#198, add enum converter factory

Author: hauner

src/main/kotlin/io/openapiprocessor/spring/processor/SpringProcessor.kt

@@ -85,6 +85,7 @@ class SpringProcessor {
                     generatedWriter,
                     javaDocWriter
                 ),
+                listOf(AdditionalEnumWriter()::write),
                 GoogleFormatter(),
                 writerFactory
             )

src/main/kotlin/io/openapiprocessor/spring/writer/java/AdditionalEnumWriter.kt

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2023 https://github.com/openapi-processor/openapi-processor-spring
+ * PDX-License-Identifier: Apache-2.0
+ */
+
+package io.openapiprocessor.spring.writer.java
+
+import io.openapiprocessor.core.converter.ApiOptions
+import io.openapiprocessor.core.writer.SourceFormatter
+import io.openapiprocessor.core.writer.WriterFactory
+import java.io.StringWriter
+import java.io.Writer
+
+class AdditionalEnumWriter {
+
+    fun write(options: ApiOptions, formatter: SourceFormatter, factory: WriterFactory) {
+        if (options.enumType != "framework") {
+            return
+        }
+
+        val writer = createFactoryWriter(options, factory)
+        writeEnumConverterFactory(options, writer, formatter)
+        writer.close()
+    }
+
+    private fun writeEnumConverterFactory(options: ApiOptions, writer: Writer, formatter: SourceFormatter) {
+        val raw = StringWriter()
+        EnumConverterFactoryWriter(options).writeConverterFactory(raw)
+        writer.write(formatter.format(raw.toString()))
+    }
+
+    private fun createFactoryWriter(options: ApiOptions, writerFactory: WriterFactory): Writer {
+        return writerFactory.createWriter(
+            "${options.packageName}.spring",
+            "StringToEnumConverterFactory")
+    }
+
+}

src/main/kotlin/io/openapiprocessor/spring/writer/java/EnumConverterFactoryWriter.kt

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2023 https://github.com/openapi-processor/openapi-processor-spring
+ * PDX-License-Identifier: Apache-2.0
+ */
+
+package io.openapiprocessor.spring.writer.java
+
+import io.openapiprocessor.core.converter.ApiOptions
+import java.io.Writer
+
+class EnumConverterFactoryWriter(val options: ApiOptions) {
+
+    fun writeConverterFactory(target: Writer) {
+        target.write("""
+            package ${options.packageName}.spring;
+            
+            import org.springframework.core.convert.converter.Converter;
+            import org.springframework.core.convert.converter.ConverterFactory;
+            import org.springframework.stereotype.Component;
+
+            import java.util.EnumSet;
+            import java.util.function.Supplier;
+
+            public class StringToEnumConverterFactory<T extends Enum<T> & Supplier<String>>
+                implements ConverterFactory<String, T> {
+
+                @Override
+                @SuppressWarnings({"unchecked", "rawtypes"})
+                public <E extends T> Converter<String, E> getConverter(Class<E> targetType) {
+                    return new StringToEnumConverter(targetType);
+                }
+
+                static class StringToEnumConverter<T extends Enum<T> & Supplier<String>> implements Converter<String, T> {
+
+                    private final Class<T> enumType;
+
+                    public StringToEnumConverter(Class<T> enumType) {
+                        this.enumType = enumType;
+                    }
+
+                    public T convert(String source) {
+                        String sourceValue = source.trim();
+
+                        for (T e : EnumSet.allOf(enumType)) {
+                            if (e.get().equals(sourceValue)) {
+                                return e;
+                            }
+                        }
+
+                        throw new IllegalArgumentException(String.format("No enum constant of %s has the value %s",
+                            enumType.getCanonicalName(),
+                            sourceValue));
+                    }
+                }
+            }
+        """.trimIndent())
+    }
+}

src/main/kotlin/io/openapiprocessor/spring/writer/java/SpringWriterFactory.kt

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2023 https://github.com/openapi-processor/openapi-processor-spring
+ * PDX-License-Identifier: Apache-2.0
+ */
+
+package io.openapiprocessor.spring.writer.java
+
+import io.openapiprocessor.core.converter.ApiOptions
+import io.openapiprocessor.core.writer.DefaultWriterFactory
+import java.nio.file.Path
+
+class SpringWriterFactory(options: ApiOptions): DefaultWriterFactory(options) {
+
+    override fun initAdditionalPackages(options: ApiOptions): Map<String, Path> {
+        val pkgPaths = HashMap<String, Path>()
+
+        if (options.enumType == "framework") {
+            val (name, path) = initTargetPackage("spring")
+            pkgPaths[name] = path
+        }
+
+        return pkgPaths
+    }
+}