Add java websocket support (#137)

* add decode example for mic

* some changes to README.md

* add java websocket srv

* change to readwav to static

* make some changes to code comments

* little change for readme.md

* fix bug about multiple threads

* made little modification

* add protocol in readme, removed static Queue and add lmConfig

---------

Co-authored-by: root <root@localhost.localdomain>

java-api-examples/Makefile

@@ -7,11 +7,21 @@ LIB_FILES = \
 	$(LIB_SRC_DIR)/EndpointRule.java \
 	$(LIB_SRC_DIR)/EndpointConfig.java \
 	$(LIB_SRC_DIR)/FeatureConfig.java \
+	$(LIB_SRC_DIR)/OnlineLMConfig.java \
 	$(LIB_SRC_DIR)/OnlineTransducerModelConfig.java \
 	$(LIB_SRC_DIR)/OnlineRecognizerConfig.java \
 	$(LIB_SRC_DIR)/OnlineStream.java \
 	$(LIB_SRC_DIR)/OnlineRecognizer.java \
 
+WEBSOCKET_DIR:= ./src/websocketsrv
+WEBSOCKET_FILES = \
+	$(WEBSOCKET_DIR)/ConnectionData.java \
+	$(WEBSOCKET_DIR)/DecoderThreadHandler.java \
+	$(WEBSOCKET_DIR)/StreamThreadHandler.java \
+	$(WEBSOCKET_DIR)/AsrWebsocketServer.java \
+	$(WEBSOCKET_DIR)/AsrWebsocketClient.java \
+
+
 LIB_BUILD_DIR = ./lib
 
 
@@ -39,7 +49,13 @@ buildmic:
 	
 rebuild: clean all
 	
-.PHONY:  clean run
+.PHONY:  clean run downjar
+
+downjar:
+	wget https://repo1.maven.org/maven2/org/slf4j/slf4j-api/1.7.25/slf4j-api-1.7.25.jar -P ./lib/
+	wget https://repo1.maven.org/maven2/org/slf4j/slf4j-simple/1.7.25/slf4j-simple-1.7.25.jar -P ./lib/
+	wget https://github.com/TooTallNate/Java-WebSocket/releases/download/v1.5.3/Java-WebSocket-1.5.3.jar -P ./lib/
+
 	
 clean:
 	rm -frv  $(BUILD_DIR)/*
@@ -56,6 +72,12 @@ runmic:
 
 		java -cp ./lib/sherpaonnx.jar:build $(RUNJFLAGS)  DecodeMic
 
+runsrv:
+		java   -cp $(BUILD_DIR):lib/Java-WebSocket-1.5.3.jar:lib/slf4j-simple-1.7.25.jar:lib/slf4j-api-1.7.25.jar:../lib/sherpaonnx.jar  $(RUNJFLAGS)  websocketsrv.AsrWebsocketServer /sherpa-onnx/20230515/zhaoming/sherpa-onnx/build/lib/libsherpa-onnx-jni.so ./modelconfig.cfg
+
+runclient:
+		java   -cp $(BUILD_DIR):lib/Java-WebSocket-1.5.3.jar:lib/slf4j-simple-1.7.25.jar:lib/slf4j-api-1.7.25.jar:../lib/sherpaonnx.jar  $(RUNJFLAGS)  websocketsrv.AsrWebsocketClient /sherpa-onnx/20230515/zhaoming/sherpa-onnx/build/lib/libsherpa-onnx-jni.so 127.0.0.1 8890 ./test.wav 32
+
 buildlib: $(LIB_FILES:.java=.class)
 	
 
@@ -63,10 +85,19 @@ buildlib: $(LIB_FILES:.java=.class)
 
 				$(JAVAC) -cp $(BUILD_DIR) -d $(BUILD_DIR) -encoding UTF-8 $<
 
+buildwebsocket: $(WEBSOCKET_FILES:.java=.class)
+	
+
+%.class: %.java
+
+				$(JAVAC) -cp $(BUILD_DIR):lib/slf4j-simple-1.7.25.jar:lib/slf4j-api-1.7.25.jar:lib/Java-WebSocket-1.5.3.jar:../lib/sherpaonnx.jar -d $(BUILD_DIR) -encoding UTF-8 $<
+
 packjar:
 				jar cvfe lib/sherpaonnx.jar . -C $(BUILD_DIR) .
 				
-all: clean buildlib packjar buildfile buildmic
+all: clean buildlib packjar buildfile buildmic downjar buildwebsocket
+
+ 
 
 
 

java-api-examples/README.md

@@ -2,6 +2,7 @@
 --------------
 
 Java wrapper `com.k2fsa.sherpa.onnx.OnlineRecognizer` for `sherpa-onnx`. Java is a cross-platform language; you can build jni .so lib according to your system, and then use the same java api for all your platform.
+now support multiple threads for websocket server
 
 ```xml
 Depend on:
@@ -35,7 +36,7 @@ Example for Ubuntu 18.04 LTS, Openjdk 1.8.0_362:
 
 3.Config model config.cfg
 -------------------------
-
+/**change model path in config.cfg according to your env**/
 ```xml
   #model config 
   sample_rate=16000 
@@ -51,6 +52,21 @@ Example for Ubuntu 18.04 LTS, Openjdk 1.8.0_362:
   enable_endpoint_detection=false
   decoding_method=greedy_search
   max_active_paths=4
+
+  #websocket server config
+  port=8890
+  #number of threads pool for network io
+  connection_thread_num=16 
+  #number of threads pool for stream
+  stream_thread_num=16 
+  #number of threads pool for decoder 
+  decoder_thread_num=16 
+  #size of streams for parallel decoding
+  parallel_decoder_num=16
+  #time(ms) idle for decoder thread when no job
+  decoder_time_idle=10
+  #time(ms) out for connection data
+  deocder_time_out=3000
 ```
 
 ---
@@ -114,5 +130,58 @@ Build package path: /sherpa-onnx/java-api-examples/lib/sherpaonnx.jar
     make runmic
 ```
 
+---
+
+6.WebSocket Server
+----------
+
+support multiple threads for websocket server
+6.0 Protocol for communication
+1) client connect to server
+```shell
+   ws client -> srv ws address
+   ws address example: ws://127.0.0.1:8889/
+```
+2) client send 16k pcm_s16le binary stream data to server
+```shell
+   PCM   sampleRate 16000
+         single channel
+		 sampleSize 16bit
+		 little endian
+		 type short
+```
+3) client send "Done" text to server when all data is sent
+```shell
+	ws_socket.send("Done")
+```
+4) client will receive json message from server whenever asr engine decoded new text
+```shell
+   json example: {"text":"甚至出现交易几乎停滞的情况","eof":false"}
+``` 
  
 
+6.1 Build
+
+```bash
+    cd sherpa-onnx/java-api-examples
+    make all
+```
+
+6.2 Run srv example
+
+usage: AsrWebsocketServer soPath modelCfgPath
+
+```bash
+    make runsrv  /**change path in Makefile according to your env**/
+```
+
+6.3 Run multiple threads client example
+
+usage: AsrWebsocketClient soPath srvIp srvPort wavPath numThreads
+
+json result example: {"text":"甚至出现交易几乎停滞的情况","eof":"true"}
+
+```bash
+    make runclient  /**change path in Makefile according to your env**/
+```
+

java-api-examples/modelconfig.cfg

@@ -9,6 +9,17 @@ decoder=/sherpa-onnx/build_old/bin/sherpa-onnx-streaming-zipformer-bilingual-zh-
 joiner=/sherpa-onnx/build_old/bin/sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20/joiner-epoch-99-avg-1.onnx
 tokens=/sherpa-onnx/build_old/bin/sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20/tokens.txt
 num_threads=4
-enable_endpoint_detection=false
+enable_endpoint_detection=true
 decoding_method=modified_beam_search
 max_active_paths=4
+lm_model=
+lm_scale=0.5
+
+#websocket server config
+port=8890
+connection_thread_num=16
+stream_thread_num=16
+decoder_thread_num=16
+parallel_decoder_num=16
+decoder_time_idle=200
+deocder_time_out=30000

java-api-examples/src/DecodeFile.java

@@ -49,7 +49,8 @@ public class DecodeFile {
       float rule3MinUtteranceLength = 20F;
       String decodingMethod = "greedy_search";
       int maxActivePaths = 4;
-
+      String lm_model="";
+	  float lm_scale=0.5F;
       rcgOjb =
           new OnlineRecognizer(
               tokens,
@@ -64,6 +65,8 @@ public class DecodeFile {
               rule2MinTrailingSilence,
               rule3MinUtteranceLength,
               decodingMethod,
+			  lm_model,
+			  lm_scale,
               maxActivePaths);
       streamObj = rcgOjb.createStream();
     } catch (Exception e) {

java-api-examples/src/websocketsrv/AsrWebsocketClient.java

@@ -0,0 +1,131 @@
+/*
+ * // Copyright 2022-2023 by zhaomingwork
+ */
+// java AsrWebsocketClient
+// usage: AsrWebsocketClient soPath srvIp srvPort wavPath numThreads
+package websocketsrv;
+
+import com.k2fsa.sherpa.onnx.OnlineRecognizer;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.nio.*;
+import java.util.Map;
+import org.java_websocket.client.WebSocketClient;
+import org.java_websocket.drafts.Draft;
+import org.java_websocket.handshake.ServerHandshake;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/** This example demonstrates how to connect to websocket server. */
+public class AsrWebsocketClient extends WebSocketClient {
+  private static final Logger logger = LoggerFactory.getLogger(AsrWebsocketClient.class);
+
+  public AsrWebsocketClient(URI serverUri, Draft draft) {
+    super(serverUri, draft);
+  }
+
+  public AsrWebsocketClient(URI serverURI) {
+    super(serverURI);
+  }
+
+  public AsrWebsocketClient(URI serverUri, Map<String, String> httpHeaders) {
+    super(serverUri, httpHeaders);
+  }
+
+  @Override
+  public void onOpen(ServerHandshake handshakedata) {
+
+    float[] floats = OnlineRecognizer.readWavFile(AsrWebsocketClient.wavPath);
+    ByteBuffer buffer =
+        ByteBuffer.allocate(4 * floats.length)
+            .order(ByteOrder.LITTLE_ENDIAN); // float is sizeof 4. allocate enough buffer
+
+    for (float f : floats) {
+      buffer.putFloat(f);
+    }
+    buffer.rewind();
+    buffer.flip();
+    buffer.order(ByteOrder.LITTLE_ENDIAN);
+
+    send(buffer.array()); // send buf to server
+    send("Done"); // send 'Done' means finished
+  }
+
+  @Override
+  public void onMessage(String message) {
+
+    logger.info("received: " + message);
+  }
+
+  @Override
+  public void onClose(int code, String reason, boolean remote) {
+
+    logger.info(
+        "Connection closed by "
+            + (remote ? "remote peer" : "us")
+            + " Code: "
+            + code
+            + " Reason: "
+            + reason);
+  }
+
+  @Override
+  public void onError(Exception ex) {
+    ex.printStackTrace();
+    // if the error is fatal then onClose will be called additionally
+  }
+
+  public static OnlineRecognizer rcgobj;
+  public static String wavPath;
+
+  public static void main(String[] args) throws URISyntaxException {
+
+    if (args.length != 5) {
+      System.out.println("usage: AsrWebsocketClient soPath srvIp srvPort wavPath numThreads");
+      return;
+    }
+
+    String soPath = args[0];
+    String srvIp = args[1];
+    String srvPort = args[2];
+    String wavPath = args[3];
+    int numThreads = Integer.parseInt(args[4]);
+    System.out.println("serIp=" + srvIp + ",srvPort=" + srvPort + ",wavPath=" + wavPath);
+
+    class ClientThread implements Runnable {
+
+      String soPath;
+      String srvIp;
+      String srvPort;
+      String wavPath;
+
+      ClientThread(String soPath, String srvIp, String srvPort, String wavPath) {
+        this.soPath = soPath;
+        this.srvIp = srvIp;
+        this.srvPort = srvPort;
+        this.wavPath = wavPath;
+      }
+
+      public void run() {
+        try {
+
+          OnlineRecognizer.setSoPath(soPath);
+
+          AsrWebsocketClient.wavPath = wavPath;
+
+          String wsAddress = "ws://" + srvIp + ":" + srvPort;
+          AsrWebsocketClient c = new AsrWebsocketClient(new URI(wsAddress));
+
+          c.connect();
+        } catch (Exception e) {
+          e.printStackTrace();
+        }
+      }
+    }
+    for (int i = 0; i < numThreads; i++) {
+      System.out.println("Thread1 is running...");
+      Thread t = new Thread(new ClientThread(soPath, srvIp, srvPort, wavPath));
+      t.start();
+    }
+  }
+}

java-api-examples/src/websocketsrv/AsrWebsocketServer.java

@@ -0,0 +1,248 @@
+/*
+ * // Copyright 2022-2023 by zhaoming
+ */
+// java websocketServer
+// usage: AsrWebsocketServer soPath modelCfgPath
+package websocketsrv;
+
+import com.k2fsa.sherpa.onnx.OnlineRecognizer;
+import com.k2fsa.sherpa.onnx.OnlineStream;
+import java.io.*;
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.net.UnknownHostException;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.nio.FloatBuffer;
+import java.util.*;
+import java.util.Collections;
+import java.util.concurrent.*;
+import java.util.concurrent.LinkedBlockingQueue;
+import org.java_websocket.WebSocket;
+import org.java_websocket.drafts.Draft;
+import org.java_websocket.drafts.Draft_6455;
+import org.java_websocket.handshake.ClientHandshake;
+import org.java_websocket.server.WebSocketServer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * AsrWebSocketServer has three threads pools, one pool for network io, one pool for asr stream and
+ * one pool for asr decoder.
+ */
+public class AsrWebsocketServer extends WebSocketServer {
+  private static final Logger logger = LoggerFactory.getLogger(AsrWebsocketServer.class);
+  //  Queue between io network io thread pool and stream thread pool, use websocket as the key
+  private LinkedBlockingQueue<WebSocket> streamQueue = new LinkedBlockingQueue<WebSocket>();
+  //  Queue waiting for deocdeing, use websocket as the key
+  private LinkedBlockingQueue<WebSocket> decoderQueue = new LinkedBlockingQueue<WebSocket>();
+
+  // recogizer object
+  private OnlineRecognizer rcgOjb = null;
+
+  // mapping between websocket connection and connection data
+  private ConcurrentHashMap<WebSocket, ConnectionData> connectionMap =
+      new ConcurrentHashMap<WebSocket, ConnectionData>();
+
+  public AsrWebsocketServer(int port, int numThread) throws UnknownHostException {
+    // server port and num of threads for  network io
+    super(new InetSocketAddress(port), numThread);
+  }
+
+  public AsrWebsocketServer(InetSocketAddress address) {
+    super(address);
+  }
+
+  public AsrWebsocketServer(int port, Draft_6455 draft) {
+    super(new InetSocketAddress(port), Collections.<Draft>singletonList(draft));
+  }
+
+  @Override
+  public void onOpen(WebSocket conn, ClientHandshake handshake) {}
+
+  @Override
+  public void onClose(WebSocket conn, int code, String reason, boolean remote) {
+    connectionMap.remove(conn);
+    logger.info(
+        conn
+            + " remove one connection!, now connection number="
+            + String.valueOf(connectionMap.size()));
+  }
+
+  @Override
+  public void onMessage(WebSocket conn, String message) {
+    // this is text message
+    try {
+      // if rec "Done" msg from client
+      if (message.equals("Done")) {
+        ConnectionData connData = creatOrGetConnectionData(conn);
+        connData.setEof(true);
+        if (!streamQueueFind(conn)) {
+          streamQueue.put(conn);
+        }
+      }
+
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+  }
+
+  private ConnectionData creatOrGetConnectionData(WebSocket conn) {
+    // create a new connection data if not in connection map or return the existed one
+
+    ConnectionData connData = null;
+    try {
+      if (!connectionMap.containsKey(conn)) {
+        OnlineStream stream = rcgOjb.createStream();
+        connData = new ConnectionData(conn, stream);
+        connectionMap.put(conn, connData);
+      } else {
+        connData = connectionMap.get(conn);
+      }
+
+      logger.info(
+          conn.getRemoteSocketAddress().getAddress().getHostAddress()
+              + " open one connection,, now connection number="
+              + String.valueOf(connectionMap.size()));
+
+    } catch (Exception e) {
+      System.err.println(e);
+      e.printStackTrace();
+    }
+    return connData;
+  }
+
+  @Override
+  public void onMessage(WebSocket conn, ByteBuffer blob) {
+    try {
+
+      // for handle binary data
+      blob.order(ByteOrder.LITTLE_ENDIAN); // set little endian
+
+      // set to float
+      FloatBuffer floatbuf = blob.asFloatBuffer();
+
+      if (floatbuf.capacity() > 0) {
+        // allocate memory for float data
+        float[] arr = new float[floatbuf.capacity()];
+
+        floatbuf.get(arr);
+        ConnectionData connData = creatOrGetConnectionData(conn);
+        // put websocket  to stream queue with binary type==1
+        connData.addSamplesToData(arr);
+
+        if (!streamQueueFind(conn)) {
+          streamQueue.put(conn);
+        }
+      }
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+  }
+
+ 
+
+  public boolean streamQueueFind(WebSocket conn) {
+    return streamQueue.contains(conn);
+  }
+
+  public void initModelWithCfg(Map<String, String> cfgMap, String cfgPath) {
+    try {
+
+      rcgOjb = new OnlineRecognizer(cfgPath);
+      // size of stream thread pool
+      int streamThreadNum = Integer.valueOf(cfgMap.get("stream_thread_num"));
+      // size of decoder thread pool
+      int decoderThreadNum = Integer.valueOf(cfgMap.get("decoder_thread_num"));
+
+      // time(ms) idle for decoder thread when no job
+      int decoderTimeIdle = Integer.valueOf(cfgMap.get("decoder_time_idle"));
+      // size of streams for parallel decoding
+      int parallelDecoderNum = Integer.valueOf(cfgMap.get("parallel_decoder_num"));
+      // time(ms) out for connection data
+      int deocderTimeOut = Integer.valueOf(cfgMap.get("deocder_time_out"));
+
+      // create stream threads
+      for (int i = 0; i < streamThreadNum; i++) {
+        new StreamThreadHandler(streamQueue, decoderQueue, connectionMap).start();
+      }
+      // create decoder threads
+      for (int i = 0; i < decoderThreadNum; i++) {
+        new DecoderThreadHandler(
+                decoderQueue,
+                connectionMap,
+                rcgOjb,
+                decoderTimeIdle,
+                parallelDecoderNum,
+                deocderTimeOut)
+            .start();
+      }
+    } catch (Exception e) {
+      System.err.println(e);
+      e.printStackTrace();
+    }
+  }
+
+  public static Map<String, String> readProperties(String CfgPath) {
+    // read and parse config file
+    Properties props = new Properties();
+    Map<String, String> proMap = new HashMap<String, String>();
+    try {
+
+      File file = new File(CfgPath);
+      if (!file.exists()) {
+        logger.info(String.valueOf(CfgPath) + " cfg file not exists!");
+        System.exit(0);
+      }
+      InputStream in = new BufferedInputStream(new FileInputStream(CfgPath));
+      props.load(in);
+      Enumeration en = props.propertyNames();
+      while (en.hasMoreElements()) {
+        String key = (String) en.nextElement();
+        String Property = props.getProperty(key);
+        proMap.put(key, Property);
+      }
+
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+    return proMap;
+  }
+
+  public static void main(String[] args) throws InterruptedException, IOException {
+    if (args.length != 2) {
+      logger.info("usage: AsrWebsocketServer soPath modelCfgPath");
+
+      return;
+    }
+
+    String soPath = args[0];
+    String cfgPath = args[1];
+
+    OnlineRecognizer.setSoPath(soPath);
+
+    Map<String, String> cfgMap = AsrWebsocketServer.readProperties(cfgPath);
+    int port = Integer.valueOf(cfgMap.get("port"));
+
+    int connectionThreadNum = Integer.valueOf(cfgMap.get("connection_thread_num"));
+    AsrWebsocketServer s = new AsrWebsocketServer(port, connectionThreadNum);
+    s.initModelWithCfg(cfgMap, cfgPath);
+    logger.info("Server started on port: " + s.getPort());
+    s.start();
+  }
+
+  @Override
+  public void onError(WebSocket conn, Exception ex) {
+    ex.printStackTrace();
+    if (conn != null) {
+      // some errors like port binding failed may not be assignable to a specific websocket
+    }
+  }
+
+  @Override
+  public void onStart() {
+    logger.info("Server started!");
+    setConnectionLostTimeout(0);
+    setConnectionLostTimeout(100);
+  }
+}

java-api-examples/src/websocketsrv/ConnectionData.java

@@ -0,0 +1,65 @@
+/*
+ * // Copyright 2022-2023 by zhaoming
+ */
+// connection data act as a bridge between different threads pools
+
+package websocketsrv;
+
+import com.k2fsa.sherpa.onnx.OnlineStream;
+import java.time.LocalDateTime;
+import java.util.LinkedList;
+import java.util.Queue;
+import java.util.concurrent.*;
+import org.java_websocket.WebSocket;
+
+public class ConnectionData {
+
+  private WebSocket webSocket; // the websocket for this connection data
+
+  private OnlineStream stream; // connection stream
+
+  private Queue<float[]> queueSamples =
+      new LinkedList<float[]>(); // binary data rec from the client
+
+  private boolean eof = false; // connection data is done
+
+  private LocalDateTime lastHandleTime; // used for time out in ms
+
+  public ConnectionData(WebSocket webSocket, OnlineStream stream) {
+    this.webSocket = webSocket;
+
+    this.stream = stream;
+  }
+
+  public void addSamplesToData(float[] samples) {
+    this.queueSamples.add(samples);
+  }
+
+  public LocalDateTime getLastHandleTime() {
+    return this.lastHandleTime;
+  }
+
+  public void setLastHandleTime(LocalDateTime now) {
+    this.lastHandleTime = now;
+  }
+
+  public boolean getEof() {
+    return this.eof;
+  }
+
+  public void setEof(boolean eof) {
+    this.eof = eof;
+  }
+
+  public WebSocket getWebSocket() {
+    return this.webSocket;
+  }
+
+  public Queue<float[]> getQueueSamples() {
+    return this.queueSamples;
+  }
+
+  public OnlineStream getStream() {
+    return this.stream;
+  }
+}

java-api-examples/src/websocketsrv/DecoderThreadHandler.java

@@ -0,0 +1,173 @@
+/*
+ * // Copyright 2022-2023 by zhaoming
+ */
+// java DecoderThreadHandler
+package websocketsrv;
+
+import com.k2fsa.sherpa.onnx.OnlineRecognizer;
+import com.k2fsa.sherpa.onnx.OnlineStream;
+import java.nio.*;
+import java.nio.charset.StandardCharsets;
+import java.time.LocalDateTime;
+import java.util.*;
+import java.util.List;
+import java.util.concurrent.*;
+import java.util.concurrent.LinkedBlockingQueue;
+import org.java_websocket.WebSocket;
+import org.java_websocket.drafts.Draft;
+import org.java_websocket.framing.Framedata;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class DecoderThreadHandler extends Thread {
+  private static final Logger logger = LoggerFactory.getLogger(DecoderThreadHandler.class);
+  // Websocket Queue that waiting for decoding
+  private LinkedBlockingQueue<WebSocket> decoderQueue;
+  // the mapping between websocket and connection data
+  private ConcurrentHashMap<WebSocket, ConnectionData> connMap;
+
+  private OnlineRecognizer rcgOjb = null; // recgnizer object
+
+  // connection data list for this thread to decode in parallel
+  private List<ConnectionData> connDataList = new ArrayList<ConnectionData>();
+
+  private int parallelDecoderNum = 10; // parallel decoding number
+  private int deocderTimeIdle = 10; // idle time(ms) when no job
+  private int deocderTimeOut = 3000; // if it is timeout(ms), the connection data will be removed
+
+  public DecoderThreadHandler(
+      LinkedBlockingQueue<WebSocket> decoderQueue,
+      ConcurrentHashMap<WebSocket, ConnectionData> connMap,
+      OnlineRecognizer rcgOjb,
+      int deocderTimeIdle,
+      int parallelDecoderNum,
+      int deocderTimeOut) {
+    this.decoderQueue = decoderQueue;
+    this.connMap = connMap;
+    this.rcgOjb = rcgOjb;
+    this.deocderTimeIdle = deocderTimeIdle;
+    this.parallelDecoderNum = parallelDecoderNum;
+    this.deocderTimeOut = deocderTimeOut;
+  }
+
+  public void run() {
+    while (true) {
+      try {
+        // time(ms) idle  if there is no job
+
+        Thread.sleep(deocderTimeIdle);
+        // clear data list for this threads
+        connDataList.clear();
+        if (rcgOjb == null) continue;
+
+        // loop for total decoder Queue
+        while (!decoderQueue.isEmpty()) {
+
+          // get websocket
+          WebSocket conn = decoderQueue.take();
+          // get connection data according to websocket
+          ConnectionData connData = connMap.get(conn);
+
+          // if the websocket closed, continue
+          if (connData == null) continue;
+          // get the stream
+          OnlineStream stream = connData.getStream();
+
+          // put to decoder list if 1) stream is ready; 2) and
+          // size not > parallelDecoderNum
+          if ((rcgOjb.isReady(stream) && connDataList.size() < parallelDecoderNum)) {
+
+            // add to this thread's decoder list
+            connDataList.add(connData);
+            // change the handled time for this connection data
+            connData.setLastHandleTime(LocalDateTime.now());
+          }
+          // break when decoder list size >= parallelDecoderNum
+          if (connDataList.size() >= parallelDecoderNum) {
+            break;
+          }
+        }
+
+        // if decoder data list for this thread >0
+        if (connDataList.size() > 0) {
+
+          // create a stream array for parallel decoding
+          OnlineStream[] arr = new OnlineStream[connDataList.size()];
+          for (int i = 0; i < connDataList.size(); i++) {
+
+            arr[i] = connDataList.get(i).getStream();
+          }
+
+          // parallel decoding
+          rcgOjb.decodeStreams(arr);
+        }
+
+        // get result for each connection
+        for (ConnectionData connData : connDataList) {
+
+          OnlineStream stream = connData.getStream();
+          WebSocket webSocket = connData.getWebSocket();
+
+          String txtResult = rcgOjb.getResult(stream);
+
+          // decode text in utf-8
+          byte[] utf8Data = txtResult.getBytes(StandardCharsets.UTF_8);
+
+          boolean isEof = (connData.getEof() == true && !rcgOjb.isReady(stream));
+          // result
+          if (utf8Data.length > 0) {
+
+            String jsonResult =
+                "{\"text\":\"" + txtResult + "\",\"eof\":" + String.valueOf(isEof) + "\"}";
+
+            if (webSocket.isOpen()) {
+              // create a TEXT Frame for send back json result
+              Draft draft = webSocket.getDraft();
+              List<Framedata> frames = null;
+              frames = draft.createFrames(jsonResult, false);
+              // send to client
+              webSocket.sendFrame(frames);
+            }
+          }
+        }
+        // loop for each connection data in this thread
+        for (ConnectionData connData : connDataList) {
+          OnlineStream stream = connData.getStream();
+          WebSocket webSocket = connData.getWebSocket();
+          // if the stream is still ready, put it to decoder Queue again for next decoding
+          if (rcgOjb.isReady(stream)) {
+            decoderQueue.put(webSocket);
+          }
+          // the duration between last handled time and now
+          java.time.Duration duration =
+              java.time.Duration.between(connData.getLastHandleTime(), LocalDateTime.now());
+          // close the websocket if 1) data is done  and  stream not ready; 2) or data is time out;
+          // 3) or
+          // connection is closed
+          if ((connData.getEof() == true
+                  && !rcgOjb.isReady(stream)
+                  && connData.getQueueSamples().isEmpty())
+              || duration.toMillis() > deocderTimeOut
+              || !connData.getWebSocket().isOpen()) {
+
+            logger.info("close websocket!!!");
+
+            // delay close web socket as data may still in processing
+            Timer timer = new Timer();
+            timer.schedule(
+                new TimerTask() {
+                  public void run() {
+
+                    webSocket.close();
+                  }
+                },
+                5000); // 5 seconds
+          }
+        }
+
+      } catch (Exception e) {
+        e.printStackTrace();
+      }
+    }
+  }
+}

java-api-examples/src/websocketsrv/StreamThreadHandler.java

@@ -0,0 +1,67 @@
+/*
+ * // Copyright 2022-2023 by zhaoming
+ */
+// java StreamThreadHandler
+package websocketsrv;
+
+import com.k2fsa.sherpa.onnx.OnlineStream;
+import java.nio.*;
+import java.util.*;
+import java.util.concurrent.*;
+import java.util.concurrent.LinkedBlockingQueue;
+import org.java_websocket.WebSocket;
+// thread for processing stream
+
+public class StreamThreadHandler extends Thread {
+  //  Queue between io network io thread pool and stream thread pool, use websocket as the key
+  private LinkedBlockingQueue<WebSocket> streamQueue;
+  //  Queue waiting for deocdeing, use websocket as the key
+  private LinkedBlockingQueue<WebSocket> decoderQueue;
+  // mapping between websocket connection and connection data
+  private ConcurrentHashMap<WebSocket, ConnectionData> connMap;
+
+  public StreamThreadHandler(
+      LinkedBlockingQueue<WebSocket> streamQueue,
+      LinkedBlockingQueue<WebSocket> decoderQueue,
+      ConcurrentHashMap<WebSocket, ConnectionData> connMap) {
+    this.streamQueue = streamQueue;
+    this.decoderQueue = decoderQueue;
+    this.connMap = connMap;
+  }
+
+  public void run() {
+    while (true) {
+      try {
+        // fetch one websocket from queue
+        WebSocket conn = (WebSocket) this.streamQueue.take();
+        // get the connection data according to websocket
+        ConnectionData connData = connMap.get(conn);
+        OnlineStream stream = connData.getStream();
+
+        // handle received binary data
+        if (!connData.getQueueSamples().isEmpty()) {
+          // loop to put all received binary data to stream
+          while (!connData.getQueueSamples().isEmpty()) {
+
+            float[] samples = connData.getQueueSamples().poll();
+
+            stream.acceptWaveform(samples);
+          }
+          //  if data is finished
+          if (connData.getEof() == true) {
+
+            stream.inputFinished();
+          }
+          // add this websocket to decoder Queue if not in the Queue
+          if (!decoderQueue.contains(conn)) {
+
+            decoderQueue.put(conn);
+          }
+        }
+
+      } catch (Exception e) {
+        e.printStackTrace();
+      }
+    }
+  }
+}

sherpa-onnx/java-api/src/com/k2fsa/sherpa/onnx/OnlineLMConfig.java

@@ -0,0 +1,23 @@
+/*
+ * // Copyright 2022-2023 by zhaoming
+ */
+
+package com.k2fsa.sherpa.onnx;
+
+public class OnlineLMConfig {
+  private final String model;
+  private final float scale;
+
+  public OnlineLMConfig(String model, float scale) {
+    this.model = model;
+    this.scale = scale;
+  }
+
+  public String getModel() {
+    return model;
+  }
+
+  public float getScale() {
+    return scale;
+  }
+}

sherpa-onnx/java-api/src/com/k2fsa/sherpa/onnx/OnlineRecognizer.java

@@ -65,11 +65,14 @@ public class OnlineRecognizer {
               false);
       FeatureConfig featConfig =
           new FeatureConfig(sampleRate, Integer.parseInt(proMap.get("feature_dim").trim()));
-      OnlineRecognizerConfig rcgCfg =
+      OnlineLMConfig onlineLmConfig=new OnlineLMConfig(proMap.get("lm_model").trim(),Float.parseFloat(proMap.get("lm_scale").trim()));
+	  
+	  OnlineRecognizerConfig rcgCfg =
           new OnlineRecognizerConfig(
               featConfig,
               modelCfg,
               endCfg,
+			  onlineLmConfig,
               Boolean.parseBoolean(proMap.get("enable_endpoint_detection").trim()),
               proMap.get("decoding_method").trim(),
               Integer.parseInt(proMap.get("max_active_paths").trim()));
@@ -107,11 +110,15 @@ public class OnlineRecognizer {
               false);
       FeatureConfig featConfig =
           new FeatureConfig(sampleRate, Integer.parseInt(proMap.get("feature_dim").trim()));
-      OnlineRecognizerConfig rcgCfg =
+      
+	  OnlineLMConfig onlineLmConfig=new OnlineLMConfig(proMap.get("lm_model").trim(),Float.parseFloat(proMap.get("lm_scale").trim()));
+	  
+	  OnlineRecognizerConfig rcgCfg =
           new OnlineRecognizerConfig(
               featConfig,
               modelCfg,
               endCfg,
+			  onlineLmConfig,
               Boolean.parseBoolean(proMap.get("enable_endpoint_detection").trim()),
               proMap.get("decoding_method").trim(),
               Integer.parseInt(proMap.get("max_active_paths").trim()));
@@ -137,6 +144,8 @@ public class OnlineRecognizer {
       float rule2MinTrailingSilence,
       float rule3MinUtteranceLength,
       String decodingMethod,
+	  String lm_model,
+	  float lm_scale,
       int maxActivePaths) {
     this.sampleRate = sampleRate;
     EndpointRule rule1 = new EndpointRule(false, rule1MinTrailingSilence, 0.0F);
@@ -146,14 +155,10 @@ public class OnlineRecognizer {
     OnlineTransducerModelConfig modelCfg =
         new OnlineTransducerModelConfig(encoder, decoder, joiner, tokens, numThreads, false);
     FeatureConfig featConfig = new FeatureConfig(sampleRate, featureDim);
-    OnlineRecognizerConfig rcgCfg =
+    OnlineLMConfig onlineLmConfig=new OnlineLMConfig(lm_model,lm_scale);
+	OnlineRecognizerConfig rcgCfg =
         new OnlineRecognizerConfig(
-            featConfig,
+            featConfig, modelCfg, endCfg, onlineLmConfig,enableEndpointDetection, decodingMethod, maxActivePaths);
-            modelCfg,
-            endCfg,
-            enableEndpointDetection,
-            decodingMethod,
-            maxActivePaths);
     // create a new Recognizer, first parameter kept for android asset_manager ANDROID_API__ >= 9
     this.ptr = createOnlineRecognizer(new Object(), rcgCfg);
   }
@@ -241,7 +246,7 @@ public class OnlineRecognizer {
     return stream;
   }
 
-  public float[] readWavFile(String fileName) {
+  public static float[] readWavFile(String fileName) {
     // read data from the filename
     Object[] wavdata = readWave(fileName);
     Object data = wavdata[0]; // data[0] is float data, data[1] sample rate
@@ -281,7 +286,7 @@ public class OnlineRecognizer {
   }
   // JNI interface libsherpa-onnx-jni.so
 
-  private native Object[] readWave(String fileName);
+  private static native Object[] readWave(String fileName);  // static
 
   private native String getResult(long ptr, long streamPtr);
 

sherpa-onnx/java-api/src/com/k2fsa/sherpa/onnx/OnlineRecognizerConfig.java

@@ -8,25 +8,33 @@ public class OnlineRecognizerConfig {
   private final FeatureConfig featConfig;
   private final OnlineTransducerModelConfig modelConfig;
   private final EndpointConfig endpointConfig;
+  private final OnlineLMConfig lmConfig;
   private final boolean enableEndpoint;
   private final String decodingMethod;
   private final int maxActivePaths;
   
+
   public OnlineRecognizerConfig(
       FeatureConfig featConfig,
       OnlineTransducerModelConfig modelConfig,
       EndpointConfig endpointConfig,
+	  OnlineLMConfig lmConfig,
       boolean enableEndpoint,
       String decodingMethod,
       int maxActivePaths) {
     this.featConfig = featConfig;
     this.modelConfig = modelConfig;
     this.endpointConfig = endpointConfig;
+	this.lmConfig = lmConfig;
     this.enableEndpoint = enableEndpoint;
     this.decodingMethod = decodingMethod;
     this.maxActivePaths = maxActivePaths;
   }
 
+  public OnlineLMConfig getLmConfig() {
+    return lmConfig;
+  }
+
   public FeatureConfig getFeatConfig() {
     return featConfig;
   }