ScriptConditionHandler/ScriptActionHandler: Add support for pre-compilation of scripts

Signed-off-by: Florian Hotze <florianh_dev@icloud.com>

Author: florian-h05

bundles/org.openhab.core.automation.module.script/src/main/java/org/openhab/core/automation/module/script/internal/handler/AbstractScriptModuleHandler.java

@@ -18,10 +18,14 @@
 import java.util.Optional;
 import java.util.UUID;
 
+import javax.script.Compilable;
+import javax.script.CompiledScript;
 import javax.script.ScriptContext;
 import javax.script.ScriptEngine;
+import javax.script.ScriptException;
 
 import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.eclipse.jdt.annotation.Nullable;
 import org.openhab.core.automation.Module;
 import org.openhab.core.automation.handler.BaseModuleHandler;
 import org.openhab.core.automation.module.script.ScriptEngineContainer;
@@ -35,6 +39,7 @@
  *
  * @author Kai Kreuzer - Initial contribution
  * @author Simon Merschjohann - Initial contribution
+ * @author Florian Hotze - Add support for script pre-compilation
  *
  * @param <T> the type of module the concrete handler can handle
  */
@@ -54,6 +59,7 @@ public abstract class AbstractScriptModuleHandler<T extends Module> extends Base
     private final String engineIdentifier;
 
     private Optional<ScriptEngine> scriptEngine = Optional.empty();
+    private Optional<CompiledScript> compiledScript = Optional.empty();
     private final String type;
     protected final String script;
 
@@ -80,6 +86,31 @@ private static String getValidConfigParameter(String parameter, Configuration co
         }
     }
 
+    /**
+     * Compiles the script if the script engine supports pre-compilation.
+     */
+    protected void compileScriptIfSupported() throws ScriptException {
+        if (!scriptEngineManager.isPreCompilationSupported(type)) {
+            return;
+        }
+
+        if (compiledScript.isPresent()) {
+            return;
+        }
+        Optional<ScriptEngine> engine = getScriptEngine();
+        if (engine.isPresent()) {
+            ScriptEngine scriptEngine = engine.get();
+            if (scriptEngine instanceof Compilable) {
+                logger.debug("Pre-compiling script of rule with UID '{}'", ruleUID);
+                compiledScript = Optional.ofNullable(((Compilable) scriptEngine).compile(script));
+            } else {
+                logger.error(
+                        "Script engine of rule with UID '{}' does not implement Compilable but claims to support pre-compilation",
+                        module.getId());
+            }
+        }
+    }
+
     @Override
     public void dispose() {
         scriptEngineManager.removeEngine(engineIdentifier);
@@ -169,4 +200,26 @@ protected void resetExecutionContext(ScriptEngine engine, Map<String, ?> context
             executionContext.removeAttribute(key, ScriptContext.ENGINE_SCOPE);
         }
     }
+
+    /**
+     * Evaluates the passed script with the ScriptEngine.
+     *
+     * @param engine the script engine that is used
+     * @param script the script to evaluate
+     * @return the value returned from the execution of the script
+     */
+    protected @Nullable Object eval(ScriptEngine engine, String script) {
+        try {
+            if (compiledScript.isPresent()) {
+                logger.debug("Executing pre-compiled script of rule with UID '{}'", ruleUID);
+                return compiledScript.get().eval(engine.getContext());
+            }
+            logger.debug("Executing script of rule with UID '{}'", ruleUID);
+            return engine.eval(script);
+        } catch (ScriptException e) {
+            logger.error("Script execution of rule with UID '{}' failed: {}", ruleUID, e.getMessage(),
+                    logger.isDebugEnabled() ? e : null);
+            return null;
+        }
+    }
 }

bundles/org.openhab.core.automation.module.script/src/main/java/org/openhab/core/automation/module/script/internal/handler/ScriptActionHandler.java

@@ -31,6 +31,7 @@
  *
  * @author Kai Kreuzer - Initial contribution
  * @author Simon Merschjohann - Initial contribution
+ * @author Florian Hotze - Add support for script pre-compilation
  */
 @NonNullByDefault
 public class ScriptActionHandler extends AbstractScriptModuleHandler<Action> implements ActionHandler {
@@ -61,6 +62,11 @@ public void dispose() {
         super.dispose();
     }
 
+    @Override
+    public void compile() throws ScriptException {
+        super.compileScriptIfSupported();
+    }
+
     @Override
     public @Nullable Map<String, Object> execute(final Map<String, Object> context) {
         Map<String, Object> resultMap = new HashMap<>();
@@ -71,13 +77,8 @@ public void dispose() {
 
         getScriptEngine().ifPresent(scriptEngine -> {
             setExecutionContext(scriptEngine, context);
-            try {
-                Object result = scriptEngine.eval(script);
-                resultMap.put("result", result);
-            } catch (ScriptException e) {
-                logger.error("Script execution of rule with UID '{}' failed: {}", ruleUID, e.getMessage(),
-                        logger.isDebugEnabled() ? e : null);
-            }
+            Object result = eval(scriptEngine, script);
+            resultMap.put("result", result);
             resetExecutionContext(scriptEngine, context);
         });
 

bundles/org.openhab.core.automation.module.script/src/main/java/org/openhab/core/automation/module/script/internal/handler/ScriptConditionHandler.java

@@ -30,6 +30,7 @@
  *
  * @author Kai Kreuzer - Initial contribution
  * @author Simon Merschjohann - Initial contribution
+ * @author Florian Hotze - Add support for script pre-compilation
  */
 @NonNullByDefault
 public class ScriptConditionHandler extends AbstractScriptModuleHandler<Condition> implements ConditionHandler {
@@ -42,6 +43,11 @@ public ScriptConditionHandler(Condition module, String ruleUID, ScriptEngineMana
         super(module, ruleUID, scriptEngineManager);
     }
 
+    @Override
+    public void compile() throws ScriptException {
+        super.compileScriptIfSupported();
+    }
+
     @Override
     public boolean isSatisfied(final Map<String, Object> context) {
         boolean result = false;
@@ -55,18 +61,14 @@ public boolean isSatisfied(final Map<String, Object> context) {
         if (engine.isPresent()) {
             ScriptEngine scriptEngine = engine.get();
             setExecutionContext(scriptEngine, context);
-            try {
-                Object returnVal = scriptEngine.eval(script);
-                if (returnVal instanceof Boolean boolean1) {
-                    result = boolean1;
-                } else {
-                    logger.error("Script of rule with UID '{}' did not return a boolean value, but '{}'", ruleUID,
-                            returnVal);
-                }
-            } catch (ScriptException e) {
-                logger.error("Script execution of rule with UID '{}' failed: {}", ruleUID, e.getMessage(),
-                        logger.isDebugEnabled() ? e : null);
+            Object returnVal = eval(scriptEngine, script);
+            if (returnVal instanceof Boolean boolean1) {
+                result = boolean1;
+            } else {
+                logger.error("Script of rule with UID '{}' did not return a boolean value, but '{}'", ruleUID,
+                        returnVal);
             }
+            resetExecutionContext(scriptEngine, context);
         }
 
         return result;

bundles/org.openhab.core.automation/src/main/java/org/openhab/core/automation/handler/ActionHandler.java

@@ -31,6 +31,14 @@
  */
 @NonNullByDefault
 public interface ActionHandler extends ModuleHandler {
+    /**
+     * Called to compile an {@link Action} of the {@link Rule} when the rule is initialized.
+     *
+     * @throws Exception if the compilation fails
+     */
+    default void compile() throws Exception {
+        // Do nothing by default
+    }
 
     /**
      * Called to execute an {@link Action} of the {@link Rule} when it is needed.

bundles/org.openhab.core.automation/src/main/java/org/openhab/core/automation/handler/ConditionHandler.java

@@ -29,6 +29,14 @@
  */
 @NonNullByDefault
 public interface ConditionHandler extends ModuleHandler {
+    /**
+     * Called to compile the {@link Condition} when the {@link Rule} is initialized.
+     *
+     * @throws Exception if the compilation fails
+     */
+    default void compile() throws Exception {
+        // Do nothing by default
+    }
 
     /**
      * Checks if the Condition is satisfied in the given {@code context}.