| /* ==================================================================== |
| Licensed to the Apache Software Foundation (ASF) under one or more |
| contributor license agreements. See the NOTICE file distributed with |
| this work for additional information regarding copyright ownership. |
| The ASF licenses this file to You under the Apache License, Version 2.0 |
| (the "License"); you may not use this file except in compliance with |
| the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| See the License for the specific language governing permissions and |
| limitations under the License. |
| ==================================================================== */ |
| |
| package org.apache.poi.ss.formula.functions; |
| |
| 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 Excel function LOOKUP.<p> |
| * |
| * LOOKUP finds an index row in a lookup table by the first column value and returns the value from another column. |
| * |
| * <b>Syntax</b>:<br> |
| * <b>VLOOKUP</b>(<b>lookup_value</b>, <b>lookup_vector</b>, result_vector)<p> |
| * |
| * <b>lookup_value</b> The value to be found in the lookup vector.<br> |
| * <b>lookup_vector</> An area reference for the lookup data. <br> |
| * <b>result_vector</b> Single row or single column area reference from which the result value is chosen.<br> |
| * |
| * @author Josh Micich |
| */ |
| public final class Lookup extends Var2or3ArgFunction { |
| |
| @Override |
| public ValueEval evaluate(int srcRowIndex, int srcColumnIndex, ValueEval arg0, ValueEval arg1) { |
| // complex rules to choose lookupVector and resultVector from the single area ref |
| |
| try { |
| /* |
| The array form of LOOKUP is very similar to the HLOOKUP and VLOOKUP functions. The difference is that HLOOKUP searches for the value of lookup_value in the first row, VLOOKUP searches in the first column, and LOOKUP searches according to the dimensions of array. |
| If array covers an area that is wider than it is tall (more columns than rows), LOOKUP searches for the value of lookup_value in the first row. |
| If an array is square or is taller than it is wide (more rows than columns), LOOKUP searches in the first column. |
| With the HLOOKUP and VLOOKUP functions, you can index down or across, but LOOKUP always selects the last value in the row or column. |
| */ |
| ValueEval lookupValue = OperandResolver.getSingleValue(arg0, srcRowIndex, srcColumnIndex); |
| TwoDEval lookupArray = LookupUtils.resolveTableArrayArg(arg1); |
| ValueVector lookupVector; |
| ValueVector resultVector; |
| |
| if (lookupArray.getWidth() > lookupArray.getHeight()) { |
| // If array covers an area that is wider than it is tall (more columns than rows), LOOKUP searches for the value of lookup_value in the first row. |
| lookupVector = createVector(lookupArray.getRow(0)); |
| resultVector = createVector(lookupArray.getRow(lookupArray.getHeight() - 1)); |
| } else { |
| // If an array is square or is taller than it is wide (more rows than columns), LOOKUP searches in the first column. |
| lookupVector = createVector(lookupArray.getColumn(0)); |
| resultVector = createVector(lookupArray.getColumn(lookupArray.getWidth() - 1)); |
| } |
| // if a rectangular area reference was passed in as arg1, lookupVector and resultVector should be the same size |
| assert (lookupVector.getSize() == resultVector.getSize()); |
| |
| int index = LookupUtils.lookupIndexOfValue(lookupValue, lookupVector, true); |
| return resultVector.getItem(index); |
| } catch (final EvaluationException e) { |
| return e.getErrorEval(); |
| } |
| } |
| |
| @Override |
| public ValueEval evaluate(int srcRowIndex, int srcColumnIndex, ValueEval arg0, ValueEval arg1, |
| ValueEval arg2) { |
| try { |
| ValueEval lookupValue = OperandResolver.getSingleValue(arg0, srcRowIndex, srcColumnIndex); |
| TwoDEval aeLookupVector = LookupUtils.resolveTableArrayArg(arg1); |
| TwoDEval aeResultVector = LookupUtils.resolveTableArrayArg(arg2); |
| |
| ValueVector lookupVector = createVector(aeLookupVector); |
| ValueVector resultVector = createVector(aeResultVector); |
| if(lookupVector.getSize() > resultVector.getSize()) { |
| // Excel seems to handle this by accessing past the end of the result vector. |
| throw new RuntimeException("Lookup vector and result vector of differing sizes not supported yet"); |
| } |
| int index = LookupUtils.lookupIndexOfValue(lookupValue, lookupVector, true); |
| |
| return resultVector.getItem(index); |
| } catch (EvaluationException e) { |
| return e.getErrorEval(); |
| } |
| } |
| |
| private static ValueVector createVector(TwoDEval ae) { |
| ValueVector result = LookupUtils.createVector(ae); |
| if (result != null) { |
| return result; |
| } |
| // extra complexity required to emulate the way LOOKUP can handles these abnormal cases. |
| throw new RuntimeException("non-vector lookup or result areas not supported yet"); |
| } |
| } |