Examples with TableModifiers com.google.cloud.bigquery.storage.v1.ReadSession.TableModifiers used on opensource projects

Example 1 with TableModifiers

use of com.google.cloud.bigquery.storage.v1.ReadSession.TableModifiers in project java-bigquerystorage by googleapis.

the class StorageArrowSample method main.

public static void main(String... args) throws Exception {
    // Sets your Google Cloud Platform project ID.
    // String projectId = "YOUR_PROJECT_ID";
    String projectId = args[0];
    Integer snapshotMillis = null;
    if (args.length > 1) {
        snapshotMillis = Integer.parseInt(args[1]);
    }
    try (BigQueryReadClient client = BigQueryReadClient.create()) {
        String parent = String.format("projects/%s", projectId);
        // This example uses baby name data from the public datasets.
        String srcTable = String.format("projects/%s/datasets/%s/tables/%s", "bigquery-public-data", "usa_names", "usa_1910_current");
        // We specify the columns to be projected by adding them to the selected fields,
        // and set a simple filter to restrict which rows are transmitted.
        TableReadOptions options = TableReadOptions.newBuilder().addSelectedFields("name").addSelectedFields("number").addSelectedFields("state").setRowRestriction("state = \"WA\"").build();
        // Start specifying the read session we want created.
        ReadSession.Builder sessionBuilder = ReadSession.newBuilder().setTable(srcTable).setDataFormat(DataFormat.ARROW).setReadOptions(options);
        // Optionally specify the snapshot time.  When unspecified, snapshot time is "now".
        if (snapshotMillis != null) {
            Timestamp t = Timestamp.newBuilder().setSeconds(snapshotMillis / 1000).setNanos((int) ((snapshotMillis % 1000) * 1000000)).build();
            TableModifiers modifiers = TableModifiers.newBuilder().setSnapshotTime(t).build();
            sessionBuilder.setTableModifiers(modifiers);
        }
        // Begin building the session creation request.
        CreateReadSessionRequest.Builder builder = CreateReadSessionRequest.newBuilder().setParent(parent).setReadSession(sessionBuilder).setMaxStreamCount(1);
        ReadSession session = client.createReadSession(builder.build());
        // Setup a simple reader and start a read session.
        try (SimpleRowReader reader = new SimpleRowReader(session.getArrowSchema())) {
            // Assert that there are streams available in the session.  An empty table may not have
            // data available.  If no sessions are available for an anonymous (cached) table, consider
            // writing results of a query to a named table rather than consuming cached results
            // directly.
            Preconditions.checkState(session.getStreamsCount() > 0);
            // Use the first stream to perform reading.
            String streamName = session.getStreams(0).getName();
            ReadRowsRequest readRowsRequest = ReadRowsRequest.newBuilder().setReadStream(streamName).build();
            // Process each block of rows as they arrive and decode using our simple row reader.
            ServerStream<ReadRowsResponse> stream = client.readRowsCallable().call(readRowsRequest);
            for (ReadRowsResponse response : stream) {
                Preconditions.checkState(response.hasArrowRecordBatch());
                reader.processRows(response.getArrowRecordBatch());
            }
        }
    }
}

Example 2 with TableModifiers

use of com.google.cloud.bigquery.storage.v1.ReadSession.TableModifiers in project java-bigquerystorage by googleapis.

the class StorageSample method main.

public static void main(String... args) throws Exception {
    // Sets your Google Cloud Platform project ID.
    // String projectId = "YOUR_PROJECT_ID";
    String projectId = args[0];
    Integer snapshotMillis = null;
    if (args.length > 1) {
        snapshotMillis = Integer.parseInt(args[1]);
    }
    try (BigQueryReadClient client = BigQueryReadClient.create()) {
        String parent = String.format("projects/%s", projectId);
        // This example uses baby name data from the public datasets.
        String srcTable = String.format("projects/%s/datasets/%s/tables/%s", "bigquery-public-data", "usa_names", "usa_1910_current");
        // We specify the columns to be projected by adding them to the selected fields,
        // and set a simple filter to restrict which rows are transmitted.
        TableReadOptions options = TableReadOptions.newBuilder().addSelectedFields("name").addSelectedFields("number").addSelectedFields("state").setRowRestriction("state = \"WA\"").build();
        // Start specifying the read session we want created.
        ReadSession.Builder sessionBuilder = ReadSession.newBuilder().setTable(srcTable).setDataFormat(DataFormat.AVRO).setReadOptions(options);
        // Optionally specify the snapshot time.  When unspecified, snapshot time is "now".
        if (snapshotMillis != null) {
            Timestamp t = Timestamp.newBuilder().setSeconds(snapshotMillis / 1000).setNanos((int) ((snapshotMillis % 1000) * 1000000)).build();
            TableModifiers modifiers = TableModifiers.newBuilder().setSnapshotTime(t).build();
            sessionBuilder.setTableModifiers(modifiers);
        }
        // Begin building the session creation request.
        CreateReadSessionRequest.Builder builder = CreateReadSessionRequest.newBuilder().setParent(parent).setReadSession(sessionBuilder).setMaxStreamCount(1);
        // Request the session creation.
        ReadSession session = client.createReadSession(builder.build());
        SimpleRowReader reader = new SimpleRowReader(new Schema.Parser().parse(session.getAvroSchema().getSchema()));
        // Assert that there are streams available in the session.  An empty table may not have
        // data available.  If no sessions are available for an anonymous (cached) table, consider
        // writing results of a query to a named table rather than consuming cached results directly.
        Preconditions.checkState(session.getStreamsCount() > 0);
        // Use the first stream to perform reading.
        String streamName = session.getStreams(0).getName();
        ReadRowsRequest readRowsRequest = ReadRowsRequest.newBuilder().setReadStream(streamName).build();
        // Process each block of rows as they arrive and decode using our simple row reader.
        ServerStream<ReadRowsResponse> stream = client.readRowsCallable().call(readRowsRequest);
        for (ReadRowsResponse response : stream) {
            Preconditions.checkState(response.hasAvroRows());
            reader.processRows(response.getAvroRows());
        }
    }
}