Object2Expr.java :  » Algebra » symja » org » matheclipse » core » convert » Java Open Source

package org.matheclipse.core.convert;

import static org.matheclipse.core.expression.F.List;

import java.math.BigDecimal;

import org.matheclipse.core.expression.AST;
import org.matheclipse.core.expression.F;
import org.matheclipse.core.interfaces.IAST;
import org.matheclipse.core.interfaces.IExpr;
import org.matheclipse.core.interfaces.ISymbol;

import apache.harmony.math.BigInteger;

/**
 * Converts objects into an IExpr expression
 * 
 */
public class Object2Expr { // extends Converter<Object, IExpr> {

  /**
   * Typical instance of an <code>java.lang.Object</code> to <code>IExpr</code>
   * converter
   */
  public final static Object2Expr CONST = new Object2Expr(Object.class, IExpr.class);

  public Object2Expr(final Class sType, final Class tType) {
    super();
  }

  /**
   * Converts the following J<va objects into an IExpr expression
   * 
   * <pre>
   * Java Object     -&gt; MathEclipse object
   * -------------------------------------
   * null object          Null symbol
   * IExpr                IExpr type
   * Boolean              True or False symbol
   * BigInteger           Integer value  
   * java.math.BigInteger Integer value  
   * BigDecimal           Double with doubleValue() value
   * Double               Double with doubleValue() value
   * Float                Double with doubleValue() value
   * Number               Integer with longValue() value
   * java.util.List       0-th element of the list gives the head of the function 
   *                      1..nth element of the list give the arguments of the function
   * Object[]             a list of converted objects  
   * int[]                a list of Integer values
   * double[]             a list of Double values
   * double[][]           a matrix (i.e. nested lists) of Double values
   * boolean[]            a list of True or False symbols
   * 
   * </pre>
   */
  public IExpr convert(Object obj) throws ConversionException {
    if (obj == null) {
      return F.Null;
    }
    if (obj instanceof IExpr) {
      return (IExpr) obj;
    }
    if (obj instanceof Boolean) {
      if (((Boolean) obj).booleanValue()) {
        return F.True;
      }
      return F.False;
    }
    if (obj instanceof BigInteger) {
      return F.integer((BigInteger) obj);
    }
    if (obj instanceof java.math.BigInteger) {
      return F.integer((java.math.BigInteger) obj);
    }
    if (obj instanceof Number) {
      if (obj instanceof BigDecimal) {
        return F.num(((BigDecimal) obj).doubleValue());
      }

      if (obj instanceof Double) {
        return F.num(((Double) obj).doubleValue());
      }
      if (obj instanceof Float) {
        return F.num(((Float) obj).doubleValue());
      }
      return F.integer(((Number) obj).longValue());
    }
    if (obj instanceof java.util.List) {
      final java.util.List lst = (java.util.List) obj;
      IAST list = null;
      if (lst.size() == 0) {
        list = List();
      } else {
        final ISymbol head = F.$s(lst.get(0).toString());
        list = F.function(head);

        for (int i = 1; i < lst.size(); i++) {
          list.add(convert(lst.get(i)));
        }
      }
      return list;
    }
    if (obj instanceof Object[]) {
      final IAST list = List();
      final Object[] array = (Object[]) obj;
      for (int i = 0; i < array.length; i++) {
        list.add(convert(array[i]));
      }
      return list;
    }
    if (obj instanceof int[]) {
      return AST.newInstance(F.List, (int[]) obj);
    }
    if (obj instanceof double[]) {
      return AST.newInstance(F.List, (double[]) obj);
    }
    if (obj instanceof double[][]) {
      final double[][] dd = (double[][]) obj;
      final IAST list = List();
      for (int i = 0; i < dd.length; i++) {
        final IAST row = List();
        for (int j = 0; j < dd[i].length; j++) {
          row.add(F.num(dd[i][j]));
        }
        list.add(row);
      }
      return list;
    }
    if (obj instanceof boolean[]) {
      final IAST list = List();
      final boolean[] array = (boolean[]) obj;
      for (int i = 0; i < array.length; i++) {
        if (array[i]) {
          list.add(F.True);
        } else {
          list.add(F.False);
        }
      }
      return list;
    }
    return F.stringx(obj.toString());
  }
}