Add terminal

This is some functionality based on the way that MVS/other IBM OSes
handle their UI

1 files changed, 51 insertions, 0 deletions

diff --git a/base/src/main/java/bjc/utils/cli/Terminal.java b/base/src/main/java/bjc/utils/cli/Terminal.java
new file mode 100644
index 0000000..a10d82e
--- /dev/null
+++ b/base/src/main/java/bjc/utils/cli/Terminal.java
@@ -0,0 +1,51 @@
+package bjc.utils.cli;
+
+import java.util.*;
+
+/**
+ * A terminal with support for asking multiple questions, and retrieving the
+ * results piecemeal.
+ * 
+ * This class is heavily inspired by the way that the old IBM MVS terminal
+ * worked, where the terminal would send you a series of requests and you would
+ * reply to them in whatever order you wanted.
+ * 
+ * @author bjcul
+ */
+public interface Terminal {
+	/**
+	 * Submit a request to the terminal
+	 * 
+	 * @param req The body of the request
+	 * @return The ID of the request
+	 */
+	long submitRequest(String req);
+
+	/**
+	 * Await a reply for a given request. Will block the current thread until a
+	 * response is available.
+	 * 
+	 * @param id The ID of the request
+	 * @return The response to that request
+	 * @throws InterruptedException If we are interrupted waiting for the reply
+	 */
+	String awaitReply(long id) throws InterruptedException;
+
+	/**
+	 * Check if a reply for a request is available, without blocking.
+	 * 
+	 * @param id The ID of the request
+	 * @return The reply to the request if one is available, and empty otherwise
+	 */
+	Optional<String> checkReply(long id);
+
+	/**
+	 * Submit a request and await the reply to it. Will block the current thread
+	 * until a response is received.
+	 * 
+	 * @param req The request to submit
+	 * @return The reply to the request
+	 * @throws InterruptedException If we are interrupted waiting for the reply
+	 */
+	String submitRequestSync(String req) throws InterruptedException;;
+}
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