1 files changed, 66 insertions, 0 deletions
diff --git a/samples/src/jvmMain/java/okio/samples/FileChannelSink.java b/samples/src/jvmMain/java/okio/samples/FileChannelSink.java
new file mode 100644
index 00000000..b810a328
--- /dev/null
+++ b/samples/src/jvmMain/java/okio/samples/FileChannelSink.java
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2018 Square, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package okio.samples;
+
+import java.io.IOException;
+import java.nio.channels.FileChannel;
+import java.nio.channels.ReadableByteChannel;
+import okio.Buffer;
+import okio.Sink;
+import okio.Timeout;
+
+/**
+ * Special Sink for a FileChannel to take advantage of the
+ * {@link FileChannel#transferFrom(ReadableByteChannel, long, long) transfer} method available.
+ */
+final class FileChannelSink implements Sink {
+  private final FileChannel channel;
+  private final Timeout timeout;
+
+  private long position;
+
+  FileChannelSink(FileChannel channel, Timeout timeout) throws IOException {
+    this.channel = channel;
+    this.timeout = timeout;
+
+    this.position = channel.position();
+  }
+
+  @Override public void write(Buffer source, long byteCount) throws IOException {
+    if (!channel.isOpen()) throw new IllegalStateException("closed");
+    if (byteCount == 0) return;
+
+    long remaining = byteCount;
+    while (remaining > 0) {
+      long written = channel.transferFrom(source, position, remaining);
+      position += written;
+      remaining -= written;
+    }
+  }
+
+  @Override public void flush() throws IOException {
+    // Cannot alter meta data through this Sink
+    channel.force(false);
+  }
+
+  @Override public Timeout timeout() {
+    return timeout;
+  }
+
+  @Override public void close() throws IOException {
+    channel.close();
+  }
+}