Add Java API example for hotwords. (#1442)

java-api-examples/.gitignore

@@ -1,3 +1,4 @@
 lib
 hs_err*
 !run-*.sh
+./hotwords_cn.txt

java-api-examples/NonStreamingDecodeFileTransducerHotwords.java

@@ -0,0 +1,62 @@
+// Copyright 2024 Xiaomi Corporation
+
+// This file shows how to use an offline transducer, i.e., non-streaming transducer,
+// to decode files with hotwords support.
+//
+// See also
+// https://k2-fsa.github.io/sherpa/onnx/hotwords/index.html#modeling-unit-is-cjkchar
+import com.k2fsa.sherpa.onnx.*;
+
+public class NonStreamingDecodeFileTransducerHotwords {
+  public static void main(String[] args) {
+    // please refer to
+    // https://k2-fsa.github.io/sherpa/onnx/hotwords/index.html#modeling-unit-is-cjkchar
+    // to download model files
+    String encoder =
+        "./sherpa-onnx-conformer-zh-stateless2-2023-05-23/encoder-epoch-99-avg-1.int8.onnx";
+    String decoder = "./sherpa-onnx-conformer-zh-stateless2-2023-05-23/decoder-epoch-99-avg-1.onnx";
+    String joiner = "./sherpa-onnx-conformer-zh-stateless2-2023-05-23/joiner-epoch-99-avg-1.onnx";
+    String tokens = "./sherpa-onnx-conformer-zh-stateless2-2023-05-23/tokens.txt";
+
+    String waveFilename = "./sherpa-onnx-conformer-zh-stateless2-2023-05-23/test_wavs/6.wav";
+
+    WaveReader reader = new WaveReader(waveFilename);
+
+    OfflineTransducerModelConfig transducer =
+        OfflineTransducerModelConfig.builder()
+            .setEncoder(encoder)
+            .setDecoder(decoder)
+            .setJoiner(joiner)
+            .build();
+
+    OfflineModelConfig modelConfig =
+        OfflineModelConfig.builder()
+            .setTransducer(transducer)
+            .setTokens(tokens)
+            .setNumThreads(1)
+            .setDebug(true)
+            .setModelingUnit("cjkchar")
+            .build();
+
+    OfflineRecognizerConfig config =
+        OfflineRecognizerConfig.builder()
+            .setOfflineModelConfig(modelConfig)
+            .setDecodingMethod("modified_beam_search")
+            .setHotwordsFile("./hotwords_cn.txt")
+            .setHotwordsScore(2.0f)
+            .build();
+
+    OfflineRecognizer recognizer = new OfflineRecognizer(config);
+    OfflineStream stream = recognizer.createStream();
+    stream.acceptWaveform(reader.getSamples(), reader.getSampleRate());
+
+    recognizer.decode(stream);
+
+    String text = recognizer.getResult(stream).getText();
+
+    System.out.printf("filename:%s\nresult:%s\n", waveFilename, text);
+
+    stream.release();
+    recognizer.release();
+  }
+}

java-api-examples/run-non-streaming-decode-file-transducer-hotwords.sh

@@ -0,0 +1,43 @@
+#!/usr/bin/env bash
+
+set -ex
+
+if [[ ! -f ../build/lib/libsherpa-onnx-jni.dylib  && ! -f ../build/lib/libsherpa-onnx-jni.so ]]; then
+  mkdir -p ../build
+  pushd ../build
+  cmake \
+    -DSHERPA_ONNX_ENABLE_PYTHON=OFF \
+    -DSHERPA_ONNX_ENABLE_TESTS=OFF \
+    -DSHERPA_ONNX_ENABLE_CHECK=OFF \
+    -DBUILD_SHARED_LIBS=ON \
+    -DSHERPA_ONNX_ENABLE_PORTAUDIO=OFF \
+    -DSHERPA_ONNX_ENABLE_JNI=ON \
+    ..
+
+  make -j4
+  ls -lh lib
+  popd
+fi
+
+if [ ! -f ../sherpa-onnx/java-api/build/sherpa-onnx.jar ]; then
+  pushd ../sherpa-onnx/java-api
+  make
+  popd
+fi
+
+if [ ! -f ./sherpa-onnx-conformer-zh-stateless2-2023-05-23/tokens.txt ]; then
+  wget https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/sherpa-onnx-conformer-zh-stateless2-2023-05-23.tar.bz2
+  tar xvf sherpa-onnx-conformer-zh-stateless2-2023-05-23.tar.bz2
+  rm sherpa-onnx-conformer-zh-stateless2-2023-05-23.tar.bz2
+fi
+
+if [ ! -f hotwords_cn.txt ]; then
+  cat > hotwords_cn.txt <<EOF
+朱丽楠
+EOF
+fi
+
+java \
+  -Djava.library.path=$PWD/../build/lib \
+  -cp ../sherpa-onnx/java-api/build/sherpa-onnx.jar \
+  NonStreamingDecodeFileTransducerHotwords.java