Add: Javadoc for PlayableCard class

src/main/java/it/polimi/ingsw/gc14/Model/PlayableCard.java

@@ -1,10 +1,31 @@
 package it.polimi.ingsw.gc14.Model;
 
+/**
+ * Abstract base class for all playable cards.
+ * A PlayableCard is characterized by an era value.
+ */
 public abstract class PlayableCard {
+
+    /**
+     * The era associated with this playable card.
+     */
     private int Era;
+
+    /**
+     * Returns the era of this playable card.
+     *
+     * @return the era of this playable card.
+     */
     public int getEra(){
         return Era;
     }
+
+    /**
+     * Creates a playable card with the specified era.
+     *
+     * @param Era the era of the playable card.
+     * @throws IllegalArgumentException if {@code Era <= 0} or {@code Era >= 4}.
+     */
     public PlayableCard (int Era) throws IllegalArgumentException{
         if (Era>0 && Era<4) {
             this.Era = Era;
@@ -13,6 +34,11 @@ public abstract class PlayableCard {
         }
     }
 
+    /**
+     * Returns the string representation of this playable card.
+     *
+     * @return the string representation of this playable card.
+     */
     @Override
     public String toString() {
         return "Era:"+String.valueOf(Era);