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
|
package com.android.launcher3.util;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteFullException;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
/**
* An extension of {@link SQLiteOpenHelper} with utility methods for a single table cache DB.
* Any exception during write operations are ignored, and any version change causes a DB reset.
*/
public abstract class SQLiteCacheHelper {
private static final String TAG = "SQLiteCacheHelper";
private final String mTableName;
private final MySQLiteOpenHelper mOpenHelper;
private boolean mIgnoreWrites;
public SQLiteCacheHelper(Context context, String name, int version, String tableName) {
mTableName = tableName;
mOpenHelper = new MySQLiteOpenHelper(context, name, version);
mIgnoreWrites = false;
}
/**
* @see SQLiteDatabase#delete(String, String, String[])
*/
public void delete(String whereClause, String[] whereArgs) {
if (mIgnoreWrites) {
return;
}
try {
mOpenHelper.getWritableDatabase().delete(mTableName, whereClause, whereArgs);
} catch (SQLiteFullException e) {
onDiskFull(e);
} catch (SQLiteException e) {
Log.d(TAG, "Ignoring sqlite exception", e);
}
}
/**
* @see SQLiteDatabase#insertWithOnConflict(String, String, ContentValues, int)
*/
public void insertOrReplace(ContentValues values) {
if (mIgnoreWrites) {
return;
}
try {
mOpenHelper.getWritableDatabase().insertWithOnConflict(
mTableName, null, values, SQLiteDatabase.CONFLICT_REPLACE);
} catch (SQLiteFullException e) {
onDiskFull(e);
} catch (SQLiteException e) {
Log.d(TAG, "Ignoring sqlite exception", e);
}
}
private void onDiskFull(SQLiteFullException e) {
Log.e(TAG, "Disk full, all write operations will be ignored", e);
mIgnoreWrites = true;
}
/**
* @see SQLiteDatabase#query(String, String[], String, String[], String, String, String)
*/
public Cursor query(String[] columns, String selection, String[] selectionArgs) {
return mOpenHelper.getReadableDatabase().query(
mTableName, columns, selection, selectionArgs, null, null, null);
}
protected abstract void onCreateTable(SQLiteDatabase db);
/**
* A private inner class to prevent direct DB access.
*/
private class MySQLiteOpenHelper extends SQLiteOpenHelper {
public MySQLiteOpenHelper(Context context, String name, int version) {
super(new NoLocaleSqliteContext(context), name, null, version);
}
@Override
public void onCreate(SQLiteDatabase db) {
onCreateTable(db);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
if (oldVersion != newVersion) {
clearDB(db);
}
}
@Override
public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {
if (oldVersion != newVersion) {
clearDB(db);
}
}
private void clearDB(SQLiteDatabase db) {
db.execSQL("DROP TABLE IF EXISTS " + mTableName);
onCreate(db);
}
}
}
|
