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      1 /*
      2  * Copyright (C) 2014 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 com.android.inputmethod.latin.utils;
     18 
     19 import com.android.inputmethod.latin.SuggestedWords.SuggestedWordInfo;
     20 import com.android.inputmethod.latin.define.ProductionFlags;
     21 
     22 import java.util.ArrayList;
     23 import java.util.Collection;
     24 import java.util.Comparator;
     25 import java.util.TreeSet;
     26 
     27 /**
     28  * A TreeSet of SuggestedWordInfo that is bounded in size and throws everything that's smaller
     29  * than its limit
     30  */
     31 public final class SuggestionResults extends TreeSet<SuggestedWordInfo> {
     32     public final ArrayList<SuggestedWordInfo> mRawSuggestions;
     33     // TODO: Instead of a boolean , we may want to include the context of this suggestion results,
     34     // such as {@link NgramContext}.
     35     public final boolean mIsBeginningOfSentence;
     36     public final boolean mFirstSuggestionExceedsConfidenceThreshold;
     37     private final int mCapacity;
     38 
     39     public SuggestionResults(final int capacity, final boolean isBeginningOfSentence,
     40             final boolean firstSuggestionExceedsConfidenceThreshold) {
     41         this(sSuggestedWordInfoComparator, capacity, isBeginningOfSentence,
     42                 firstSuggestionExceedsConfidenceThreshold);
     43     }
     44 
     45     private SuggestionResults(final Comparator<SuggestedWordInfo> comparator, final int capacity,
     46             final boolean isBeginningOfSentence,
     47             final boolean firstSuggestionExceedsConfidenceThreshold) {
     48         super(comparator);
     49         mCapacity = capacity;
     50         if (ProductionFlags.INCLUDE_RAW_SUGGESTIONS) {
     51             mRawSuggestions = new ArrayList<>();
     52         } else {
     53             mRawSuggestions = null;
     54         }
     55         mIsBeginningOfSentence = isBeginningOfSentence;
     56         mFirstSuggestionExceedsConfidenceThreshold = firstSuggestionExceedsConfidenceThreshold;
     57     }
     58 
     59     @Override
     60     public boolean add(final SuggestedWordInfo e) {
     61         if (size() < mCapacity) return super.add(e);
     62         if (comparator().compare(e, last()) > 0) return false;
     63         super.add(e);
     64         pollLast(); // removes the last element
     65         return true;
     66     }
     67 
     68     @Override
     69     public boolean addAll(final Collection<? extends SuggestedWordInfo> e) {
     70         if (null == e) return false;
     71         return super.addAll(e);
     72     }
     73 
     74     static final class SuggestedWordInfoComparator implements Comparator<SuggestedWordInfo> {
     75         // This comparator ranks the word info with the higher frequency first. That's because
     76         // that's the order we want our elements in.
     77         @Override
     78         public int compare(final SuggestedWordInfo o1, final SuggestedWordInfo o2) {
     79             if (o1.mScore > o2.mScore) return -1;
     80             if (o1.mScore < o2.mScore) return 1;
     81             if (o1.mCodePointCount < o2.mCodePointCount) return -1;
     82             if (o1.mCodePointCount > o2.mCodePointCount) return 1;
     83             return o1.mWord.compareTo(o2.mWord);
     84         }
     85     }
     86 
     87     private static final SuggestedWordInfoComparator sSuggestedWordInfoComparator =
     88             new SuggestedWordInfoComparator();
     89 }
     90