add java wrapper suppport (#117)

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

@@ -0,0 +1,86 @@
+/*
+ * // Copyright 2022-2023 by zhaoming
+ */
+// Stream is used for feeding data to the asr engine
+package com.k2fsa.sherpa.onnx;
+
+import java.io.*;
+import java.util.*;
+
+public class OnlineStream {
+  private long ptr = 0; // this is the  stream ptr
+
+  private int sampleRate = 16000;
+  // assign ptr to this stream in construction
+  public OnlineStream(long ptr, int sampleRate) {
+    this.ptr = ptr;
+    this.sampleRate = sampleRate;
+  }
+
+  public long getPtr() {
+    return ptr;
+  }
+
+  public void acceptWaveform(float[] samples) throws Exception {
+    if (this.ptr == 0) throw new Exception("null exception for stream ptr");
+
+    // feed wave data to asr engine
+    acceptWaveform(this.ptr, this.sampleRate, samples);
+  }
+
+  public void inputFinished() {
+    // add some tail padding
+    int padLen = (int) (this.sampleRate * 0.3); // 0.3 seconds at 16 kHz sample rate
+    float tailPaddings[] = new float[padLen]; // default value is 0
+    acceptWaveform(this.ptr, this.sampleRate, tailPaddings);
+
+    // tell the engine all data are feeded
+    inputFinished(this.ptr);
+  }
+
+  public static void loadSoLib(String soPath) {
+    // load .so lib from the path
+    System.load(soPath.trim()); // ("sherpa-onnx-jni-java");
+  }
+
+  public void release() {
+    // stream object must be release after used
+    if (this.ptr == 0) return;
+    deleteStream(this.ptr);
+    this.ptr = 0;
+  }
+
+  protected void finalize() throws Throwable {
+    release();
+  }
+
+  public boolean isLastFrame() throws Exception {
+    if (this.ptr == 0) throw new Exception("null exception for stream ptr");
+    return isLastFrame(this.ptr);
+  }
+
+  public void reSet() throws Exception {
+    if (this.ptr == 0) throw new Exception("null exception for stream ptr");
+    reSet(this.ptr);
+  }
+
+  public int featureDim() throws Exception {
+    if (this.ptr == 0) throw new Exception("null exception for stream ptr");
+    return featureDim(this.ptr);
+  }
+
+  // JNI interface libsherpa-onnx-jni.so
+  private native void acceptWaveform(long ptr, int sampleRate, float[] samples);
+
+  private native void inputFinished(long ptr);
+
+  private native void deleteStream(long ptr);
+
+  private native int numFramesReady(long ptr);
+
+  private native boolean isLastFrame(long ptr);
+
+  private native void reSet(long ptr);
+
+  private native int featureDim(long ptr);
+}