feat(java): add store implementation

java/com/google/dotprompt/helpers/Helpers.java

@@ -77,8 +77,7 @@ public static Object json(Object context, Options options) throws IOException {
 
     Integer indent = options.hash("indent", null);
     if (indent != null) {
-      DefaultPrettyPrinter printer =
-          new DefaultPrettyPrinter();
+      DefaultPrettyPrinter printer = new DefaultPrettyPrinter();
       printer.indentObjectsWith(new DefaultIndenter("  ", "\n"));
 
       localMapper =
@@ -90,16 +89,15 @@ public static Object json(Object context, Options options) throws IOException {
                     public DefaultPrettyPrinter createInstance() {
                       return new DefaultPrettyPrinter(this) {
                         @Override
-                        public void writeObjectFieldValueSeparator(
-                            JsonGenerator g) throws IOException {
+                        public void writeObjectFieldValueSeparator(JsonGenerator g)
+                            throws IOException {
                           g.writeRaw(": ");
                         }
                       };
                     }
 
                     @Override
-                    public void writeObjectFieldValueSeparator(
-                        JsonGenerator g) throws IOException {
+                    public void writeObjectFieldValueSeparator(JsonGenerator g) throws IOException {
                       g.writeRaw(": ");
                     }
                   })

java/com/google/dotprompt/resolvers/SchemaResolver.java

@@ -20,6 +20,7 @@
 
 import java.util.Map;
 import java.util.concurrent.CompletableFuture;
+import java.util.function.Function;
 
 /**
  * Resolves a provided schema name to an underlying JSON schema.
@@ -86,8 +87,7 @@ public interface SchemaResolver {
    *     corresponding JSON Schema, or {@code null}.
    * @return An async {@link SchemaResolver} wrapping the synchronous function.
    */
-  static SchemaResolver fromSync(
-      java.util.function.Function<String, Map<String, Object>> syncResolver) {
+  static SchemaResolver fromSync(Function<String, Map<String, Object>> syncResolver) {
     return schemaName -> CompletableFuture.completedFuture(syncResolver.apply(schemaName));
   }
 }

java/com/google/dotprompt/store/BUILD.bazel

@@ -19,11 +19,49 @@ load("@rules_java//java:defs.bzl", "java_library")
 java_library(
     name = "store",
     srcs = [
+        "DirStore.java",
+        "DirStoreOptions.java",
+        "DirStoreSync.java",
         "PromptStore.java",
+        "PromptStoreSync.java",
         "PromptStoreWritable.java",
+        "PromptStoreWritableSync.java",
+        "StoreUtils.java",
     ],
     visibility = ["//visibility:public"],
     deps = [
         "//java/com/google/dotprompt/models",
     ],
 )
+
+java_test(
+    name = "DirStoreSyncTest",
+    srcs = ["DirStoreSyncTest.java"],
+    deps = [
+        ":store",
+        "//java/com/google/dotprompt/models",
+        "@maven//:com_google_truth_truth",
+        "@maven//:junit_junit",
+    ],
+)
+
+java_test(
+    name = "DirStoreTest",
+    srcs = ["DirStoreTest.java"],
+    deps = [
+        ":store",
+        "//java/com/google/dotprompt/models",
+        "@maven//:com_google_truth_truth",
+        "@maven//:junit_junit",
+    ],
+)
+
+java_test(
+    name = "StoreUtilsTest",
+    srcs = ["StoreUtilsTest.java"],
+    deps = [
+        ":store",
+        "@maven//:com_google_truth_truth",
+        "@maven//:junit_junit",
+    ],
+)

java/com/google/dotprompt/store/DirStore.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.google.dotprompt.store;
+
+import com.google.dotprompt.models.DeletePromptOrPartialOptions;
+import com.google.dotprompt.models.ListPartialsOptions;
+import com.google.dotprompt.models.ListPromptsOptions;
+import com.google.dotprompt.models.LoadPartialOptions;
+import com.google.dotprompt.models.LoadPromptOptions;
+import com.google.dotprompt.models.PaginatedPartials;
+import com.google.dotprompt.models.PaginatedPrompts;
+import com.google.dotprompt.models.PromptData;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Executor;
+import java.util.concurrent.ForkJoinPool;
+
+/**
+ * Asynchronous filesystem-based prompt store implementation.
+ *
+ * <p>Reads and writes prompts and partials from/to the local file system within a specified
+ * directory using asynchronous operations backed by {@link CompletableFuture}.
+ *
+ * <h2>File Naming Conventions</h2>
+ *
+ * <ul>
+ *   <li>Prompts: {@code [name][.variant].prompt}
+ *   <li>Partials: {@code _[name][.variant].prompt}
+ * </ul>
+ *
+ * <h2>Usage Example</h2>
+ *
+ * <pre>{@code
+ * DirStore store = new DirStore(DirStoreOptions.of("/path/to/prompts"));
+ *
+ * // List prompts asynchronously
+ * store.list(null).thenAccept(prompts -> {
+ *     prompts.prompts().forEach(p -> System.out.println(p.name()));
+ * });
+ *
+ * // Load a specific prompt
+ * PromptData data = store.load("my_prompt", null).join();
+ * }</pre>
+ *
+ * <p>This class wraps {@link DirStoreSync} to provide async operations. All operations are executed
+ * on a configurable {@link Executor}.
+ */
+public class DirStore implements PromptStoreWritable {
+
+  private final DirStoreSync syncStore;
+  private final Executor executor;
+
+  /**
+   * Creates a new DirStore instance using the common ForkJoinPool.
+   *
+   * @param options Configuration options including the base directory.
+   */
+  public DirStore(DirStoreOptions options) {
+    this(options, ForkJoinPool.commonPool());
+  }
+
+  /**
+   * Creates a new DirStore instance with a custom executor.
+   *
+   * @param options Configuration options including the base directory.
+   * @param executor The executor to use for async operations.
+   */
+  public DirStore(DirStoreOptions options, Executor executor) {
+    this.syncStore = new DirStoreSync(options);
+    this.executor = executor;
+  }
+
+  @Override
+  public CompletableFuture<PaginatedPrompts> list(ListPromptsOptions options) {
+    return CompletableFuture.supplyAsync(() -> syncStore.list(options), executor);
+  }
+
+  @Override
+  public CompletableFuture<PaginatedPartials> listPartials(ListPartialsOptions options) {
+    return CompletableFuture.supplyAsync(() -> syncStore.listPartials(options), executor);
+  }
+
+  @Override
+  public CompletableFuture<PromptData> load(String name, LoadPromptOptions options) {
+    return CompletableFuture.supplyAsync(() -> syncStore.load(name, options), executor);
+  }
+
+  @Override
+  public CompletableFuture<PromptData> loadPartial(String name, LoadPartialOptions options) {
+    return CompletableFuture.supplyAsync(() -> syncStore.loadPartial(name, options), executor);
+  }
+
+  @Override
+  public CompletableFuture<Void> save(PromptData prompt) {
+    return CompletableFuture.runAsync(() -> syncStore.save(prompt), executor);
+  }
+
+  @Override
+  public CompletableFuture<Void> delete(String name, DeletePromptOrPartialOptions options) {
+    return CompletableFuture.runAsync(() -> syncStore.delete(name, options), executor);
+  }
+}

java/com/google/dotprompt/store/DirStoreOptions.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.google.dotprompt.store;
+
+import java.nio.file.Path;
+
+/**
+ * Configuration options for directory-based prompt stores.
+ *
+ * @param directory The base directory where prompt files are stored.
+ */
+public record DirStoreOptions(Path directory) {
+
+  /**
+   * Creates options from a string path.
+   *
+   * @param directory The directory path as a string.
+   * @return A new DirStoreOptions instance.
+   */
+  public static DirStoreOptions of(String directory) {
+    return new DirStoreOptions(Path.of(directory));
+  }
+}