Google BigQuery java wrapper

Simplify access to BigQuery with power of Apache velocity SQL templates and lazy result pagination.

Use it in a next simple steps.

• Create SQL template resource file(sql.vm)

#macro(alltabledata $table)
SELECT * FROM [${DATASET}.$table] $filter
#end

• Create context object to connect BigQuery with specified credentials and SQL templates

BqContext context = new BqContext.Builder()
            .withProjectId("my-big-query-project")
            .withServiceAccount("272433143339-rs14caqptempvr50reqn5mc6b41mb655@developer.gserviceaccount.com")
            .withP12KeyURL(this.getClass().getResource("service-account-key.p12"))
            .withTemplateLibrary("sql.vm")
            .build();

• Populate context with some global template variables

context.with("DATASET", "v_0bd737781f004ffe9b7f6ebe5bc3991d");

• Build template based query with local template variables and macro parameters

BqSelect rows = context.select("alltabledata", "mytable")
            .useCache(true)
            .withPageSize(1000)
            .withPriority("INTERACTIVE")
            .with("filter","where myvalue > 10")
            .build();

• Iterate paginated results (lazy loading)

for (BqSelect.Row row : rows) {
        if (row.asString("col1") != null) {
         ....
        }
    }