1 files changed, 74 insertions, 61 deletions

diff --git a/src/main/java/bjc/esodata/PushdownMap.java b/src/main/java/bjc/esodata/PushdownMap.java
index 54ae939..76dd2db 100644
--- a/src/main/java/bjc/esodata/PushdownMap.java
+++ b/src/main/java/bjc/esodata/PushdownMap.java
@@ -1,12 +1,10 @@
 package bjc.esodata;
 
-import java.util.function.BiConsumer;
-import java.util.function.Consumer;
-import java.util.function.Function;
+import java.util.*;
+import java.util.function.*;
 
-import bjc.funcdata.FunctionalMap;
-import bjc.funcdata.IList;
-import bjc.funcdata.IMap;
+import bjc.data.*;
+import bjc.funcdata.*;
 
 /**
  * A variant of a map where inserting a duplicate key shadows the existing value
@@ -22,22 +20,22 @@ import bjc.funcdata.IMap;
  * @param <ValueType>
  *                    The values in the map.
  */
-public class PushdownMap<KeyType, ValueType> implements IMap<KeyType, ValueType> {
+public class PushdownMap<KeyType, ValueType> implements MapEx<KeyType, ValueType> {
 	/* Our backing storage. */
-	private final IMap<KeyType, Stack<ValueType>> backing;
+	private final MapEx<KeyType, Stack<ValueType>> backing;
 
+	private boolean isFrozen    = false;
+	private boolean thawEnabled = true;
+	
 	/** Create a new empty stack-based map. */
 	public PushdownMap() {
 		backing = new FunctionalMap<>();
 	}
 
-	/** Create a new empty stack-based map using the specified backing. */
-	private PushdownMap(final IMap<KeyType, Stack<ValueType>> back) {
-		backing = back;
-	}
-
 	@Override
 	public void clear() {
+		if (isFrozen) throw new ObjectFrozen("Can't clear frozen map");
+		
 		backing.clear();
 	}
 
@@ -45,30 +43,15 @@ public class PushdownMap<KeyType, ValueType> implements IMap<KeyType, ValueType>
 	public boolean containsKey(final KeyType key) {
 		return backing.containsKey(key);
 	}
-
-	@Override
-	public IMap<KeyType, ValueType> extend() {
-		return new PushdownMap<>(backing.extend());
-	}
-
+	
 	@Override
 	public void forEach(final BiConsumer<KeyType, ValueType> action) {
 		backing.forEach((key, stk) -> action.accept(key, stk.top()));
 	}
 
 	@Override
-	public void forEachKey(final Consumer<KeyType> action) {
-		backing.forEachKey(action);
-	}
-
-	@Override
-	public void forEachValue(final Consumer<ValueType> action) {
-		backing.forEachValue(stk -> action.accept(stk.top()));
-	}
-
-	@Override
-	public ValueType get(final KeyType key) {
-		return backing.get(key).top();
+	public Optional<ValueType> get(final KeyType key) {
+		return backing.get(key).map((stack) -> stack.top());
 	}
 
 	@Override
@@ -77,23 +60,16 @@ public class PushdownMap<KeyType, ValueType> implements IMap<KeyType, ValueType>
 	}
 
 	@Override
-	public IList<KeyType> keyList() {
+	public ListEx<KeyType> keyList() {
 		return backing.keyList();
 	}
 
 	@Override
-	public <V2> IMap<KeyType, V2> transform(final Function<ValueType, V2> transformer) {
-		/*
-		 * @NOTE Can and should we support this? More to the point, maybe this should be
-		 * a map sub-type that does what it needs to?
-		 */
-		throw new UnsupportedOperationException("Cannot transform pushdown maps.");
-	}
-
-	@Override
 	public ValueType put(final KeyType key, final ValueType val) {
+		if (isFrozen) throw new ObjectFrozen("Can't insert key " + key + " into frozen map");
+		
 		if (backing.containsKey(key)) {
-			final Stack<ValueType> stk = backing.get(key);
+			final Stack<ValueType> stk = backing.get(key).get();
 
 			final ValueType vl = stk.top();
 
@@ -111,18 +87,19 @@ public class PushdownMap<KeyType, ValueType> implements IMap<KeyType, ValueType>
 
 	@Override
 	public ValueType remove(final KeyType key) {
-		final Stack<ValueType> stk = backing.get(key);
+		if (isFrozen) throw new ObjectFrozen("Can't remove key " + key + " from frozen map");
 
-		if (stk.size() > 1) {
-			return stk.pop();
-		}
+		Holder<ValueType> result = Holder.of(null);
+		
+		backing.get(key).ifPresent((stk) -> {
+			if (stk.size() > 1) {
+				result.replace(stk.pop());
+			} else {
+				result.replace(backing.remove(key).top());
+			}
+		});
 
-		return backing.remove(key).top();
-	}
-
-	@Override
-	public IList<ValueType> valueList() {
-		return backing.valueList().map(Stack::top);
+		return result.getValue();
 	}
 
 	@Override
@@ -137,20 +114,17 @@ public class PushdownMap<KeyType, ValueType> implements IMap<KeyType, ValueType>
 
 	@Override
 	public boolean equals(final Object obj) {
-		if (this == obj)
-			return true;
-		if (obj == null)
-			return false;
-		if (!(obj instanceof PushdownMap<?, ?>))
-			return false;
+		if (this == obj)                         return true;
+		if (obj == null)                         return false;
+		if (!(obj instanceof PushdownMap<?, ?>)) return false;
 
 		final PushdownMap<?, ?> other = (PushdownMap<?, ?>) obj;
 
 		if (backing == null) {
-			if (other.backing != null)
-				return false;
-		} else if (!backing.equals(other.backing))
+			if (other.backing != null) return false;
+		} else if (!backing.equals(other.backing)) {
 			return false;
+		}
 
 		return true;
 	}
@@ -159,4 +133,43 @@ public class PushdownMap<KeyType, ValueType> implements IMap<KeyType, ValueType>
 	public String toString() {
 		return String.format("PushdownMap [backing=%s]", backing);
 	}
+
+	@Override
+	public boolean freeze() {
+		isFrozen = true;
+		
+		return true;
+	}
+
+	@Override
+	public boolean thaw() {
+		if (thawEnabled) {
+			isFrozen = false;
+			return true;
+		} else {
+			return false;
+		}
+	}
+
+	@Override
+	public boolean deepFreeze() {
+		thawEnabled = true;
+		
+		return freeze();
+	}
+	
+	@Override
+	public boolean canFreeze() {
+		return true;
+	}
+	
+	@Override
+	public boolean canThaw() {
+		return thawEnabled;
+	}
+	
+	@Override
+	public boolean isFrozen() {
+		return isFrozen;
+	}
 }