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ClojureMapcat.java
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ClojureMapcat.java
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/*
Copyright 2010 Nathan Marz
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package cascalog;
import cascading.operation.BaseOperation;
import cascading.operation.Function;
import cascading.operation.FunctionCall;
import cascading.operation.OperationCall;
import cascading.flow.FlowProcess;
import cascading.tuple.TupleEntry;
import cascading.tuple.TupleEntryCollector;
import cascading.tuple.Tuple;
import cascading.tuple.Fields;
import clojure.lang.IFn;
import clojure.lang.RT;
import clojure.lang.ISeq;
import java.util.Collection;
public class ClojureMapcat extends BaseOperation implements Function {
private Object[] fn_spec;
private IFn fn;
public ClojureMapcat(Fields out_fields, Object[] fn_spec) {
super(out_fields);
this.fn_spec = fn_spec;
}
public void prepare(FlowProcess flow_process, OperationCall op_call) {
this.fn = Util.bootFn(fn_spec);
}
public void operate(FlowProcess flow_process, FunctionCall fn_call) {
ISeq fn_args_seq = Util.coerceFromTuple(fn_call.getArguments().getTuple());
try {
ISeq result_seq = RT.seq(this.fn.applyTo(fn_args_seq));
TupleEntryCollector collector = fn_call.getOutputCollector();
while (result_seq != null) {
Object obj = result_seq.first();
collector.add(Util.coerceToTuple(obj));
result_seq = result_seq.next();
}
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}