smithy-rules-engine/src/main/java/software/amazon/smithy/rulesengine/language/EndpointComponentFactory.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package software.amazon.smithy.rulesengine.language;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.ServiceLoader;
+import java.util.function.Function;
+import software.amazon.smithy.rulesengine.language.syntax.expressions.functions.FunctionDefinition;
+import software.amazon.smithy.rulesengine.language.syntax.expressions.functions.FunctionNode;
+import software.amazon.smithy.rulesengine.language.syntax.expressions.functions.LibraryFunction;
+import software.amazon.smithy.rulesengine.language.syntax.parameters.Parameter;
+import software.amazon.smithy.rulesengine.validators.AuthSchemeValidator;
+import software.amazon.smithy.utils.SmithyInternalApi;
+
+/**
+ * Provides access to endpoint components loaded through {@link EndpointRuleSetExtension}s.
+ */
+@SmithyInternalApi
+public interface EndpointComponentFactory {
+
+    /**
+     * Returns true if a built-in of the provided name has been registered.
+     *
+     * @param name the name of the built-in to check for.
+     * @return true if the built-in is present, false otherwise.
+     */
+    boolean hasBuiltIn(String name);
+
+    /**
+     * Gets the built-in names as a joined string.
+     *
+     * @return a string of the built-in names.
+     */
+    String getKeyString();
+
+    /**
+     * Creates a {@link LibraryFunction} factory function using the loaded function definitions.
+     *
+     * @return the created factory.
+     */
+    Function<FunctionNode, Optional<LibraryFunction>> createFunctionFactory();
+
+    /**
+     * Gets loaded authentication scheme validators.
+     *
+     * @return a list of {@link AuthSchemeValidator}s.
+     */
+    List<AuthSchemeValidator> getAuthSchemeValidators();
+
+    static EndpointComponentFactory createServiceFactory(
+            Map<String, Parameter> builtIns,
+            Map<String, FunctionDefinition> libraryFunctions,
+            List<AuthSchemeValidator> authSchemeValidators
+    ) {
+        return new EndpointComponentFactory() {
+            @Override
+            public boolean hasBuiltIn(String name) {
+                return builtIns.containsKey(name);
+            }
+
+            @Override
+            public String getKeyString() {
+                return String.join(", ", builtIns.keySet());
+            }
+
+            @Override
+            public Function<FunctionNode, Optional<LibraryFunction>> createFunctionFactory() {
+                return node -> {
+                    if (libraryFunctions.containsKey(node.getName())) {
+                        return Optional.of(libraryFunctions.get(node.getName()).createFunction(node));
+                    }
+                    return Optional.empty();
+                };
+            }
+
+            @Override
+            public List<AuthSchemeValidator> getAuthSchemeValidators() {
+                return authSchemeValidators;
+            }
+        };
+    }
+
+    static EndpointComponentFactory createServiceFactory(ClassLoader classLoader) {
+        Map<String, Parameter> builtIns = new HashMap<>();
+        Map<String, FunctionDefinition> libraryFunctions = new HashMap<>();
+        List<AuthSchemeValidator> authSchemeValidators = new ArrayList<>();
+        for (EndpointRuleSetExtension extension : ServiceLoader.load(EndpointRuleSetExtension.class, classLoader)) {
+            String name;
+            for (Parameter builtIn : extension.getBuiltIns()) {
+                name = builtIn.getBuiltIn().get();
+                if (builtIns.containsKey(name)) {
+                    throw new RuntimeException("Attempted to load a duplicate built-in parameter: " + name);
+                }
+                builtIns.put(name, builtIn);
+            }
+
+            for (FunctionDefinition functionDefinition : extension.getLibraryFunctions()) {
+                name = functionDefinition.getId();
+                if (libraryFunctions.containsKey(name)) {
+                    throw new RuntimeException("Attempted to load a duplicate library function: " + name);
+                }
+                libraryFunctions.put(name, functionDefinition);
+            }
+
+            authSchemeValidators.addAll(extension.getAuthSchemeValidators());
+        }
+
+        return createServiceFactory(builtIns, libraryFunctions, authSchemeValidators);
+    }
+}

smithy-rules-engine/src/main/java/software/amazon/smithy/rulesengine/language/EndpointRuleSet.java

@@ -7,14 +7,10 @@
 
 import static software.amazon.smithy.rulesengine.language.error.RuleError.context;
 
-import java.util.ArrayList;
 import java.util.Collection;
-import java.util.HashMap;
 import java.util.List;
-import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
-import java.util.ServiceLoader;
 import java.util.function.Function;
 import software.amazon.smithy.model.FromSourceLocation;
 import software.amazon.smithy.model.SourceLocation;
@@ -26,16 +22,15 @@
 import software.amazon.smithy.rulesengine.language.evaluation.Scope;
 import software.amazon.smithy.rulesengine.language.evaluation.TypeCheck;
 import software.amazon.smithy.rulesengine.language.evaluation.type.Type;
-import software.amazon.smithy.rulesengine.language.syntax.expressions.functions.FunctionDefinition;
 import software.amazon.smithy.rulesengine.language.syntax.expressions.functions.FunctionNode;
 import software.amazon.smithy.rulesengine.language.syntax.expressions.functions.LibraryFunction;
-import software.amazon.smithy.rulesengine.language.syntax.parameters.Parameter;
 import software.amazon.smithy.rulesengine.language.syntax.parameters.Parameters;
 import software.amazon.smithy.rulesengine.language.syntax.rule.EndpointRule;
 import software.amazon.smithy.rulesengine.language.syntax.rule.Rule;
 import software.amazon.smithy.rulesengine.validators.AuthSchemeValidator;
 import software.amazon.smithy.utils.BuilderRef;
 import software.amazon.smithy.utils.SmithyBuilder;
+import software.amazon.smithy.utils.SmithyInternalApi;
 import software.amazon.smithy.utils.SmithyUnstableApi;
 import software.amazon.smithy.utils.StringUtils;
 import software.amazon.smithy.utils.ToSmithyBuilder;
@@ -50,37 +45,9 @@ public final class EndpointRuleSet implements FromSourceLocation, ToNode, ToSmit
     private static final String PARAMETERS = "parameters";
     private static final String RULES = "rules";
 
-    private static final Map<String, Parameter> BUILT_INS = new HashMap<>();
-    private static final Map<String, FunctionDefinition> FUNCTIONS = new HashMap<>();
-    private static final List<AuthSchemeValidator> AUTH_SCHEME_VALIDATORS = new ArrayList<>();
-
-    static {
-        // Provide an explicit classloader, as the thread's classloader may be different in cases
-        // where a model is loaded in extraneous contexts, like a build tool.
-        // TODO Change how the classloader is configured.
-        for (EndpointRuleSetExtension extension : ServiceLoader.load(EndpointRuleSetExtension.class,
-                EndpointRuleSet.class.getClassLoader())
-        ) {
-            System.out.println(extension.getClass().getCanonicalName());
-            String name;
-            for (Parameter builtIn : extension.getBuiltIns()) {
-                name = builtIn.getBuiltIn().get();
-                if (BUILT_INS.containsKey(name)) {
-                    throw new RuntimeException("Attempted to load a duplicate built-in parameter: " + name);
-                }
-                BUILT_INS.put(name, builtIn);
-            }
-
-            for (FunctionDefinition functionDefinition : extension.getLibraryFunctions()) {
-                name = functionDefinition.getId();
-                if (FUNCTIONS.containsKey(name)) {
-                    throw new RuntimeException("Attempted to load a duplicate library function: " + name);
-                }
-                FUNCTIONS.put(name, functionDefinition);
-            }
-
-            AUTH_SCHEME_VALIDATORS.addAll(extension.getAuthSchemeValidators());
-        }
+    private static final class LazyEndpointComponentFactoryHolder {
+        static final EndpointComponentFactory INSTANCE = EndpointComponentFactory.createServiceFactory(
+                EndpointRuleSet.class.getClassLoader());
     }
 
     private final Parameters parameters;
@@ -228,40 +195,39 @@ public String toString() {
      * @param name the name of the built-in to check for.
      * @return true if the built-in is present, false otherwise.
      */
+    @SmithyInternalApi
     public static boolean hasBuiltIn(String name) {
-        return BUILT_INS.containsKey(name);
+        return LazyEndpointComponentFactoryHolder.INSTANCE.hasBuiltIn(name);
     }
 
     /**
      * Gets the built-in names as a joined string.
      *
      * @return a string of the built-in names.
      */
+    @SmithyInternalApi
     public static String getKeyString() {
-        return String.join(", ", BUILT_INS.keySet());
+        return LazyEndpointComponentFactoryHolder.INSTANCE.getKeyString();
     }
 
     /**
      * Creates a {@link LibraryFunction} factory function using the loaded function definitions.
      *
      * @return the created factory.
      */
+    @SmithyInternalApi
     public static Function<FunctionNode, Optional<LibraryFunction>> createFunctionFactory() {
-        return node -> {
-            if (FUNCTIONS.containsKey(node.getName())) {
-                return Optional.of(FUNCTIONS.get(node.getName()).createFunction(node));
-            }
-            return Optional.empty();
-        };
+        return LazyEndpointComponentFactoryHolder.INSTANCE.createFunctionFactory();
     }
 
     /**
      * Gets loaded authentication scheme validators.
      *
      * @return a list of {@link AuthSchemeValidator}s.
      */
+    @SmithyInternalApi
     public static List<AuthSchemeValidator> getAuthSchemeValidators() {
-        return AUTH_SCHEME_VALIDATORS;
+        return LazyEndpointComponentFactoryHolder.INSTANCE.getAuthSchemeValidators();
     }
 
     /**