Examples with QuerySnapshot com.google.cloud.firestore.QuerySnapshot used on opensource projects

Example 1 with QuerySnapshot

use of com.google.cloud.firestore.QuerySnapshot in project java-docs-samples by GoogleCloudPlatform.

the class Quickstart method runAQuery.

void runAQuery() throws Exception {
    // [START fs_add_query]
    // asynchronously query for all users born before 1900
    ApiFuture<QuerySnapshot> query = db.collection("users").whereLessThan("born", 1900).get();
    // ...
    // query.get() blocks on response
    QuerySnapshot querySnapshot = query.get();
    List<QueryDocumentSnapshot> documents = querySnapshot.getDocuments();
    for (QueryDocumentSnapshot document : documents) {
        System.out.println("User: " + document.getId());
        System.out.println("First: " + document.getString("first"));
        if (document.contains("middle")) {
            System.out.println("Middle: " + document.getString("middle"));
        }
        System.out.println("Last: " + document.getString("last"));
        System.out.println("Born: " + document.getLong("born"));
    }
// [END fs_add_query]
}

Example 2 with QuerySnapshot

use of com.google.cloud.firestore.QuerySnapshot in project java-docs-samples by GoogleCloudPlatform.

the class ListenDataSnippets method detachListener.

/**
 * Demonstrate how to detach an event listener.
 */
void detachListener() {
    // [START detach_errors]
    Query query = db.collection("cities");
    ListenerRegistration registration = query.addSnapshotListener(new EventListener<QuerySnapshot>() {

        // [START_EXCLUDE]
        @Override
        public void onEvent(@Nullable QuerySnapshot snapshots, @Nullable FirestoreException e) {
        }
    });
    // ...
    // Stop listening to changes
    registration.remove();
// [END detach_errors]
}

Example 3 with QuerySnapshot

use of com.google.cloud.firestore.QuerySnapshot in project java-docs-samples by GoogleCloudPlatform.

the class QueryDataSnippets method createAQuery.

/**
 * Creates a sample query.
 *
 * @return query
 */
Query createAQuery() throws Exception {
    // [START fs_create_query]
    // Create a reference to the cities collection
    CollectionReference cities = db.collection("cities");
    // Create a query against the collection.
    Query query = cities.whereEqualTo("capital", true);
    // retrieve  query results asynchronously using query.get()
    ApiFuture<QuerySnapshot> querySnapshot = query.get();
    for (DocumentSnapshot document : querySnapshot.get().getDocuments()) {
        System.out.println(document.getId());
    }
    // [END fs_create_query]
    return query;
}

Example 4 with QuerySnapshot

use of com.google.cloud.firestore.QuerySnapshot in project java-docs-samples by GoogleCloudPlatform.

the class RetrieveDataSnippets method getAllDocuments.

/**
 * Return all documents in the cities collection.
 *
 * @return list of documents
 */
public List<QueryDocumentSnapshot> getAllDocuments() throws Exception {
    // [START fs_get_all_docs]
    // asynchronously retrieve all documents
    ApiFuture<QuerySnapshot> future = db.collection("cities").get();
    // future.get() blocks on response
    List<QueryDocumentSnapshot> documents = future.get().getDocuments();
    for (QueryDocumentSnapshot document : documents) {
        System.out.println(document.getId() + " => " + document.toObject(City.class));
    }
    // [END fs_get_all_docs]
    return documents;
}

Example 5 with QuerySnapshot

use of com.google.cloud.firestore.QuerySnapshot in project java-docs-samples by GoogleCloudPlatform.

the class ManageDataSnippets method deleteCollection.

// [START fs_delete_collection]
/**
 * Delete a collection in batches to avoid out-of-memory errors.
 * Batch size may be tuned based on document size (atmost 1MB) and application requirements.
 */
void deleteCollection(CollectionReference collection, int batchSize) {
    try {
        // retrieve a small batch of documents to avoid out-of-memory errors
        ApiFuture<QuerySnapshot> future = collection.limit(batchSize).get();
        int deleted = 0;
        // future.get() blocks on document retrieval
        List<QueryDocumentSnapshot> documents = future.get().getDocuments();
        for (QueryDocumentSnapshot document : documents) {
            document.getReference().delete();
            ++deleted;
        }
        if (deleted >= batchSize) {
            // retrieve and delete another batch
            deleteCollection(collection, batchSize);
        }
    } catch (Exception e) {
        System.err.println("Error deleting collection : " + e.getMessage());
    }
}