Added ScriptUtils

eco-api/src/main/java/com/willfp/eco/core/integrations/shop/ShopWrapper.java

@@ -16,7 +16,9 @@ public interface ShopWrapper extends Integration {
     }
 
     /**
-     * Register sell event adapters.
+     * Get the sell event adapter.
+     *
+     * @return The listener.
      */
     @Nullable
     default Listener getSellEventAdapter() {

eco-api/src/main/java/com/willfp/eco/util/ScriptUtils.java

@@ -0,0 +1,115 @@
+package com.willfp.eco.util;
+
+import com.github.benmanes.caffeine.cache.Cache;
+import com.github.benmanes.caffeine.cache.Caffeine;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import javax.script.Bindings;
+import javax.script.Compilable;
+import javax.script.CompiledScript;
+import javax.script.ScriptContext;
+import javax.script.ScriptEngine;
+import javax.script.ScriptEngineManager;
+import javax.script.ScriptException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Consumer;
+
+/**
+ * Utilities / API methods for kotlin scripts.
+ */
+public final class ScriptUtils {
+    /**
+     * The cache of compiled scripts.
+     */
+    private static final Cache<ScriptToCompile, CompiledScript> COMPILED_SCRIPTS = Caffeine.newBuilder()
+            .build();
+
+    /**
+     * Empty (dummy) compiled script.
+     */
+    private static final CompiledScript EMPTY_SCRIPT = new CompiledScript() {
+        @Override
+        public Object eval(@NotNull final ScriptContext context) {
+            return null;
+        }
+
+        @Override
+        public ScriptEngine getEngine() {
+            return ScriptUtils.getEngine();
+        }
+    };
+
+    /**
+     * Evaluate a script.
+     *
+     * @param script The script.
+     * @return The return value of the script.
+     */
+    @Nullable
+    public static Object eval(@NotNull final String script) {
+        return eval(script, (x) -> {
+            // Do nothing.
+        });
+    }
+
+    /**
+     * Evaluate a script.
+     *
+     * @param script          The script.
+     * @param bindingsFactory The consumer to create bindings.
+     * @return The return value of the script.
+     */
+    @Nullable
+    public static Object eval(@NotNull final String script,
+                              @NotNull final Consumer<Bindings> bindingsFactory) {
+        Bindings toHash = getEngine().createBindings();
+        bindingsFactory.accept(toHash);
+        Map<String, Object> bindingsMap = new HashMap<>(toHash);
+
+        try {
+            return COMPILED_SCRIPTS.get(new ScriptToCompile(script, bindingsMap), (it) -> {
+                try {
+                    var engine = getEngine();
+                    Bindings bindings = engine.createBindings();
+                    bindingsFactory.accept(bindings);
+                    engine.setBindings(bindings, ScriptContext.ENGINE_SCOPE);
+                    return engine.compile(it.script);
+                } catch (ScriptException e) {
+                    e.printStackTrace();
+                    return EMPTY_SCRIPT;
+                }
+            }).eval();
+        } catch (ScriptException e) {
+            e.printStackTrace();
+            return null;
+        }
+    }
+
+    /**
+     * Get new engine instance.
+     *
+     * @param <T> Intersection type.
+     * @return The engine.
+     */
+    @SuppressWarnings("unchecked")
+    private static <T extends ScriptEngine & Compilable> T getEngine() {
+        return (T) new ScriptEngineManager().getEngineByExtension("kts");
+    }
+
+    /**
+     * Metadata to compile a script.
+     *
+     * @param script   The script.
+     * @param bindings The bindings.
+     */
+    private record ScriptToCompile(@NotNull String script,
+                                   @NotNull Map<String, Object> bindings) {
+
+    }
+
+    private ScriptUtils() {
+        throw new UnsupportedOperationException("This is a utility class and cannot be instantiated");
+    }
+}