Android Open Source - graph-android Term

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License

The source code is released under:
GNU General Public License
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Java Source Code

package lorian.graph.function;
/*  w w  w  . ja v  a2s  . c  o m*/
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;

public class Term {
  
  protected boolean parsed = false;
  
  protected int index = 0;
  protected char argumentChar = 'x';
  protected List<Factor> factors;
  
  public Term()
  {
    factors = new ArrayList<Factor>();
  }
  public Term(char argumentChar)
  {
    this.argumentChar = argumentChar;
    factors = new ArrayList<Factor>();
  }
  
  
  
  protected String GetEverythingBetweenParentheses(String s)
  {
    char ch;
    int funcdepth = 0;
    String result = "(";
    index++;
    while(index < s.length())
    {
      ch = s.charAt(index);
      if(ch == '(')
      {
        funcdepth++;
      }
      else if(ch == ')')
      {
        if(funcdepth > 0 ) funcdepth--;
        else if(funcdepth==0)
        {
          result += ch;
          return result;
        }
      }
      result += ch;
      index++;
    }
    return result;
  }
  
  protected String exponentTimesMinusOne(String s)
  {
    if(s.trim().length() == 0) return "";
    return String.format("(%s)^-1", s);
  }
  protected List<String> SplitIntoFactors(String s)
  {
    List<String> factors = new ArrayList<String>();
    char ch;
    String newfactor = "";
    boolean ignoreminplus = true;
    boolean inexponent = false;
    boolean division = false;
    while(index < s.length())
    {
      ch = s.charAt(index); 

        if(!((ch >= '0' && ch <= '9') || ch == '.'))
        {
          if(ch=='*' || ch == '/')
          { 
            if(division) newfactor = exponentTimesMinusOne(newfactor);
            if(newfactor.length() > 0) factors.add(newfactor);
            newfactor = "";
            ignoreminplus = true;
            if(ch == '/') division = true;
            else division = false;
          }
          
          else if(ch==argumentChar)
          {
            if(inexponent)
            {
              newfactor += ch;
            }
            else if(newfactor.length() > 0)
            {
              if(!ignoreminplus)
              {
                if(division) newfactor = exponentTimesMinusOne(newfactor);
                if(newfactor.length() > 0) factors.add(newfactor);
                newfactor = "";
                division = false;
                ignoreminplus = true;
                inexponent = false;
                continue;
              }
              else
              {
                boolean neg = false;
                int i=0;
                String tmp = "";
                while(i < newfactor.length())
                {
                  if(newfactor.charAt(i) == '-') neg = !neg;
                  i++;
                }
                if(neg) tmp += "-";
                tmp += "1";
                if(division) tmp = exponentTimesMinusOne(tmp);
                factors.add(tmp);
                newfactor = "";
                division = false;
                ignoreminplus = true;
                continue;
              }
            }
            
            else
            {
              newfactor += ch;
              if(index+1 < s.length())
              {
                if(s.charAt(index+1) != '^')
                {
                  if(division) newfactor = exponentTimesMinusOne(newfactor);
                  if(newfactor.length() > 0) factors.add(newfactor);
                  division = false;
                  newfactor = "";
                  ignoreminplus = true;
                }
                
              }
              
              
              
            }
          }
          
          
          else if(ch=='+' || ch=='-')
          {
            if(!ignoreminplus)
            {
              if(division) newfactor = exponentTimesMinusOne(newfactor);
              if(newfactor.length() > 0) factors.add(newfactor);
              division = false;
              newfactor = "";
              ignoreminplus = true;
              inexponent = false;
              continue;
            }
            else newfactor += ch;
          }
          else if(ch == '(')
          {
            if(!Util.StringContains(newfactor, Util.LowercaseAlphabethWithout(argumentChar)) && !Util.StringContains(newfactor, "^"))
            {
              if(newfactor.length() > 0) 
              {
                if(division) newfactor = exponentTimesMinusOne(newfactor);
                factors.add(newfactor);
                division = false;
                newfactor = "";
              }
            }
            newfactor += GetEverythingBetweenParentheses(s);
            if(index+1 < s.length())
            {
              if(s.charAt(index+1) == '^')
              {
                index++;
                continue;
              }
            }
            if(division) newfactor = exponentTimesMinusOne(newfactor);
            if(newfactor.length() > 0) factors.add(newfactor);
            division = false;
            newfactor = "";
            ignoreminplus = true;
            inexponent = false;
            
          }
          else if(ch == '^')
          {
            ignoreminplus = true;
            inexponent = true;
            newfactor += ch;
            index++;
            continue;
          }

          else if(Util.StringContains("" + ch, Util.LowercaseAlphabethWithout(argumentChar) + "()+-^"))
          {
            if(division) newfactor = exponentTimesMinusOne(newfactor);
            if(newfactor.length() > 0) factors.add(newfactor);
            int tmpindex = s.indexOf('(', index);
            newfactor = s.substring(index, tmpindex);
            index = tmpindex;
            newfactor += GetEverythingBetweenParentheses(s);
            if(index+1 < s.length())
            {
              if(s.charAt(index+1) == '^')
              {
                index++;
                continue;
              }
            }
            if(division) newfactor = exponentTimesMinusOne(newfactor);
            if(newfactor.length() > 0) factors.add(newfactor);
            division = false;
            newfactor = "";
            ignoreminplus = true;
            inexponent = false;
            
          }
          
          else
            newfactor += ch;
        }
        else
        {
          newfactor += ch;
        }
        if(ignoreminplus && newfactor.length() > 0 && !(ch == '+' || ch == '-')) ignoreminplus = false;
      
      index++;
    }
    if(division) newfactor = exponentTimesMinusOne(newfactor);
    if(newfactor.length() > 0) factors.add(newfactor);
    return factors;
  }
  
  public boolean Parse(String s)
  {
    s = Util.removeWhiteSpace(s).toLowerCase(Locale.ENGLISH);
    boolean result = true;
    List<String> factorstrs = SplitIntoFactors(s);
    //System.out.println(factorstrs);
    for(String factorstr: factorstrs)
    {
      Factor factor = new Factor(this.argumentChar);
      if(!factor.Parse(factorstr)) { 
        result = false;
        factors.add(null);
      }
      else
        factors.add(factor);
    }
    parsed = result;
    return result;
  }
  

  public double Calc(double arg)
  {
    if(!parsed) return 0;
    double product = 1;
    for(Factor fac: factors)
    {
      product *= fac.Calc(arg);
    }
    return product;
    
  }
  
  public List<Factor> getFactors()
  {
    return this.factors;
  }
}
Java Source Code List
