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package org.apache.poi.ss.formula.functions;
import org.apache.poi.ss.formula.eval.BoolEval;
import org.apache.poi.ss.formula.eval.EvaluationException;
import org.apache.poi.ss.formula.eval.OperandResolver;
import org.apache.poi.ss.formula.eval.ValueEval;
import org.apache.poi.ss.formula.functions.LookupUtils.ValueVector;
import org.apache.poi.ss.formula.TwoDEval;
/**
* Implementation of the VLOOKUP() function.
*
* VLOOKUP finds a row in a lookup table by the first column value and returns the value from another column.
*
* Syntax:
* VLOOKUP(lookup_value, table_array, col_index_num, range_lookup)
*
* lookup_value The value to be found in the first column of the table array.
* table_array An area reference for the lookup data.
* col_index_num a 1 based index specifying which column value of the lookup data will be returned.
* range_lookup If TRUE (default), VLOOKUP finds the largest value less than or equal to
* the lookup_value. If FALSE, only exact matches will be considered
*/
public final class Vlookup extends Var3or4ArgFunction {
private static final ValueEval DEFAULT_ARG3 = BoolEval.TRUE;
public ValueEval evaluate(int srcRowIndex, int srcColumnIndex, ValueEval arg0, ValueEval arg1,
ValueEval arg2) {
return evaluate(srcRowIndex, srcColumnIndex, arg0, arg1, arg2, DEFAULT_ARG3);
}
public ValueEval evaluate(int srcRowIndex, int srcColumnIndex, ValueEval lookup_value, ValueEval table_array,
ValueEval col_index, ValueEval range_lookup) {
try {
// Evaluation order:
// lookup_value , table_array, range_lookup, find lookup value, col_index, fetch result
ValueEval lookupValue = OperandResolver.getSingleValue(lookup_value, srcRowIndex, srcColumnIndex);
TwoDEval tableArray = LookupUtils.resolveTableArrayArg(table_array);
boolean isRangeLookup;
try {
isRangeLookup = LookupUtils.resolveRangeLookupArg(range_lookup, srcRowIndex, srcColumnIndex);
} catch(RuntimeException e) {
isRangeLookup = true;
}
int rowIndex = LookupUtils.lookupIndexOfValue(lookupValue, LookupUtils.createColumnVector(tableArray, 0), isRangeLookup);
int colIndex = LookupUtils.resolveRowOrColIndexArg(col_index, srcRowIndex, srcColumnIndex);
ValueVector resultCol = createResultColumnVector(tableArray, colIndex);
return resultCol.getItem(rowIndex);
} catch (EvaluationException e) {
return e.getErrorEval();
}
}
/**
* Returns one column from an AreaEval
*
* @param colIndex assumed to be non-negative
*
* @throws EvaluationException (#REF!) if colIndex is too high
*/
private ValueVector createResultColumnVector(TwoDEval tableArray, int colIndex) throws EvaluationException {
if(colIndex >= tableArray.getWidth()) {
throw EvaluationException.invalidRef();
}
return LookupUtils.createColumnVector(tableArray, colIndex);
}
}