1 /* 2 * Copyright (C) 2013 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.event; 18 19 import java.util.ArrayList; 20 21 import javax.annotation.Nonnull; 22 23 /** 24 * A generic interface for combiners. Combiners are objects that transform chains of input events 25 * into committable strings and manage feedback to show to the user on the combining state. 26 */ 27 public interface Combiner { 28 /** 29 * Process an event, possibly combining it with the existing state and return the new event. 30 * 31 * If this event does not result in any new event getting passed down the chain, this method 32 * returns null. It may also modify the previous event list if appropriate. 33 * 34 * @param previousEvents the previous events in this composition. 35 * @param event the event to combine with the existing state. 36 * @return the resulting event. 37 */ 38 @Nonnull 39 Event processEvent(ArrayList<Event> previousEvents, Event event); 40 41 /** 42 * Get the feedback that should be shown to the user for the current state of this combiner. 43 * @return A CharSequence representing the feedback to show users. It may include styles. 44 */ 45 CharSequence getCombiningStateFeedback(); 46 47 /** 48 * Reset the state of this combiner, for example when the cursor was moved. 49 */ 50 void reset(); 51 } 52
