Application: gvSIG desktop » gvSIG tools: ToolBox

package es.unex.sextante.gridCalculus.gridCalculator;

import java.util.ArrayList;

import java.util.List;

import org.nfunk.jep.JEP;

import es.unex.sextante.core.ObjectAndDescription;

import es.unex.sextante.core.Sextante;

import es.unex.sextante.dataObjects.IRasterLayer;

import es.unex.sextante.parameters.RasterLayerAndBand;

public class FormulaParser {

   private static final int MAX_BANDS = 256;

   public static String prepareFormula(final String sFormula,

                                       final List<String> names) {

      int i;

      int iIndex;

      String sName;

      String sSubstring;

      final StringBuffer sb = new StringBuffer(sFormula);

      iIndex = 0;

      while ((iIndex = sb.indexOf("|", iIndex)) != -1) {

         if ((sb.indexOf("|", iIndex - 1) == -1) && (sb.indexOf("|", iIndex + 1) == -1)) {

            sb.delete(iIndex, iIndex + 1);

            sb.insert(iIndex, " Band ");

            iIndex = 0;

         }

         else {

            iIndex++;

         }

      }

      iIndex = 0;

      for (i = 0; i < names.size(); i++) {

         sName = ((String) names.get(i)).toLowerCase();

         while ((iIndex = sb.indexOf(sName, iIndex)) != -1) {

            sSubstring = sb.substring(iIndex, Math.min(iIndex + sName.length() + " band ".length(), sb.length()));

            if (!sSubstring.toLowerCase().equals(sName + " band ")) {

               sb.delete(iIndex, iIndex + sName.length());

               sb.insert(iIndex, sName + " Band 1");

               iIndex = 0;

            }

            else {

               iIndex++;

            }

         }

      }

      return sb.toString();

   }

   /**

    * Converts the name of a layer in a normalized name. 

    * @param name

    * @return

    */

   public static String getNormalizedName(String name) {

           //If the name starts with a number adds a prefix

           String pattern = "^[\\d].*";

           if(name != null && name.matches(pattern)) {

               name = "prefix_" + name; 

       }

           return name;

   }

   /**

    * Replace all variables in a formula by a normalized name

    * @param formula

    * @param layerName

    * @param normalizedName

    * @return

    */

   public static String replaceVariables(String formula, String layerName, String normalizedName) {

           if(!normalizedName.equals(layerName)) {

                   return formula.replaceAll(layerName, normalizedName);

       }

           return formula;

   }

   public static List<RasterLayerAndBand> getBandsFromFormula(String sFormula,

                                               final List<IRasterLayer> layers) {

      int i, j;

      IRasterLayer layer;

      String sLayerName;

      final List<RasterLayerAndBand> array = new ArrayList<RasterLayerAndBand>();

      final List<String> names = new ArrayList<String>();

      final JEP jep = new JEP();

      jep.addStandardConstants();

      jep.addStandardFunctions();

      for (i = 0; i < layers.size(); i++) {

         layer = (IRasterLayer) layers.get(i);

         String layerName = layer.getName();

         String normalizedLayerName = getNormalizedName(layerName);

         sFormula = replaceVariables(sFormula, layerName, normalizedLayerName);

         names.add(normalizedLayerName);

      }

      sFormula = FormulaParser.prepareFormula(sFormula.toLowerCase(), names);

      sFormula = sFormula.toLowerCase().replaceAll(" ", "");

      sFormula = sFormula.replaceAll("\\[", "_");

      sFormula = sFormula.replaceAll("\\]", "_");

      sFormula = FormulaParser.replaceDots(sFormula);

      for (i = 0; i < layers.size(); i++) {

         layer = (IRasterLayer) layers.get(i);

         for (j = 0; j < layer.getBandsCount(); j++) {

            sLayerName = layer.getName() + " Band " + Integer.toString(j + 1);

            sLayerName = sLayerName.toLowerCase();

            sLayerName = sLayerName.replaceAll(" ", "");

            sLayerName = sLayerName.replaceAll("\\[", "_");

            sLayerName = sLayerName.replaceAll("\\]", "_");

            sLayerName = FormulaParser.replaceDots(sLayerName);

            sLayerName = getNormalizedName(sLayerName);

            if (sFormula.lastIndexOf(sLayerName) != -1) {

               array.add(new RasterLayerAndBand(layer, j));

               jep.addVariable(sLayerName, 0.0);

            }

         }

      }

      jep.parseExpression(sFormula);

      if (jep.hasError()) {

         Sextante.addErrorToLog(jep.getErrorInfo());

         return null;

      }

      if (array.size() == 0) {

         return null;

      }

      return array;

   }

   public static List<String> getBandsFromFormulaForModeler(String sFormula,

                                                         final ObjectAndDescription[] layers,

                                                         final ObjectAndDescription[] numerical) {

      int i, j;

      ObjectAndDescription oad;

      String sLayerName, sName;

      final List<String> array = new ArrayList<String>();

      final List<String> names = new ArrayList<String>();

      final JEP jep = new JEP();

      jep.addStandardConstants();

      jep.addStandardFunctions();

      for (i = 0; i < layers.length; i++) {

         oad = layers[i];

         String layerName = (String) oad.getObject();

         String normalizedLayerName = getNormalizedName(layerName);

         sFormula = replaceVariables(sFormula, layerName, normalizedLayerName);

         names.add(layerName);

      }

      for (i = 0; i < numerical.length; i++) {

         jep.addVariable(((String) numerical[i].getObject()).toLowerCase(), 0.0);

      }

      sFormula = FormulaParser.prepareFormula(sFormula.toLowerCase(), names);

      sFormula = sFormula.toLowerCase().replaceAll(" ", "");

      sFormula = sFormula.replaceAll("\\[", "_");

      sFormula = sFormula.replaceAll("\\]", "_");

      sFormula = sFormula.replaceAll("\\:", "_");

      sFormula = sFormula.replaceAll("\"", "_");

      sFormula = FormulaParser.replaceDots(sFormula);

      for (i = 0; i < names.size(); i++) {

         sName = names.get(i);

         for (j = 0; j < MAX_BANDS; j++) {

            sLayerName = sName + " Band " + Integer.toString(j + 1);

            sLayerName = sLayerName.toLowerCase();

            sLayerName = sLayerName.replaceAll(" ", "");

            sLayerName = sLayerName.replaceAll("\\[", "_");

            sLayerName = sLayerName.replaceAll("\\]", "_");

            sLayerName = sLayerName.replaceAll("\\:", "_");

            sLayerName = sLayerName.replaceAll("\"", "_");

            sLayerName = FormulaParser.replaceDots(sLayerName);

            sLayerName = getNormalizedName(sLayerName);

            if (sFormula.lastIndexOf(sLayerName) != -1) {

               array.add((String) layers[i].getObject());

               jep.addVariable(sLayerName, 0.0);

            }

         }

      }

      jep.parseExpression(sFormula);

      if (jep.hasError()) {

         return null;

      }

      if (array.size() == 0) {

         return null;

      }

      return array;

   }

   public static String replaceDots(final String s) {

      char c, c2;

      StringBuffer sb = new StringBuffer(s);

      for (int i = 0; i < sb.length() - 1; i++) {

         c = sb.charAt(i);

         c2 = sb.charAt(i + 1);

         if ((c == '.') && !Character.isDigit(c2)) {

            sb = sb.deleteCharAt(i);

         }

      }

      return sb.toString();

   }

}