Make MethodGenerator.generate return an Optional

Remove SkipGenerationException.
apache · Jun 21, 2019 · fef5c9f · fef5c9f
1 parent 91f45a0
commit fef5c9f
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Showing 16 changed files with 261 additions and 152 deletions.
diff --git a/...ssor/src/main/java/com/datastax/oss/driver/internal/mapper/processor/MethodGenerator.java b/...ssor/src/main/java/com/datastax/oss/driver/internal/mapper/processor/MethodGenerator.java
@@ -16,8 +16,15 @@
 package com.datastax.oss.driver.internal.mapper.processor;
 
 import com.squareup.javapoet.MethodSpec;
+import java.util.Optional;
 
 /** A component that generates a single method. */
 public interface MethodGenerator {
-  MethodSpec.Builder generate();
+
+  /**
+   * @return empty if an error occurred during generation. In that case, the caller doesn't have
+   *     anything to do: it's the generator's responsibility to report the error via {@link
+   *     DecoratedMessager}.
+   */
+  Optional<MethodSpec> generate();
 }
diff --git a/.../main/java/com/datastax/oss/driver/internal/mapper/processor/SkipGenerationException.java b/.../main/java/com/datastax/oss/driver/internal/mapper/processor/SkipGenerationException.java
diff --git a/...va/com/datastax/oss/driver/internal/mapper/processor/dao/DaoGetEntityMethodGenerator.java b/...va/com/datastax/oss/driver/internal/mapper/processor/dao/DaoGetEntityMethodGenerator.java
@@ -25,10 +25,10 @@
 import com.datastax.oss.driver.api.mapper.annotations.GetEntity;
 import com.datastax.oss.driver.internal.mapper.processor.MethodGenerator;
 import com.datastax.oss.driver.internal.mapper.processor.ProcessorContext;
-import com.datastax.oss.driver.internal.mapper.processor.SkipGenerationException;
 import com.datastax.oss.driver.internal.mapper.processor.util.generation.GeneratedCodePatterns;
 import com.squareup.javapoet.ClassName;
 import com.squareup.javapoet.MethodSpec;
+import java.util.Optional;
 import javax.lang.model.element.Element;
 import javax.lang.model.element.ElementKind;
 import javax.lang.model.element.ExecutableElement;
@@ -64,15 +64,15 @@ public DaoGetEntityMethodGenerator(
   }
 
   @Override
-  public MethodSpec.Builder generate() {
+  public Optional<MethodSpec> generate() {
 
     // Validate the parameter: there must be exactly one, of type GettableByName or a ResultSet:
     if (methodElement.getParameters().size() != 1) {
       context
           .getMessager()
           .error(
               methodElement, "%s methods must have one parameter", GetEntity.class.getSimpleName());
-      throw new SkipGenerationException();
+      return Optional.empty();
     }
     VariableElement parameterElement = methodElement.getParameters().get(0);
     String parameterName = parameterElement.getSimpleName().toString();
@@ -90,7 +90,7 @@ public MethodSpec.Builder generate() {
               GettableByName.class.getSimpleName(),
               ResultSet.class.getSimpleName(),
               AsyncResultSet.class.getSimpleName());
-      throw new SkipGenerationException();
+      return Optional.empty();
     }
 
     // Validate the return type. Make sure it matches the parameter type
@@ -112,7 +112,7 @@ public MethodSpec.Builder generate() {
                   "Invalid return type. Can only return %s if the argument is %s",
                   PagingIterable.class.getSimpleName(),
                   ResultSet.class.getSimpleName());
-          throw new SkipGenerationException();
+          return Optional.empty();
         }
         entityElement = extractTypeParameter(returnType);
         transformation = Transformation.MAP;
@@ -125,7 +125,7 @@ public MethodSpec.Builder generate() {
                   "Invalid return type. Can only return %s if the argument is %s",
                   MappedAsyncPagingIterable.class.getSimpleName(),
                   AsyncResultSet.class.getSimpleName());
-          throw new SkipGenerationException();
+          return Optional.empty();
         }
         entityElement = extractTypeParameter(returnType);
         transformation = Transformation.MAP;
@@ -140,7 +140,7 @@ public MethodSpec.Builder generate() {
               Entity.class.getSimpleName(),
               PagingIterable.class.getSimpleName(),
               MappedAsyncPagingIterable.class.getSimpleName());
-      throw new SkipGenerationException();
+      return Optional.empty();
     }
 
     // Generate the implementation:
@@ -162,7 +162,7 @@ public MethodSpec.Builder generate() {
             "return $L.map($L::get)", parameterName, helperFieldName);
         break;
     }
-    return overridingMethodBuilder;
+    return Optional.of(overridingMethodBuilder.build());
   }
 
   /** @return the type argument if it's an annotated entity, otherwise null */

diff --git a/...ava/com/datastax/oss/driver/internal/mapper/processor/dao/DaoImplementationGenerator.java b/...ava/com/datastax/oss/driver/internal/mapper/processor/dao/DaoImplementationGenerator.java
@@ -24,7 +24,6 @@
 import com.datastax.oss.driver.internal.mapper.processor.MethodGenerator;
 import com.datastax.oss.driver.internal.mapper.processor.ProcessorContext;
 import com.datastax.oss.driver.internal.mapper.processor.SingleFileCodeGenerator;
-import com.datastax.oss.driver.internal.mapper.processor.SkipGenerationException;
 import com.datastax.oss.driver.internal.mapper.processor.util.NameIndex;
 import com.datastax.oss.driver.internal.mapper.processor.util.generation.GenericTypeConstantGenerator;
 import com.squareup.javapoet.ClassName;
@@ -111,39 +110,32 @@ protected String getFileName() {
 
   @Override
   protected JavaFile.Builder getContents() {
-    List<MethodGenerator> methodGenerators = new ArrayList<>();
+
+    TypeSpec.Builder classBuilder =
+        TypeSpec.classBuilder(implementationName)
+            .addJavadoc(JAVADOC_GENERATED_WARNING)
+            .addModifiers(Modifier.PUBLIC)
+            .superclass(DaoBase.class)
+            .addSuperinterface(ClassName.get(interfaceElement));
+
     for (Element child : interfaceElement.getEnclosedElements()) {
       if (child.getKind() == ElementKind.METHOD) {
         ExecutableElement methodElement = (ExecutableElement) child;
         Set<Modifier> modifiers = methodElement.getModifiers();
         if (!modifiers.contains(Modifier.STATIC) && !modifiers.contains(Modifier.DEFAULT)) {
           Optional<MethodGenerator> maybeGenerator =
               context.getCodeGeneratorFactory().newDaoImplementationMethod(methodElement, this);
-          if (maybeGenerator.isPresent()) {
-            methodGenerators.add(maybeGenerator.get());
-          } else {
+          if (!maybeGenerator.isPresent()) {
             context
                 .getMessager()
                 .error(methodElement, "Don't know what implementation to generate for this method");
+          } else {
+            maybeGenerator.flatMap(MethodGenerator::generate).ifPresent(classBuilder::addMethod);
           }
         }
       }
     }
 
-    TypeSpec.Builder classBuilder =
-        TypeSpec.classBuilder(implementationName)
-            .addJavadoc(JAVADOC_GENERATED_WARNING)
-            .addModifiers(Modifier.PUBLIC)
-            .superclass(DaoBase.class)
-            .addSuperinterface(ClassName.get(interfaceElement));
-
-    for (MethodGenerator methodGenerator : methodGenerators) {
-      try {
-        classBuilder.addMethod(methodGenerator.generate().build());
-      } catch (SkipGenerationException ignored) {
-      }
-    }
-
     genericTypeConstantGenerator.generate(classBuilder);
 
     MethodSpec.Builder initAsyncBuilder = getInitAsyncContents();

diff --git a/.../java/com/datastax/oss/driver/internal/mapper/processor/dao/DaoInsertMethodGenerator.java b/.../java/com/datastax/oss/driver/internal/mapper/processor/dao/DaoInsertMethodGenerator.java
@@ -23,11 +23,11 @@
 import com.datastax.oss.driver.internal.core.util.concurrent.CompletableFutures;
 import com.datastax.oss.driver.internal.mapper.processor.MethodGenerator;
 import com.datastax.oss.driver.internal.mapper.processor.ProcessorContext;
-import com.datastax.oss.driver.internal.mapper.processor.SkipGenerationException;
 import com.datastax.oss.driver.internal.mapper.processor.util.generation.GeneratedCodePatterns;
 import com.squareup.javapoet.ClassName;
 import com.squareup.javapoet.MethodSpec;
 import java.util.List;
+import java.util.Optional;
 import javax.lang.model.element.Element;
 import javax.lang.model.element.ElementKind;
 import javax.lang.model.element.ExecutableElement;
@@ -53,7 +53,7 @@ public DaoInsertMethodGenerator(
   }
 
   @Override
-  public MethodSpec.Builder generate() {
+  public Optional<MethodSpec> generate() {
 
     // Validate the parameters:
     // - the first one must be the entity.
@@ -65,7 +65,7 @@ public MethodSpec.Builder generate() {
               methodElement,
               "%s methods must have at least one parameter",
               Insert.class.getSimpleName());
-      throw new SkipGenerationException();
+      return Optional.empty();
     }
     VariableElement firstParameter = methodElement.getParameters().get(0);
     TypeElement entityElement = extractEntityElement(firstParameter);
@@ -76,7 +76,7 @@ public MethodSpec.Builder generate() {
               methodElement,
               "%s methods must take the entity to insert as the first parameter",
               Insert.class.getSimpleName());
-      throw new SkipGenerationException();
+      return Optional.empty();
     }
 
     // Validate the return type:
@@ -114,7 +114,7 @@ public MethodSpec.Builder generate() {
               "%s methods must return either void or the entity class "
                   + "(possibly wrapped in a CompletionStage/CompletableFuture)",
               Insert.class.getSimpleName());
-      throw new SkipGenerationException();
+      return Optional.empty();
     }
 
     // Generate the method:
@@ -169,7 +169,7 @@ public MethodSpec.Builder generate() {
             "return executeAndMapToSingleEntity(boundStatement, $L)", helperFieldName);
       }
     }
-    return insertBuilder;
+    return Optional.of(insertBuilder.build());
   }
 
   private TypeElement extractEntityElement(VariableElement parameter) {

diff --git a/...va/com/datastax/oss/driver/internal/mapper/processor/dao/DaoSetEntityMethodGenerator.java b/...va/com/datastax/oss/driver/internal/mapper/processor/dao/DaoSetEntityMethodGenerator.java
@@ -20,10 +20,10 @@
 import com.datastax.oss.driver.api.mapper.annotations.SetEntity;
 import com.datastax.oss.driver.internal.mapper.processor.MethodGenerator;
 import com.datastax.oss.driver.internal.mapper.processor.ProcessorContext;
-import com.datastax.oss.driver.internal.mapper.processor.SkipGenerationException;
 import com.datastax.oss.driver.internal.mapper.processor.util.generation.GeneratedCodePatterns;
 import com.squareup.javapoet.ClassName;
 import com.squareup.javapoet.MethodSpec;
+import java.util.Optional;
 import javax.lang.model.element.Element;
 import javax.lang.model.element.ElementKind;
 import javax.lang.model.element.ExecutableElement;
@@ -49,7 +49,7 @@ public DaoSetEntityMethodGenerator(
   }
 
   @Override
-  public MethodSpec.Builder generate() {
+  public Optional<MethodSpec> generate() {
 
     String entityParameterName = null;
     TypeElement entityElement = null;
@@ -64,7 +64,7 @@ public MethodSpec.Builder generate() {
               methodElement,
               "%s methods must have two parameters",
               SetEntity.class.getSimpleName());
-      throw new SkipGenerationException();
+      return Optional.empty();
     }
     TypeMirror targetParameterType = null;
     for (VariableElement parameterElement : methodElement.getParameters()) {
@@ -88,7 +88,7 @@ public MethodSpec.Builder generate() {
               methodElement,
               "Could not match parameters, expected a SettableByName "
                   + "and an annotated entity (in any order)");
-      throw new SkipGenerationException();
+      return Optional.empty();
     }
 
     // Validate the return type: either void or the same SettableByName as the parameter
@@ -113,19 +113,21 @@ public MethodSpec.Builder generate() {
               "Invalid return type, should be either void or the same as '%s' (%s)",
               targetParameterName,
               targetParameterType);
-      throw new SkipGenerationException();
+      return Optional.empty();
     }
 
     // Generate the method:
     String helperFieldName = enclosingClass.addEntityHelperField(ClassName.get(entityElement));
 
     // Forward to the base injector in the helper:
-    return GeneratedCodePatterns.override(methodElement)
-        .addStatement(
-            "$L$L.set($L, $L)",
-            isVoid ? "" : "return ",
-            helperFieldName,
-            entityParameterName,
-            targetParameterName);
+    return Optional.of(
+        GeneratedCodePatterns.override(methodElement)
+            .addStatement(
+                "$L$L.set($L, $L)",
+                isVoid ? "" : "return ",
+                helperFieldName,
+                entityParameterName,
+                targetParameterName)
+            .build());
   }
 }
diff --git a/.../java/com/datastax/oss/driver/internal/mapper/processor/entity/EntityHelperGenerator.java b/.../java/com/datastax/oss/driver/internal/mapper/processor/entity/EntityHelperGenerator.java
@@ -36,7 +36,6 @@
 import com.squareup.javapoet.TypeSpec;
 import java.beans.Introspector;
 import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
 import javax.lang.model.element.Modifier;
 import javax.lang.model.element.TypeElement;
@@ -87,12 +86,6 @@ public String addEntityHelperField(ClassName childEntityName) {
   @Override
   protected JavaFile.Builder getContents() {
 
-    List<MethodGenerator> methodGenerators =
-        ImmutableList.of(
-            new EntityHelperSetMethodGenerator(entityDefinition, this, context),
-            new EntityHelperGetMethodGenerator(entityDefinition, this, context),
-            new EntityHelperInsertMethodGenerator(entityDefinition, this, context));
-
     TypeSpec.Builder classContents =
         TypeSpec.classBuilder(helperName)
             .addJavadoc(JAVADOC_GENERATED_WARNING)
@@ -111,16 +104,20 @@ protected JavaFile.Builder getContents() {
                         "$T.fromCql($S)", CqlIdentifier.class, entityDefinition.getCqlName())
                     .build());
 
+    for (MethodGenerator methodGenerator :
+        ImmutableList.of(
+            new EntityHelperSetMethodGenerator(entityDefinition, this, context),
+            new EntityHelperGetMethodGenerator(entityDefinition, this, context),
+            new EntityHelperInsertMethodGenerator(entityDefinition, this, context))) {
+      methodGenerator.generate().ifPresent(classContents::addMethod);
+    }
+
     MethodSpec.Builder constructorContents =
         MethodSpec.constructorBuilder().addModifiers(Modifier.PUBLIC);
 
     GeneratedCodePatterns.addFinalFieldAndConstructorArgument(
         ClassName.get(MapperContext.class), "context", classContents, constructorContents);
 
-    for (MethodGenerator methodGenerator : methodGenerators) {
-      classContents.addMethod(methodGenerator.generate().build());
-    }
-
     genericTypeConstantGenerator.generate(classContents);
 
     for (Map.Entry<ClassName, String> entry : childHelpers.entrySet()) {

diff --git a/.../datastax/oss/driver/internal/mapper/processor/entity/EntityHelperGetMethodGenerator.java b/.../datastax/oss/driver/internal/mapper/processor/entity/EntityHelperGetMethodGenerator.java
@@ -32,6 +32,7 @@
 import com.squareup.javapoet.ParameterizedTypeName;
 import com.squareup.javapoet.TypeName;
 import java.util.Map;
+import java.util.Optional;
 import javax.lang.model.element.Modifier;
 
 public class EntityHelperGetMethodGenerator implements MethodGenerator {
@@ -48,7 +49,7 @@ public EntityHelperGetMethodGenerator(
   }
 
   @Override
-  public MethodSpec.Builder generate() {
+  public Optional<MethodSpec> generate() {
     MethodSpec.Builder getBuilder =
         MethodSpec.methodBuilder("get")
             .addAnnotation(Override.class)
@@ -136,7 +137,7 @@ public MethodSpec.Builder generate() {
       }
     }
     getBuilder.addStatement("return returnValue");
-    return getBuilder;
+    return Optional.of(getBuilder.build());
   }
 
   /**

diff --git a/...tastax/oss/driver/internal/mapper/processor/entity/EntityHelperInsertMethodGenerator.java b/...tastax/oss/driver/internal/mapper/processor/entity/EntityHelperInsertMethodGenerator.java
@@ -22,6 +22,7 @@
 import com.datastax.oss.driver.internal.mapper.processor.MethodGenerator;
 import com.datastax.oss.driver.internal.mapper.processor.ProcessorContext;
 import com.squareup.javapoet.MethodSpec;
+import java.util.Optional;
 import javax.lang.model.element.Modifier;
 
 public class EntityHelperInsertMethodGenerator implements MethodGenerator {
@@ -36,7 +37,7 @@ public EntityHelperInsertMethodGenerator(
   }
 
   @Override
-  public MethodSpec.Builder generate() {
+  public Optional<MethodSpec> generate() {
     MethodSpec.Builder insertBuilder =
         MethodSpec.methodBuilder("insert")
             .addAnnotation(Override.class)
@@ -60,6 +61,6 @@ public MethodSpec.Builder generate() {
           "\n.value($1S, $2T.bindMarker($1S))", property.getCqlName(), QueryBuilder.class);
     }
     insertBuilder.addCode("$];\n");
-    return insertBuilder;
+    return Optional.of(insertBuilder.build());
   }
 }