refact: Class Element, get all defined components. (#794)

* feat: new function get all defined components
docfix
* test: added test

src/main/java/neqsim/thermo/atomElement/Element.java

@@ -23,35 +23,29 @@ public class Element implements ThermodynamicConstantsInterface {
   private static final long serialVersionUID = 1000;
   static Logger logger = LogManager.getLogger(Element.class);
 
-  String[] nameArray;
-  double[] coefArray;
-
-  /**
-   * <p>
-   * Constructor for Element.
-   * </p>
-   */
-  public Element() {}
+  private String name;
+  private String[] nameArray;
+  private double[] coefArray;
 
   /**
    * <p>
    * Constructor for Element.
    * </p>
    *
-   * @param name a {@link java.lang.String} object
+   * @param name Name of component.
    */
   public Element(String name) {
+    this.name = name;
+
     ArrayList<String> names = new ArrayList<String>();
     ArrayList<String> stocCoef = new ArrayList<String>();
 
     try (neqsim.util.database.NeqSimDataBase database = new neqsim.util.database.NeqSimDataBase();
         java.sql.ResultSet dataSet =
             database.getResultSet(("SELECT * FROM element WHERE componentname='" + name + "'"))) {
       dataSet.next();
-      // System.out.println("comp name " + dataSet.getString("componentname"));
       do {
         names.add(dataSet.getString("atomelement").trim());
-        // System.out.println("name " + dataSet.getString("atomelement"));
         stocCoef.add(dataSet.getString("number"));
       } while (dataSet.next());
 
@@ -67,24 +61,49 @@ public Element(String name) {
   }
 
   /**
-   * <p>
-   * getElementNames.
-   * </p>
+   * Getter for property name.
    *
-   * @return an array of {@link java.lang.String} objects
+   * @return Component name.
+   */
+  public String getName() {
+    return this.name;
+  }
+
+  /**
+   * Getter for property nameArray.
+   *
+   * @return an array of {@link java.lang.String} objects. Names of Elements of component.
    */
   public String[] getElementNames() {
     return nameArray;
   }
 
   /**
-   * <p>
-   * getElementCoefs.
-   * </p>
+   * Getter for property coefArray.
    *
-   * @return an array of {@link double} objects
+   * @return an array of {@link double} objects. Coefficient corresponding to nameArray.
    */
   public double[] getElementCoefs() {
     return coefArray;
   }
+
+  /**
+   * Get all defined components.
+   *
+   * @return All element names in database.
+   */
+  public static ArrayList<String> getAllElementComponentNames() {
+    ArrayList<String> names = new ArrayList<String>();
+    try (neqsim.util.database.NeqSimDataBase database = new neqsim.util.database.NeqSimDataBase();
+        java.sql.ResultSet dataSet = database.getResultSet(("SELECT * FROM element"))) {
+      dataSet.next();
+      do {
+        names.add(dataSet.getString("componentname").trim());
+      } while (dataSet.next());
+    } catch (Exception ex) {
+      logger.error(ex.getMessage(), ex);
+    }
+
+    return names;
+  }
 }

src/test/java/neqsim/thermo/atomElement/ElementTest.java

@@ -0,0 +1,31 @@
+package neqsim.thermo.atomElement;
+
+import java.util.ArrayList;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class ElementTest {
+
+  @Test
+  public void testExistingElement() {
+    ArrayList<String> names = Element.getAllElementComponentNames();
+
+    Assertions.assertTrue(names.size() > 0);
+
+    Element a = new Element(names.get(0));
+    Assertions.assertEquals(a.getName(), names.get(0));
+  }
+
+  @Test
+  public void testNonExistingElement() {
+    ArrayList<String> names = Element.getAllElementComponentNames();
+
+    String nonExistingElement = "DUMMY_ELEMENT";
+
+    Assertions.assertFalse(names.contains(nonExistingElement));
+
+    Element e = new Element(nonExistingElement);
+    Assertions.assertNull(e.getElementNames());
+    Assertions.assertNull(e.getElementCoefs());
+  }
+}