputStream</code>.
+     * <p>
+     * 
+     * @param input
+     *            the <code>InputStream</code> to read from
+     * @param output
+     *            the <code>OutputStream</code> to write to
+     * @param bufferSize
+     *            the bufferSize used to copy from the input to the output
+     * @return the number of bytes copied
+     * @throws NullPointerException
+     *             if the input or output is null
+     * @throws IOException
+     *             if an I/O error occurs
+     * @since 2.5
+     */
+    public static long copy(InputStream input, OutputStream output, int bufferSize) throws IOException {
+        return copyLarge(input, output, new byte[bufferSize]);
+    }
+
     /**
      * Copy bytes from a large (over 2GB) <code>InputStream</code> to an
      * <code>OutputStream</code>.
@@ -1766,7 +1790,7 @@ public static int copy(InputStream input, OutputStream output) throws IOExceptio
      */
     public static long copyLarge(InputStream input, OutputStream output)
             throws IOException {
-        return copyLarge(input, output, new byte[DEFAULT_BUFFER_SIZE]);
+        return copy(input, output, DEFAULT_BUFFER_SIZE);
     }
 
     /**
diff --git a/src/test/java/org/apache/commons/io/IOUtilsCopyTestCase.java b/src/test/java/org/apache/commons/io/IOUtilsCopyTestCase.java
@@ -86,6 +86,39 @@ public void testCopy_inputStreamToOutputStream() throws Exception {
         assertEquals(inData.length,count);
     }
 
+    public void testCopy_inputStreamToOutputStreamWithBufferSize() throws Exception {
+        testCopy_inputStreamToOutputStreamWithBufferSize(1);
+        testCopy_inputStreamToOutputStreamWithBufferSize(2);
+        testCopy_inputStreamToOutputStreamWithBufferSize(4);
+        testCopy_inputStreamToOutputStreamWithBufferSize(8);
+        testCopy_inputStreamToOutputStreamWithBufferSize(16);
+        testCopy_inputStreamToOutputStreamWithBufferSize(32);
+        testCopy_inputStreamToOutputStreamWithBufferSize(64);
+        testCopy_inputStreamToOutputStreamWithBufferSize(128);
+        testCopy_inputStreamToOutputStreamWithBufferSize(256);
+        testCopy_inputStreamToOutputStreamWithBufferSize(512);
+        testCopy_inputStreamToOutputStreamWithBufferSize(1024);
+        testCopy_inputStreamToOutputStreamWithBufferSize(2048);
+        testCopy_inputStreamToOutputStreamWithBufferSize(4096);
+        testCopy_inputStreamToOutputStreamWithBufferSize(8192);
+        testCopy_inputStreamToOutputStreamWithBufferSize(16384);
+    }
+
+    private void testCopy_inputStreamToOutputStreamWithBufferSize(int bufferSize) throws Exception {
+        InputStream in = new ByteArrayInputStream(inData);
+        in = new YellOnCloseInputStream(in);
+
+        ByteArrayOutputStream baout = new ByteArrayOutputStream();
+        OutputStream out = new YellOnFlushAndCloseOutputStream(baout, false, true);
+
+        long count = IOUtils.copy(in, out, bufferSize);
+        
+        assertEquals("Not all bytes were read", 0, in.available());
+        assertEquals("Sizes differ", inData.length, baout.size());
+        assertTrue("Content differs", Arrays.equals(inData, baout.toByteArray()));
+        assertEquals(inData.length,count);
+    }
+
     public void testCopy_inputStreamToOutputStream_nullIn() throws Exception {
         OutputStream out = new ByteArrayOutputStream();
         try {
