mapstruct · eforest · Apr 15, 2021
diff --git a/...rc/main/java/org/mapstruct/ap/internal/conversion/AbstractJavaTimeToStringConversion.java b/...rc/main/java/org/mapstruct/ap/internal/conversion/AbstractJavaTimeToStringConversion.java
@@ -6,9 +6,11 @@
 package org.mapstruct.ap.internal.conversion;
 
 import java.time.format.DateTimeFormatter;
+import java.util.List;
 import java.util.Set;
 
 import org.mapstruct.ap.internal.model.common.ConversionContext;
+import org.mapstruct.ap.internal.model.common.FieldReference;
 import org.mapstruct.ap.internal.model.common.Type;
 import org.mapstruct.ap.internal.util.Collections;
 import org.mapstruct.ap.internal.util.Strings;
@@ -38,10 +40,8 @@ protected String getToExpression(ConversionContext conversionContext) {
     }
 
     private String dateTimeFormatter(ConversionContext conversionContext) {
-        if ( !Strings.isEmpty( conversionContext.getDateFormat() ) ) {
-            return ConversionUtils.dateTimeFormatter( conversionContext )
-                + ".ofPattern( \"" + conversionContext.getDateFormat()
-                + "\" )";
+        if ( Strings.isNotEmpty( conversionContext.getDateFormat() ) ) {
+            return GetDateTimeFormatterField.getDateTimeFormatterFieldName( conversionContext.getDateFormat() );
         }
         else {
             return ConversionUtils.dateTimeFormatter( conversionContext ) + "." + defaultFormatterSuffix();
@@ -88,4 +88,15 @@ protected Set<Type> getFromConversionImportTypes(ConversionContext conversionCon
         return Collections.asSet( conversionContext.getTargetType() );
     }
 
+    @Override
+    public List<FieldReference> getRequiredHelperFields(ConversionContext conversionContext) {
+        if ( Strings.isNotEmpty( conversionContext.getDateFormat() ) ) {
+            return java.util.Collections.singletonList(
+                new GetDateTimeFormatterField(
+                    conversionContext.getTypeFactory(),
+                    conversionContext.getDateFormat() ) );
+        }
+
+        return super.getRequiredHelperFields( conversionContext );
+    }
 }
diff --git a/processor/src/main/java/org/mapstruct/ap/internal/conversion/ConversionProvider.java b/processor/src/main/java/org/mapstruct/ap/internal/conversion/ConversionProvider.java
@@ -5,11 +5,14 @@
  */
 package org.mapstruct.ap.internal.conversion;
 
+import java.util.Collections;
 import java.util.List;
+
+import org.mapstruct.ap.internal.model.HelperMethod;
 import org.mapstruct.ap.internal.model.TypeConversion;
 import org.mapstruct.ap.internal.model.common.Assignment;
 import org.mapstruct.ap.internal.model.common.ConversionContext;
-import org.mapstruct.ap.internal.model.HelperMethod;
+import org.mapstruct.ap.internal.model.common.FieldReference;
 
 /**
  * Implementations create inline {@link TypeConversion}s such as
@@ -49,4 +52,13 @@ public interface ConversionProvider {
      */
     List<HelperMethod> getRequiredHelperMethods(ConversionContext conversionContext);
 
+    /**
+     * @param conversionContext ConversionContext providing optional information required for creating the conversion.
+     *
+     * @return any fields when required.
+     */
+    default List<FieldReference> getRequiredHelperFields(ConversionContext conversionContext) {
+        return Collections.emptyList();
+    }
+
 }
diff --git a/processor/src/main/java/org/mapstruct/ap/internal/conversion/GetDateTimeFormatterField.java b/processor/src/main/java/org/mapstruct/ap/internal/conversion/GetDateTimeFormatterField.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright MapStruct Authors.
+ *
+ * Licensed under the Apache License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
+ */
+package org.mapstruct.ap.internal.conversion;
+
+import java.time.format.DateTimeFormatter;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.mapstruct.ap.internal.model.common.FieldReference;
+import org.mapstruct.ap.internal.model.common.FinalField;
+import org.mapstruct.ap.internal.model.common.TypeFactory;
+
+public class GetDateTimeFormatterField extends FinalField implements FieldReference {
+
+    private final String dateFormat;
+
+    public GetDateTimeFormatterField(TypeFactory typeFactory, String dateFormat) {
+        super(  typeFactory.getType( DateTimeFormatter.class ), getDateTimeFormatterFieldName( dateFormat ) );
+        this.dateFormat = dateFormat;
+    }
+
+    @Override
+    public Map<String, Object> getTemplateParameter() {
+        Map<String, Object> parameter = new HashMap<>();
+        parameter.put( "dateFormat", dateFormat );
+        return parameter;
+    }
+
+    public static String getDateTimeFormatterFieldName(String dateFormat) {
+        StringBuilder sb = new StringBuilder();
+        sb.append( "dateTimeFormatter_" );
+
+        dateFormat.codePoints().forEach( cp -> {
+            if ( Character.isJavaIdentifierPart( cp ) ) {
+                // safe to character to method name as is
+                sb.append( Character.toChars( cp ) );
+            }
+            else {
+                // could not be used in method name
+                sb.append( "_" );
+            }
+        } );
+
+        sb.append( "_" );
+
+        int hashCode = dateFormat.hashCode();
+        sb.append( hashCode < 0 ? "0" : "1" );
+        sb.append( Math.abs( hashCode ) );
+
+        return sb.toString();
+    }
+}
diff --git a/processor/src/main/java/org/mapstruct/ap/internal/model/HelperMethod.java b/processor/src/main/java/org/mapstruct/ap/internal/model/HelperMethod.java
@@ -9,11 +9,15 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
+
 import javax.lang.model.element.ExecutableElement;
 
 import org.mapstruct.ap.internal.model.common.Accessibility;
+import org.mapstruct.ap.internal.model.common.ConstructorFragment;
 import org.mapstruct.ap.internal.model.common.ConversionContext;
+import org.mapstruct.ap.internal.model.common.FieldReference;
 import org.mapstruct.ap.internal.model.common.Parameter;
 import org.mapstruct.ap.internal.model.common.Type;
 import org.mapstruct.ap.internal.model.source.Method;
@@ -216,7 +220,7 @@ public List<String> getParameterNames() {
 
     @Override
     public boolean overridesMethod() {
-        return  false;
+        return false;
     }
 
     @Override
@@ -248,4 +252,19 @@ public boolean isLifecycleCallbackMethod() {
     public boolean isUpdateMethod() {
         return false; // irrelevant
     }
+
+    public FieldReference getFieldReference() {
+        return null;
+    }
+
+    public ConstructorFragment getConstructorFragment() {
+        return null;
+    }
+
+    /**
+     * @return additional template parameters
+     */
+    public Map<String, Object> getTemplateParameter() {
+        return null;
+    }
 }
diff --git a/processor/src/main/java/org/mapstruct/ap/internal/model/MappingBuilderContext.java b/processor/src/main/java/org/mapstruct/ap/internal/model/MappingBuilderContext.java
@@ -15,8 +15,6 @@
 
 import javax.lang.model.element.AnnotationMirror;
 import javax.lang.model.element.TypeElement;
-import org.mapstruct.ap.internal.util.ElementUtils;
-import org.mapstruct.ap.internal.util.TypeUtils;
 
 import org.mapstruct.ap.internal.model.common.Assignment;
 import org.mapstruct.ap.internal.model.common.FormattingParameters;
@@ -28,8 +26,10 @@
 import org.mapstruct.ap.internal.model.source.selector.SelectionCriteria;
 import org.mapstruct.ap.internal.option.Options;
 import org.mapstruct.ap.internal.util.AccessorNamingUtils;
+import org.mapstruct.ap.internal.util.ElementUtils;
 import org.mapstruct.ap.internal.util.FormattingMessager;
 import org.mapstruct.ap.internal.util.Services;
+import org.mapstruct.ap.internal.util.TypeUtils;
 import org.mapstruct.ap.spi.EnumMappingStrategy;
 import org.mapstruct.ap.spi.EnumTransformationStrategy;
 import org.mapstruct.ap.spi.MappingExclusionProvider;
@@ -101,6 +101,8 @@ Assignment getTargetAssignment(Method mappingMethod, ForgedMethodHistory descrip
                                        Supplier<Assignment> forger);
 
         Set<SupportingMappingMethod> getUsedSupportedMappings();
+
+        Set<Field> getUsedSupportedFields();
     }
 
     private final TypeFactory typeFactory;
@@ -241,6 +243,10 @@ public Set<SupportingMappingMethod> getUsedSupportedMappings() {
         return mappingResolver.getUsedSupportedMappings();
     }
 
+    public Set<Field> getUsedSupportedFields() {
+        return mappingResolver.getUsedSupportedFields();
+    }
+
     /**
      * @param sourceType from which an automatic sub-mapping needs to be generated
      * @param targetType to which an automatic sub-mapping needs to be generated

diff --git a/processor/src/main/java/org/mapstruct/ap/internal/model/SupportingConstructorFragment.java b/processor/src/main/java/org/mapstruct/ap/internal/model/SupportingConstructorFragment.java
@@ -9,9 +9,9 @@
 import java.util.Objects;
 import java.util.Set;
 
+import org.mapstruct.ap.internal.model.common.ConstructorFragment;
 import org.mapstruct.ap.internal.model.common.ModelElement;
 import org.mapstruct.ap.internal.model.common.Type;
-import org.mapstruct.ap.internal.model.source.builtin.BuiltInConstructorFragment;
 
 /**
  * A mapper instance field, initialized as null
@@ -20,13 +20,15 @@
  */
 public class SupportingConstructorFragment extends ModelElement {
 
+    private final String variableName;
     private final String templateName;
     private final SupportingMappingMethod definingMethod;
 
     public SupportingConstructorFragment(SupportingMappingMethod definingMethod,
-                                         BuiltInConstructorFragment constructorFragment) {
+                                         ConstructorFragment constructorFragment, String variableName) {
         this.templateName = getTemplateNameForClass( constructorFragment.getClass() );
         this.definingMethod = definingMethod;
+        this.variableName = variableName;
     }
 
     @Override
@@ -43,10 +45,15 @@ public SupportingMappingMethod getDefiningMethod() {
         return definingMethod;
     }
 
+    public String getVariableName() {
+        return variableName;
+    }
+
     @Override
     public int hashCode() {
         final int prime = 31;
         int result = 1;
+        result = prime * result + ( ( variableName == null ) ? 0 : variableName.hashCode() );
         result = prime * result + ( ( templateName == null ) ? 0 : templateName.hashCode() );
         return result;
     }
@@ -64,10 +71,12 @@ public boolean equals(Object obj) {
         }
         SupportingConstructorFragment other = (SupportingConstructorFragment) obj;
 
+        if ( !Objects.equals( variableName, other.variableName ) ) {
+            return false;
+        }
         if ( !Objects.equals( templateName, other.templateName ) ) {
             return false;
         }
-
         return true;
     }
 
@@ -80,4 +89,17 @@ public static void addAllFragmentsIn(Set<SupportingMappingMethod> supportingMapp
             }
         }
     }
+
+    public static SupportingConstructorFragment getSafeConstructorFragment(SupportingMappingMethod method,
+                                                                           ConstructorFragment fragment,
+                                                                           Field supportingField) {
+        if ( fragment == null ) {
+            return null;
+        }
+
+        return new SupportingConstructorFragment(
+            method,
+            fragment,
+            supportingField != null ? supportingField.getVariableName() : null );
+    }
 }
diff --git a/processor/src/main/java/org/mapstruct/ap/internal/model/SupportingField.java b/processor/src/main/java/org/mapstruct/ap/internal/model/SupportingField.java
@@ -5,10 +5,11 @@
  */
 package org.mapstruct.ap.internal.model;
 
-import java.util.Objects;
+import java.util.Map;
 import java.util.Set;
 
-import org.mapstruct.ap.internal.model.source.builtin.BuiltInFieldReference;
+import org.mapstruct.ap.internal.model.common.FieldReference;
+import org.mapstruct.ap.internal.util.Strings;
 
 /**
  * supports the
@@ -18,11 +19,14 @@
 public class SupportingField extends Field {
 
     private final String templateName;
+    private final Map<String, Object> templateParameter;
+
     private final SupportingMappingMethod definingMethod;
 
-    public SupportingField(SupportingMappingMethod definingMethod, BuiltInFieldReference fieldReference, String name) {
+    public SupportingField(SupportingMappingMethod definingMethod, FieldReference fieldReference, String name) {
         super( fieldReference.getType(), name, true );
         this.templateName = getTemplateNameForClass( fieldReference.getClass() );
+        this.templateParameter = fieldReference.getTemplateParameter();
         this.definingMethod = definingMethod;
     }
 
@@ -31,36 +35,12 @@ public String getTemplateName() {
         return templateName;
     }
 
-    public SupportingMappingMethod getDefiningMethod() {
-        return definingMethod;
-    }
-
-    @Override
-    public int hashCode() {
-        final int prime = 31;
-        int result = 1;
-        result = prime * result + ( ( templateName == null ) ? 0 : templateName.hashCode() );
-        return result;
+    public Map<String, Object> getTemplateParameter() {
+        return templateParameter;
     }
 
-    @Override
-    public boolean equals(Object obj) {
-        if ( this == obj ) {
-            return true;
-        }
-        if ( obj == null ) {
-            return false;
-        }
-        if ( getClass() != obj.getClass() ) {
-            return false;
-        }
-        SupportingField other = (SupportingField) obj;
-
-        if ( !Objects.equals( templateName, other.templateName ) ) {
-            return false;
-        }
-
-        return true;
+    public SupportingMappingMethod getDefiningMethod() {
+        return definingMethod;
     }
 
     public static void addAllFieldsIn(Set<SupportingMappingMethod> supportingMappingMethods, Set<Field> targets) {
@@ -71,4 +51,21 @@ public static void addAllFieldsIn(Set<SupportingMappingMethod> supportingMapping
             }
         }
     }
+
+    public static Field getSafeField(SupportingMappingMethod method, FieldReference ref, Set<Field> existingFields) {
+        if ( ref == null ) {
+            return null;
+        }
+
+        String name = ref.getVariableName();
+        for ( Field existingField : existingFields ) {
+            if ( existingField.getVariableName().equals( ref.getVariableName() )
+                && existingField.getType().equals( ref.getType() ) ) {
+                // field already exists, use that one
+                return existingField;
+            }
+        }
+        name = Strings.getSafeVariableName( name, Field.getFieldNames( existingFields ) );
+        return new SupportingField( method, ref, name );
+    }
 }