1 files changed, 73 insertions, 0 deletions
diff --git a/src/main/java/bjc/funcdata/Freezable.java b/src/main/java/bjc/funcdata/Freezable.java
new file mode 100644
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+++ b/src/main/java/bjc/funcdata/Freezable.java
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+package bjc.funcdata;
+
+/**
+ * Indicates that an object can switch between immutable and mutable modes.
+ * 
+ * Note that this only implements 'shallow' immutability. Namely, any sub-objects
+ * are not made immutable, and if the type is a collection, the elements are still
+ * as mutable as they were before.
+ * 
+ * Implementations of this interface may choose to throw {@link ObjectFrozen} if
+ * you attempt to modify a frozen object, but they may also choose not to.
+ * 
+ * @author Ben Culkin
+ */
+public interface Freezable {
+	/**
+	 * Freezes the internal state of this object, making it immutable.
+	 * 
+	 * @return True if the object is frozen, false if it couldn't be frozen.
+	 */
+	public boolean freeze();
+	/**
+	 * Thaws the internal state of this object, making it mutable.
+	 * 
+	 * @return True if the object is thawed, false if it couldn't be thawed.
+	 */
+	public boolean thaw();
+
+	/**
+	 * 'Deep-freeze' this object, making it immutable and disabling the ability to
+	 * thaw it.
+	 * 
+	 * @return True if the object was deep-frozen, false if that couldn't happen.
+	 */
+	default boolean deepFreeze() {
+		return false;
+	}
+	
+	/**
+	 * Check if this object can be frozen.
+	 * 
+	 * @return Whether or not the object can be frozen.
+	 */
+	default boolean canFreeze() {
+		return false;
+	}
+	
+	/**
+	 * Checks if this object can be thawed.
+	 * 
+	 * @return Whether or not the object can be thawed.
+	 */
+	default boolean canThaw() {
+		return false;
+	}
+	
+	/**
+	 * Determines if this object is frozen.
+	 * 
+	 * @return True if the object is frozen, false if the object is thawed.
+	 */
+	public boolean isFrozen();
+	
+
+	/**
+	 * Determines if this object is thawed.
+	 * 
+	 * @return True if the object is thawed, false if the object is thawed.
+	 */
+	default boolean isThawed() {
+		return !isFrozen();
+	}
+}