1 files changed, 84 insertions, 0 deletions
diff --git a/JPratt/src/main/java/com/ashardalon/pratt/tokens/StringTokenStream.java b/JPratt/src/main/java/com/ashardalon/pratt/tokens/StringTokenStream.java
new file mode 100644
index 0000000..fb25016
--- /dev/null
+++ b/JPratt/src/main/java/com/ashardalon/pratt/tokens/StringTokenStream.java
@@ -0,0 +1,84 @@
+package com.ashardalon.pratt.tokens;
+
+import static com.ashardalon.pratt.tokens.StringToken.litToken;
+
+import java.util.Iterator;
+
+import bjc.data.MarkListIterator;
+
+/**
+ * Simple implementation of token stream for strings.
+ *
+ * The terminal token here is represented by a token with type and value
+ * '(end)'.
+ *
+ * @author EVE
+ *
+ */
+public class StringTokenStream extends TokenStream<String, String> {
+	private final MarkListIterator<Token<String, String>> iter;
+	
+	private Token<String, String> curr;
+
+	/**
+	 * Create a new token stream from a iterator.
+	 *
+	 * @param itr
+	 *        The iterator to use.
+	 *
+	 */
+	public StringTokenStream(final Iterator<Token<String, String>> itr) {
+		iter = new MarkListIterator<>(itr);
+	}
+
+	@Override
+	public Token<String, String> current() {
+		// Prime stream if necessary
+		if (curr == null)
+			return next();
+		return curr;
+	}
+
+	@Override
+	public Token<String, String> next() {
+		if(iter.hasNext()) {
+			curr = iter.next();
+		} else {
+			curr = litToken("(end)");
+		}
+
+		return curr;
+	}
+
+	@Override
+	public boolean hasNext() {
+		return iter.hasNext();
+	}
+	
+	@Override
+	public void mark() {
+		iter.mark();
+	}
+	
+	@Override
+	public void commit() {
+		iter.commit();
+		
+		if (!iter.hasMark()) {
+			// No marks outstanding; we can release the previous state
+			iter.reset();
+		}
+	}
+	
+	@Override
+	public void rollback() {
+		iter.rollback();
+		
+		curr = iter.current();
+	}
+	
+	@Override
+	public boolean hasMark() {
+ 		return iter.hasMark();
+	}
+}