Added generic AlternateCostSourceAbility. Some adjustments to alternate cost handling.

Mage/src/mage/abilities/AbilityImpl.java

@@ -58,6 +58,7 @@ import mage.game.command.Emblem;
 /**
  *
  * @author BetaSteward_at_googlemail.com
+ * @param <T>
  */
 public abstract class AbilityImpl<T extends AbilityImpl<T>> implements Ability {
 
@@ -204,9 +205,12 @@ public abstract class AbilityImpl<T extends AbilityImpl<T>> implements Ability {
         if (card != null) {
             for (Ability ability : card.getAbilities()) {
                 if (ability instanceof AlternativeSourceCosts) {
-                    if (((AlternativeSourceCosts)ability).askToActivateAlternativeCosts(this, game)) {
-                        // only one alternative costs may be activated
-                        break;
+                    AlternativeSourceCosts alternativeSpellCosts = (AlternativeSourceCosts) ability;
+                    if (alternativeSpellCosts.isAvailable(this, game)) {
+                        if (alternativeSpellCosts.askToActivateAlternativeCosts(this, game)) {
+                            // only one alternative costs may be activated
+                            break;
+                        }
                     }
                 }
                 if (ability instanceof OptionalAdditionalSourceCosts) {

Mage/src/mage/abilities/costs/AlternativeCost2.java

@@ -66,7 +66,6 @@ public interface AlternativeCost2 extends Cost {
     /**
      * If the player intends to pay the alternate cost, the cost will be activated
      *
-     * @param activated
      */
     void activate();
 

Mage/src/mage/abilities/costs/AlternativeCost2Impl.java

@@ -29,8 +29,11 @@
 package mage.abilities.costs;
 
 /**
- *
- * @author Ludwig
+ * Alternative costs
+ * 
+ * @author LevelX2
+ * 
+ * @param <T>
  */
 
 public class AlternativeCost2Impl <T extends AlternativeCost2Impl<T>> extends CostsImpl<Cost> implements AlternativeCost2 {
@@ -49,7 +52,9 @@ public class AlternativeCost2Impl <T extends AlternativeCost2Impl<T>> extends Co
         this.activated = false;
         this.name = name;
         this.delimiter = delimiter;
-        this.reminderText = new StringBuilder("<i>").append(reminderText).append("</i>").toString();
+        if (reminderText != null) {
+            this.reminderText = new StringBuilder("<i>").append(reminderText).append("</i>").toString();
+        }
         this.add((Cost) cost);
     }
 
@@ -67,7 +72,7 @@ public class AlternativeCost2Impl <T extends AlternativeCost2Impl<T>> extends Co
     }
     /**
      * Returns the complete text for the addional cost or if onlyCost is true
-     * only the pure text fore the included native cost
+     * only the pure text for the included native cost
      *
      * @param onlyCost
      * @return
@@ -77,7 +82,7 @@ public class AlternativeCost2Impl <T extends AlternativeCost2Impl<T>> extends Co
         if (onlyCost) {
             return getText();
         } else {
-            return new StringBuffer(name).append(delimiter).append(getText()).toString();
+            return new StringBuffer(name != null ? name: "").append(delimiter != null ? delimiter: "").append(getText()).toString();
         }
     }
 
@@ -113,7 +118,6 @@ public class AlternativeCost2Impl <T extends AlternativeCost2Impl<T>> extends Co
     /**
      * If the player intends to pay the cost, the cost will be activated
      *
-     * @param activated
      */
     @Override
     public void activate() {

Mage/src/mage/abilities/costs/AlternativeCostSourceAbility.java

@@ -0,0 +1,168 @@
+/*
+ *  Copyright 2010 BetaSteward_at_googlemail.com. All rights reserved.
+ *
+ *  Redistribution and use in source and binary forms, with or without modification, are
+ *  permitted provided that the following conditions are met:
+ *
+ *     1. Redistributions of source code must retain the above copyright notice, this list of
+ *        conditions and the following disclaimer.
+ *
+ *     2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *        of conditions and the following disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ *  THIS SOFTWARE IS PROVIDED BY BetaSteward_at_googlemail.com ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ *  FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BetaSteward_at_googlemail.com OR
+ *  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ *  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ *  ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ *  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *  The views and conclusions contained in the software and documentation are those of the
+ *  authors and should not be interpreted as representing official policies, either expressed
+ *  or implied, of BetaSteward_at_googlemail.com.
+ */
+
+package mage.abilities.costs;
+
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+import mage.abilities.Ability;
+import mage.abilities.SpellAbility;
+import mage.abilities.StaticAbility;
+import mage.abilities.condition.Condition;
+import mage.abilities.costs.mana.ManaCostsImpl;
+import mage.constants.Outcome;
+import mage.constants.Zone;
+import mage.game.Game;
+import mage.players.Player;
+
+/**
+ *
+ * @author LevelX2
+ */
+public class AlternativeCostSourceAbility extends StaticAbility<AlternativeCostSourceAbility> implements AlternativeSourceCosts {
+   
+    protected List<AlternativeCost2> alternateCosts = new LinkedList<AlternativeCost2>();
+    protected Condition condition;
+    protected String rule;
+    
+    public AlternativeCostSourceAbility(Cost cost) {
+        this(cost, null);
+    }
+
+    public AlternativeCostSourceAbility(Cost cost, Condition conditon) {
+        this(cost, conditon, null);
+    }
+    
+    public AlternativeCostSourceAbility(Cost cost, Condition condition, String rule) {
+        super(Zone.ALL, null);
+        this.convertToAlternativeCostAndAdd(cost);
+        this.setRuleAtTheTop(true);
+        this.condition = condition;
+        this.rule = rule;
+    }
+    
+    private void convertToAlternativeCostAndAdd(Cost cost) {        
+        AlternativeCost2 alternativeCost = new AlternativeCost2Impl(null, null, cost);        
+        this.alternateCosts.add(alternativeCost);    
+    }
+    
+    public AlternativeCostSourceAbility(final AlternativeCostSourceAbility ability) {
+       super(ability);
+       this.alternateCosts = ability.alternateCosts;
+       this.condition = ability.condition;
+       this.rule = ability.rule;
+    }
+
+    @Override
+    public AlternativeCostSourceAbility copy() {
+       return new AlternativeCostSourceAbility(this);
+    }
+    
+    @Override
+    public boolean isAvailable(Ability source, Game game) {
+        if (condition != null) {
+            return condition.apply(game, source);
+        }
+        return true;
+    }
+    
+    @Override
+    public boolean askToActivateAlternativeCosts(Ability ability, Game game) {
+        if (ability instanceof SpellAbility) {
+            Player player = game.getPlayer(controllerId);
+            if (player != null) {
+                for (AlternativeCost2 alternateCost: alternateCosts) {
+                    if (alternateCost.canPay(sourceId, controllerId, game) &&
+                        player.chooseUse(Outcome.Benefit, new StringBuilder("Pay alternative costs: ").append(alternateCost.getText()).append(" ?").toString(), game)) {
+                        alternateCost.activate();
+                        ability.getManaCostsToPay().clear();
+                        ability.getCosts().clear();
+                        for (Iterator it = ((Costs) alternateCost).iterator(); it.hasNext();) {
+                            Cost cost = (Cost) it.next();
+                            if (cost instanceof ManaCostsImpl) {
+                                ability.getManaCostsToPay().add((ManaCostsImpl) cost.copy());
+                            } else {
+                                ability.getCosts().add(cost.copy());
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        return isActivated();
+    }
+       
+    @Override
+    public boolean isActivated() {
+        for (AlternativeCost2 cost: alternateCosts) {
+            if(cost.isActivated()) {
+                return true;
+            }
+        }
+        return false;
+    }
+    
+    @Override
+    public String getCastMessageSuffix() {
+        return " using alternative casting costs";
+    }
+    
+    @Override
+    public String getRule() {
+        if (rule != null) {
+            return rule;
+        }
+// You may exile a black card from your hand rather than pay Unmask's mana cost.
+        
+       StringBuilder sb = new StringBuilder();
+       if (condition != null) {
+           sb.append(condition.toString());
+           sb.append(", rather than pay {source}'s mana cost, ");
+       }       
+       int numberCosts = 0;
+       String remarkText = "";
+       for (AlternativeCost2 alternativeCost: alternateCosts) {
+           if (numberCosts == 0) {
+               sb.append(alternativeCost.getText(false));
+               remarkText = alternativeCost.getReminderText();
+           } else {
+               sb.append(" and/or ").append(alternativeCost.getText(true));
+           }
+           ++numberCosts;
+       }
+       if (condition == null) {
+           sb.append(" rather than pay {source}'s mana cost");
+       }
+       sb.append(".");
+       if (numberCosts == 1 && remarkText != null) {
+            sb.append(" ").append(remarkText);
+       }
+       return sb.toString();
+    }    
+}

Mage/src/mage/abilities/costs/AlternativeSourceCosts.java

@@ -44,9 +44,19 @@ public interface AlternativeSourceCosts {
      * 
      * @param ability ability the alternative cost is activated for
      * @param game
+     * @return 
      */
     boolean askToActivateAlternativeCosts(Ability ability, Game game);
-
+    
+    /**
+     * Is the alternative spell cost currently available
+     * 
+     * @param source spell ability the alternative costs can be paid for
+     * @param game
+     * @return 
+     */
+    boolean isAvailable(Ability source, Game game);
+    
     /**
      * Was the alternative cost activated
      * @return

Mage/src/mage/abilities/keyword/EvokeAbility.java

@@ -103,7 +103,12 @@ public class EvokeAbility extends StaticAbility<EvokeAbility> implements Alterna
         }
         return false;
     }
-
+    
+    @Override
+    public boolean isAvailable(Ability source, Game game) {
+        return true;
+    }
+    
     @Override
     public boolean askToActivateAlternativeCosts(Ability ability, Game game) {
         if (ability instanceof SpellAbility) {

Mage/src/mage/abilities/keyword/ProwlAbility.java

@@ -62,7 +62,7 @@ import mage.watchers.common.ProwlWatcher;
 public class ProwlAbility extends StaticAbility<ProwlAbility> implements AlternativeSourceCosts {
 
     private static final String PROWL_KEYWORD = "Prowl";
-    private List<AlternativeCost2> prowlCosts = new LinkedList<AlternativeCost2>();
+    private final List<AlternativeCost2> prowlCosts = new LinkedList<AlternativeCost2>();
     private String reminderText;
 
     public ProwlAbility(Card card, String manaString) {
@@ -106,7 +106,12 @@ public class ProwlAbility extends StaticAbility<ProwlAbility> implements Alterna
         }
         return false;
     }
-
+    
+    @Override
+    public boolean isAvailable(Ability source, Game game) {
+        return true;
+    }
+    
     @Override
     public boolean askToActivateAlternativeCosts(Ability ability, Game game) {
         if (ability instanceof SpellAbility) {