From 097a33bc2ecaa64a664550ddd62ccd8de47c51d0 Mon Sep 17 00:00:00 2001
From: Ben Culkin <scorpress@gmail.com>
Date: Tue, 1 Dec 2020 20:20:27 -0500
Subject: An assortment of changes

---
 src/main/java/bjc/esodata/TapeLibrary.java | 163 +++++++++++++++++++++++++++++
 1 file changed, 163 insertions(+)
 create mode 100644 src/main/java/bjc/esodata/TapeLibrary.java

(limited to 'src/main/java/bjc/esodata/TapeLibrary.java')

diff --git a/src/main/java/bjc/esodata/TapeLibrary.java b/src/main/java/bjc/esodata/TapeLibrary.java
new file mode 100644
index 0000000..922833f
--- /dev/null
+++ b/src/main/java/bjc/esodata/TapeLibrary.java
@@ -0,0 +1,163 @@
+package bjc.esodata;
+
+import java.util.*;
+
+/**
+ * Represents a library of possible tapes, with a single tape 'mounted' or active
+ * at a time.
+ * 
+ * @author Ben Culkin
+ *
+ * @param <ElementType> The type stored on each tape.
+ */
+public class TapeLibrary<ElementType> implements TapeView<ElementType>
+{
+	private final Map<String, Tape<ElementType>> library;
+	
+	private String            currentLabel;
+	private Tape<ElementType> currentTape;
+
+	private boolean allowAutoCreation;
+	
+	/**
+	 * Get a view of this tape library as a map.
+	 * 
+	 * Modifications to this map will apply to the library, but will not
+	 * affect whether a given tape is mounted or not. Be forewarned.
+	 * 
+	 * @return A view onto this tape library as a map.
+	 */
+	public Map<String, Tape<ElementType>> asMap()
+	{
+		return library;
+	}
+
+	/**
+	 * Create a new empty tape library, with no tape mounted.
+	 */
+	public TapeLibrary()
+	{
+		library = new HashMap<>();
+	}
+
+	/**
+	 * Create a new tape, with a given tape mounted by default.
+	 * 
+	 * @param label The label of the tape.
+	 * @param tape  The tape to mount.
+	 */
+	public TapeLibrary(String label, Tape<ElementType> tape)
+	{
+		this();
+		library.put(label, tape);
+		
+		this.currentLabel = label;
+		this.currentTape  = tape;
+	}
+
+	@Override
+	public Tape<ElementType> tapeView()
+	{
+		return currentTape;
+	}
+	
+	/**
+	 * Insert a tape into this library.
+	 * 
+	 * @param label The label to use for the tape.
+	 * @param tape The tape to add.
+	 * 
+	 * @return The tape which previously had that label, or null if there was not one.
+	 */
+	public Tape<ElementType> insertTape(String label, Tape<ElementType> tape)
+	{
+		return library.put(label, tape);
+	}
+	
+	/**
+	 * Remove a tape from this library.
+	 * 
+	 * @param label The label of the tape to remove.
+	 * 
+	 * @return The tape which had that label, or null if there was not one.
+	 */
+	public Tape<ElementType> removeTape(String label)
+	{
+		return library.remove(label);
+	}
+	
+	/**
+	 * Check if this library has a tape with a given label.
+	 * 
+	 * @param label The label of the tape to check for.
+	 * 
+	 * @return Whether or not the library contains a tape with that label.
+	 */
+	public boolean hasTape(String label) 
+	{
+		return allowAutoCreation ? true : library.containsKey(label);
+	}
+	
+	/**
+	 * Mount a different tape in the library.
+	 * 
+	 * @param label The label of the tape to mount.
+	 * 
+	 * @return True if the tape was successfully mounted, false otherwise.
+	 */
+	public boolean mountTape(String label)
+	{
+		if (library.containsKey(label) || allowAutoCreation)
+		{
+			currentLabel = label;
+			currentTape  = library.computeIfAbsent(
+						label,
+						(ignored) -> new SingleTape<>());
+			
+			return true;
+		} else {
+			return false;
+		}
+	}
+	
+	/**
+	 * Returns the label of the current tape.
+	 * 
+	 * @return The label of the current tape, or null if no tape is
+	 *         currently 'mounted'.
+	 */
+	public String currentLabel()
+	{
+		return currentLabel;
+	}
+	
+	/**
+	 * Unmount the currently mounted tape.
+	 */
+	public void ejectTape()
+	{
+		currentTape  = null;
+		currentLabel = null;
+	}
+	
+	/**
+	 * Check if this tape library currently allows auto-creation of
+	 * non-existing tapes.
+	 * 
+	 * @return Whether or not auto-creation of tapes is currently allowed.
+	 */
+	public boolean isAllowAutoCreation() {
+		return allowAutoCreation;
+	}
+	
+	/**
+	 * Set whether or not this library allows auto-creation of non-existing
+	 * tapes.
+	 * 
+	 * @param allowAutoCreation Whether tape auto-creation is allowed.
+	 */
+	public void setAllowAutoCreation(boolean allowAutoCreation)
+	{
+		this.allowAutoCreation = allowAutoCreation;
+	}
+}
-- 
cgit v1.2.3