Check-in initial version of TextClassifierService in external/libtc

1. Move existing native codes to native folder.
2. Move existing jni java codes to jni.
3. Copy TextClassifierService java codes to java

Three build targets are introduced:
1. TextClassifierServiceLibNoManifest:All the java codes without
   AndroidManifest, will be used by ExtServices.
2. TextClassifierServiceLib: All the java codes with AndroidManifest,
   used by our test and our own APK.
3. TextClassifierService: Our standalone TCS APK, mostly for our own
   testing.

Test: atest TextClassifierServiceTest
Test: Install the apk, try smart selection.
Bug: 135110855

Change-Id: I17173769bc20cc36d6d16bd8ea511ecbaac4bb5d

6 files changed, 1200 insertions, 0 deletions

diff --git a/jni/Android.bp b/jni/Android.bp
new file mode 100644
index 0000000..569368e
--- /dev/null
+++ b/jni/Android.bp
@@ -0,0 +1,19 @@
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+java_library_static {
+    name: "libtextclassifier-java",
+    sdk_version: "core_current",
+    srcs: ["**/*.java"],
+}
\ No newline at end of file
diff --git a/jni/com/google/android/textclassifier/ActionsSuggestionsModel.java b/jni/com/google/android/textclassifier/ActionsSuggestionsModel.java
new file mode 100644
index 0000000..9132b1f
--- /dev/null
+++ b/jni/com/google/android/textclassifier/ActionsSuggestionsModel.java
@@ -0,0 +1,265 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.textclassifier;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
+/**
+ * Java wrapper for ActionsSuggestions native library interface. This library is used to suggest
+ * actions and replies in a given conversation.
+ *
+ * @hide
+ */
+public final class ActionsSuggestionsModel implements AutoCloseable {
+  private final AtomicBoolean isClosed = new AtomicBoolean(false);
+
+  static {
+    System.loadLibrary("textclassifier");
+  }
+
+  private long actionsModelPtr;
+
+  /**
+   * Creates a new instance of Actions predictor, using the provided model image, given as a file
+   * descriptor.
+   */
+  public ActionsSuggestionsModel(int fileDescriptor, byte[] serializedPreconditions) {
+    actionsModelPtr = nativeNewActionsModel(fileDescriptor, serializedPreconditions);
+    if (actionsModelPtr == 0L) {
+      throw new IllegalArgumentException("Couldn't initialize actions model from file descriptor.");
+    }
+  }
+
+  public ActionsSuggestionsModel(int fileDescriptor) {
+    this(fileDescriptor, /* serializedPreconditions= */ null);
+  }
+
+  /**
+   * Creates a new instance of Actions predictor, using the provided model image, given as a file
+   * path.
+   */
+  public ActionsSuggestionsModel(String path, byte[] serializedPreconditions) {
+    actionsModelPtr = nativeNewActionsModelFromPath(path, serializedPreconditions);
+    if (actionsModelPtr == 0L) {
+      throw new IllegalArgumentException("Couldn't initialize actions model from given file.");
+    }
+  }
+
+  public ActionsSuggestionsModel(String path) {
+    this(path, /* serializedPreconditions= */ null);
+  }
+
+  /** Suggests actions / replies to the given conversation. */
+  public ActionSuggestion[] suggestActions(
+      Conversation conversation, ActionSuggestionOptions options, AnnotatorModel annotator) {
+    return nativeSuggestActions(
+        actionsModelPtr,
+        conversation,
+        options,
+        (annotator != null ? annotator.getNativeAnnotator() : 0),
+        /* appContext= */ null,
+        /* deviceLocales= */ null,
+        /* generateAndroidIntents= */ false);
+  }
+
+  public ActionSuggestion[] suggestActionsWithIntents(
+      Conversation conversation,
+      ActionSuggestionOptions options,
+      Object appContext,
+      String deviceLocales,
+      AnnotatorModel annotator) {
+    return nativeSuggestActions(
+        actionsModelPtr,
+        conversation,
+        options,
+        (annotator != null ? annotator.getNativeAnnotator() : 0),
+        appContext,
+        deviceLocales,
+        /* generateAndroidIntents= */ true);
+  }
+
+  /** Frees up the allocated memory. */
+  @Override
+  public void close() {
+    if (isClosed.compareAndSet(false, true)) {
+      nativeCloseActionsModel(actionsModelPtr);
+      actionsModelPtr = 0L;
+    }
+  }
+
+  @Override
+  protected void finalize() throws Throwable {
+    try {
+      close();
+    } finally {
+      super.finalize();
+    }
+  }
+
+  /** Returns a comma separated list of locales supported by the model as BCP 47 tags. */
+  public static String getLocales(int fd) {
+    return nativeGetLocales(fd);
+  }
+
+  /** Returns the version of the model. */
+  public static int getVersion(int fd) {
+    return nativeGetVersion(fd);
+  }
+
+  /** Returns the name of the model. */
+  public static String getName(int fd) {
+    return nativeGetName(fd);
+  }
+
+  /** Action suggestion that contains a response text and the type of the response. */
+  public static final class ActionSuggestion {
+    private final String responseText;
+    private final String actionType;
+    private final float score;
+    private final NamedVariant[] entityData;
+    private final byte[] serializedEntityData;
+    private final RemoteActionTemplate[] remoteActionTemplates;
+
+    public ActionSuggestion(
+        String responseText,
+        String actionType,
+        float score,
+        NamedVariant[] entityData,
+        byte[] serializedEntityData,
+        RemoteActionTemplate[] remoteActionTemplates) {
+      this.responseText = responseText;
+      this.actionType = actionType;
+      this.score = score;
+      this.entityData = entityData;
+      this.serializedEntityData = serializedEntityData;
+      this.remoteActionTemplates = remoteActionTemplates;
+    }
+
+    public String getResponseText() {
+      return responseText;
+    }
+
+    public String getActionType() {
+      return actionType;
+    }
+
+    /** Confidence score between 0 and 1 */
+    public float getScore() {
+      return score;
+    }
+
+    public NamedVariant[] getEntityData() {
+      return entityData;
+    }
+
+    public byte[] getSerializedEntityData() {
+      return serializedEntityData;
+    }
+
+    public RemoteActionTemplate[] getRemoteActionTemplates() {
+      return remoteActionTemplates;
+    }
+  }
+
+  /** Represents a single message in the conversation. */
+  public static final class ConversationMessage {
+    private final int userId;
+    private final String text;
+    private final long referenceTimeMsUtc;
+    private final String referenceTimezone;
+    private final String detectedTextLanguageTags;
+
+    public ConversationMessage(
+        int userId,
+        String text,
+        long referenceTimeMsUtc,
+        String referenceTimezone,
+        String detectedTextLanguageTags) {
+      this.userId = userId;
+      this.text = text;
+      this.referenceTimeMsUtc = referenceTimeMsUtc;
+      this.referenceTimezone = referenceTimezone;
+      this.detectedTextLanguageTags = detectedTextLanguageTags;
+    }
+
+    /** The identifier of the sender */
+    public int getUserId() {
+      return userId;
+    }
+
+    public String getText() {
+      return text;
+    }
+
+    /**
+     * Return the reference time of the message, for example, it could be compose time or send time.
+     * {@code 0} means unspecified.
+     */
+    public long getReferenceTimeMsUtc() {
+      return referenceTimeMsUtc;
+    }
+
+    public String getReferenceTimezone() {
+      return referenceTimezone;
+    }
+
+    /** Returns a comma separated list of BCP 47 language tags. */
+    public String getDetectedTextLanguageTags() {
+      return detectedTextLanguageTags;
+    }
+  }
+
+  /** Represents conversation between multiple users. */
+  public static final class Conversation {
+    public final ConversationMessage[] conversationMessages;
+
+    public Conversation(ConversationMessage[] conversationMessages) {
+      this.conversationMessages = conversationMessages;
+    }
+
+    public ConversationMessage[] getConversationMessages() {
+      return conversationMessages;
+    }
+  }
+
+  /** Represents options for the SuggestActions call. */
+  public static final class ActionSuggestionOptions {
+    public ActionSuggestionOptions() {}
+  }
+
+  private static native long nativeNewActionsModel(int fd, byte[] serializedPreconditions);
+
+  private static native long nativeNewActionsModelFromPath(
+      String path, byte[] preconditionsOverwrite);
+
+  private static native String nativeGetLocales(int fd);
+
+  private static native int nativeGetVersion(int fd);
+
+  private static native String nativeGetName(int fd);
+
+  private native ActionSuggestion[] nativeSuggestActions(
+      long context,
+      Conversation conversation,
+      ActionSuggestionOptions options,
+      long annotatorPtr,
+      Object appContext,
+      String deviceLocales,
+      boolean generateAndroidIntents);
+
+  private native void nativeCloseActionsModel(long ptr);
+}
diff --git a/jni/com/google/android/textclassifier/AnnotatorModel.java b/jni/com/google/android/textclassifier/AnnotatorModel.java
new file mode 100644
index 0000000..5f99f74
--- /dev/null
+++ b/jni/com/google/android/textclassifier/AnnotatorModel.java
@@ -0,0 +1,591 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.textclassifier;
+
+import java.util.Collection;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+/**
+ * Java wrapper for Annotator native library interface. This library is used for detecting entities
+ * in text.
+ *
+ * @hide
+ */
+public final class AnnotatorModel implements AutoCloseable {
+  private final AtomicBoolean isClosed = new AtomicBoolean(false);
+
+  static {
+    System.loadLibrary("textclassifier");
+  }
+
+  // Keep these in sync with the constants defined in AOSP.
+  static final String TYPE_UNKNOWN = "";
+  static final String TYPE_OTHER = "other";
+  static final String TYPE_EMAIL = "email";
+  static final String TYPE_PHONE = "phone";
+  static final String TYPE_ADDRESS = "address";
+  static final String TYPE_URL = "url";
+  static final String TYPE_DATE = "date";
+  static final String TYPE_DATE_TIME = "datetime";
+  static final String TYPE_FLIGHT_NUMBER = "flight";
+
+  private long annotatorPtr;
+
+  /** Enumeration for specifying the usecase of the annotations. */
+  public static enum AnnotationUsecase {
+    /** Results are optimized for Smart{Select,Share,Linkify}. */
+    SMART(0),
+
+    /**
+     * Results are optimized for using TextClassifier as an infrastructure that annotates as much as
+     * possible.
+     */
+    RAW(1);
+
+    private final int value;
+
+    AnnotationUsecase(int value) {
+      this.value = value;
+    }
+
+    public int getValue() {
+      return value;
+    }
+  };
+
+  /**
+   * Creates a new instance of SmartSelect predictor, using the provided model image, given as a
+   * file descriptor.
+   */
+  public AnnotatorModel(int fileDescriptor) {
+    annotatorPtr = nativeNewAnnotator(fileDescriptor);
+    if (annotatorPtr == 0L) {
+      throw new IllegalArgumentException("Couldn't initialize TC from file descriptor.");
+    }
+  }
+
+  /**
+   * Creates a new instance of SmartSelect predictor, using the provided model image, given as a
+   * file path.
+   */
+  public AnnotatorModel(String path) {
+    annotatorPtr = nativeNewAnnotatorFromPath(path);
+    if (annotatorPtr == 0L) {
+      throw new IllegalArgumentException("Couldn't initialize TC from given file.");
+    }
+  }
+
+  /** Initializes the knowledge engine, passing the given serialized config to it. */
+  public void initializeKnowledgeEngine(byte[] serializedConfig) {
+    if (!nativeInitializeKnowledgeEngine(annotatorPtr, serializedConfig)) {
+      throw new IllegalArgumentException("Couldn't initialize the KG engine");
+    }
+  }
+
+  /** Initializes the contact engine, passing the given serialized config to it. */
+  public void initializeContactEngine(byte[] serializedConfig) {
+    if (!nativeInitializeContactEngine(annotatorPtr, serializedConfig)) {
+      throw new IllegalArgumentException("Couldn't initialize the contact engine");
+    }
+  }
+
+  /** Initializes the installed app engine, passing the given serialized config to it. */
+  public void initializeInstalledAppEngine(byte[] serializedConfig) {
+    if (!nativeInitializeInstalledAppEngine(annotatorPtr, serializedConfig)) {
+      throw new IllegalArgumentException("Couldn't initialize the installed app engine");
+    }
+  }
+
+  /**
+   * Given a string context and current selection, computes the selection suggestion.
+   *
+   * <p>The begin and end are character indices into the context UTF8 string. selectionBegin is the
+   * character index where the selection begins, and selectionEnd is the index of one character past
+   * the selection span.
+   *
+   * <p>The return value is an array of two ints: suggested selection beginning and end, with the
+   * same semantics as the input selectionBeginning and selectionEnd.
+   */
+  public int[] suggestSelection(
+      String context, int selectionBegin, int selectionEnd, SelectionOptions options) {
+    return nativeSuggestSelection(annotatorPtr, context, selectionBegin, selectionEnd, options);
+  }
+
+  /**
+   * Given a string context and current selection, classifies the type of the selected text.
+   *
+   * <p>The begin and end params are character indices in the context string.
+   *
+   * <p>Returns an array of ClassificationResult objects with the probability scores for different
+   * collections.
+   */
+  public ClassificationResult[] classifyText(
+      String context, int selectionBegin, int selectionEnd, ClassificationOptions options) {
+    return classifyText(
+        context,
+        selectionBegin,
+        selectionEnd,
+        options,
+        /*appContext=*/ null,
+        /*deviceLocales=*/ null);
+  }
+
+  public ClassificationResult[] classifyText(
+      String context,
+      int selectionBegin,
+      int selectionEnd,
+      ClassificationOptions options,
+      Object appContext,
+      String deviceLocales) {
+    return nativeClassifyText(
+        annotatorPtr, context, selectionBegin, selectionEnd, options, appContext, deviceLocales);
+  }
+
+  /**
+   * Annotates given input text. The annotations should cover the whole input context except for
+   * whitespaces, and are sorted by their position in the context string.
+   */
+  public AnnotatedSpan[] annotate(String text, AnnotationOptions options) {
+    return nativeAnnotate(annotatorPtr, text, options);
+  }
+
+  /**
+   * Looks up a knowledge entity by its identifier. Returns null if the entity is not found or on
+   * error.
+   */
+  public byte[] lookUpKnowledgeEntity(String id) {
+    return nativeLookUpKnowledgeEntity(annotatorPtr, id);
+  }
+
+  /** Frees up the allocated memory. */
+  @Override
+  public void close() {
+    if (isClosed.compareAndSet(false, true)) {
+      nativeCloseAnnotator(annotatorPtr);
+      annotatorPtr = 0L;
+    }
+  }
+
+  @Override
+  protected void finalize() throws Throwable {
+    try {
+      close();
+    } finally {
+      super.finalize();
+    }
+  }
+
+  /** Returns a comma separated list of locales supported by the model as BCP 47 tags. */
+  public static String getLocales(int fd) {
+    return nativeGetLocales(fd);
+  }
+
+  /** Returns the version of the model. */
+  public static int getVersion(int fd) {
+    return nativeGetVersion(fd);
+  }
+
+  /** Returns the name of the model. */
+  public static String getName(int fd) {
+    return nativeGetName(fd);
+  }
+
+  /** Information about a parsed time/date. */
+  public static final class DatetimeResult {
+
+    public static final int GRANULARITY_YEAR = 0;
+    public static final int GRANULARITY_MONTH = 1;
+    public static final int GRANULARITY_WEEK = 2;
+    public static final int GRANULARITY_DAY = 3;
+    public static final int GRANULARITY_HOUR = 4;
+    public static final int GRANULARITY_MINUTE = 5;
+    public static final int GRANULARITY_SECOND = 6;
+
+    private final long timeMsUtc;
+    private final int granularity;
+
+    public DatetimeResult(long timeMsUtc, int granularity) {
+      this.timeMsUtc = timeMsUtc;
+      this.granularity = granularity;
+    }
+
+    public long getTimeMsUtc() {
+      return timeMsUtc;
+    }
+
+    public int getGranularity() {
+      return granularity;
+    }
+  }
+
+  /** Classification result for classifyText method. */
+  public static final class ClassificationResult {
+    private final String collection;
+    private final float score;
+    private final DatetimeResult datetimeResult;
+    private final byte[] serializedKnowledgeResult;
+    private final String contactName;
+    private final String contactGivenName;
+    private final String contactNickname;
+    private final String contactEmailAddress;
+    private final String contactPhoneNumber;
+    private final String contactId;
+    private final String appName;
+    private final String appPackageName;
+    private final NamedVariant[] entityData;
+    private final byte[] serializedEntityData;
+    private final RemoteActionTemplate[] remoteActionTemplates;
+    private final long durationMs;
+    private final long numericValue;
+
+    public ClassificationResult(
+        String collection,
+        float score,
+        DatetimeResult datetimeResult,
+        byte[] serializedKnowledgeResult,
+        String contactName,
+        String contactGivenName,
+        String contactNickname,
+        String contactEmailAddress,
+        String contactPhoneNumber,
+        String contactId,
+        String appName,
+        String appPackageName,
+        NamedVariant[] entityData,
+        byte[] serializedEntityData,
+        RemoteActionTemplate[] remoteActionTemplates,
+        long durationMs,
+        long numericValue) {
+      this.collection = collection;
+      this.score = score;
+      this.datetimeResult = datetimeResult;
+      this.serializedKnowledgeResult = serializedKnowledgeResult;
+      this.contactName = contactName;
+      this.contactGivenName = contactGivenName;
+      this.contactNickname = contactNickname;
+      this.contactEmailAddress = contactEmailAddress;
+      this.contactPhoneNumber = contactPhoneNumber;
+      this.contactId = contactId;
+      this.appName = appName;
+      this.appPackageName = appPackageName;
+      this.entityData = entityData;
+      this.serializedEntityData = serializedEntityData;
+      this.remoteActionTemplates = remoteActionTemplates;
+      this.durationMs = durationMs;
+      this.numericValue = numericValue;
+    }
+
+    /** Returns the classified entity type. */
+    public String getCollection() {
+      return collection;
+    }
+
+    /** Confidence score between 0 and 1. */
+    public float getScore() {
+      return score;
+    }
+
+    public DatetimeResult getDatetimeResult() {
+      return datetimeResult;
+    }
+
+    public byte[] getSerializedKnowledgeResult() {
+      return serializedKnowledgeResult;
+    }
+
+    public String getContactName() {
+      return contactName;
+    }
+
+    public String getContactGivenName() {
+      return contactGivenName;
+    }
+
+    public String getContactNickname() {
+      return contactNickname;
+    }
+
+    public String getContactEmailAddress() {
+      return contactEmailAddress;
+    }
+
+    public String getContactPhoneNumber() {
+      return contactPhoneNumber;
+    }
+
+    public String getContactId() {
+      return contactId;
+    }
+
+    public String getAppName() {
+      return appName;
+    }
+
+    public String getAppPackageName() {
+      return appPackageName;
+    }
+
+    public NamedVariant[] getEntityData() {
+      return entityData;
+    }
+
+    public byte[] getSerializedEntityData() {
+      return serializedEntityData;
+    }
+
+    public RemoteActionTemplate[] getRemoteActionTemplates() {
+      return remoteActionTemplates;
+    }
+
+    public long getDurationMs() {
+      return durationMs;
+    }
+
+    public long getNumericValue() {
+      return numericValue;
+    }
+  }
+
+  /** Represents a result of Annotate call. */
+  public static final class AnnotatedSpan {
+    private final int startIndex;
+    private final int endIndex;
+    private final ClassificationResult[] classification;
+
+    AnnotatedSpan(int startIndex, int endIndex, ClassificationResult[] classification) {
+      this.startIndex = startIndex;
+      this.endIndex = endIndex;
+      this.classification = classification;
+    }
+
+    public int getStartIndex() {
+      return startIndex;
+    }
+
+    public int getEndIndex() {
+      return endIndex;
+    }
+
+    public ClassificationResult[] getClassification() {
+      return classification;
+    }
+  }
+
+  /** Represents options for the suggestSelection call. */
+  public static final class SelectionOptions {
+    private final String locales;
+    private final String detectedTextLanguageTags;
+    private final int annotationUsecase;
+
+    public SelectionOptions(
+        String locales, String detectedTextLanguageTags, int annotationUsecase) {
+      this.locales = locales;
+      this.detectedTextLanguageTags = detectedTextLanguageTags;
+      this.annotationUsecase = annotationUsecase;
+    }
+
+    public SelectionOptions(String locales, String detectedTextLanguageTags) {
+      this(locales, detectedTextLanguageTags, AnnotationUsecase.SMART.getValue());
+    }
+
+    public String getLocales() {
+      return locales;
+    }
+
+    /** Returns a comma separated list of BCP 47 language tags. */
+    public String getDetectedTextLanguageTags() {
+      return detectedTextLanguageTags;
+    }
+
+    public int getAnnotationUsecase() {
+      return annotationUsecase;
+    }
+  }
+
+  /** Represents options for the classifyText call. */
+  public static final class ClassificationOptions {
+    private final long referenceTimeMsUtc;
+    private final String referenceTimezone;
+    private final String locales;
+    private final String detectedTextLanguageTags;
+    private final int annotationUsecase;
+
+    public ClassificationOptions(
+        long referenceTimeMsUtc,
+        String referenceTimezone,
+        String locales,
+        String detectedTextLanguageTags,
+        int annotationUsecase) {
+      this.referenceTimeMsUtc = referenceTimeMsUtc;
+      this.referenceTimezone = referenceTimezone;
+      this.locales = locales;
+      this.detectedTextLanguageTags = detectedTextLanguageTags;
+      this.annotationUsecase = annotationUsecase;
+    }
+
+    public ClassificationOptions(
+        long referenceTimeMsUtc,
+        String referenceTimezone,
+        String locales,
+        String detectedTextLanguageTags) {
+      this(
+          referenceTimeMsUtc,
+          referenceTimezone,
+          locales,
+          detectedTextLanguageTags,
+          AnnotationUsecase.SMART.getValue());
+    }
+
+    public long getReferenceTimeMsUtc() {
+      return referenceTimeMsUtc;
+    }
+
+    public String getReferenceTimezone() {
+      return referenceTimezone;
+    }
+
+    public String getLocale() {
+      return locales;
+    }
+
+    /** Returns a comma separated list of BCP 47 language tags. */
+    public String getDetectedTextLanguageTags() {
+      return detectedTextLanguageTags;
+    }
+
+    public int getAnnotationUsecase() {
+      return annotationUsecase;
+    }
+  }
+
+  /** Represents options for the annotate call. */
+  public static final class AnnotationOptions {
+    private final long referenceTimeMsUtc;
+    private final String referenceTimezone;
+    private final String locales;
+    private final String detectedTextLanguageTags;
+    private final String[] entityTypes;
+    private final int annotationUsecase;
+    private final boolean isSerializedEntityDataEnabled;
+
+    public AnnotationOptions(
+        long referenceTimeMsUtc,
+        String referenceTimezone,
+        String locales,
+        String detectedTextLanguageTags,
+        Collection<String> entityTypes,
+        int annotationUsecase,
+        boolean isSerializedEntityDataEnabled) {
+      this.referenceTimeMsUtc = referenceTimeMsUtc;
+      this.referenceTimezone = referenceTimezone;
+      this.locales = locales;
+      this.detectedTextLanguageTags = detectedTextLanguageTags;
+      this.entityTypes = entityTypes == null ? new String[0] : entityTypes.toArray(new String[0]);
+      this.annotationUsecase = annotationUsecase;
+      this.isSerializedEntityDataEnabled = isSerializedEntityDataEnabled;
+    }
+
+    public AnnotationOptions(
+        long referenceTimeMsUtc,
+        String referenceTimezone,
+        String locales,
+        String detectedTextLanguageTags) {
+      this(
+          referenceTimeMsUtc,
+          referenceTimezone,
+          locales,
+          detectedTextLanguageTags,
+          null,
+          AnnotationUsecase.SMART.getValue(),
+          /* isSerializedEntityDataEnabled */ false);
+    }
+
+    public long getReferenceTimeMsUtc() {
+      return referenceTimeMsUtc;
+    }
+
+    public String getReferenceTimezone() {
+      return referenceTimezone;
+    }
+
+    public String getLocale() {
+      return locales;
+    }
+
+    /** Returns a comma separated list of BCP 47 language tags. */
+    public String getDetectedTextLanguageTags() {
+      return detectedTextLanguageTags;
+    }
+
+    public String[] getEntityTypes() {
+      return entityTypes;
+    }
+
+    public int getAnnotationUsecase() {
+      return annotationUsecase;
+    }
+
+    public boolean isSerializedEntityDataEnabled() {
+      return isSerializedEntityDataEnabled;
+    }
+  }
+
+  /**
+   * Retrieves the pointer to the native object. Note: Need to keep the AnnotatorModel alive as long
+   * as the pointer is used.
+   */
+  long getNativeAnnotator() {
+    return nativeGetNativeModelPtr(annotatorPtr);
+  }
+
+  private static native long nativeNewAnnotator(int fd);
+
+  private static native long nativeNewAnnotatorFromPath(String path);
+
+  private static native String nativeGetLocales(int fd);
+
+  private static native int nativeGetVersion(int fd);
+
+  private static native String nativeGetName(int fd);
+
+  private native long nativeGetNativeModelPtr(long context);
+
+  private native boolean nativeInitializeKnowledgeEngine(long context, byte[] serializedConfig);
+
+  private native boolean nativeInitializeContactEngine(long context, byte[] serializedConfig);
+
+  private native boolean nativeInitializeInstalledAppEngine(long context, byte[] serializedConfig);
+
+  private native int[] nativeSuggestSelection(
+      long context, String text, int selectionBegin, int selectionEnd, SelectionOptions options);
+
+  private native ClassificationResult[] nativeClassifyText(
+      long context,
+      String text,
+      int selectionBegin,
+      int selectionEnd,
+      ClassificationOptions options,
+      Object appContext,
+      String deviceLocales);
+
+  private native AnnotatedSpan[] nativeAnnotate(
+      long context, String text, AnnotationOptions options);
+
+  private native byte[] nativeLookUpKnowledgeEntity(long context, String id);
+
+  private native void nativeCloseAnnotator(long context);
+}
diff --git a/jni/com/google/android/textclassifier/LangIdModel.java b/jni/com/google/android/textclassifier/LangIdModel.java
new file mode 100644
index 0000000..d3e166f
--- /dev/null
+++ b/jni/com/google/android/textclassifier/LangIdModel.java
@@ -0,0 +1,119 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.textclassifier;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
+/**
+ * Java wrapper for LangId native library interface. This class is used to detect languages in text.
+ *
+ * @hide
+ */
+public final class LangIdModel implements AutoCloseable {
+  private final AtomicBoolean isClosed = new AtomicBoolean(false);
+
+  static {
+    System.loadLibrary("textclassifier");
+  }
+
+  private long modelPtr;
+
+  /** Creates a new instance of LangId predictor, using the provided model image. */
+  public LangIdModel(int fd) {
+    modelPtr = nativeNew(fd);
+    if (modelPtr == 0L) {
+      throw new IllegalArgumentException("Couldn't initialize LangId from given file descriptor.");
+    }
+  }
+
+  /** Creates a new instance of LangId predictor, using the provided model image. */
+  public LangIdModel(String modelPath) {
+    modelPtr = nativeNewFromPath(modelPath);
+    if (modelPtr == 0L) {
+      throw new IllegalArgumentException("Couldn't initialize LangId from given file.");
+    }
+  }
+
+  /** Detects the languages for given text. */
+  public LanguageResult[] detectLanguages(String text) {
+    return nativeDetectLanguages(modelPtr, text);
+  }
+
+  /** Frees up the allocated memory. */
+  @Override
+  public void close() {
+    if (isClosed.compareAndSet(false, true)) {
+      nativeClose(modelPtr);
+      modelPtr = 0L;
+    }
+  }
+
+  @Override
+  protected void finalize() throws Throwable {
+    try {
+      close();
+    } finally {
+      super.finalize();
+    }
+  }
+
+  /** Result for detectLanguages method. */
+  public static final class LanguageResult {
+    final String mLanguage;
+    final float mScore;
+
+    LanguageResult(String language, float score) {
+      mLanguage = language;
+      mScore = score;
+    }
+
+    public final String getLanguage() {
+      return mLanguage;
+    }
+
+    public final float getScore() {
+      return mScore;
+    }
+  }
+
+  /** Returns the version of the LangId model used. */
+  public int getVersion() {
+    return nativeGetVersion(modelPtr);
+  }
+
+  public float getLangIdThreshold() {
+    return nativeGetLangIdThreshold(modelPtr);
+  }
+
+  public static int getVersion(int fd) {
+    return nativeGetVersionFromFd(fd);
+  }
+
+  private static native long nativeNew(int fd);
+
+  private static native long nativeNewFromPath(String path);
+
+  private native LanguageResult[] nativeDetectLanguages(long nativePtr, String text);
+
+  private native void nativeClose(long nativePtr);
+
+  private native int nativeGetVersion(long nativePtr);
+
+  private static native int nativeGetVersionFromFd(int fd);
+
+  private native float nativeGetLangIdThreshold(long nativePtr);
+}
diff --git a/jni/com/google/android/textclassifier/NamedVariant.java b/jni/com/google/android/textclassifier/NamedVariant.java
new file mode 100644
index 0000000..d04bb11
--- /dev/null
+++ b/jni/com/google/android/textclassifier/NamedVariant.java
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.textclassifier;
+
+/**
+ * Represents a union of different basic types.
+ *
+ * @hide
+ */
+public final class NamedVariant {
+  public static final int TYPE_EMPTY = 0;
+  public static final int TYPE_INT = 1;
+  public static final int TYPE_LONG = 2;
+  public static final int TYPE_FLOAT = 3;
+  public static final int TYPE_DOUBLE = 4;
+  public static final int TYPE_BOOL = 5;
+  public static final int TYPE_STRING = 6;
+
+  public NamedVariant(String name, int value) {
+    this.name = name;
+    this.intValue = value;
+    this.type = TYPE_INT;
+  }
+
+  public NamedVariant(String name, long value) {
+    this.name = name;
+    this.longValue = value;
+    this.type = TYPE_LONG;
+  }
+
+  public NamedVariant(String name, float value) {
+    this.name = name;
+    this.floatValue = value;
+    this.type = TYPE_FLOAT;
+  }
+
+  public NamedVariant(String name, double value) {
+    this.name = name;
+    this.doubleValue = value;
+    this.type = TYPE_DOUBLE;
+  }
+
+  public NamedVariant(String name, boolean value) {
+    this.name = name;
+    this.boolValue = value;
+    this.type = TYPE_BOOL;
+  }
+
+  public NamedVariant(String name, String value) {
+    this.name = name;
+    this.stringValue = value;
+    this.type = TYPE_STRING;
+  }
+
+  public String getName() {
+    return name;
+  }
+
+  public int getType() {
+    return type;
+  }
+
+  public int getInt() {
+    assert (type == TYPE_INT);
+    return intValue;
+  }
+
+  public long getLong() {
+    assert (type == TYPE_LONG);
+    return longValue;
+  }
+
+  public float getFloat() {
+    assert (type == TYPE_FLOAT);
+    return floatValue;
+  }
+
+  public double getDouble() {
+    assert (type == TYPE_DOUBLE);
+    return doubleValue;
+  }
+
+  public boolean getBool() {
+    assert (type == TYPE_BOOL);
+    return boolValue;
+  }
+
+  public String getString() {
+    assert (type == TYPE_STRING);
+    return stringValue;
+  }
+
+  private final String name;
+  private final int type;
+  private int intValue;
+  private long longValue;
+  private float floatValue;
+  private double doubleValue;
+  private boolean boolValue;
+  private String stringValue;
+}
diff --git a/jni/com/google/android/textclassifier/RemoteActionTemplate.java b/jni/com/google/android/textclassifier/RemoteActionTemplate.java
new file mode 100644
index 0000000..308d809
--- /dev/null
+++ b/jni/com/google/android/textclassifier/RemoteActionTemplate.java
@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.textclassifier;
+
+/**
+ * Represents a template for an Android RemoteAction.
+ *
+ * @hide
+ */
+public final class RemoteActionTemplate {
+  /** Title shown for the action (see: RemoteAction.getTitle). */
+  public final String titleWithoutEntity;
+
+  /** Title with entity for the action. */
+  public final String titleWithEntity;
+
+  /** Description shown for the action (see: RemoteAction.getContentDescription). */
+  public final String description;
+
+  /**
+   * Description shown for the action (see: RemoteAction.getContentDescription) when app name is
+   * available. Caller is expected to replace the placeholder by the name of the app that is going
+   * to handle the action.
+   */
+  public final String descriptionWithAppName;
+
+  /** The action to set on the Intent (see: Intent.setAction). */
+  public final String action;
+
+  /** The data to set on the Intent (see: Intent.setData). */
+  public final String data;
+
+  /** The type to set on the Intent (see: Intent.setType). */
+  public final String type;
+
+  /** Flags for launching the Intent (see: Intent.setFlags). */
+  public final Integer flags;
+
+  /** Categories to set on the Intent (see: Intent.addCategory). */
+  public final String[] category;
+
+  /** Explicit application package to set on the Intent (see: Intent.setPackage). */
+  public final String packageName;
+
+  /** The list of all the extras to add to the Intent. */
+  public final NamedVariant[] extras;
+
+  /** Private request code to use for the Intent. */
+  public final Integer requestCode;
+
+  public RemoteActionTemplate(
+      String titleWithoutEntity,
+      String titleWithEntity,
+      String description,
+      String descriptionWithAppName,
+      String action,
+      String data,
+      String type,
+      Integer flags,
+      String[] category,
+      String packageName,
+      NamedVariant[] extras,
+      Integer requestCode) {
+    this.titleWithoutEntity = titleWithoutEntity;
+    this.titleWithEntity = titleWithEntity;
+    this.description = description;
+    this.descriptionWithAppName = descriptionWithAppName;
+    this.action = action;
+    this.data = data;
+    this.type = type;
+    this.flags = flags;
+    this.category = category;
+    this.packageName = packageName;
+    this.extras = extras;
+    this.requestCode = requestCode;
+  }
+}