square/ sqlbrite
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Description
A lightweight wrapper around SQLiteOpenHelper which introduces reactive stream semantics to SQL operations.
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SQL Brite
A lightweight wrapper around
SupportSQLiteOpenHelperand
ContentResolverwhich introduces reactive stream semantics to queries.
Deprecated
This library is no longer actively developed and is considered complete.
Its database features (and far, far more) are now offered by SQLDelight and its upgrading guide offers some migration help.
For content provider monitoring please use Copper instead.
Usage
Create a
SqlBriteinstance which is an adapter for the library functionality.
SqlBrite sqlBrite = new SqlBrite.Builder().build();
Pass a
SupportSQLiteOpenHelperinstance and a
Schedulerto create a
BriteDatabase.
BriteDatabase db = sqlBrite.wrapDatabaseHelper(openHelper, Schedulers.io());
A
Scheduleris required for a few reasons, but the most important is that query notifications can trigger on the thread of your choice. The query can then be run without blocking the main thread or the thread which caused the trigger.
The
BriteDatabase.createQuerymethod is similar to
SupportSQLiteDatabase.queryexcept it takes an additional parameter of table(s) on which to listen for changes. Subscribe to the returned
Observablewhich will immediately notify with a
Queryto run.
Observable users = db.createQuery("users", "SELECT * FROM users");
users.subscribe(new Consumer() {
@Override public void accept(Query query) {
Cursor cursor = query.run();
// TODO parse data...
}
});
Unlike a traditional
query, updates to the specified table(s) will trigger additional notifications for as long as you remain subscribed to the observable. This means that when you insert, update, or delete data, any subscribed queries will update with the new data instantly.
final AtomicInteger queries = new AtomicInteger();
users.subscribe(new Consumer() {
@Override public void accept(Query query) {
queries.getAndIncrement();
}
});
System.out.println("Queries: " + queries.get()); // Prints 1
db.insert("users", SQLiteDatabase.CONFLICT_ABORT, createUser("jw", "Jake Wharton"));
db.insert("users", SQLiteDatabase.CONFLICT_ABORT, createUser("mattp", "Matt Precious"));
db.insert("users", SQLiteDatabase.CONFLICT_ABORT, createUser("strong", "Alec Strong"));
System.out.println("Queries: " + queries.get()); // Prints 4
In the previous example we re-used the
BriteDatabaseobject "db" for inserts. All insert, update, or delete operations must go through this object in order to correctly notify subscribers.
Unsubscribe from the returned
Subscriptionto stop getting updates.
final AtomicInteger queries = new AtomicInteger();
Subscription s = users.subscribe(new Consumer() {
@Override public void accept(Query query) {
queries.getAndIncrement();
}
});
System.out.println("Queries: " + queries.get()); // Prints 1
db.insert("users", SQLiteDatabase.CONFLICT_ABORT, createUser("jw", "Jake Wharton"));
db.insert("users", SQLiteDatabase.CONFLICT_ABORT, createUser("mattp", "Matt Precious"));
s.unsubscribe();
db.insert("users", SQLiteDatabase.CONFLICT_ABORT, createUser("strong", "Alec Strong"));
System.out.println("Queries: " + queries.get()); // Prints 3
Use transactions to prevent large changes to the data from spamming your subscribers.
final AtomicInteger queries = new AtomicInteger();
users.subscribe(new Consumer() {
@Override public void accept(Query query) {
queries.getAndIncrement();
}
});
System.out.println("Queries: " + queries.get()); // Prints 1
Transaction transaction = db.newTransaction();
try {
db.insert("users", SQLiteDatabase.CONFLICT_ABORT, createUser("jw", "Jake Wharton"));
db.insert("users", SQLiteDatabase.CONFLICT_ABORT, createUser("mattp", "Matt Precious"));
db.insert("users", SQLiteDatabase.CONFLICT_ABORT, createUser("strong", "Alec Strong"));
transaction.markSuccessful();
} finally {
transaction.end();
}
System.out.println("Queries: " + queries.get()); // Prints 2
Note: You can also use try-with-resources with a
Transactioninstance.
Since queries are just regular RxJava
Observableobjects, operators can also be used to control the frequency of notifications to subscribers.
users.debounce(500, MILLISECONDS).subscribe(new Consumer() {
@Override public void accept(Query query) {
// TODO...
}
});
The
SqlBriteobject can also wrap a
ContentResolverfor observing a query on another app's content provider.
BriteContentResolver resolver = sqlBrite.wrapContentProvider(contentResolver, Schedulers.io()); Observable query = resolver.createQuery(/*...*/);
The full power of RxJava's operators are available for combining, filtering, and triggering any number of queries and data changes.
Philosophy
SQL Brite's only responsibility is to be a mechanism for coordinating and composing the notification of updates to tables such that you can update queries as soon as data changes.
This library is not an ORM. It is not a type-safe query mechanism. It won't serialize the same POJOs you use for Gson. It's not going to perform database migrations for you.
Some of these features are offered by SQL Delight which can be used with SQL Brite.
Download
implementation 'com.squareup.sqlbrite3:sqlbrite:3.2.0'
For the 'kotlin' module that adds extension functions to
Observable:
groovy implementation 'com.squareup.sqlbrite3:sqlbrite-kotlin:3.2.0'
Snapshots of the development version are available in Sonatype's
snapshotsrepository.
License
Copyright 2015 Square, Inc.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.