Expose and use model sample rate in Java

native_client/java/app/src/main/java/org/mozilla/deepspeech/DeepSpeechActivity.java

@@ -77,7 +77,7 @@ public class DeepSpeechActivity extends AppCompatActivity {
             // tv_numChannels.setText("numChannels=" + (numChannels == 1 ? "MONO" : "!MONO"));
 
             wave.seek(24); int sampleRate = this.readLEInt(wave);
-            assert (sampleRate == 16000); // 16000 Hz
+            assert (sampleRate == this._m.sampleRate()); // desired sample rate
             // tv_sampleRate.setText("sampleRate=" + (sampleRate == 16000 ? "16kHz" : "!16kHz"));
 
             wave.seek(34); char bitsPerSample = this.readLEChar(wave);

native_client/java/libdeepspeech/src/main/java/org/mozilla/deepspeech/libdeepspeech/DeepSpeechModel.java

@@ -32,6 +32,15 @@ public class DeepSpeechModel {
         this._msp  = impl.modelstatep_value(this._mspp);
     }
 
+   /**
+    * @brief Return the sample rate expected by the model.
+    *
+    * @return Sample rate.
+    */
+    public int sampleRate() {
+        return impl.GetModelSampleRate(this._msp);
+    }
+
    /**
     * @brief Frees associated resources and destroys model object.
     */