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Thread: Creating an object with a String from file IO

  1. #1
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    Default Creating an object with a String from file IO

    Hi folks,

    I have a chemicals class with various instance variables such as chemical name, boiling point, freeze point etc.

    I have created a stream input file with a .csv extension where I want the user to specify a process stream (flow rate, temperature, chemicals inside the stream etc.).

    I have the following code in the main method:

    Chemicals [] chemObject = new Chemicals[2]; //2 chemicals per stream
    //If i add this line next: System.out.println(inputStream.next()); it prints the name of the chemical I want
    chemObject[0] = new Chemicals(inputStream.next());
    System.out.println(chemObject[0].getName()); //this prints out null meaning that the chemObject[0] did not get created?

    I realized I should have provided more info on the actual Chemicals class and its constructors:

     public Chemicals(String name) //Overloaded consutrctor
      {
        if (name  == "toluene")
        {
          this.name = "toluene";
          this.boilingPoint=110.6;
        }
      }
    public String getName()
      {
        return this.name; 
      }

    How do I create an object with a string from an input stream?

    Cheers


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Creating an object with a String from file IO

    How do I create an object with a string from an input stream?
    String aStr = <get from input stream>; //  read a String from an Input Stream
    SomeClass scObject = new SomeClass(aStr): // create object with String from IS

    You should have a default name value.
    Use the equals() method to compare Strings, not the == operator.
    If you don't understand my answer, don't ignore it, ask a question.

  3. #3
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    Default Re: Creating an object with a String from file IO

    thanks Norm.

    It was indeed a problem with the Strings being compared and not with my input streams.

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