Cast a ByteBuffer to a Buffer before calling flip. This fixes compili…

…ng to JDK 7 from JDK9+ compilers.

Details: plasma-umass/doppio#497

src/main/java/nl/cwi/monetdb/mcl/connection/helpers/BufferReallocator.java

@@ -8,6 +8,7 @@
 
 package nl.cwi.monetdb.mcl.connection.helpers;
 
+import java.nio.Buffer;
 import java.nio.CharBuffer;
 
 /**
@@ -56,7 +57,7 @@ private static int getNewCapacity(CharBuffer buffer) {
 	public static CharBuffer reallocateBuffer(CharBuffer buffer) {
 		int newCapacity = getNewCapacity(buffer);
 		CharBuffer newBuffer = CharBuffer.wrap(new char[newCapacity]);
-		buffer.flip();
+		((Buffer)buffer).flip();
 		newBuffer.put(buffer.array());
 		return newBuffer;
 	}

src/main/java/nl/cwi/monetdb/mcl/connection/mapi/AbstractSocket.java

@@ -14,6 +14,7 @@
 import java.io.IOException;
 import java.net.Socket;
 import java.net.SocketException;
+import java.nio.Buffer;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.nio.CharBuffer;
@@ -56,7 +57,7 @@ public abstract class AbstractSocket implements Closeable {
 		this.bufferIn = ByteBuffer.wrap(new byte[getFullBlockSize()]);
 		this.bufferOut = ByteBuffer.wrap(new byte[getFullBlockSize()]);
 		this.stringsDecoded = CharBuffer.allocate(getFullBlockSize());
-		this.stringsDecoded.flip();
+		((Buffer)this.stringsDecoded).flip();
 		this.stringsEncoded = CharBuffer.allocate(getFullBlockSize());
 	}
 
@@ -151,7 +152,7 @@ private void readToInputBuffer() throws IOException {
 		this.utf8Decoder.reset();
 		this.utf8Decoder.decode(this.bufferIn, this.stringsDecoded,true);
 		this.utf8Decoder.flush(this.stringsDecoded);
-		this.stringsDecoded.flip();
+		((Buffer)this.stringsDecoded).flip();
 	}
 
 	/**
@@ -193,7 +194,7 @@ public CharBuffer readLine(CharBuffer lineBuffer) throws IOException {
 		}
 		this.stringsDecoded.position(sourcePosition);
 		lineBuffer.position(destinationPosition);
-		lineBuffer.flip();
+		((Buffer)lineBuffer).flip();
 		return lineBuffer;
 	}
 
@@ -204,7 +205,7 @@ public CharBuffer readLine(CharBuffer lineBuffer) throws IOException {
 	 * @throws IOException If an error in the underlying connection happened
 	 */
 	private void writeToOutputBuffer(boolean toFlush) throws IOException {
-		this.stringsEncoded.flip();
+		((Buffer)this.stringsEncoded).flip();
 		this.utf8Encoder.reset();
 		CoderResult res;
 		int written = 0;

src/main/java/nl/cwi/monetdb/mcl/connection/mapi/OldMapiSocket.java

@@ -11,6 +11,7 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.nio.Buffer;
 import java.nio.ByteBuffer;
 
 /**
@@ -241,7 +242,7 @@ public int read(ByteBuffer b, int off, int len) throws IOException {
 						connection.getPort() + ": Incomplete block read from stream");
 			}
 			b.position(size);
-			b.flip();
+			((Buffer)b).flip();
 			return size;
 		}
 

src/main/java/nl/cwi/monetdb/mcl/protocol/oldmapi/OldMapiProtocol.java

@@ -20,6 +20,7 @@
 import nl.cwi.monetdb.mcl.responses.UpdateResponse;
 
 import java.io.IOException;
+import java.nio.Buffer;
 import java.nio.CharBuffer;
 import java.text.SimpleDateFormat;
 import java.util.Map;
@@ -126,7 +127,7 @@ public void fetchNextResponseData() throws IOException {
 			newbuffer.put("!22000");
 			newbuffer.put(this.lineBuffer.array(), 0, limit);
 			newbuffer.limit(limit + 6);
-			newbuffer.flip();
+			((Buffer)newbuffer).flip();
 			this.lineBuffer = newbuffer;
 		}
 		this.lineBuffer.position(1);

src/main/java/nl/cwi/monetdb/mcl/protocol/oldmapi/OldMapiTupleLineParser.java

@@ -16,6 +16,7 @@
 import nl.cwi.monetdb.mcl.protocol.ProtocolException;
 
 import java.math.BigDecimal;
+import java.nio.Buffer;
 import java.nio.CharBuffer;
 import java.sql.Types;
 import java.util.Calendar;
@@ -163,7 +164,7 @@ static int oldMapiParseTupleLine(OldMapiProtocol protocol, int lineNumber, int[]
 								}
 							}
 							// put the unescaped string in the right place
-							tupleLineBuffer.flip();
+							((Buffer)tupleLineBuffer).flip();
 							oldMapiStringToJavaDataConversion(protocol, tupleLineBuffer.array(), 0,
 									tupleLineBuffer.limit(), lineNumber, values[column], typesMap[column]);
 						} else if ((i - 1) - cursor == 4 && OldMapiTupleLineParserHelper.charIndexOf(array,