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+# API Reference
+
+This page summarizes the key classes in **Conflux**.
+
+## Ctx
+
+- `put(Key<T>, T value)` — store or update a value for a key
+- `get(Key<T>)` — retrieve a value
+- `contains(Key<?>)` — check if a key is present
+- `remove(Key<?>)` — remove a key and its listeners
+- `clear()` — remove everything
+- `addListener(Key<T>, Listener<T>)` — register a weakly referenced listener
+- `removeListener(Key<T>, Listener<T>)` — remove a listener
+
+## Key
+
+A strongly typed key:
+
+```java
+Key<String> nameKey = new Key<>("name", String.class);
+````
+
+* `name()` returns the key name
+* `type()` returns the key type
+
+## Listener
+
+An interface for change notifications:
+
+```java
+public interface Listener<T> {
+    void valueChanged(T newValue);
+}
+```
+
+Registered listeners will be weakly referenced and called on value change.
+
+---
+
+\[\[Home]] | \[\[Programming Guide]] | \[\[Design and Architecture]]
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