From 2ce269bbdc69e6072d1ec9f69be8dd03050538b6 Mon Sep 17 00:00:00 2001
From: JesseBrault0709 <62299747+JesseBrault0709@users.noreply.github.com>
Date: Wed, 26 Apr 2023 10:00:15 +0200
Subject: [PATCH] Changing Closures to various functional interfaces.

---
 ...faultBuildScriptConfiguratorFactory.groovy |  2 +-
 .../com/jessebrault/ssg/model/Models.groovy   | 35 ++-----------------
 ...Model.groovy => SupplierBasedModel.groovy} |  8 +++--
 .../ssg/page/PagesProviders.groovy            | 20 ++++++-----
 .../ssg/part/PartsProviders.groovy            | 20 ++++++-----
 .../AbstractCollectionProvider.groovy         |  2 +-
 .../ssg/provider/AbstractProvider.groovy      |  4 +--
 .../ssg/provider/CollectionProviders.groovy   | 20 +++++------
 .../FileBasedCollectionProvider.groovy        | 32 +++++++----------
 .../jessebrault/ssg/provider/Providers.groovy |  6 ++--
 ...=> SupplierBasedCollectionProvider.groovy} | 12 +++----
 ...er.groovy => SupplierBasedProvider.groovy} | 12 +++----
 .../ssg/template/TemplatesProviders.groovy    | 20 ++++++-----
 .../ssg/text/TextsProviders.groovy            | 20 ++++++-----
 .../jessebrault/ssg/util/ExtensionUtil.groovy |  6 ++--
 15 files changed, 100 insertions(+), 119 deletions(-)
 rename api/src/main/groovy/com/jessebrault/ssg/model/{ClosureBasedModel.groovy => SupplierBasedModel.groovy} (71%)
 rename api/src/main/groovy/com/jessebrault/ssg/provider/{ClosureBasedCollectionProvider.groovy => SupplierBasedCollectionProvider.groovy} (57%)
 rename api/src/main/groovy/com/jessebrault/ssg/provider/{ClosureBasedProvider.groovy => SupplierBasedProvider.groovy} (62%)

diff --git a/api/src/main/groovy/com/jessebrault/ssg/buildscript/DefaultBuildScriptConfiguratorFactory.groovy b/api/src/main/groovy/com/jessebrault/ssg/buildscript/DefaultBuildScriptConfiguratorFactory.groovy
index 144ac45..cf91c3c 100644
--- a/api/src/main/groovy/com/jessebrault/ssg/buildscript/DefaultBuildScriptConfiguratorFactory.groovy
+++ b/api/src/main/groovy/com/jessebrault/ssg/buildscript/DefaultBuildScriptConfiguratorFactory.groovy
@@ -38,7 +38,7 @@ final class DefaultBuildScriptConfiguratorFactory implements BuildScriptConfigur
 
                 taskFactories { sourceProviders ->
                     register('textToHtml', TextToHtmlTaskFactory::new) {
-                        it.specProvider += CollectionProviders.from {
+                        it.specProvider += CollectionProviders.fromSupplier {
                             def templates = sourceProviders.templatesProvider.provide()
                             sourceProviders.textsProvider.provide().collect {
                                 def frontMatterResult = it.type.frontMatterGetter.get(it)
diff --git a/api/src/main/groovy/com/jessebrault/ssg/model/Models.groovy b/api/src/main/groovy/com/jessebrault/ssg/model/Models.groovy
index d503f55..e5997e9 100644
--- a/api/src/main/groovy/com/jessebrault/ssg/model/Models.groovy
+++ b/api/src/main/groovy/com/jessebrault/ssg/model/Models.groovy
@@ -1,10 +1,6 @@
 package com.jessebrault.ssg.model
 
-import groovy.io.FileType
-import groovy.transform.stc.ClosureParams
-import groovy.transform.stc.FromString
-
-import java.nio.file.Path
+import java.util.function.Supplier
 
 final class Models {
 
@@ -12,33 +8,8 @@ final class Models {
         new SimpleModel<>(name, t)
     }
 
-    static <T> Model<T> from(String name, Closure<T> tClosure) {
-        new ClosureBasedModel<>(name, tClosure)
-    }
-
-    /**
-     * Takes a directory and iterates recursively through all files present in the directory and sub-directories,
-     * supplying each File along with a String representing that File's path relative to the base Directory to the
-     * given Closure, which then returns a Model containing T, all of which are collected and then returned together.
-     *
-     * @param directory The base directory in which to search for Files to process.
-     * @param fileToModelClosure A Closure which receives two params: the File being processed,
-     * and a String representing the path of that File relative to the base directory. Must return
-     * a Model containing T.
-     * @return A Collection of Models containing Ts.
-     */
-    static <T> Collection<Model<T>> fromDirectory(
-            File directory,
-            @ClosureParams(value = FromString, options = ['java.io.File, java.lang.String'])
-            Closure<Model<T>> fileToModelClosure
-    ) {
-        final Collection<Model<T>> models = []
-        def directoryPath = Path.of(directory.path)
-        directory.eachFileRecurse(FileType.FILES) {
-            def relativePath = directoryPath.relativize(Path.of(it.path)).toString()
-            models << fileToModelClosure(it, relativePath)
-        }
-        models
+    static <T> Model<T> fromSupplier(String name, Supplier<T> tClosure) {
+        new SupplierBasedModel<>(name, tClosure)
     }
 
     private Models() {}
diff --git a/api/src/main/groovy/com/jessebrault/ssg/model/ClosureBasedModel.groovy b/api/src/main/groovy/com/jessebrault/ssg/model/SupplierBasedModel.groovy
similarity index 71%
rename from api/src/main/groovy/com/jessebrault/ssg/model/ClosureBasedModel.groovy
rename to api/src/main/groovy/com/jessebrault/ssg/model/SupplierBasedModel.groovy
index d098dc9..3b6a9d1 100644
--- a/api/src/main/groovy/com/jessebrault/ssg/model/ClosureBasedModel.groovy
+++ b/api/src/main/groovy/com/jessebrault/ssg/model/SupplierBasedModel.groovy
@@ -5,18 +5,20 @@ import groovy.transform.NullCheck
 import groovy.transform.PackageScope
 import groovy.transform.TupleConstructor
 
+import java.util.function.Supplier
+
 @PackageScope
 @TupleConstructor(includeFields = true, defaults = false)
 @NullCheck(includeGenerated = true)
 @EqualsAndHashCode(includeFields = true)
-final class ClosureBasedModel<T> implements Model<T> {
+final class SupplierBasedModel<T> implements Model<T> {
 
     final String name
-    private final Closure<T> tClosure
+    private final Supplier<T> supplier
 
     @Override
     T get() {
-        this.tClosure()
+        this.supplier.get()
     }
 
 }
diff --git a/api/src/main/groovy/com/jessebrault/ssg/page/PagesProviders.groovy b/api/src/main/groovy/com/jessebrault/ssg/page/PagesProviders.groovy
index c33eb80..9da7af5 100644
--- a/api/src/main/groovy/com/jessebrault/ssg/page/PagesProviders.groovy
+++ b/api/src/main/groovy/com/jessebrault/ssg/page/PagesProviders.groovy
@@ -3,7 +3,6 @@ package com.jessebrault.ssg.page
 import com.jessebrault.ssg.provider.CollectionProvider
 import com.jessebrault.ssg.provider.CollectionProviders
 import com.jessebrault.ssg.util.ExtensionUtil
-import com.jessebrault.ssg.util.PathUtil
 import org.slf4j.Logger
 import org.slf4j.LoggerFactory
 
@@ -12,14 +11,19 @@ final class PagesProviders {
     private static final Logger logger = LoggerFactory.getLogger(PagesProviders)
 
     static CollectionProvider<Page> from(File pagesDirectory, Collection<PageType> pageTypes) {
-        CollectionProviders.from(pagesDirectory) {
-            def extension = ExtensionUtil.getExtension(it.path)
-            def pageType = pageTypes.find { it.ids.contains(extension) }
-            if (!pageType) {
-                logger.warn('there is no PageType for file {}; skipping', it)
-                null
+        CollectionProviders.fromDirectory(pagesDirectory) { file, relativePath ->
+            def extension = ExtensionUtil.getExtension(relativePath)
+            if (extension) {
+                def pageType = pageTypes.find { it.ids.contains(extension) }
+                if (!pageType) {
+                    logger.debug('there is no PageType for file {}; skipping', file)
+                    return null
+                } else {
+                    return new Page(relativePath, pageType, file.getText())
+                }
             } else {
-                new Page(PathUtil.relative(pagesDirectory.path, it.path), pageType, it.getText())
+                logger.debug('there is no extension for file {}; skipping', file)
+                return null
             }
         }
     }
diff --git a/api/src/main/groovy/com/jessebrault/ssg/part/PartsProviders.groovy b/api/src/main/groovy/com/jessebrault/ssg/part/PartsProviders.groovy
index 7220288..392aa27 100644
--- a/api/src/main/groovy/com/jessebrault/ssg/part/PartsProviders.groovy
+++ b/api/src/main/groovy/com/jessebrault/ssg/part/PartsProviders.groovy
@@ -3,7 +3,6 @@ package com.jessebrault.ssg.part
 import com.jessebrault.ssg.provider.CollectionProvider
 import com.jessebrault.ssg.provider.CollectionProviders
 import com.jessebrault.ssg.util.ExtensionUtil
-import com.jessebrault.ssg.util.PathUtil
 import org.slf4j.Logger
 import org.slf4j.LoggerFactory
 
@@ -12,14 +11,19 @@ final class PartsProviders {
     private static final Logger logger = LoggerFactory.getLogger(PartsProviders)
 
     static CollectionProvider<Part> of(File partsDir, Collection<PartType> partTypes) {
-        CollectionProviders.from(partsDir) {
-            def extension = ExtensionUtil.getExtension(it.path)
-            def partType = partTypes.find { it.ids.contains(extension) }
-            if (!partType) {
-                logger.warn('there is no PartType for file {}; skipping', it)
-                null
+        CollectionProviders.fromDirectory(partsDir) { file, relativePath ->
+            def extension = ExtensionUtil.getExtension(relativePath)
+            if (extension) {
+                def partType = partTypes.find { it.ids.contains(extension) }
+                if (!partType) {
+                    logger.debug('there is no PartType for file {}; skipping', file)
+                    return null
+                } else {
+                    return new Part(relativePath, partType, file.getText())
+                }
             } else {
-                new Part(PathUtil.relative(partsDir.path, it.path), partType, it.getText())
+                logger.debug('there is no extension for file {}; skipping', file)
+                return null
             }
         }
     }
diff --git a/api/src/main/groovy/com/jessebrault/ssg/provider/AbstractCollectionProvider.groovy b/api/src/main/groovy/com/jessebrault/ssg/provider/AbstractCollectionProvider.groovy
index 0ccd4a5..215e08e 100644
--- a/api/src/main/groovy/com/jessebrault/ssg/provider/AbstractCollectionProvider.groovy
+++ b/api/src/main/groovy/com/jessebrault/ssg/provider/AbstractCollectionProvider.groovy
@@ -6,7 +6,7 @@ abstract class AbstractCollectionProvider<T> implements CollectionProvider<T> {
             CollectionProvider<T> cp0,
             CollectionProvider<T> cp1
     ) {
-        ClosureBasedCollectionProvider.get {
+        SupplierBasedCollectionProvider.get {
             cp0.provide() + cp1.provide()
         }
     }
diff --git a/api/src/main/groovy/com/jessebrault/ssg/provider/AbstractProvider.groovy b/api/src/main/groovy/com/jessebrault/ssg/provider/AbstractProvider.groovy
index b837033..2cf51e1 100644
--- a/api/src/main/groovy/com/jessebrault/ssg/provider/AbstractProvider.groovy
+++ b/api/src/main/groovy/com/jessebrault/ssg/provider/AbstractProvider.groovy
@@ -6,7 +6,7 @@ abstract class AbstractProvider<T> implements Provider<T> {
             Provider<T> p0,
             Provider<T> p1
     ) {
-        ClosureBasedCollectionProvider.get {
+        SupplierBasedCollectionProvider.get {
             [p0.provide(), p1.provide()]
         }
     }
@@ -18,7 +18,7 @@ abstract class AbstractProvider<T> implements Provider<T> {
 
     @Override
     CollectionProvider<T> asType(Class<CollectionProvider> collectionProviderClass) {
-        ClosureBasedCollectionProvider.get {
+        SupplierBasedCollectionProvider.get {
             [this.provide() as T]
         }
     }
diff --git a/api/src/main/groovy/com/jessebrault/ssg/provider/CollectionProviders.groovy b/api/src/main/groovy/com/jessebrault/ssg/provider/CollectionProviders.groovy
index fb5874d..882746e 100644
--- a/api/src/main/groovy/com/jessebrault/ssg/provider/CollectionProviders.groovy
+++ b/api/src/main/groovy/com/jessebrault/ssg/provider/CollectionProviders.groovy
@@ -1,29 +1,29 @@
 package com.jessebrault.ssg.provider
 
-import groovy.transform.stc.ClosureParams
-import groovy.transform.stc.FromString
 import org.jetbrains.annotations.Nullable
 
+import java.util.function.BiFunction
+import java.util.function.Supplier
+
 final class CollectionProviders {
 
     static <T> CollectionProvider<T> getEmpty() {
         new SimpleCollectionProvider<>([])
     }
 
-    static <T> CollectionProvider<T> of(Collection<T> ts) {
+    static <T> CollectionProvider<T> fromCollection(Collection<T> ts) {
         new SimpleCollectionProvider<T>(ts)
     }
 
-    static <T> CollectionProvider<T> from(Closure<Collection<T>> closure) {
-        ClosureBasedCollectionProvider.get(closure)
+    static <T> CollectionProvider<T> fromSupplier(Supplier<Collection<T>> supplier) {
+        new SupplierBasedCollectionProvider<>(supplier)
     }
 
-    static <T> CollectionProvider<T> from(
-            File dir,
-            @ClosureParams(value = FromString, options = 'java.io.File')
-            Closure<@Nullable T> fileToElementClosure
+    static <T> CollectionProvider<T> fromDirectory(
+            File baseDirectory,
+            BiFunction<File, String, @Nullable T> elementFunction
     ) {
-        new FileBasedCollectionProvider<>(dir, fileToElementClosure)
+        new FileBasedCollectionProvider<>(baseDirectory, elementFunction)
     }
 
     private CollectionProviders() {}
diff --git a/api/src/main/groovy/com/jessebrault/ssg/provider/FileBasedCollectionProvider.groovy b/api/src/main/groovy/com/jessebrault/ssg/provider/FileBasedCollectionProvider.groovy
index dbede24..b5aa37a 100644
--- a/api/src/main/groovy/com/jessebrault/ssg/provider/FileBasedCollectionProvider.groovy
+++ b/api/src/main/groovy/com/jessebrault/ssg/provider/FileBasedCollectionProvider.groovy
@@ -1,43 +1,37 @@
 package com.jessebrault.ssg.provider
 
+import com.jessebrault.ssg.util.PathUtil
 import groovy.io.FileType
 import groovy.transform.EqualsAndHashCode
 import groovy.transform.NullCheck
 import groovy.transform.PackageScope
-import groovy.transform.stc.ClosureParams
-import groovy.transform.stc.FromString
+import groovy.transform.TupleConstructor
 import org.jetbrains.annotations.Nullable
 import org.slf4j.Logger
 import org.slf4j.LoggerFactory
 
+import java.util.function.BiFunction
+
 @PackageScope
-@NullCheck
+@TupleConstructor(includeFields = true, defaults = false)
+@NullCheck(includeGenerated = true)
 @EqualsAndHashCode(includeFields = true)
 final class FileBasedCollectionProvider<T> extends AbstractCollectionProvider<T> {
 
     private static final Logger logger = LoggerFactory.getLogger(FileBasedCollectionProvider)
 
-    private final File dir
-    private final Closure<@Nullable T> fileToElementClosure
-
-    FileBasedCollectionProvider(
-            File dir,
-            @ClosureParams(value = FromString, options = 'java.io.File')
-            Closure<@Nullable T> fileToElementClosure
-    ) {
-        this.dir = dir
-        this.fileToElementClosure = fileToElementClosure
-    }
+    private final File baseDirectory
+    private final BiFunction<File, String, @Nullable T> elementFunction
 
     @Override
     Collection<T> provide() {
-        if (!this.dir.isDirectory()) {
-            logger.error('{} does not exist or is not a directory; returning empty collection', this.dir)
+        if (!this.baseDirectory.isDirectory()) {
+            logger.error('{} does not exist or is not a directory; returning empty collection', this.baseDirectory)
             []
         } else {
-            def ts = []
-            this.dir.eachFileRecurse(FileType.FILES) {
-                def t = this.fileToElementClosure(it)
+            final Collection<T> ts = []
+            this.baseDirectory.eachFileRecurse(FileType.FILES) {
+                def t = this.elementFunction.apply(it, PathUtil.relative(this.baseDirectory.path, it.path)) as T
                 if (t) {
                     ts << t
                 }
diff --git a/api/src/main/groovy/com/jessebrault/ssg/provider/Providers.groovy b/api/src/main/groovy/com/jessebrault/ssg/provider/Providers.groovy
index 6393633..ecb875f 100644
--- a/api/src/main/groovy/com/jessebrault/ssg/provider/Providers.groovy
+++ b/api/src/main/groovy/com/jessebrault/ssg/provider/Providers.groovy
@@ -1,6 +1,6 @@
 package com.jessebrault.ssg.provider
 
-import org.codehaus.groovy.runtime.InvokerHelper
+import java.util.function.Supplier
 
 final class Providers {
 
@@ -8,8 +8,8 @@ final class Providers {
         new SimpleProvider<>(t)
     }
 
-    static <T> Provider<T> from(Closure<T> closure) {
-        ClosureBasedProvider.of(closure)
+    static <T> Provider<T> fromSupplier(Supplier<T> supplier) {
+        new SupplierBasedProvider<>(supplier)
     }
 
     static <T> CollectionProvider<T> concat(Provider<T> ...providers) {
diff --git a/api/src/main/groovy/com/jessebrault/ssg/provider/ClosureBasedCollectionProvider.groovy b/api/src/main/groovy/com/jessebrault/ssg/provider/SupplierBasedCollectionProvider.groovy
similarity index 57%
rename from api/src/main/groovy/com/jessebrault/ssg/provider/ClosureBasedCollectionProvider.groovy
rename to api/src/main/groovy/com/jessebrault/ssg/provider/SupplierBasedCollectionProvider.groovy
index a3132c9..8cdbba9 100644
--- a/api/src/main/groovy/com/jessebrault/ssg/provider/ClosureBasedCollectionProvider.groovy
+++ b/api/src/main/groovy/com/jessebrault/ssg/provider/SupplierBasedCollectionProvider.groovy
@@ -5,21 +5,19 @@ import groovy.transform.NullCheck
 import groovy.transform.PackageScope
 import groovy.transform.TupleConstructor
 
+import java.util.function.Supplier
+
 @PackageScope
 @TupleConstructor(defaults = false, includeFields = true)
 @NullCheck(includeGenerated = true)
 @EqualsAndHashCode(includeFields = true)
-final class ClosureBasedCollectionProvider<T> extends AbstractCollectionProvider<T> {
+final class SupplierBasedCollectionProvider<T> extends AbstractCollectionProvider<T> {
 
-    static <T> CollectionProvider<T> get(Closure<Collection<T>> closure) {
-        new ClosureBasedCollectionProvider<>(closure)
-    }
-
-    private final Closure<Collection<T>> closure
+    private final Supplier<Collection<T>> supplier
 
     @Override
     Collection<T> provide() {
-        this.closure()
+        this.supplier.get()
     }
 
 }
diff --git a/api/src/main/groovy/com/jessebrault/ssg/provider/ClosureBasedProvider.groovy b/api/src/main/groovy/com/jessebrault/ssg/provider/SupplierBasedProvider.groovy
similarity index 62%
rename from api/src/main/groovy/com/jessebrault/ssg/provider/ClosureBasedProvider.groovy
rename to api/src/main/groovy/com/jessebrault/ssg/provider/SupplierBasedProvider.groovy
index 56c5a7c..c6629c5 100644
--- a/api/src/main/groovy/com/jessebrault/ssg/provider/ClosureBasedProvider.groovy
+++ b/api/src/main/groovy/com/jessebrault/ssg/provider/SupplierBasedProvider.groovy
@@ -5,21 +5,19 @@ import groovy.transform.NullCheck
 import groovy.transform.PackageScope
 import groovy.transform.TupleConstructor
 
+import java.util.function.Supplier
+
 @PackageScope
 @TupleConstructor(includeFields = true, defaults = false)
 @NullCheck(includeGenerated = true)
 @EqualsAndHashCode(includeFields = true)
-final class ClosureBasedProvider<T> extends AbstractProvider<T> {
+final class SupplierBasedProvider<T> extends AbstractProvider<T> {
 
-    static <T> Provider<T> of(Closure<T> closure) {
-        new ClosureBasedProvider<>(closure)
-    }
-
-    private final Closure<T> closure
+    private final Supplier<T> supplier
 
     @Override
     T provide() {
-        this.closure()
+        this.supplier.get()
     }
 
 }
diff --git a/api/src/main/groovy/com/jessebrault/ssg/template/TemplatesProviders.groovy b/api/src/main/groovy/com/jessebrault/ssg/template/TemplatesProviders.groovy
index 9f53283..af5d61c 100644
--- a/api/src/main/groovy/com/jessebrault/ssg/template/TemplatesProviders.groovy
+++ b/api/src/main/groovy/com/jessebrault/ssg/template/TemplatesProviders.groovy
@@ -3,7 +3,6 @@ package com.jessebrault.ssg.template
 import com.jessebrault.ssg.provider.CollectionProvider
 import com.jessebrault.ssg.provider.CollectionProviders
 import com.jessebrault.ssg.util.ExtensionUtil
-import com.jessebrault.ssg.util.PathUtil
 import org.slf4j.Logger
 import org.slf4j.LoggerFactory
 
@@ -12,14 +11,19 @@ final class TemplatesProviders {
     private static final Logger logger = LoggerFactory.getLogger(TemplatesProviders)
 
     static CollectionProvider<Template> from(File templatesDir, Collection<TemplateType> templateTypes) {
-        CollectionProviders.from(templatesDir) {
-            def extension = ExtensionUtil.getExtension(it.path)
-            def templateType = templateTypes.find { it.ids.contains(extension) }
-            if (!templateType) {
-                logger.warn('there is no TemplateType for file {}; skipping', it)
-                null
+        CollectionProviders.fromDirectory(templatesDir) { file, relativePath ->
+            def extension = ExtensionUtil.getExtension(relativePath)
+            if (extension) {
+                def templateType = templateTypes.find { it.ids.contains(extension) }
+                if (!templateType) {
+                    logger.debug('there is no TemplateType for file {}; skipping', file)
+                    return null
+                } else {
+                    return new Template(relativePath, templateType, file.getText())
+                }
             } else {
-                new Template(PathUtil.relative(templatesDir.path, it.path), templateType, it.getText())
+                logger.debug('there is no extension for file {}; skipping', file)
+                return null
             }
         }
     }
diff --git a/api/src/main/groovy/com/jessebrault/ssg/text/TextsProviders.groovy b/api/src/main/groovy/com/jessebrault/ssg/text/TextsProviders.groovy
index 716e6f4..d7c01ff 100644
--- a/api/src/main/groovy/com/jessebrault/ssg/text/TextsProviders.groovy
+++ b/api/src/main/groovy/com/jessebrault/ssg/text/TextsProviders.groovy
@@ -3,7 +3,6 @@ package com.jessebrault.ssg.text
 import com.jessebrault.ssg.provider.CollectionProvider
 import com.jessebrault.ssg.provider.CollectionProviders
 import com.jessebrault.ssg.util.ExtensionUtil
-import com.jessebrault.ssg.util.PathUtil
 import org.slf4j.Logger
 import org.slf4j.LoggerFactory
 
@@ -12,14 +11,19 @@ final class TextsProviders {
     private static final Logger logger = LoggerFactory.getLogger(TextsProviders)
 
     static CollectionProvider<Text> from(File textsDir, Collection<TextType> types) {
-        CollectionProviders.from(textsDir) {
-            def extension = ExtensionUtil.getExtension(it.path)
-            def textType = types.find { it.ids.contains(extension) }
-            if (!textType) {
-                logger.warn('there is no TextType for file {}; skipping', it)
-                null
+        CollectionProviders.fromDirectory(textsDir) { file, relativePath ->
+            def extension = ExtensionUtil.getExtension(relativePath)
+            if (extension) {
+                def textType = types.find { it.ids.contains(extension) }
+                if (!textType) {
+                    logger.warn('there is no TextType for file {}; skipping', file)
+                    return null
+                } else {
+                    return new Text(relativePath, textType, file.getText())
+                }
             } else {
-                new Text(PathUtil.relative(textsDir.path, it.path), textType, it.text)
+                logger.debug('there is no extension for file {}; skipping', file)
+                return null
             }
         }
     }
diff --git a/api/src/main/groovy/com/jessebrault/ssg/util/ExtensionUtil.groovy b/api/src/main/groovy/com/jessebrault/ssg/util/ExtensionUtil.groovy
index 3656191..4d517b3 100644
--- a/api/src/main/groovy/com/jessebrault/ssg/util/ExtensionUtil.groovy
+++ b/api/src/main/groovy/com/jessebrault/ssg/util/ExtensionUtil.groovy
@@ -1,5 +1,7 @@
 package com.jessebrault.ssg.util
 
+import org.jetbrains.annotations.Nullable
+
 import java.util.regex.Pattern
 
 final class ExtensionUtil {
@@ -12,12 +14,12 @@ final class ExtensionUtil {
         m.matches() ? m.group(1) : path
     }
 
-    static String getExtension(String path) {
+    static @Nullable String getExtension(String path) {
         def m = getExtensionPattern.matcher(path)
         if (m.matches()) {
             m.group(1)
         } else {
-            throw new IllegalArgumentException("cannot get extension for path: ${ path }")
+            null
         }
     }