Java: creating multiple instances of an object in a class or restructuring
I'm a java beginner and wondering how best to structure a cooking program. I have a class called Ingredient, this class looks like this:
public class Ingredient {
private String identifier;
private double ingredientFactor;
private String titleInterface;
public Ingredient(String identifier, double ingredientFactor,String titleInterface) {
this.identifier = identifier;
this.ingredientFactor = ingredientFactor;
this.titleInterface = titleInterface;
}
I want to initialize multiple objects (about 40) with specific values โโas instance variables and store them in the map like
Map<String, Ingredient> allIngredients = new HashMap<String, Ingredient>();
allIngredients.put("Almonds (ground)", new Ingredient("Almonds (ground)", 0.7185, "Almonds (ground)");
Later, I want to get all these objects as Map / HashMap in another class. I'm not sure how best to proceed, initialize all these objects in the Ingredient class itself, or provide a method that initializes it, or would it be better to create a superclass (AllIngredients or something?) That has a map with ingredients as variables instance?
Happy for any suggestions, thanks in advance :)
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Please do not initialize all of these objects in the Ingredient class itself. This would be bad practice for oops.
Just think that your class is a template from which you create copies (objects) with different values โโfor the attributes. In the real world, if your class is a toy plane model that you would use to create multiple toy planes, but each with a different name and color, consider how such a system would be designed. You will have a model (class). Then a system (another class) to get the required color and name from different colors and names (e.g. in database, files, properties file), etc.
Regarding your situation.
- Where predefined values โโstore values โโin a text file, properties file, database, constants in a class, etc. depending on the sensitivity of the data.
- Create class Ingredient with constructors
- Create a class that will have methods to initialize the Ingredient class using predefined values, update the values โโas needed, store the values โโin the -database text file, etc. and in your case, return as a card.
Also check the links below
http://www.tutorialspoint.com/design_pattern/data_access_object_pattern.htm
http://www.oracle.com/technetwork/java/dataaccessobject-138824.html
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It seems to me what you are looking for static Map
.
public class Ingredient {
private String identifier;
private double ingredientFactor;
private String titleInterface;
public Ingredient(String identifier, double ingredientFactor, String titleInterface) {
this.identifier = identifier;
this.ingredientFactor = ingredientFactor;
this.titleInterface = titleInterface;
}
static Map<String, Ingredient> allIngredients = new HashMap<String, Ingredient>();
static {
// Build my main set.
allIngredients.put("Almonds (ground)", new Ingredient("Almonds (ground)", 0.7185, "Almonds (ground)"));
}
}
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