Remove PerMessageDeflateExtension#getCompressionRatio()

This new API was intended to be called by library users, but could never
have worked, as it would need to be called on the class instance which
is actually processing frames, but that instance is created internally
in the library using copyInstance() and thus inaccessible to the library
users.

Remove the API and the stats kept for it.

Author: robert-s-ubi

src/main/java/org/java_websocket/extensions/permessage_deflate/PerMessageDeflateExtension.java

@@ -96,8 +96,6 @@ public class PerMessageDeflateExtension extends CompressionExtension {
   private boolean isDecompressorResetAllowed;
   private boolean isCompressing;
   private boolean isDecompressing;
-  private long compressedBytes;
-  private long decompressedBytes;
 
   public PerMessageDeflateExtension() {
     this(DEFAULT_COMPRESSION);
@@ -128,8 +126,6 @@ public PerMessageDeflateExtension(int compressionLevel, int maxFragmentSize) {
     isDecompressorResetAllowed = false;
     isCompressing = false;
     isDecompressing = false;
-    compressedBytes = 0;
-    decompressedBytes = 0;
   }
 
   public int getCompressionLevel() {
@@ -164,21 +160,6 @@ public void setServerNoContextTakeover(boolean serverNoContextTakeover) {
     this.serverNoContextTakeover = serverNoContextTakeover;
   }
 
-  /**
-   * Returns the overall compression ratio of all incoming and outgoing payloads which were
-   * compressed.
-   *
-   * <p>Values below 1 mean the compression is effective, the lower, the better. If you get values
-   * above 1, look into increasing the compression level or the threshold. If that does not help,
-   * consider not using this extension.
-   *
-   * @return the overall compression ratio of all incoming and outgoing payloads
-   */
-  public double getCompressionRatio() {
-    double decompressed = decompressedBytes;
-    return decompressed > 0 ? compressedBytes / decompressed : 1;
-  }
-
   @Override
   public void isFrameValid(Framedata inputFrame) throws InvalidDataException {
     // RFC 7692: RSV1 may only be set for the first fragment of a message
@@ -213,9 +194,7 @@ public void decodeFrame(Framedata inputFrame) throws InvalidDataException {
     // decompress the frame payload
     DataFrame dataFrame = (DataFrame) inputFrame;
     ByteBuffer payload = dataFrame.getPayloadData();
-    compressedBytes += payload.remaining();
     byte[] decompressed = decompress(payload, dataFrame.isFin());
-    decompressedBytes += decompressed.length;
     dataFrame.setPayload(ByteBuffer.wrap(decompressed));
 
     // payload is no longer compressed, clear the RFC 7692 compression marker RSV1
@@ -298,9 +277,7 @@ public void encodeFrame(Framedata inputFrame) {
     // compress the frame payload
     DataFrame dataFrame = (DataFrame) inputFrame;
     ByteBuffer payload = dataFrame.getPayloadData();
-    decompressedBytes += payload.remaining();
     byte[] compressed = compress(payload, dataFrame.isFin());
-    compressedBytes += compressed.length;
     dataFrame.setPayload(ByteBuffer.wrap(compressed));
 
     // payload is compressed now, set the RFC 7692 compression marker RSV1
@@ -568,10 +545,9 @@ public IExtension copyInstance() {
 
   @Override
   public void reset() {
+    super.reset();
     isCompressing = false;
     isDecompressing = false;
-    compressedBytes = 0;
-    decompressedBytes = 0;
   }
 
   @Override