Stack updates.

4 files changed, 83 insertions, 4 deletions

diff --git a/BJC-Utils2/src/main/java/bjc/utils/esodata/QueueStack.java b/BJC-Utils2/src/main/java/bjc/utils/esodata/QueueStack.java
index c1a21b6..a2c2f32 100644
--- a/BJC-Utils2/src/main/java/bjc/utils/esodata/QueueStack.java
+++ b/BJC-Utils2/src/main/java/bjc/utils/esodata/QueueStack.java
@@ -6,7 +6,7 @@ import java.util.LinkedList;
 /**
  * A FIFO implementation of a stack.
  *
- * @param T
+ * @param <T>
  *                The datatype stored in the stack.
  * @author Ben Culkin
  */
@@ -28,11 +28,15 @@ public class QueueStack<T> extends Stack<T> {
 
 	@Override
 	public T pop() {
+		if(backing.isEmpty()) throw new StackUnderflowException();
+		
 		return backing.remove();
 	}
 
 	@Override
 	public T top() {
+		if(backing.isEmpty()) throw new StackUnderflowException();
+		
 		return backing.peek();
 	}
 
@@ -45,4 +49,15 @@ public class QueueStack<T> extends Stack<T> {
 	public boolean empty() {
 		return backing.size() == 0;
 	}
+	
+	@Override
+	public String toString() {
+		return backing.toString();
+	}
+	
+	@SuppressWarnings("unchecked")
+	@Override
+	public T[] toArray() {
+		return (T[]) backing.toArray();
+	}
 }
diff --git a/BJC-Utils2/src/main/java/bjc/utils/esodata/SimpleStack.java b/BJC-Utils2/src/main/java/bjc/utils/esodata/SimpleStack.java
index 1344754..ec01280 100644
--- a/BJC-Utils2/src/main/java/bjc/utils/esodata/SimpleStack.java
+++ b/BJC-Utils2/src/main/java/bjc/utils/esodata/SimpleStack.java
@@ -28,11 +28,15 @@ public class SimpleStack<T> extends Stack<T> {
 
 	@Override
 	public T pop() {
+		if(backing.isEmpty()) throw new StackUnderflowException();
+		
 		return backing.pop();
 	}
 
 	@Override
 	public T top() {
+		if(backing.isEmpty()) throw new StackUnderflowException();
+		
 		return backing.peek();
 	}
 
@@ -45,4 +49,14 @@ public class SimpleStack<T> extends Stack<T> {
 	public boolean empty() {
 		return backing.size() == 0;
 	}
+	
+	@Override
+	public String toString() {
+		return backing.toString();
+	}
+	
+	@SuppressWarnings("unchecked")
+	public T[] toArray() {
+		return (T[]) backing.toArray();
+	}
 }
diff --git a/BJC-Utils2/src/main/java/bjc/utils/esodata/SpaghettiStack.java b/BJC-Utils2/src/main/java/bjc/utils/esodata/SpaghettiStack.java
index c5e338b..fdf9cc8 100644
--- a/BJC-Utils2/src/main/java/bjc/utils/esodata/SpaghettiStack.java
+++ b/BJC-Utils2/src/main/java/bjc/utils/esodata/SpaghettiStack.java
@@ -1,5 +1,8 @@
 package bjc.utils.esodata;
 
+import java.util.Arrays;
+import java.util.stream.Stream;
+
 /*
  * Implements a spaghetti stack, which is a stack that is branched off of a
  * parent stack.
@@ -52,4 +55,15 @@ class SpaghettiStack<T> extends Stack<T> {
 	public boolean empty() {
 		return backing.empty() && parent.empty();
 	}
+
+	@Override
+	public String toString() {
+		return "[base=" + parent.toString() + ", own=" + backing.toString() + "]";
+	}
+
+	@SuppressWarnings("unchecked")
+	@Override
+	public T[] toArray() {
+		return (T[]) Stream.concat(Arrays.stream(parent.toArray()), Arrays.stream(backing.toArray())).toArray();
+	}
 }
diff --git a/BJC-Utils2/src/main/java/bjc/utils/esodata/Stack.java b/BJC-Utils2/src/main/java/bjc/utils/esodata/Stack.java
index 5f7be6c..c112732 100644
--- a/BJC-Utils2/src/main/java/bjc/utils/esodata/Stack.java
+++ b/BJC-Utils2/src/main/java/bjc/utils/esodata/Stack.java
@@ -9,12 +9,32 @@ import java.util.function.Consumer;
  *
  * A FILO stack with support for forth/factor style combinators.
  *
- * @param T
+ * <p>
+ * <h2>Stack underflow</h2>
+ * <p>
+ * NOTE: In general, using any operation that attempts to remove more data from
+ * the stack than exists will cause a {@link StackUnderflowException} to be
+ * thrown. Check the size of the stack if you want to avoid this.
+ * <p>
+ * </p>
+ * 
+ * @param <T>
  *                The datatype stored in the stack.
+ * 
  * @author Ben Culkin
  */
 public abstract class Stack<T> {
 	/**
+	 * The exception thrown when attempting to access an element from the
+	 * stack that isn't there.
+	 * 
+	 * @author EVE
+	 *
+	 */
+	public static class StackUnderflowException extends RuntimeException {
+	}
+
+	/**
 	 * Push an element onto the stack.
 	 *
 	 * @param elm
@@ -29,6 +49,12 @@ public abstract class Stack<T> {
 	 */
 	public abstract T pop();
 
+	/**
+	 * Retrieve the top element of this stack without removing it from the
+	 * stack.
+	 * 
+	 * @return The top element of this stack.
+	 */
 	public abstract T top();
 
 	/**
@@ -53,7 +79,7 @@ public abstract class Stack<T> {
 	public Stack<T> spaghettify() {
 		return new SpaghettiStack<>(this);
 	}
-
+	
 	/*
 	 * Basic combinators
 	 */
@@ -377,7 +403,7 @@ public abstract class Stack<T> {
 	/**
 	 * Apply the actions in cons to corresponding elements from the stack.
 	 *
-	 * @parma conses The actions to execute.
+	 * @param conses The actions to execute.
 	 */
 	public void spread(List<Consumer<Stack<T>>> conses) {
 		multispread(1, conses);
@@ -414,4 +440,14 @@ public abstract class Stack<T> {
 	public void apply(int n, Consumer<Stack<T>> cons) {
 		multiapply(1, n, cons);
 	}
+	
+	/*
+	 * Misc. functions
+	 */
+	/**
+	 * Get an array representing this stack.
+	 * 
+	 * @return The stack as an array.
+	 */
+	public abstract T[] toArray();
 }