Method exec

src/org/apache/pig/scripting/js/JsFunction.java:197–232

(Tuple tuple)

    ///////////////////////////

    @Override
    public Object exec(Tuple tuple) throws IOException {
    	Schema inputSchema = this.getInputSchema();
        if (LOG.isDebugEnabled()) {
            LOG.debug( "CALL " + stringify(outputSchema) + " " + functionName + " " + stringify(inputSchema));
        }
        // UDF always take a tuple: unwrapping when not necessary to simplify UDFs
        if (inputSchema.size() == 1 && inputSchema.getField(0).type == DataType.TUPLE) {
            inputSchema = inputSchema.getField(0).schema;
        }

        Scriptable params = pigTupleToJS(tuple, inputSchema, 0);

        Object[] passedParams = new Object[inputSchema.size()];
        for (int j = 0; j < passedParams.length; j++) {
            passedParams[j] = params.get(inputSchema.getField(j).alias, params);
        }

        Object result = jsScriptEngine.jsCall(functionName, passedParams);
        if (LOG.isDebugEnabled()) {
            LOG.debug( "call "+functionName+"("+Arrays.toString(passedParams)+") => "+toString(result));
        }

        // We wrap the result with an object in the following cases:
        //   1. Result is not an object type.
        //   2. OutputSchema is a tuple type. 
        if (!(result instanceof NativeObject) || outputSchema.getField(0).type == DataType.TUPLE) {
            Scriptable wrapper = jsScriptEngine.jsNewObject();
            wrapper.put(outputSchema.getField(0).alias, wrapper, result);
            result = wrapper;
        }
        Tuple evalTuple = jsToPigTuple((Scriptable)result, outputSchema, 0);
        Object eval = outputSchema.size() == 1 ? evalTuple.get(0) : evalTuple;
        LOG.debug(eval);
        return eval;
    }

    @Override
    public Schema outputSchema(Schema input) {