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      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package android.view.textclassifier;
     18 
     19 /**
     20  *  Java wrapper for SmartSelection native library interface.
     21  *  This library is used for detecting entities in text.
     22  */
     23 final class SmartSelection {
     24 
     25     static {
     26         System.loadLibrary("textclassifier");
     27     }
     28 
     29     /** Hints the classifier that this may be a url. */
     30     static final int HINT_FLAG_URL = 0x01;
     31     /** Hints the classifier that this may be an email. */
     32     static final int HINT_FLAG_EMAIL = 0x02;
     33 
     34     private final long mCtx;
     35 
     36     /**
     37      * Creates a new instance of SmartSelect predictor, using the provided model image,
     38      * given as a file descriptor.
     39      */
     40     SmartSelection(int fd) {
     41         mCtx = nativeNew(fd);
     42     }
     43 
     44     /**
     45      * Given a string context and current selection, computes the SmartSelection suggestion.
     46      *
     47      * The begin and end are character indices into the context UTF8 string. selectionBegin is the
     48      * character index where the selection begins, and selectionEnd is the index of one character
     49      * past the selection span.
     50      *
     51      * The return value is an array of two ints: suggested selection beginning and end, with the
     52      * same semantics as the input selectionBeginning and selectionEnd.
     53      */
     54     public int[] suggest(String context, int selectionBegin, int selectionEnd) {
     55         return nativeSuggest(mCtx, context, selectionBegin, selectionEnd);
     56     }
     57 
     58     /**
     59      * Given a string context and current selection, classifies the type of the selected text.
     60      *
     61      * The begin and end params are character indices in the context string.
     62      *
     63      * Returns an array of ClassificationResult objects with the probability
     64      * scores for different collections.
     65      */
     66     public ClassificationResult[] classifyText(
     67             String context, int selectionBegin, int selectionEnd, int hintFlags) {
     68         return nativeClassifyText(mCtx, context, selectionBegin, selectionEnd, hintFlags);
     69     }
     70 
     71     /**
     72      * Frees up the allocated memory.
     73      */
     74     public void close() {
     75         nativeClose(mCtx);
     76     }
     77 
     78     /**
     79      * Returns the language of the model.
     80      */
     81     public static String getLanguage(int fd) {
     82         return nativeGetLanguage(fd);
     83     }
     84 
     85     /**
     86      * Returns the version of the model.
     87      */
     88     public static int getVersion(int fd) {
     89         return nativeGetVersion(fd);
     90     }
     91 
     92     private static native long nativeNew(int fd);
     93 
     94     private static native int[] nativeSuggest(
     95             long context, String text, int selectionBegin, int selectionEnd);
     96 
     97     private static native ClassificationResult[] nativeClassifyText(
     98             long context, String text, int selectionBegin, int selectionEnd, int hintFlags);
     99 
    100     private static native void nativeClose(long context);
    101 
    102     private static native String nativeGetLanguage(int fd);
    103 
    104     private static native int nativeGetVersion(int fd);
    105 
    106     /** Classification result for classifyText method. */
    107     static final class ClassificationResult {
    108         final String mCollection;
    109         /** float range: 0 - 1 */
    110         final float mScore;
    111 
    112         ClassificationResult(String collection, float score) {
    113             mCollection = collection;
    114             mScore = score;
    115         }
    116     }
    117 }
    118