[core] Add file format provider SPI

paimon-api/src/main/java/org/apache/paimon/CoreOptions.java

@@ -21,6 +21,7 @@
 import org.apache.paimon.annotation.Documentation;
 import org.apache.paimon.annotation.Documentation.ExcludeFromDocumentation;
 import org.apache.paimon.annotation.Documentation.Immutable;
+import org.apache.paimon.annotation.Experimental;
 import org.apache.paimon.compression.CompressOptions;
 import org.apache.paimon.fileindex.FileIndexOptions;
 import org.apache.paimon.fs.Path;
@@ -304,6 +305,40 @@ public InlineElement getDescription() {
                     .withDescription(
                             "Specify the message format of data files, currently orc, parquet and avro are supported.");
 
+    @Experimental
+    @ExcludeFromDocumentation("Experimental format-provider SPI")
+    public static final ConfigOption<String> FILE_FORMAT_PROVIDER =
+            key("file.format.provider")
+                    .stringType()
+                    .noDefaultValue()
+                    .withDescription(
+                            "Selects an experimental file format provider discovered from the classpath.");
+
+    @Experimental
+    @ExcludeFromDocumentation("Experimental format-provider SPI")
+    public static final ConfigOption<String> FILE_FORMAT_READ_PROVIDER =
+            key("file.format.read-provider")
+                    .stringType()
+                    .noDefaultValue()
+                    .withDescription("Selects an experimental file format provider for readers.");
+
+    @Experimental
+    @ExcludeFromDocumentation("Experimental format-provider SPI")
+    public static final ConfigOption<String> FILE_FORMAT_WRITE_PROVIDER =
+            key("file.format.write-provider")
+                    .stringType()
+                    .noDefaultValue()
+                    .withDescription("Selects an experimental file format provider for writers.");
+
+    @Experimental
+    @ExcludeFromDocumentation("Experimental format-provider SPI")
+    public static final ConfigOption<String> FILE_FORMAT_VALIDATION_PROVIDER =
+            key("file.format.validation-provider")
+                    .stringType()
+                    .noDefaultValue()
+                    .withDescription(
+                            "Selects an experimental file format provider for schema validation.");
+
     public static final ConfigOption<Map<String, String>> FILE_COMPRESSION_PER_LEVEL =
             key("file.compression.per.level")
                     .mapType()
@@ -2777,7 +2812,7 @@ public Map<Integer, String> statsModePerLevel() {
     }
 
     public static String normalizeFileFormat(String fileFormat) {
-        return StringUtils.isEmpty(fileFormat) ? fileFormat : fileFormat.toLowerCase();
+        return StringUtils.isEmpty(fileFormat) ? fileFormat : fileFormat.toLowerCase(Locale.ROOT);
     }
 
     public String dataFilePrefix() {

paimon-common/src/main/java/org/apache/paimon/factories/FormatFactoryUtil.java

@@ -19,11 +19,13 @@
 package org.apache.paimon.factories;
 
 import org.apache.paimon.format.FileFormatFactory;
+import org.apache.paimon.format.FileFormatProvider;
 
 import org.apache.paimon.shade.caffeine2.com.github.benmanes.caffeine.cache.Cache;
 import org.apache.paimon.shade.caffeine2.com.github.benmanes.caffeine.cache.Caffeine;
 
 import java.util.List;
+import java.util.Locale;
 import java.util.stream.Collectors;
 
 import static org.apache.paimon.factories.FactoryUtil.discoverFactories;
@@ -34,6 +36,9 @@ public class FormatFactoryUtil {
     private static final Cache<ClassLoader, List<FileFormatFactory>> FACTORIES =
             Caffeine.newBuilder().softValues().maximumSize(100).executor(Runnable::run).build();
 
+    private static final Cache<ClassLoader, List<FileFormatProvider>> PROVIDERS =
+            Caffeine.newBuilder().softValues().maximumSize(100).executor(Runnable::run).build();
+
     /** Discovers a file format factory. */
     @SuppressWarnings("unchecked")
     public static <T extends FileFormatFactory> T discoverFactory(
@@ -64,4 +69,53 @@ private static List<FileFormatFactory> getFactories(ClassLoader classLoader) {
         return FACTORIES.get(
                 classLoader, s -> discoverFactories(classLoader, FileFormatFactory.class));
     }
+
+    /** Discovers file format providers. */
+    public static List<FileFormatProvider> discoverProviders(ClassLoader classLoader) {
+        return PROVIDERS.get(
+                classLoader, s -> discoverFactories(classLoader, FileFormatProvider.class));
+    }
+
+    /** Discovers a file format provider. */
+    public static FileFormatProvider discoverProvider(ClassLoader classLoader, String identifier) {
+        final List<FileFormatProvider> foundProviders = discoverProviders(classLoader);
+        final String normalizedIdentifier = identifier.trim().toLowerCase(Locale.ROOT);
+
+        final List<FileFormatProvider> matchingProviders =
+                foundProviders.stream()
+                        .filter(
+                                f ->
+                                        f.identifier()
+                                                .trim()
+                                                .toLowerCase(Locale.ROOT)
+                                                .equals(normalizedIdentifier))
+                        .collect(Collectors.toList());
+
+        if (matchingProviders.isEmpty()) {
+            throw new FactoryException(
+                    String.format(
+                            "Could not find any provider for identifier '%s' that implements FileFormatProvider in the classpath.\n\n"
+                                    + "Available provider identifiers are:\n\n"
+                                    + "%s",
+                            identifier,
+                            foundProviders.stream()
+                                    .map(FileFormatProvider::identifier)
+                                    .collect(Collectors.joining("\n"))));
+        }
+
+        if (matchingProviders.size() > 1) {
+            throw new FactoryException(
+                    String.format(
+                            "Multiple providers for identifier '%s' that implement FileFormatProvider found in the classpath.\n\n"
+                                    + "Ambiguous provider classes are:\n\n"
+                                    + "%s",
+                            identifier,
+                            matchingProviders.stream()
+                                    .map(p -> p.getClass().getName())
+                                    .sorted()
+                                    .collect(Collectors.joining("\n"))));
+        }
+
+        return matchingProviders.get(0);
+    }
 }

paimon-common/src/main/java/org/apache/paimon/format/FileFormat.java

@@ -30,6 +30,7 @@
 
 import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Optional;
 
@@ -74,6 +75,23 @@ public Optional<SimpleStatsExtractor> createStatsExtractor(
     }
 
     public static FileFormat fromIdentifier(String identifier, Options options) {
+        return fromIdentifier(identifier, options, FileFormatProvider.FORMAT_PROVIDER);
+    }
+
+    public static FileFormat readerFromIdentifier(String identifier, Options options) {
+        return fromIdentifier(identifier, options, FileFormatProvider.READ_FORMAT_PROVIDER);
+    }
+
+    public static FileFormat writerFromIdentifier(String identifier, Options options) {
+        return fromIdentifier(identifier, options, FileFormatProvider.WRITE_FORMAT_PROVIDER);
+    }
+
+    public static FileFormat validationFromIdentifier(String identifier, Options options) {
+        return fromIdentifier(identifier, options, FileFormatProvider.VALIDATION_FORMAT_PROVIDER);
+    }
+
+    private static FileFormat fromIdentifier(
+            String identifier, Options options, String providerOptionKey) {
         return fromIdentifier(
                 normalizeFileFormat(identifier),
                 new FormatContext(
@@ -82,21 +100,88 @@ public static FileFormat fromIdentifier(String identifier, Options options) {
                         options.get(CoreOptions.WRITE_BATCH_SIZE),
                         options.get(CoreOptions.WRITE_BATCH_MEMORY),
                         options.get(CoreOptions.FILE_COMPRESSION_ZSTD_LEVEL),
-                        options.get(CoreOptions.FILE_BLOCK_SIZE)));
+                        options.get(CoreOptions.FILE_BLOCK_SIZE)),
+                providerOptionKey);
     }
 
     /** Create a {@link FileFormat} from format identifier and format options. */
     public static FileFormat fromIdentifier(String identifier, FormatContext context) {
+        return fromIdentifier(identifier, context, FileFormatProvider.FORMAT_PROVIDER);
+    }
+
+    public static FileFormat readerFromIdentifier(String identifier, FormatContext context) {
+        return fromIdentifier(identifier, context, FileFormatProvider.READ_FORMAT_PROVIDER);
+    }
+
+    public static FileFormat writerFromIdentifier(String identifier, FormatContext context) {
+        return fromIdentifier(identifier, context, FileFormatProvider.WRITE_FORMAT_PROVIDER);
+    }
+
+    public static FileFormat validationFromIdentifier(String identifier, FormatContext context) {
+        return fromIdentifier(identifier, context, FileFormatProvider.VALIDATION_FORMAT_PROVIDER);
+    }
+
+    private static FileFormat fromIdentifier(
+            String identifier, FormatContext context, String providerOptionKey) {
+        String normalizedIdentifier = normalizeFileFormat(identifier);
+        ClassLoader classLoader = providerClassLoader();
+        Optional<FileFormat> operationFormat =
+                createFromProvider(classLoader, context, providerOptionKey, normalizedIdentifier);
+        if (operationFormat.isPresent()) {
+            return operationFormat.get();
+        }
+
+        if (!FileFormatProvider.FORMAT_PROVIDER.equals(providerOptionKey)) {
+            Optional<FileFormat> genericFormat =
+                    createFromProvider(
+                            classLoader,
+                            context,
+                            FileFormatProvider.FORMAT_PROVIDER,
+                            normalizedIdentifier);
+            if (genericFormat.isPresent()) {
+                return genericFormat.get();
+            }
+        }
+
         return FormatFactoryUtil.discoverFactory(
-                        FileFormat.class.getClassLoader(), identifier.toLowerCase())
+                        FileFormat.class.getClassLoader(), normalizedIdentifier)
                 .create(context);
     }
 
+    private static Optional<FileFormat> createFromProvider(
+            ClassLoader classLoader,
+            FormatContext context,
+            String providerOptionKey,
+            String normalizedIdentifier) {
+        String providerIdentifier = context.options().getString(providerOptionKey, null);
+        if (providerIdentifier == null || providerIdentifier.trim().isEmpty()) {
+            return Optional.empty();
+        }
+        return FormatFactoryUtil.discoverProvider(
+                        classLoader, providerIdentifier.trim().toLowerCase(Locale.ROOT))
+                .create(normalizedIdentifier, context);
+    }
+
+    private static ClassLoader providerClassLoader() {
+        ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
+        if (contextClassLoader != null) {
+            try {
+                if (contextClassLoader.loadClass(FileFormatProvider.class.getName())
+                        == FileFormatProvider.class) {
+                    return contextClassLoader;
+                }
+            } catch (ClassNotFoundException ignored) {
+                // Fall back to the class loader that loaded Paimon's format API.
+            }
+        }
+        return FileFormat.class.getClassLoader();
+    }
+
     protected Options getIdentifierPrefixOptions(Options options) {
         Map<String, String> result = new HashMap<>();
-        String prefix = formatIdentifier.toLowerCase() + ".";
+        String prefix = formatIdentifier.toLowerCase(Locale.ROOT) + ".";
         for (String key : options.keySet()) {
-            if (key.toLowerCase().startsWith(prefix)) {
+            if (key.toLowerCase(Locale.ROOT).startsWith(prefix)) {
                 result.put(prefix + key.substring(prefix.length()), options.get(key));
             }
         }
@@ -107,13 +192,37 @@ public static FileFormat fileFormat(CoreOptions options) {
         return FileFormat.fromIdentifier(options.fileFormatString(), options.toConfiguration());
     }
 
+    public static FileFormat readerFileFormat(CoreOptions options) {
+        return FileFormat.readerFromIdentifier(
+                options.fileFormatString(), options.toConfiguration());
+    }
+
+    public static FileFormat writerFileFormat(CoreOptions options) {
+        return FileFormat.writerFromIdentifier(
+                options.fileFormatString(), options.toConfiguration());
+    }
+
+    public static FileFormat validationFileFormat(CoreOptions options) {
+        return FileFormat.validationFromIdentifier(
+                options.fileFormatString(), options.toConfiguration());
+    }
+
     @Nullable
     public static FileFormat vectorFileFormat(CoreOptions options) {
         String vectorFileFormat = options.vectorFileFormatString();
         if (vectorFileFormat == null) {
             return null;
         }
-        return FileFormat.fromIdentifier(vectorFileFormat, options.toConfiguration());
+        return FileFormat.writerFromIdentifier(vectorFileFormat, options.toConfiguration());
+    }
+
+    @Nullable
+    public static FileFormat validationVectorFileFormat(CoreOptions options) {
+        String vectorFileFormat = options.vectorFileFormatString();
+        if (vectorFileFormat == null) {
+            return null;
+        }
+        return FileFormat.validationFromIdentifier(vectorFileFormat, options.toConfiguration());
     }
 
     public static FileFormat manifestFormat(CoreOptions options) {

paimon-common/src/main/java/org/apache/paimon/format/FileFormatProvider.java

@@ -0,0 +1,65 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+package org.apache.paimon.format;
+
+import org.apache.paimon.CoreOptions;
+import org.apache.paimon.annotation.Experimental;
+import org.apache.paimon.format.FileFormatFactory.FormatContext;
+
+import java.util.Optional;
+
+/**
+ * Provider for engine-specific file format implementations.
+ *
+ * <p>Engines can use this SPI to provide readers, writers, or validation logic without exposing the
+ * implementation dependencies used by Paimon's built-in file formats. For example, an engine may
+ * provide ORC or Parquet implementations backed by its own filesystem and format libraries.
+ *
+ * <p>The operation-specific options take precedence for their operation. If the operation-specific
+ * provider is not configured or returns {@link Optional#empty()}, Paimon falls back to {@link
+ * #FORMAT_PROVIDER}. If no configured provider handles the format, Paimon uses the built-in {@link
+ * FileFormatFactory} for the requested format.
+ */
+@Experimental
+public interface FileFormatProvider {
+
+    /** Option key used to select a provider discovered from the classpath. */
+    String FORMAT_PROVIDER = CoreOptions.FILE_FORMAT_PROVIDER.key();
+
+    /** Option key used to select a provider for file-format readers. */
+    String READ_FORMAT_PROVIDER = CoreOptions.FILE_FORMAT_READ_PROVIDER.key();
+
+    /** Option key used to select a provider for file-format writers. */
+    String WRITE_FORMAT_PROVIDER = CoreOptions.FILE_FORMAT_WRITE_PROVIDER.key();
+
+    /** Option key used to select a provider for file-format validation. */
+    String VALIDATION_FORMAT_PROVIDER = CoreOptions.FILE_FORMAT_VALIDATION_PROVIDER.key();
+
+    /** Identifier used to select this provider. */
+    String identifier();
+
+    /**
+     * Creates a file format for the identifier.
+     *
+     * <p>The identifier is the normalized file format identifier, such as {@code parquet} or {@code
+     * orc}. Return {@link Optional#empty()} to let Paimon use the default service-loaded format
+     * factory for this format.
+     */
+    Optional<FileFormat> create(String identifier, FormatContext context);
+}