Add KWS examples for Java API (#930)

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

@@ -0,0 +1,66 @@
+// Copyright 2024 Xiaomi Corporation
+
+package com.k2fsa.sherpa.onnx;
+
+public class KeywordSpotter {
+    static {
+        System.loadLibrary("sherpa-onnx-jni");
+    }
+
+    private long ptr = 0;
+
+    public KeywordSpotter(KeywordSpotterConfig config) {
+        ptr = newFromFile(config);
+    }
+
+    public OnlineStream createStream(String keywords) {
+        long p = createStream(ptr, keywords);
+        return new OnlineStream(p);
+    }
+
+    public OnlineStream createStream() {
+        long p = createStream(ptr, "");
+        return new OnlineStream(p);
+    }
+
+    public void decode(OnlineStream s) {
+        decode(ptr, s.getPtr());
+    }
+
+    public boolean isReady(OnlineStream s) {
+        return isReady(ptr, s.getPtr());
+    }
+
+    public KeywordSpotterResult getResult(OnlineStream s) {
+        Object[] arr = getResult(ptr, s.getPtr());
+        String keyword = (String) arr[0];
+        String[] tokens = (String[]) arr[1];
+        float[] timestamps = (float[]) arr[2];
+        return new KeywordSpotterResult(keyword, tokens, timestamps);
+    }
+
+    protected void finalize() throws Throwable {
+        release();
+    }
+
+    // You'd better call it manually if it is not used anymore
+    public void release() {
+        if (this.ptr == 0) {
+            return;
+        }
+        delete(this.ptr);
+        this.ptr = 0;
+    }
+
+    private native long newFromFile(KeywordSpotterConfig config);
+
+    private native void delete(long ptr);
+
+    private native long createStream(long ptr, String keywords);
+
+    private native void decode(long ptr, long streamPtr);
+
+    private native boolean isReady(long ptr, long streamPtr);
+
+    private native Object[] getResult(long ptr, long streamPtr);
+}

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

@@ -0,0 +1,77 @@
+// Copyright 2024 Xiaomi Corporation
+
+package com.k2fsa.sherpa.onnx;
+
+public class KeywordSpotterConfig {
+    private final FeatureConfig featConfig;
+    private final OnlineModelConfig modelConfig;
+
+    private final int maxActivePaths;
+    private final String keywordsFile;
+    private final float keywordsScore;
+    private final float keywordsThreshold;
+    private final int numTrailingBlanks;
+
+    private KeywordSpotterConfig(Builder builder) {
+        this.featConfig = builder.featConfig;
+        this.modelConfig = builder.modelConfig;
+        this.maxActivePaths = builder.maxActivePaths;
+        this.keywordsFile = builder.keywordsFile;
+        this.keywordsScore = builder.keywordsScore;
+        this.keywordsThreshold = builder.keywordsThreshold;
+        this.numTrailingBlanks = builder.numTrailingBlanks;
+    }
+
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    public static class Builder {
+        private FeatureConfig featConfig = FeatureConfig.builder().build();
+        private OnlineModelConfig modelConfig = OnlineModelConfig.builder().build();
+        private int maxActivePaths = 4;
+        private String keywordsFile = "keywords.txt";
+        private float keywordsScore = 1.5f;
+        private float keywordsThreshold = 0.25f;
+        private int numTrailingBlanks = 2;
+
+        public KeywordSpotterConfig build() {
+            return new KeywordSpotterConfig(this);
+        }
+
+        public Builder setFeatureConfig(FeatureConfig featConfig) {
+            this.featConfig = featConfig;
+            return this;
+        }
+
+        public Builder setOnlineModelConfig(OnlineModelConfig modelConfig) {
+            this.modelConfig = modelConfig;
+            return this;
+        }
+
+        public Builder setMaxActivePaths(int maxActivePaths) {
+            this.maxActivePaths = maxActivePaths;
+            return this;
+        }
+
+        public Builder setKeywordsFile(String keywordsFile) {
+            this.keywordsFile = keywordsFile;
+            return this;
+        }
+
+        public Builder setKeywordsScore(float keywordsScore) {
+            this.keywordsScore = keywordsScore;
+            return this;
+        }
+
+        public Builder setKeywordsThreshold(float keywordsThreshold) {
+            this.keywordsThreshold = keywordsThreshold;
+            return this;
+        }
+
+        public Builder setNumTrailingBlanks(int numTrailingBlanks) {
+            this.numTrailingBlanks = numTrailingBlanks;
+            return this;
+        }
+    }
+}

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

@@ -0,0 +1,27 @@
+// Copyright 2024 Xiaomi Corporation
+
+package com.k2fsa.sherpa.onnx;
+
+public class KeywordSpotterResult {
+    private final String keyword;
+    private final String[] tokens;
+    private final float[] timestamps;
+
+    public KeywordSpotterResult(String keyword, String[] tokens, float[] timestamps) {
+        this.keyword = keyword;
+        this.tokens = tokens;
+        this.timestamps = timestamps;
+    }
+
+    public String getKeyword() {
+        return keyword;
+    }
+
+    public String[] getTokens() {
+        return tokens;
+    }
+
+    public float[] getTimestamps() {
+        return timestamps;
+    }
+}

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

@@ -10,7 +10,6 @@ public class OnlineRecognizer {
 
     private long ptr = 0;
 
-
     public OnlineRecognizer(OnlineRecognizerConfig config) {
         ptr = newFromFile(config);
     }
@@ -19,7 +18,6 @@ public class OnlineRecognizer {
         decode(ptr, s.getPtr());
     }
 
-
     public boolean isReady(OnlineStream s) {
         return isReady(ptr, s.getPtr());
     }