Refactor Java API (#806)

sherpa-onnx/java-api/.gitignore

@@ -1,2 +1,6 @@
 .idea
 java-api.iml
+out
+META-INF
+build
+*.jar

sherpa-onnx/java-api/Makefile

@@ -0,0 +1,42 @@
+
+# all .class and .jar files are put inside out_dir
+out_dir := build
+out_jar := $(out_dir)/sherpa-onnx.jar
+
+package_dir := com/k2fsa/sherpa/onnx
+
+java_files := WaveReader.java
+java_files += EndpointRule.java
+java_files += EndpointConfig.java
+java_files += FeatureConfig.java
+java_files += OnlineLMConfig.java
+java_files += OnlineParaformerModelConfig.java
+java_files += OnlineZipformer2CtcModelConfig.java
+java_files += OnlineTransducerModelConfig.java
+java_files += OnlineModelConfig.java
+java_files += OnlineStream.java
+java_files += OnlineRecognizerConfig.java
+java_files += OnlineRecognizerResult.java
+java_files += OnlineRecognizer.java
+
+class_files := $(java_files:%.java=%.class)
+
+java_files := $(addprefix src/$(package_dir)/,$(java_files))
+class_files := $(addprefix $(out_dir)/$(package_dir)/,$(class_files))
+
+$(info -- java files $(java_files))
+$(info --)
+$(info -- class files $(class_files))
+
+.phony: all clean
+
+all: $(out_jar)
+
+$(out_jar): $(class_files)
+	jar --create --verbose --file $(out_jar) -C $(out_dir) .
+
+clean:
+	$(RM) -rfv $(out_dir)
+
+$(class_files): $(out_dir)/$(package_dir)/%.class: src/$(package_dir)/%.java
+	javac -d $(out_dir) --class-path $(out_dir) $<

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

@@ -1,18 +1,22 @@
-/*
- * // Copyright 2022-2023 by zhaoming
- */
+// Copyright 2022-2023 by zhaoming
+// Copyright 2024 Xiaomi Corporation
 
 package com.k2fsa.sherpa.onnx;
 
 public class EndpointConfig {
+
     private final EndpointRule rule1;
     private final EndpointRule rule2;
     private final EndpointRule rule3;
 
-    public EndpointConfig(EndpointRule rule1, EndpointRule rule2, EndpointRule rule3) {
-        this.rule1 = rule1;
-        this.rule2 = rule2;
-        this.rule3 = rule3;
+    private EndpointConfig(Builder builder) {
+        this.rule1 = builder.rule1;
+        this.rule2 = builder.rule2;
+        this.rule3 = builder.rule3;
+    }
+
+    public static Builder builder() {
+        return new Builder();
     }
 
     public EndpointRule getRule1() {
@@ -26,4 +30,42 @@ public class EndpointConfig {
     public EndpointRule getRule3() {
         return rule3;
     }
+
+    public static class Builder {
+
+        private EndpointRule rule1 = EndpointRule.builder().
+                setMustContainNonSilence(false).
+                setMinTrailingSilence(2.4f).
+                setMinUtteranceLength(0).
+                build();
+        private EndpointRule rule2 = EndpointRule.builder().
+                setMustContainNonSilence(true).
+                setMinTrailingSilence(1.4f).
+                setMinUtteranceLength(0).
+                build();
+        private EndpointRule rule3 = EndpointRule.builder().
+                setMustContainNonSilence(false).
+                setMinTrailingSilence(0.0f).
+                setMinUtteranceLength(20.0f).
+                build();
+
+        public EndpointConfig build() {
+            return new EndpointConfig(this);
+        }
+
+        public Builder setRule1(EndpointRule rule) {
+            this.rule1 = rule;
+            return this;
+        }
+
+        public Builder setRule2(EndpointRule rule) {
+            this.rule2 = rule;
+            return this;
+        }
+
+        public Builder setRul3(EndpointRule rule) {
+            this.rule3 = rule;
+            return this;
+        }
+    }
 }

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

@@ -1,19 +1,21 @@
-/*
- * // Copyright 2022-2023 by zhaoming
- */
-
+// Copyright 2022-2023 by zhaoming
+// Copyright 2024 Xiaomi Corporation
 package com.k2fsa.sherpa.onnx;
 
 public class EndpointRule {
+
     private final boolean mustContainNonSilence;
     private final float minTrailingSilence;
     private final float minUtteranceLength;
 
-    public EndpointRule(
-            boolean mustContainNonSilence, float minTrailingSilence, float minUtteranceLength) {
-        this.mustContainNonSilence = mustContainNonSilence;
-        this.minTrailingSilence = minTrailingSilence;
-        this.minUtteranceLength = minUtteranceLength;
+    private EndpointRule(Builder builder) {
+        this.mustContainNonSilence = builder.mustContainNonSilence;
+        this.minTrailingSilence = builder.minTrailingSilence;
+        this.minUtteranceLength = builder.minUtteranceLength;
+    }
+
+    public static Builder builder() {
+        return new Builder();
     }
 
     public float getMinTrailingSilence() {
@@ -27,4 +29,29 @@ public class EndpointRule {
     public boolean getMustContainNonSilence() {
         return mustContainNonSilence;
     }
-}
+
+    public static class Builder {
+        private boolean mustContainNonSilence = false;
+        private float minTrailingSilence = 0;
+        private float minUtteranceLength = 0;
+
+        public EndpointRule build() {
+            return new EndpointRule(this);
+        }
+
+        public Builder setMustContainNonSilence(boolean mustContainNonSilence) {
+            this.mustContainNonSilence = mustContainNonSilence;
+            return this;
+        }
+
+        public Builder setMinTrailingSilence(float minTrailingSilence) {
+            this.minTrailingSilence = minTrailingSilence;
+            return this;
+        }
+
+        public Builder setMinUtteranceLength(float minUtteranceLength) {
+            this.minUtteranceLength = minUtteranceLength;
+            return this;
+        }
+    }
+}

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

@@ -1,6 +1,5 @@
-/*
- * // Copyright 2022-2023 by zhaoming
- */
+// Copyright 2022-2023 by zhaoming
+// Copyright 2024 Xiaomi Corporation
 
 package com.k2fsa.sherpa.onnx;
 
@@ -8,9 +7,13 @@ public class FeatureConfig {
     private final int sampleRate;
     private final int featureDim;
 
-    public FeatureConfig(int sampleRate, int featureDim) {
-        this.sampleRate = sampleRate;
-        this.featureDim = featureDim;
+    private FeatureConfig(Builder builder) {
+        this.sampleRate = builder.sampleRate;
+        this.featureDim = builder.featureDim;
+    }
+
+    public static Builder builder() {
+        return new Builder();
     }
 
     public int getSampleRate() {
@@ -20,4 +23,23 @@ public class FeatureConfig {
     public int getFeatureDim() {
         return featureDim;
     }
+
+    public static class Builder {
+        private int sampleRate = 16000;
+        private int featureDim = 80;
+
+        public FeatureConfig build() {
+            return new FeatureConfig(this);
+        }
+
+        public Builder setSampleRate(int sampleRate) {
+            this.sampleRate = sampleRate;
+            return this;
+        }
+
+        public Builder setFeatureDim(int featureDim) {
+            this.featureDim = featureDim;
+            return this;
+        }
+    }
 }

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

@@ -1,16 +1,20 @@
-/*
- * // Copyright 2022-2023 by zhaoming
- */
+// Copyright 2022-2023 by zhaoming
+// Copyright 2024 Xiaomi Corporation
 
 package com.k2fsa.sherpa.onnx;
 
 public class OnlineLMConfig {
+
     private final String model;
     private final float scale;
 
-    public OnlineLMConfig(String model, float scale) {
-        this.model = model;
-        this.scale = scale;
+    private OnlineLMConfig(Builder builder) {
+        this.model = builder.model;
+        this.scale = builder.scale;
+    }
+
+    public static Builder builder() {
+        return new Builder();
     }
 
     public String getModel() {
@@ -20,4 +24,23 @@ public class OnlineLMConfig {
     public float getScale() {
         return scale;
     }
-}
+
+    public static class Builder {
+        private String model = "";
+        private float scale = 1.0f;
+
+        public OnlineLMConfig build() {
+            return new OnlineLMConfig(this);
+        }
+
+        public Builder setModel(String model) {
+            this.model = model;
+            return this;
+        }
+
+        public Builder setScale(float scale) {
+            this.scale = scale;
+            return this;
+        }
+    }
+}

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

@@ -1,36 +1,30 @@
-/*
- * // Copyright 2022-2023 by zhaoming
- */
+// Copyright 2022-2023 by zhaoming
+// Copyright 2024 Xiaomi Corporation
 
 package com.k2fsa.sherpa.onnx;
 
 public class OnlineModelConfig {
-    private final OnlineParaformerModelConfig paraformer;
     private final OnlineTransducerModelConfig transducer;
+    private final OnlineParaformerModelConfig paraformer;
     private final OnlineZipformer2CtcModelConfig zipformer2Ctc;
     private final String tokens;
     private final int numThreads;
     private final boolean debug;
-    private final String provider = "cpu";
-    private String modelType = "";
+    private final String provider;
+    private final String modelType;
+    private OnlineModelConfig(Builder builder) {
+        this.transducer = builder.transducer;
+        this.paraformer = builder.paraformer;
+        this.zipformer2Ctc = builder.zipformer2Ctc;
+        this.tokens = builder.tokens;
+        this.numThreads = builder.numThreads;
+        this.debug = builder.debug;
+        this.provider = builder.provider;
+        this.modelType = builder.modelType;
+    }
 
-    public OnlineModelConfig(
-            String tokens,
-            int numThreads,
-            boolean debug,
-            String modelType,
-            OnlineParaformerModelConfig paraformer,
-            OnlineTransducerModelConfig transducer,
-            OnlineZipformer2CtcModelConfig zipformer2Ctc
-            ) {
-
-        this.tokens = tokens;
-        this.numThreads = numThreads;
-        this.debug = debug;
-        this.modelType = modelType;
-        this.paraformer = paraformer;
-        this.transducer = transducer;
-        this.zipformer2Ctc = zipformer2Ctc;
+    public static Builder builder() {
+        return new Builder();
     }
 
     public OnlineParaformerModelConfig getParaformer() {
@@ -41,6 +35,10 @@ public class OnlineModelConfig {
         return transducer;
     }
 
+    public OnlineZipformer2CtcModelConfig getZipformer2Ctc() {
+        return zipformer2Ctc;
+    }
+
     public String getTokens() {
         return tokens;
     }
@@ -52,4 +50,67 @@ public class OnlineModelConfig {
     public boolean getDebug() {
         return debug;
     }
+
+    public String getProvider() {
+        return provider;
+    }
+
+    public String getModelType() {
+        return modelType;
+    }
+
+    public static class Builder {
+        private OnlineParaformerModelConfig paraformer = OnlineParaformerModelConfig.builder().build();
+        private OnlineTransducerModelConfig transducer = OnlineTransducerModelConfig.builder().build();
+        private OnlineZipformer2CtcModelConfig zipformer2Ctc = OnlineZipformer2CtcModelConfig.builder().build();
+        private String tokens = "";
+        private int numThreads = 1;
+        private boolean debug = true;
+        private String provider = "cpu";
+        private String modelType = "";
+
+        public OnlineModelConfig build() {
+            return new OnlineModelConfig(this);
+        }
+
+        public Builder setTransducer(OnlineTransducerModelConfig transducer) {
+            this.transducer = transducer;
+            return this;
+        }
+
+        public Builder setParaformer(OnlineParaformerModelConfig paraformer) {
+            this.paraformer = paraformer;
+            return this;
+        }
+
+        public Builder setZipformer2Ctc(OnlineZipformer2CtcModelConfig zipformer2Ctc) {
+            this.zipformer2Ctc = zipformer2Ctc;
+            return this;
+        }
+
+        public Builder setTokens(String tokens) {
+            this.tokens = tokens;
+            return this;
+        }
+
+        public Builder setNumThreads(int numThreads) {
+            this.numThreads = numThreads;
+            return this;
+        }
+
+        public Builder setDebug(boolean debug) {
+            this.debug = debug;
+            return this;
+        }
+
+        public Builder setProvider(String provider) {
+            this.provider = provider;
+            return this;
+        }
+
+        public Builder setModelType(String modelType) {
+            this.modelType = modelType;
+            return this;
+        }
+    }
 }

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

@@ -1,6 +1,5 @@
-/*
- * // Copyright 2022-2023 by zhaoming
- */
+// Copyright 2022-2023 by zhaoming
+// Copyright 2024 Xiaomi Corporation
 
 package com.k2fsa.sherpa.onnx;
 
@@ -8,9 +7,13 @@ public class OnlineParaformerModelConfig {
     private final String encoder;
     private final String decoder;
 
-    public OnlineParaformerModelConfig(String encoder, String decoder) {
-        this.encoder = encoder;
-        this.decoder = decoder;
+    private OnlineParaformerModelConfig(Builder builder) {
+        this.encoder = builder.encoder;
+        this.decoder = builder.decoder;
+    }
+
+    public static Builder builder() {
+        return new Builder();
     }
 
     public String getEncoder() {
@@ -20,4 +23,23 @@ public class OnlineParaformerModelConfig {
     public String getDecoder() {
         return decoder;
     }
+
+    public static class Builder {
+        private String encoder = "";
+        private String decoder = "";
+
+        public OnlineParaformerModelConfig build() {
+            return new OnlineParaformerModelConfig(this);
+        }
+
+        public Builder setEncoder(String encoder) {
+            this.encoder = encoder;
+            return this;
+        }
+
+        public Builder setDecoder(String decoder) {
+            this.decoder = decoder;
+            return this;
+        }
+    }
 }

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

@@ -1,234 +1,21 @@
-/*
- * // Copyright 2022-2023 by zhaoming
- * // the online recognizer for sherpa-onnx, it can load config from a file
- * // or by argument
- */
-/*
-usage example:
-
-    String cfgpath=appdir+"/modelconfig.cfg";
-	OnlineRecognizer.setSoPath(soPath);   //set so lib path
-
-    OnlineRecognizer rcgOjb = new OnlineRecognizer();   //create a recognizer
-    rcgOjb = new OnlineRecognizer(cfgFile);    //set model config file
-    CreateStream streamObj=rcgOjb.CreateStream();       //create a stream for read wav data
-    float[] buffer = rcgOjb.readWavFile(wavfilename); // read data from file
-    streamObj.acceptWaveform(buffer); // feed stream with data
-    streamObj.inputFinished(); // tell engine you done with all data
-    OnlineStream ssObj[] = new OnlineStream[1];
-    while (rcgOjb.isReady(streamObj)) { // engine is ready for unprocessed data
-                ssObj[0] = streamObj;
-                rcgOjb.decodeStreams(ssObj); // decode for multiple stream
-                // rcgOjb.DecodeStream(streamObj);   // decode for single stream
-            }
-
-    String recText = "simple:" + rcgOjb.getResult(streamObj) + "\n";
-    byte[] utf8Data = recText.getBytes(StandardCharsets.UTF_8);
-    System.out.println(new String(utf8Data));
-    rcgOjb.reSet(streamObj);
-    rcgOjb.releaseStream(streamObj); // release stream
-    rcgOjb.release(); // release recognizer
-
-*/
+// Copyright 2022-2023 by zhaoming
+// Copyright 2024 Xiaomi Corporation
 package com.k2fsa.sherpa.onnx;
 
-import java.io.BufferedInputStream;
-import java.io.File;
-import java.io.FileInputStream;
-import java.io.InputStream;
-import java.util.Enumeration;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Properties;
 
 public class OnlineRecognizer {
+    static {
+        System.loadLibrary("sherpa-onnx-jni");
+    }
+
     private long ptr = 0; // this is the asr engine ptrss
 
-    private int sampleRate = 16000;
 
-    // load config file for OnlineRecognizer
-    public OnlineRecognizer(String modelCfgPath) {
-        Map<String, String> proMap = this.readProperties(modelCfgPath);
-        try {
-            int sampleRate = Integer.parseInt(proMap.getOrDefault("sample_rate", "16000").trim());
-            this.sampleRate = sampleRate;
-            EndpointRule rule1 =
-                    new EndpointRule(
-                            false,
-                            Float.parseFloat(proMap.getOrDefault("rule1_min_trailing_silence", "2.4").trim()),
-                            0.0F);
-            EndpointRule rule2 =
-                    new EndpointRule(
-                            true,
-                            Float.parseFloat(proMap.getOrDefault("rule2_min_trailing_silence", "1.2").trim()),
-                            0.0F);
-            EndpointRule rule3 =
-                    new EndpointRule(
-                            false,
-                            0.0F,
-                            Float.parseFloat(proMap.getOrDefault("rule3_min_utterance_length", "20").trim()));
-            EndpointConfig endCfg = new EndpointConfig(rule1, rule2, rule3);
-
-            OnlineParaformerModelConfig modelParaCfg =
-                    new OnlineParaformerModelConfig(
-                            proMap.getOrDefault("encoder", "").trim(), proMap.getOrDefault("decoder", "").trim());
-            OnlineTransducerModelConfig modelTranCfg =
-                    new OnlineTransducerModelConfig(
-                            proMap.getOrDefault("encoder", "").trim(),
-                            proMap.getOrDefault("decoder", "").trim(),
-                            proMap.getOrDefault("joiner", "").trim());
-            OnlineZipformer2CtcModelConfig zipformer2CtcConfig = new OnlineZipformer2CtcModelConfig("");
-            OnlineModelConfig modelCfg =
-                    new OnlineModelConfig(
-                            proMap.getOrDefault("tokens", "").trim(),
-                            Integer.parseInt(proMap.getOrDefault("num_threads", "4").trim()),
-                            false,
-                            proMap.getOrDefault("model_type", "zipformer").trim(),
-                            modelParaCfg,
-                            modelTranCfg, zipformer2CtcConfig);
-            FeatureConfig featConfig =
-                    new FeatureConfig(
-                            sampleRate, Integer.parseInt(proMap.getOrDefault("feature_dim", "80").trim()));
-            OnlineLMConfig onlineLmConfig =
-                    new OnlineLMConfig(
-                            proMap.getOrDefault("lm_model", "").trim(),
-                            Float.parseFloat(proMap.getOrDefault("lm_scale", "0.5").trim()));
-
-            OnlineRecognizerConfig rcgCfg =
-                    new OnlineRecognizerConfig(
-                            featConfig,
-                            modelCfg,
-                            endCfg,
-                            onlineLmConfig,
-                            Boolean.parseBoolean(proMap.getOrDefault("enable_endpoint_detection", "true").trim()),
-                            proMap.getOrDefault("decoding_method", "modified_beam_search").trim(),
-                            Integer.parseInt(proMap.getOrDefault("max_active_paths", "4").trim()),
-                            proMap.getOrDefault("hotwords_file", "").trim(),
-                            Float.parseFloat(proMap.getOrDefault("hotwords_score", "1.5").trim()));
-            // create a new Recognizer, first parameter kept for android asset_manager ANDROID_API__ >= 9
-            this.ptr = createOnlineRecognizer(new Object(), rcgCfg);
-
-        } catch (Exception e) {
-            System.err.println(e);
-        }
-    }
-
-    // use for android asset_manager ANDROID_API__ >= 9
-    public OnlineRecognizer(Object assetManager, String modelCfgPath) {
-        Map<String, String> proMap = this.readProperties(modelCfgPath);
-        try {
-            int sampleRate = Integer.parseInt(proMap.getOrDefault("sample_rate", "16000").trim());
-            this.sampleRate = sampleRate;
-            EndpointRule rule1 =
-                    new EndpointRule(
-                            false,
-                            Float.parseFloat(proMap.getOrDefault("rule1_min_trailing_silence", "2.4").trim()),
-                            0.0F);
-            EndpointRule rule2 =
-                    new EndpointRule(
-                            true,
-                            Float.parseFloat(proMap.getOrDefault("rule2_min_trailing_silence", "1.2").trim()),
-                            0.0F);
-            EndpointRule rule3 =
-                    new EndpointRule(
-                            false,
-                            0.0F,
-                            Float.parseFloat(proMap.getOrDefault("rule3_min_utterance_length", "20").trim()));
-            EndpointConfig endCfg = new EndpointConfig(rule1, rule2, rule3);
-            OnlineParaformerModelConfig modelParaCfg =
-                    new OnlineParaformerModelConfig(
-                            proMap.getOrDefault("encoder", "").trim(), proMap.getOrDefault("decoder", "").trim());
-            OnlineTransducerModelConfig modelTranCfg =
-                    new OnlineTransducerModelConfig(
-                            proMap.getOrDefault("encoder", "").trim(),
-                            proMap.getOrDefault("decoder", "").trim(),
-                            proMap.getOrDefault("joiner", "").trim());
-            OnlineZipformer2CtcModelConfig zipformer2CtcConfig = new OnlineZipformer2CtcModelConfig("");
-
-            OnlineModelConfig modelCfg =
-                    new OnlineModelConfig(
-                            proMap.getOrDefault("tokens", "").trim(),
-                            Integer.parseInt(proMap.getOrDefault("num_threads", "4").trim()),
-                            false,
-                            proMap.getOrDefault("model_type", "zipformer").trim(),
-                            modelParaCfg,
-                            modelTranCfg, zipformer2CtcConfig);
-            FeatureConfig featConfig =
-                    new FeatureConfig(
-                            sampleRate, Integer.parseInt(proMap.getOrDefault("feature_dim", "80").trim()));
-
-            OnlineLMConfig onlineLmConfig =
-                    new OnlineLMConfig(
-                            proMap.getOrDefault("lm_model", "").trim(),
-                            Float.parseFloat(proMap.getOrDefault("lm_scale", "0.5").trim()));
-
-            OnlineRecognizerConfig rcgCfg =
-                    new OnlineRecognizerConfig(
-                            featConfig,
-                            modelCfg,
-                            endCfg,
-                            onlineLmConfig,
-                            Boolean.parseBoolean(proMap.getOrDefault("enable_endpoint_detection", "true").trim()),
-                            proMap.getOrDefault("decoding_method", "modified_beam_search").trim(),
-                            Integer.parseInt(proMap.getOrDefault("max_active_paths", "4").trim()),
-                            proMap.getOrDefault("hotwords_file", "").trim(),
-                            Float.parseFloat(proMap.getOrDefault("hotwords_score", "1.5").trim()));
-            // create a new Recognizer, first parameter kept for android asset_manager ANDROID_API__ >= 9
-            this.ptr = createOnlineRecognizer(assetManager, rcgCfg);
-
-        } catch (Exception e) {
-            System.err.println(e);
-        }
-    }
-
-    // set onlineRecognizer by parameter
-    public OnlineRecognizer(
-            String tokens,
-            String encoder,
-            String decoder,
-            String joiner,
-            int numThreads,
-            int sampleRate,
-            int featureDim,
-            boolean enableEndpointDetection,
-            float rule1MinTrailingSilence,
-            float rule2MinTrailingSilence,
-            float rule3MinUtteranceLength,
-            String decodingMethod,
-            String lm_model,
-            float lm_scale,
-            int maxActivePaths,
-            String hotwordsFile,
-            float hotwordsScore,
-            String modelType) {
-        this.sampleRate = sampleRate;
-        EndpointRule rule1 = new EndpointRule(false, rule1MinTrailingSilence, 0.0F);
-        EndpointRule rule2 = new EndpointRule(true, rule2MinTrailingSilence, 0.0F);
-        EndpointRule rule3 = new EndpointRule(false, 0.0F, rule3MinUtteranceLength);
-        EndpointConfig endCfg = new EndpointConfig(rule1, rule2, rule3);
-        OnlineParaformerModelConfig modelParaCfg = new OnlineParaformerModelConfig(encoder, decoder);
-        OnlineTransducerModelConfig modelTranCfg =
-                new OnlineTransducerModelConfig(encoder, decoder, joiner);
-        OnlineZipformer2CtcModelConfig zipformer2CtcConfig = new OnlineZipformer2CtcModelConfig("");
-        OnlineModelConfig modelCfg =
-                new OnlineModelConfig(tokens, numThreads, false, modelType, modelParaCfg, modelTranCfg, zipformer2CtcConfig);
-        FeatureConfig featConfig = new FeatureConfig(sampleRate, featureDim);
-        OnlineLMConfig onlineLmConfig = new OnlineLMConfig(lm_model, lm_scale);
-        OnlineRecognizerConfig rcgCfg =
-                new OnlineRecognizerConfig(
-                        featConfig,
-                        modelCfg,
-                        endCfg,
-                        onlineLmConfig,
-                        enableEndpointDetection,
-                        decodingMethod,
-                        maxActivePaths,
-                        hotwordsFile,
-                        hotwordsScore);
-        // create a new Recognizer, first parameter kept for android asset_manager ANDROID_API__ >= 9
-        this.ptr = createOnlineRecognizer(new Object(), rcgCfg);
+    public OnlineRecognizer(OnlineRecognizerConfig config) {
+        ptr = newFromFile(config);
     }
 
+    /*
     public static float[] readWavFile(String fileName) {
         // read data from the filename
         Object[] wavdata = readWave(fileName);
@@ -238,139 +25,67 @@ public class OnlineRecognizer {
 
         return floatData;
     }
+    */
 
-    // load the libsherpa-onnx-jni.so lib
-    public static void loadSoLib(String soPath) {
-        // load libsherpa-onnx-jni.so lib from the path
 
-        System.out.println("so lib path=" + soPath + "\n");
-        System.load(soPath.trim());
-        System.out.println("load so lib succeed\n");
+    public void decode(OnlineStream s) {
+        decode(ptr, s.getPtr());
     }
 
-    public static void setSoPath(String soPath) {
-        OnlineRecognizer.loadSoLib(soPath);
-        OnlineStream.loadSoLib(soPath);
+
+    public boolean isReady(OnlineStream s) {
+        return isReady(ptr, s.getPtr());
     }
 
-    private static native Object[] readWave(String fileName); // static
-
-    private Map<String, String> readProperties(String modelCfgPath) {
-        // read and parse config file
-        Properties props = new Properties();
-        Map<String, String> proMap = new HashMap<>();
-        try {
-            File file = new File(modelCfgPath);
-            if (!file.exists()) {
-                System.out.println("model cfg file not exists!");
-                System.exit(0);
-            }
-            InputStream in = new BufferedInputStream(new FileInputStream(modelCfgPath));
-            props.load(in);
-            Enumeration en = props.propertyNames();
-            while (en.hasMoreElements()) {
-                String key = (String) en.nextElement();
-                String Property = props.getProperty(key);
-                proMap.put(key, Property);
-            }
-
-        } catch (Exception e) {
-            e.printStackTrace();
-        }
-        return proMap;
+    public boolean isEndpoint(OnlineStream s) {
+        return isEndpoint(ptr, s.getPtr());
     }
 
-    public void decodeStream(OnlineStream s) throws Exception {
-        if (this.ptr == 0) throw new Exception("null exception for recognizer ptr");
-        long streamPtr = s.getPtr();
-        if (streamPtr == 0) throw new Exception("null exception for stream ptr");
-        // when feeded samples to engine, call DecodeStream to let it process
-        decodeStream(this.ptr, streamPtr);
+    public void reset(OnlineStream s) {
+        reset(ptr, s.getPtr());
     }
 
-    public void decodeStreams(OnlineStream[] ssOjb) throws Exception {
-        if (this.ptr == 0) throw new Exception("null exception for recognizer ptr");
-        // decode for multiple streams
-        long[] ss = new long[ssOjb.length];
-        for (int i = 0; i < ssOjb.length; i++) {
-            ss[i] = ssOjb[i].getPtr();
-            if (ss[i] == 0) throw new Exception("null exception for stream ptr");
-        }
-        decodeStreams(this.ptr, ss);
-    }
-
-    public boolean isReady(OnlineStream s) throws Exception {
-        // whether the engine is ready for decode
-        if (this.ptr == 0) throw new Exception("null exception for recognizer ptr");
-        long streamPtr = s.getPtr();
-        if (streamPtr == 0) throw new Exception("null exception for stream ptr");
-        return isReady(this.ptr, streamPtr);
-    }
-
-    public String getResult(OnlineStream s) throws Exception {
-        // get text from the engine
-        if (this.ptr == 0) throw new Exception("null exception for recognizer ptr");
-        long streamPtr = s.getPtr();
-        if (streamPtr == 0) throw new Exception("null exception for stream ptr");
-        return getResult(this.ptr, streamPtr);
-    }
-
-    public boolean isEndpoint(OnlineStream s) throws Exception {
-        if (this.ptr == 0) throw new Exception("null exception for recognizer ptr");
-        long streamPtr = s.getPtr();
-        if (streamPtr == 0) throw new Exception("null exception for stream ptr");
-        return isEndpoint(this.ptr, streamPtr);
-    }
-
-    public void reSet(OnlineStream s) throws Exception {
-        if (this.ptr == 0) throw new Exception("null exception for recognizer ptr");
-        long streamPtr = s.getPtr();
-        if (streamPtr == 0) throw new Exception("null exception for stream ptr");
-        reSet(this.ptr, streamPtr);
-    }
-
-    public OnlineStream createStream() throws Exception {
-        // create one stream for data to feed in
-        if (this.ptr == 0) throw new Exception("null exception for recognizer ptr");
-        long streamPtr = createStream(this.ptr);
-        OnlineStream stream = new OnlineStream(streamPtr, this.sampleRate);
-        return stream;
+    public OnlineStream createStream() {
+        long p = createStream(ptr, "");
+        return new OnlineStream(p);
     }
 
+    @Override
     protected void finalize() throws Throwable {
         release();
     }
 
     // recognizer release, you'd better call it manually if not use anymore
     public void release() {
-        if (this.ptr == 0) return;
-        deleteOnlineRecognizer(this.ptr);
+        if (this.ptr == 0) {
+            return;
+        }
+        delete(this.ptr);
         this.ptr = 0;
     }
 
-    // JNI interface libsherpa-onnx-jni.so
-
-    // stream release, you'd better call it manually if not use anymore
-    public void releaseStream(OnlineStream s) {
-        s.release();
+    public OnlineRecognizerResult getResult(OnlineStream s) {
+        Object[] arr = getResult(ptr, s.getPtr());
+        String text = (String) arr[0];
+        String[] tokens = (String[]) arr[1];
+        float[] timestamps = (float[]) arr[2];
+        return new OnlineRecognizerResult(text, tokens, timestamps);
     }
 
-    private native String getResult(long ptr, long streamPtr);
 
-    private native void decodeStream(long ptr, long streamPtr);
+    private native void delete(long ptr);
 
-    private native void decodeStreams(long ptr, long[] ssPtr);
+    private native long newFromFile(OnlineRecognizerConfig config);
 
-    private native boolean isReady(long ptr, long streamPtr);
+    private native long createStream(long ptr, String hotwords);
 
-    // first parameter keep for android asset_manager ANDROID_API__ >= 9
-    private native long createOnlineRecognizer(Object asset, OnlineRecognizerConfig config);
+    private native void reset(long ptr, long streamPtr);
 
-    private native long createStream(long ptr);
-
-    private native void deleteOnlineRecognizer(long ptr);
+    private native void decode(long ptr, long streamPtr);
 
     private native boolean isEndpoint(long ptr, long streamPtr);
 
-    private native void reSet(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/OnlineRecognizerConfig.java

@@ -1,66 +1,95 @@
-/*
- * // Copyright 2022-2023 by zhaoming
- */
-
+// Copyright 2022-2023 by zhaoming
+// Copyright 2024 Xiaomi Corporation
 package com.k2fsa.sherpa.onnx;
 
 public class OnlineRecognizerConfig {
     private final FeatureConfig featConfig;
     private final OnlineModelConfig modelConfig;
-    private final EndpointConfig endpointConfig;
     private final OnlineLMConfig lmConfig;
+    private final EndpointConfig endpointConfig;
     private final boolean enableEndpoint;
     private final String decodingMethod;
     private final int maxActivePaths;
     private final String hotwordsFile;
     private final float hotwordsScore;
-
-    public OnlineRecognizerConfig(
-            FeatureConfig featConfig,
-            OnlineModelConfig modelConfig,
-            EndpointConfig endpointConfig,
-            OnlineLMConfig lmConfig,
-            boolean enableEndpoint,
-            String decodingMethod,
-            int maxActivePaths,
-            String hotwordsFile,
-            float hotwordsScore) {
-        this.featConfig = featConfig;
-        this.modelConfig = modelConfig;
-        this.endpointConfig = endpointConfig;
-        this.lmConfig = lmConfig;
-        this.enableEndpoint = enableEndpoint;
-        this.decodingMethod = decodingMethod;
-        this.maxActivePaths = maxActivePaths;
-        this.hotwordsFile = hotwordsFile;
-        this.hotwordsScore = hotwordsScore;
+    private OnlineRecognizerConfig(Builder builder) {
+        this.featConfig = builder.featConfig;
+        this.modelConfig = builder.modelConfig;
+        this.lmConfig = builder.lmConfig;
+        this.endpointConfig = builder.endpointConfig;
+        this.enableEndpoint = builder.enableEndpoint;
+        this.decodingMethod = builder.decodingMethod;
+        this.maxActivePaths = builder.maxActivePaths;
+        this.hotwordsFile = builder.hotwordsFile;
+        this.hotwordsScore = builder.hotwordsScore;
     }
 
-    public OnlineLMConfig getLmConfig() {
-        return lmConfig;
-    }
-
-    public FeatureConfig getFeatConfig() {
-        return featConfig;
+    public static Builder builder() {
+        return new Builder();
     }
 
     public OnlineModelConfig getModelConfig() {
         return modelConfig;
     }
 
-    public EndpointConfig getEndpointConfig() {
-        return endpointConfig;
-    }
+    public static class Builder {
+        private FeatureConfig featConfig = FeatureConfig.builder().build();
+        private OnlineModelConfig modelConfig = OnlineModelConfig.builder().build();
+        private OnlineLMConfig lmConfig = OnlineLMConfig.builder().build();
+        private EndpointConfig endpointConfig = EndpointConfig.builder().build();
+        private boolean enableEndpoint = true;
+        private String decodingMethod = "greedy_search";
+        private int maxActivePaths = 4;
+        private String hotwordsFile = "";
+        private float hotwordsScore = 1.5f;
 
-    public boolean isEnableEndpoint() {
-        return enableEndpoint;
-    }
+        public OnlineRecognizerConfig build() {
+            return new OnlineRecognizerConfig(this);
+        }
 
-    public String getDecodingMethod() {
-        return decodingMethod;
-    }
+        public Builder setFeatureConfig(FeatureConfig featConfig) {
+            this.featConfig = featConfig;
+            return this;
+        }
 
-    public int getMaxActivePaths() {
-        return maxActivePaths;
+        public Builder setOnlineModelConfig(OnlineModelConfig modelConfig) {
+            this.modelConfig = modelConfig;
+            return this;
+        }
+
+        public Builder setOnlineLMConfig(OnlineLMConfig lmConfig) {
+            this.lmConfig = lmConfig;
+            return this;
+        }
+
+        public Builder setEndpointConfig(EndpointConfig endpointConfig) {
+            this.endpointConfig = endpointConfig;
+            return this;
+        }
+
+        public Builder setEnableEndpoint(boolean enableEndpoint) {
+            this.enableEndpoint = enableEndpoint;
+            return this;
+        }
+
+        public Builder setDecodingMethod(String decodingMethod) {
+            this.decodingMethod = decodingMethod;
+            return this;
+        }
+
+        public Builder setMaxActivePaths(int maxActivePaths) {
+            this.maxActivePaths = maxActivePaths;
+            return this;
+        }
+
+        public Builder setHotwordsFile(String hotwordsFile) {
+            this.hotwordsFile = hotwordsFile;
+            return this;
+        }
+
+        public Builder setHotwordsScore(float hotwordsScore) {
+            this.hotwordsScore = hotwordsScore;
+            return this;
+        }
     }
 }

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

@@ -0,0 +1,26 @@
+// Copyright 2024 Xiaomi Corporation
+package com.k2fsa.sherpa.onnx;
+
+public class OnlineRecognizerResult {
+    private final String text;
+    private final String[] tokens;
+    private final float[] timestamps;
+
+    public OnlineRecognizerResult(String text, String[] tokens, float[] timestamps) {
+        this.text = text;
+        this.tokens = tokens;
+        this.timestamps = timestamps;
+    }
+
+    public String getText() {
+        return text;
+    }
+
+    public String[] getTokens() {
+        return tokens;
+    }
+
+    public float[] getTimestamps() {
+        return timestamps;
+    }
+}

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

@@ -1,84 +1,56 @@
-/*
- * // Copyright 2022-2023 by zhaoming
- */
-// Stream is used for feeding data to the asr engine
+// Copyright 2022-2023 by zhaoming
+// Copyright 2024 Xiaomi Corporation
 package com.k2fsa.sherpa.onnx;
 
 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;
+    static {
+        System.loadLibrary("sherpa-onnx-jni");
     }
 
-    public static void loadSoLib(String soPath) {
-        // load .so lib from the path
-        System.load(soPath.trim()); // ("sherpa-onnx-jni-java");
+    private long ptr = 0;
+
+    public OnlineStream() {
+        this.ptr = 0;
+    }
+
+    public OnlineStream(long ptr) {
+        this.ptr = ptr;
     }
 
     public long getPtr() {
         return ptr;
     }
 
-    public void acceptWaveform(float[] samples) throws Exception {
-        if (this.ptr == 0) throw new Exception("null exception for stream ptr");
+    public void setPtr(long ptr) {
+        this.ptr = ptr;
+    }
 
-        // feed wave data to asr engine
-        acceptWaveform(this.ptr, this.sampleRate, samples);
+    public void acceptWaveform(float[] samples, int sampleRate) {
+        acceptWaveform(this.ptr, samples, sampleRate);
     }
 
     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 void release() {
         // stream object must be release after used
-        if (this.ptr == 0) return;
-        deleteStream(this.ptr);
+        if (this.ptr == 0) {
+            return;
+        }
+        delete(this.ptr);
         this.ptr = 0;
     }
 
+    @Override
     protected void finalize() throws Throwable {
         release();
+        super.finalize();
     }
 
-    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 acceptWaveform(long ptr, float[] samples, int sampleRate);
 
     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);
-}
+    private native void delete(long ptr);
+}

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

@@ -1,6 +1,5 @@
-/*
- * // Copyright 2022-2023 by zhaoming
- */
+// Copyright 2022-2023 by zhaoming
+// Copyright 2024 Xiaomi Corporation
 
 package com.k2fsa.sherpa.onnx;
 
@@ -9,10 +8,14 @@ public class OnlineTransducerModelConfig {
     private final String decoder;
     private final String joiner;
 
-    public OnlineTransducerModelConfig(String encoder, String decoder, String joiner) {
-        this.encoder = encoder;
-        this.decoder = decoder;
-        this.joiner = joiner;
+    private OnlineTransducerModelConfig(Builder builder) {
+        this.encoder = builder.encoder;
+        this.decoder = builder.decoder;
+        this.joiner = builder.joiner;
+    }
+
+    public static Builder builder() {
+        return new Builder();
     }
 
     public String getEncoder() {
@@ -26,4 +29,29 @@ public class OnlineTransducerModelConfig {
     public String getJoiner() {
         return joiner;
     }
+
+    public static class Builder {
+        private String encoder = "";
+        private String decoder = "";
+        private String joiner = "";
+
+        public OnlineTransducerModelConfig build() {
+            return new OnlineTransducerModelConfig(this);
+        }
+
+        public Builder setEncoder(String encoder) {
+            this.encoder = encoder;
+            return this;
+        }
+
+        public Builder setDecoder(String decoder) {
+            this.decoder = decoder;
+            return this;
+        }
+
+        public Builder setJoiner(String joiner) {
+            this.joiner = joiner;
+            return this;
+        }
+    }
 }

sherpa-onnx/java-api/src/com/k2fsa/sherpa/onnx/OnlineZipformer2CtcModelConfig.java

@@ -1,14 +1,31 @@
+// Copyright 2024 Xiaomi Corporation
 package com.k2fsa.sherpa.onnx;
 
 public class OnlineZipformer2CtcModelConfig {
     private final String model;
 
-    public OnlineZipformer2CtcModelConfig(String model) {
-        this.model = model;
+    private OnlineZipformer2CtcModelConfig(Builder builder) {
+        this.model = builder.model;
+    }
+
+    public static Builder builder() {
+        return new Builder();
     }
 
     public String getModel() {
         return model;
     }
 
+    public static class Builder {
+        private String model = "";
+
+        public OnlineZipformer2CtcModelConfig build() {
+            return new OnlineZipformer2CtcModelConfig(this);
+        }
+
+        public Builder setModel(String model) {
+            this.model = model;
+            return this;
+        }
+    }
 }

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

@@ -0,0 +1,29 @@
+// Copyright 2024 Xiaomi Corporation
+package com.k2fsa.sherpa.onnx;
+
+public class WaveReader {
+    static {
+        System.loadLibrary("sherpa-onnx-jni");
+    }
+
+    private final int sampleRate;
+    private final float[] samples;
+
+    // It supports only single channel, 16-bit wave file.
+    // It will exit the program if the given file has a wrong format
+    public WaveReader(String filename) {
+        Object[] arr = readWaveFromFile(filename);
+        samples = (float[]) arr[0];
+        sampleRate = (int) arr[1];
+    }
+
+    public int getSampleRate() {
+        return sampleRate;
+    }
+
+    public float[] getSamples() {
+        return samples;
+    }
+
+    private native Object[] readWaveFromFile(String filename);
+}