blob: a3c3e89de4767f337ea7b4cbbbf7a711431b545a (
about) (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
|
/*
* Copyright (C) 2012 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.android.inputmethod.research;
import com.android.inputmethod.latin.CollectionUtils;
import java.util.LinkedList;
/**
* A buffer that holds a fixed number of LogUnits.
*
* LogUnits are added in and shifted out in temporal order. Only a subset of the LogUnits are
* actual words; the other LogUnits do not count toward the word limit. Once the buffer reaches
* capacity, adding another LogUnit that is a word evicts the oldest LogUnits out one at a time to
* stay under the capacity limit.
*/
public class LogBuffer {
protected final LinkedList<LogUnit> mLogUnits;
/* package for test */ int mWordCapacity;
// The number of members of mLogUnits that are actual words.
protected int mNumActualWords;
/**
* Create a new LogBuffer that can hold a fixed number of LogUnits that are words (and
* unlimited number of non-word LogUnits), and that outputs its result to a researchLog.
*
* @param wordCapacity maximum number of words
*/
LogBuffer(final int wordCapacity) {
if (wordCapacity <= 0) {
throw new IllegalArgumentException("wordCapacity must be 1 or greater.");
}
mLogUnits = CollectionUtils.newLinkedList();
mWordCapacity = wordCapacity;
mNumActualWords = 0;
}
/**
* Adds a new LogUnit to the front of the LIFO queue, evicting existing LogUnit's
* (oldest first) if word capacity is reached.
*/
public void shiftIn(LogUnit newLogUnit) {
if (newLogUnit.getWord() == null) {
// This LogUnit isn't a word, so it doesn't count toward the word-limit.
mLogUnits.add(newLogUnit);
return;
}
if (mNumActualWords == mWordCapacity) {
shiftOutThroughFirstWord();
}
mLogUnits.add(newLogUnit);
mNumActualWords++; // Must be a word, or we wouldn't be here.
}
private void shiftOutThroughFirstWord() {
while (!mLogUnits.isEmpty()) {
final LogUnit logUnit = mLogUnits.removeFirst();
onShiftOut(logUnit);
if (logUnit.hasWord()) {
// Successfully shifted out a word-containing LogUnit and made space for the new
// LogUnit.
mNumActualWords--;
break;
}
}
}
/**
* Removes all LogUnits from the buffer without calling onShiftOut().
*/
public void clear() {
mLogUnits.clear();
mNumActualWords = 0;
}
/**
* Called when a LogUnit is removed from the LogBuffer as a result of a shiftIn. LogUnits are
* removed in the order entered. This method is not called when shiftOut is called directly.
*
* Base class does nothing; subclasses may override.
*/
protected void onShiftOut(LogUnit logUnit) {
}
/**
* Called to deliberately remove the oldest LogUnit. Usually called when draining the
* LogBuffer.
*/
public LogUnit shiftOut() {
if (mLogUnits.isEmpty()) {
return null;
}
final LogUnit logUnit = mLogUnits.removeFirst();
if (logUnit.hasWord()) {
mNumActualWords--;
}
return logUnit;
}
public boolean isEmpty() {
return mLogUnits.isEmpty();
}
}
|
