Cook Book
Some common patterns.
Copy a value
pipe = new Each( pipe, new Fields( "field" ), new Identity( new Fields( "copy" ) ), Fields.ALL );
Rename a field
// two incoming fields: "other" and "field" pipe = new Each( pipe, new Fields( "field" ), new Identity( new Fields( "renamed" ) ), new Fields( "other", "renamed" ) );
Convert strings to primitive types
Class[] types = new Class[] {Long.class, Float.class, Boolean.class};
pipe = new Each( pipe, new Fields( "longField", "floatField", "booleanField" ),
new Identity( types ) );
Reorder fields
// two incoming fields: "field1" and "field2" pipe = new Each( pipe, new Fields( "field2", "field1" ), new Identity() );
Discard unused fields
// two incoming fields: "field1" and "field2" pipe = new Each( pipe, new Fields( "field2" ), new Identity() );
Sort values passed to Aggregator
pipe = new GroupBy( pipe, new Fields( "group1", "group2" ), new Fields( "value" ) );
Insert constant values into a value stream
pipe = new Each( pipe, new Insert( new Fields( "field1", "field2" ), "value1", "value2" ), Fields.ALL );
Create 'timestamp' from date/time fields
// build 'datetime' string. FieldFormatter formatter = new FieldFormatter( new Fields( "datetime" ), "%s:%s:%s:%s:%s:%s.%s" ); Fields timeFields = new Fields( "year", "month", "day", "hour", "minute", "second", "millisecond" ); pipe = new Each( pipe, timeFields, formatter, Fields.ALL ); // creates a new field named 'ts' for the timestamp pipe = new Each( pipe, new Fields( "datetime" ), new DateParser( "yyyy:MM:dd:HH:mm:ss.SSS" ), Fields.ALL );
Create date/time string from 'timestamp' field
DateFormatter timeFormatter = new DateFormatter( new Fields( "datetime" ), "HH:mm:ss.SSS" ); pipe = new Each( pipe, new Fields( "ts" ), timeFormatter, sortFields );
Get 'DISTINCT' values from a Tuple stream
// group on all values pipe = new GroupBy( pipe, Fields.ALL ); // only take the first value in the grouping, ignore the rest pipe = new Every( pipe, Fields.ALL, new First(), Fields.RESULTS );