Android Open Source - Arvutaja Expr

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Back to project page Arvutaja.

License

The source code is released under:

Apache License

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Java Source Code

package ee.ioc.phon.android.arvutaja.command;
//from w  w w  . jav a  2 s  .c  o m
import java.util.regex.Pattern;

import ee.ioc.phon.android.arvutaja.R;

import android.content.Intent;

/**
 * <p>Examples of supported expressions:</p>
 * <ul>
 * <li>( 12 + - 34 ) * 123</li>
 * <li>PI ^ 0.1</li>
 * </ul>
 */
public class Expr extends DefaultCommand {

  // Tolerate anything that is composed of digits, operator symbols and brackets
  public static final Pattern PATTERN_EXPR = Pattern.compile("^[0-9().\\^+*/ -]+$");

  public Expr(String command) {
    super(command);
  }

  public int getMessage() {
    return R.string.msgActionViewWolframAlpha;
  }

  @Override
  public Intent getIntent() throws CommandParseException {
    return getActionView("http://www.wolframalpha.com/input/?i=", getCommand());
  }

  public Object getOut() {
    MathEval math = new MathEval();
    // We remove all the space characters otherwise MathEval's tokenizer can fail
    return math.evaluate(getCommand().replaceAll("\\s+", ""));
  }

  public static boolean isCommand(String command) {
    return PATTERN_EXPR.matcher(command.replace("PI", "0")).matches();
  }

}

Java Source Code List