BuildParameterParser.java :  » Inversion-of-Control » JICE » org » jicengine » expression » Java Open Source

package org.jicengine.expression;

import org.jicengine.operation.*;

/**
 * <p> </p>
 *
 * <p> </p>
 *
 * <p> </p>
 *
 * <p> </p>
 *
 * @author timo laitinen
 */
public class BuildParameterParser implements Parser {

  public static final String PREFIX = "param::";

  /**
   * @return Parsers may return null in order to signal 'abort' i.e.
   *
   * @return Parsers may return null in order to signal 'abort' i.e. if the
   *   syntax of the expression is not understood by the parser
   *   implementation. i.e. NumberParser returns null if the expression is a
   *   string-expression..
   * @throws SyntaxException
   * @param expression String
   */
  public Operation parse(String expression) throws SyntaxException
  {
    if (expression.startsWith(PREFIX)) {
      char[] chars = expression.substring(PREFIX.length()+2).toCharArray();
      for (int i = 0; i < chars.length; i++) {
        if( !Character.isLetterOrDigit(chars[i]) && chars[i] != '.' && chars[i] != '-' ){
          return null;
        }
      }
      return new VariableValueOperation(expression);
    }
    else {
      return null;
    }
  }
}