Add Java API for text-to-speech (#811)

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

@@ -0,0 +1,53 @@
+// Copyright 2024 Xiaomi Corporation
+
+package com.k2fsa.sherpa.onnx;
+
+public class OfflineTts {
+    static {
+        System.loadLibrary("sherpa-onnx-jni");
+    }
+
+    private long ptr = 0; // this is the asr engine ptrss
+
+    public OfflineTts(OfflineTtsConfig config) {
+        ptr = newFromFile(config);
+    }
+
+    public GeneratedAudio generate(String text) {
+        return generate(text, 0, 1.0f);
+    }
+
+    public GeneratedAudio generate(String text, int sid) {
+        return generate(text, sid, 1.0f);
+    }
+
+    public GeneratedAudio generate(String text, int sid, float speed) {
+        Object[] arr = generateImpl(ptr, text, sid, speed);
+        float[] samples = (float[]) arr[0];
+        int sampleRate = (int) arr[1];
+        return new GeneratedAudio(samples, sampleRate);
+    }
+
+    @Override
+    protected void finalize() throws Throwable {
+        release();
+    }
+
+    public void release() {
+        if (this.ptr == 0) {
+            return;
+        }
+        delete(this.ptr);
+        this.ptr = 0;
+    }
+
+    private native void delete(long ptr);
+
+    private native int getSampleRate(long ptr);
+
+    private native int getNumSpeakers(long ptr);
+
+    private native Object[] generateImpl(long ptr, String text, int sid, float speed);
+
+    private native long newFromFile(OfflineTtsConfig config);
+}