Added FileUtils.copy with callback for written bytes

aksw-commons-io-parent/aksw-commons-io-utils/src/main/java/org/aksw/commons/io/util/FileUtils.java

@@ -1,6 +1,7 @@
 package org.aksw.commons.io.util;
 
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.io.OutputStream;
@@ -26,6 +27,7 @@
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.function.Consumer;
 import java.util.function.Function;
+import java.util.function.IntConsumer;
 import java.util.stream.Stream;
 
 import org.aksw.commons.lambda.throwing.ThrowingConsumer;
@@ -424,4 +426,28 @@ protected static void copyDirectoryInternal(Path source, Path target, CopyOption
             }
         }
     }
+
+    // Adaption of Files.copy and InputStream.transfer to with progress tracking
+
+    private static final int DEFAULT_BUFFER_SIZE = 8192;
+
+    public static long copy(Path source, OutputStream out, IntConsumer contribCallback) throws IOException {
+        Objects.requireNonNull(out);
+        try (InputStream in = Files.newInputStream(source)) {
+            return transferTo(out, in, contribCallback);
+        }
+    }
+
+    public static long transferTo(OutputStream out, InputStream in, IntConsumer contribCallback) throws IOException {
+        Objects.requireNonNull(out, "out");
+        long transferred = 0;
+        byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
+        int read;
+        while ((read = in.read(buffer, 0, DEFAULT_BUFFER_SIZE)) >= 0) {
+            out.write(buffer, 0, read);
+            transferred += read;
+            contribCallback.accept(read);
+        }
+        return transferred;
+    }
 }