Reducing duplicate code in MRJAR using VersionSpecifics class

Signed-off-by: Markus KARG <markus@headcrashing.eu>

src/main/java/org/codehaus/plexus/util/CommonImplementation.java

@@ -0,0 +1,29 @@
+package org.codehaus.plexus.util;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.Reader;
+import java.io.Writer;
+
+/**
+ * Fallback implementation for all Java SE versions not
+ * overwriting a method version-specifically.
+ */
+abstract class CommonImplementation
+{
+    private static final int DEFAULT_BUFFER_SIZE = 1024 * 16;
+
+    void copy( final InputStream input, final OutputStream output )
+        throws IOException
+    {
+        IOUtil.copy( input, output, DEFAULT_BUFFER_SIZE );
+    }
+
+    void copy( final Reader input, final Writer output )
+        throws IOException
+    {
+        IOUtil.copy( input, output, DEFAULT_BUFFER_SIZE );
+    }
+
+}

src/main/java/org/codehaus/plexus/util/IOUtil.java

@@ -156,7 +156,7 @@ private IOUtil()
     public static void copy( final InputStream input, final OutputStream output )
         throws IOException
     {
-        copy( input, output, DEFAULT_BUFFER_SIZE );
+        VersionSpecifics.INSTANCE.copy( input, output );
     }
 
     /**
@@ -186,7 +186,7 @@ public static void copy( final InputStream input, final OutputStream output, fin
     public static void copy( final Reader input, final Writer output )
         throws IOException
     {
-        copy( input, output, DEFAULT_BUFFER_SIZE );
+        VersionSpecifics.INSTANCE.copy( input, output );
     }
 
     /**

src/main/java/org/codehaus/plexus/util/VersionSpecifics.java

@@ -0,0 +1,13 @@
+package org.codehaus.plexus.util;
+
+/**
+ * Implementation specific to Java SE 8 version.
+ */
+final class VersionSpecifics extends CommonImplementation
+{
+    static final VersionSpecifics INSTANCE = new VersionSpecifics();
+
+    private VersionSpecifics() {
+        // singleton
+    }
+}