#200 Simplifying definition of conversions

processor/src/main/java/org/mapstruct/ap/conversion/BigDecimalToBigIntegerConversion.java

@@ -35,13 +35,13 @@ import static org.mapstruct.ap.util.Collections.asSet;
 public class BigDecimalToBigIntegerConversion extends SimpleConversion {
 
     @Override
-    public ConversionExpression getToExpression(ConversionContext conversionContext) {
+    public String getToExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( "", ".toBigInteger()" );
+        return "<SOURCE>.toBigInteger()";
     }
 
     @Override
-    public ConversionExpression getFromExpression(ConversionContext conversionContext) {
+    public String getFromExpression(ConversionContext conversionContext) {
-        return new ConversionExpression("new BigDecimal( ", " )");
+        return "new BigDecimal( <SOURCE> )";
     }
 
     @Override

processor/src/main/java/org/mapstruct/ap/conversion/BigDecimalToPrimitiveConversion.java

@@ -44,13 +44,13 @@ public class BigDecimalToPrimitiveConversion extends SimpleConversion {
     }
 
     @Override
-    public ConversionExpression getToExpression(ConversionContext conversionContext) {
+    public String getToExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( "", "." + targetType.getName() + "Value()" );
+        return "<SOURCE>." + targetType.getName() + "Value()";
     }
 
     @Override
-    public ConversionExpression getFromExpression(ConversionContext conversionContext) {
+    public String getFromExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( "BigDecimal.valueOf( ", " )" );
+        return "BigDecimal.valueOf( <SOURCE> )";
     }
 
     @Override

processor/src/main/java/org/mapstruct/ap/conversion/BigDecimalToStringConversion.java

@@ -34,13 +34,13 @@ import static org.mapstruct.ap.util.Collections.asSet;
 public class BigDecimalToStringConversion extends SimpleConversion {
 
     @Override
-    public ConversionExpression getToExpression(ConversionContext conversionContext) {
+    public String getToExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( "", ".toString()" );
+        return "<SOURCE>.toString()";
     }
 
     @Override
-    public ConversionExpression getFromExpression(ConversionContext conversionContext) {
+    public String getFromExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( "new BigDecimal( ", " )" );
+        return "new BigDecimal( <SOURCE> )";
     }
 
     @Override

processor/src/main/java/org/mapstruct/ap/conversion/BigDecimalToWrapperConversion.java

@@ -45,13 +45,13 @@ public class BigDecimalToWrapperConversion extends SimpleConversion {
     }
 
     @Override
-    public ConversionExpression getToExpression(ConversionContext conversionContext) {
+    public String getToExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( "", "." + targetType.getName() + "Value()" );
+        return "<SOURCE>." + targetType.getName() + "Value()";
     }
 
     @Override
-    public ConversionExpression getFromExpression(ConversionContext conversionContext) {
+    public String getFromExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( "BigDecimal.valueOf( ",  " )" );
+        return "BigDecimal.valueOf( <SOURCE> )";
     }
 
     @Override

processor/src/main/java/org/mapstruct/ap/conversion/BigIntegerToPrimitiveConversion.java

@@ -44,17 +44,17 @@ public class BigIntegerToPrimitiveConversion extends SimpleConversion {
     }
 
     @Override
-    public ConversionExpression getToExpression(ConversionContext conversionContext) {
+    public String getToExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( "", "." + targetType.getName() + "Value()" );
+        return "<SOURCE>." + targetType.getName() + "Value()";
     }
 
     @Override
-    public ConversionExpression getFromExpression(ConversionContext conversionContext) {
+    public String getFromExpression(ConversionContext conversionContext) {
         String castString = "";
         if ( targetType == float.class || targetType == double.class ) {
             castString = "(long) ";
         }
-        return new ConversionExpression( "BigInteger.valueOf( " + castString, " )" );
+        return "BigInteger.valueOf( " + castString + "<SOURCE> )";
     }
 
     @Override

processor/src/main/java/org/mapstruct/ap/conversion/BigIntegerToStringConversion.java

@@ -34,13 +34,13 @@ import static org.mapstruct.ap.util.Collections.asSet;
 public class BigIntegerToStringConversion extends SimpleConversion {
 
     @Override
-    public ConversionExpression getToExpression(ConversionContext conversionContext) {
+    public String getToExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( "", ".toString()" );
+        return "<SOURCE>.toString()";
     }
 
     @Override
-    public ConversionExpression getFromExpression(ConversionContext conversionContext) {
+    public String getFromExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( "new BigInteger( ", " )" );
+        return "new BigInteger( <SOURCE> )";
     }
 
     @Override

processor/src/main/java/org/mapstruct/ap/conversion/BigIntegerToWrapperConversion.java

@@ -45,19 +45,18 @@ public class BigIntegerToWrapperConversion extends SimpleConversion {
     }
 
     @Override
-    public ConversionExpression getToExpression(ConversionContext conversionContext) {
+    public String getToExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( "", "." + targetType.getName() + "Value()" );
+        return "<SOURCE>." + targetType.getName() + "Value()";
     }
 
     @Override
-    public ConversionExpression getFromExpression(ConversionContext conversionContext) {
+    public String getFromExpression(ConversionContext conversionContext) {
-
         String toLongValueStr = "";
         if ( targetType == float.class || targetType == double.class ) {
             toLongValueStr = ".longValue()";
         }
 
-        return new ConversionExpression( "BigInteger.valueOf( ", toLongValueStr + " )" );
+        return "BigInteger.valueOf( <SOURCE>" + toLongValueStr + " )";
     }
 
     @Override

processor/src/main/java/org/mapstruct/ap/conversion/CharToStringConversion.java

@@ -28,12 +28,12 @@ import org.mapstruct.ap.model.common.ConversionContext;
 public class CharToStringConversion extends SimpleConversion {
 
     @Override
-    public ConversionExpression getToExpression(ConversionContext conversionContext) {
+    public String getToExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( "String.valueOf( ", " )" );
+        return "String.valueOf( <SOURCE> )";
     }
 
     @Override
-    public ConversionExpression getFromExpression(ConversionContext conversionContext) {
+    public String getFromExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( "", ".charAt( 0 )" );
+        return "<SOURCE>.charAt( 0 )";
     }
 }

processor/src/main/java/org/mapstruct/ap/conversion/CharWrapperToStringConversion.java

@@ -28,12 +28,12 @@ import org.mapstruct.ap.model.common.ConversionContext;
 public class CharWrapperToStringConversion extends SimpleConversion {
 
     @Override
-    public ConversionExpression getToExpression(ConversionContext conversionContext) {
+    public String getToExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( "", ".toString()" );
+        return "<SOURCE>.toString()";
     }
 
     @Override
-    public ConversionExpression getFromExpression(ConversionContext conversionContext) {
+    public String getFromExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( "", ".charAt( 0 )" );
+        return "<SOURCE>.charAt( 0 )";
     }
 }

processor/src/main/java/org/mapstruct/ap/conversion/ConversionExpression.java

@@ -1,56 +0,0 @@
-/**
- *  Copyright 2012-2014 Gunnar Morling (http://www.gunnarmorling.de/)
- *  and/or other contributors as indicated by the @authors tag. See the
- *  copyright.txt file in the distribution for a full listing of all
- *  contributors.
- *
- *  Licensed 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.mapstruct.ap.conversion;
-
-/**
- *
- * @author Sjaak Derksen
- */
-public class ConversionExpression {
-
-    private final String openExpression;
-    private final String closeExpression;
-    private String expression;
-
-    public static ConversionExpression empty() {
-        return new ConversionExpression( "", "" );
-    }
-
-    public ConversionExpression( String openExpression, String closeExpression ) {
-        this.openExpression = openExpression;
-        this.closeExpression = closeExpression;
-    }
-
-    public String getOpenExpression() {
-        return openExpression;
-    }
-
-    public String getCloseExpression() {
-        return closeExpression;
-    }
-
-    public String getExpression() {
-        return expression;
-    }
-
-    public void setExpression( String expression ) {
-        this.expression = expression;
-    }
-
-}

processor/src/main/java/org/mapstruct/ap/conversion/DateToStringConversion.java

@@ -22,13 +22,14 @@ import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.Collections;
 import java.util.Date;
+
 import org.mapstruct.ap.model.Assignment;
 import org.mapstruct.ap.model.assignment.AssignmentFactory;
 import org.mapstruct.ap.model.common.ConversionContext;
 import org.mapstruct.ap.model.common.Type;
 
-import static org.mapstruct.ap.util.Collections.asSet;
 import static java.util.Arrays.asList;
+import static org.mapstruct.ap.util.Collections.asSet;
 
 /**
  * Conversion between {@link String} and {@link Date}.
@@ -42,9 +43,8 @@ public class DateToStringConversion implements ConversionProvider {
         return AssignmentFactory.createTypeConversion(
             asSet( conversionContext.getTypeFactory().getType( SimpleDateFormat.class ) ),
             Collections.<Type>emptyList(),
-            getOpenExpression( conversionContext, "format" ),
+            getConversionExpression( conversionContext, "format" )
-            getCloseExpression() );
+        );
-
     }
 
     @Override
@@ -52,12 +52,11 @@ public class DateToStringConversion implements ConversionProvider {
         return AssignmentFactory.createTypeConversion(
             asSet( conversionContext.getTypeFactory().getType( SimpleDateFormat.class ) ),
             asList( conversionContext.getTypeFactory().getType( ParseException.class ) ),
-            getOpenExpression( conversionContext, "parse" ),
+            getConversionExpression( conversionContext, "parse" )
-            getCloseExpression()
         );
     }
 
-    private String getOpenExpression(ConversionContext conversionContext, String method) {
+    private String getConversionExpression(ConversionContext conversionContext, String method) {
         StringBuilder conversionString = new StringBuilder( "new SimpleDateFormat(" );
 
         if ( conversionContext.getDateFormat() != null ) {
@@ -68,12 +67,8 @@ public class DateToStringConversion implements ConversionProvider {
 
         conversionString.append( ")." );
         conversionString.append( method );
-        conversionString.append( "( " );
+        conversionString.append( "( <SOURCE> )" );
 
         return conversionString.toString();
     }
-
-    private String getCloseExpression() {
-       return " )";
-    }
 }

processor/src/main/java/org/mapstruct/ap/conversion/EnumStringConversion.java

@@ -33,15 +33,13 @@ import static org.mapstruct.ap.util.Collections.asSet;
 public class EnumStringConversion extends SimpleConversion {
 
     @Override
-    public ConversionExpression getToExpression(ConversionContext conversionContext) {
+    public String getToExpression(ConversionContext conversionContext) {
-        return new ConversionExpression("", ".toString()" );
+        return "<SOURCE>.toString()";
     }
 
     @Override
-    public ConversionExpression getFromExpression(ConversionContext conversionContext) {
+    public String getFromExpression(ConversionContext conversionContext) {
-        return new ConversionExpression(
+        return "Enum.valueOf( " + conversionContext.getTargetType().getName() + ".class, <SOURCE> )";
-                "Enum.valueOf( " + conversionContext.getTargetType().getName() + ".class, ",
-                " )" );
     }
 
     @Override

processor/src/main/java/org/mapstruct/ap/conversion/PrimitiveToPrimitiveConversion.java

@@ -38,12 +38,12 @@ public class PrimitiveToPrimitiveConversion extends SimpleConversion {
     }
 
     @Override
-    public ConversionExpression getToExpression(ConversionContext conversionContext) {
+    public String getToExpression(ConversionContext conversionContext) {
-        return ConversionExpression.empty();
+        return "<SOURCE>";
     }
 
     @Override
-    public ConversionExpression getFromExpression(ConversionContext conversionContext) {
+    public String getFromExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( "(" + sourceType + ") ", "" );
+        return "(" + sourceType + ")<SOURCE>";
     }
 }

processor/src/main/java/org/mapstruct/ap/conversion/PrimitiveToStringConversion.java

@@ -43,13 +43,13 @@ public class PrimitiveToStringConversion extends SimpleConversion {
     }
 
     @Override
-    public ConversionExpression getToExpression(ConversionContext conversionContext) {
+    public String getToExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( "String.valueOf( ", " )" );
+        return "String.valueOf( <SOURCE> )";
     }
 
     @Override
-    public ConversionExpression getFromExpression(ConversionContext conversionContext) {
+    public String getFromExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( wrapperType.getSimpleName() + ".parse" +
+        return wrapperType.getSimpleName() + ".parse" +
-                Strings.capitalize( sourceType.getSimpleName() ) + "( ",  " )" );
+            Strings.capitalize( sourceType.getSimpleName() ) + "( <SOURCE> )";
     }
 }

processor/src/main/java/org/mapstruct/ap/conversion/PrimitiveToWrapperConversion.java

@@ -45,17 +45,17 @@ public class PrimitiveToWrapperConversion extends SimpleConversion {
     }
 
     @Override
-    public ConversionExpression getToExpression(ConversionContext conversionContext) {
+    public String getToExpression(ConversionContext conversionContext) {
         if ( sourceType == targetType ) {
-            return ConversionExpression.empty();
+            return "<SOURCE>";
         }
         else {
-            return new ConversionExpression( "(" + targetType.getName() + ") ", "" );
+            return "(" + targetType.getName() + ")<SOURCE>";
         }
     }
 
     @Override
-    public ConversionExpression getFromExpression(ConversionContext conversionContext) {
+    public String getFromExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( "", "." + sourceType.getName() + "Value()" );
+        return "<SOURCE>." + sourceType.getName() + "Value()";
     }
 }

processor/src/main/java/org/mapstruct/ap/conversion/SimpleConversion.java

@@ -20,10 +20,11 @@ package org.mapstruct.ap.conversion;
 
 import java.util.Collections;
 import java.util.Set;
+
 import org.mapstruct.ap.model.Assignment;
 import org.mapstruct.ap.model.assignment.AssignmentFactory;
-import org.mapstruct.ap.model.common.ConversionContext;
 import org.mapstruct.ap.model.assignment.TypeConversion;
+import org.mapstruct.ap.model.common.ConversionContext;
 import org.mapstruct.ap.model.common.Type;
 
 /**
@@ -35,48 +36,50 @@ public abstract class SimpleConversion implements ConversionProvider {
 
     @Override
     public Assignment to(ConversionContext conversionContext) {
-        ConversionExpression toExpressions = getToExpression( conversionContext );
+        String toExpression = getToExpression( conversionContext );
         return AssignmentFactory.createTypeConversion(
-                getToConversionImportTypes( conversionContext ),
+            getToConversionImportTypes( conversionContext ),
-                Collections.<Type>emptyList(),
+            Collections.<Type>emptyList(),
-                toExpressions.getOpenExpression(),
+            toExpression
-                toExpressions.getCloseExpression() );
+        );
     }
 
     @Override
     public Assignment from(ConversionContext conversionContext) {
-        ConversionExpression fromExpressions = getFromExpression( conversionContext );
+        String fromExpression = getFromExpression( conversionContext );
         return AssignmentFactory.createTypeConversion(
-                getFromConversionImportTypes( conversionContext ),
+            getFromConversionImportTypes( conversionContext ),
-                Collections.<Type>emptyList(),
+            Collections.<Type>emptyList(),
-                fromExpressions.getOpenExpression(),
+            fromExpression
-                fromExpressions.getCloseExpression() );
+        );
     }
 
     /**
-     * Returns the conversion string (opening and closing part) from source to target.
+     * Returns the conversion string from source to target. The placeholder {@code <SOURCE>} can be used to represent a
+     * reference to the source value.
+     *
+     * @param conversionContext A context providing optional information required for creating the conversion.
+     *
+     * @return The conversion string from source to target
+     */
+    protected abstract String getToExpression(ConversionContext conversionContext);
+
+    /**
+     * Returns the conversion string from target to source. The placeholder {@code <SOURCE>} can be used to represent a
+     * reference to the target value.
      *
      * @param conversionContext ConversionContext providing optional information required for creating the conversion.
      *
-     * @return The open- and close parts of the conversion expression
+     * @return The conversion string from target to source
      */
-    protected abstract ConversionExpression getToExpression( ConversionContext conversionContext );
+    protected abstract String getFromExpression(ConversionContext conversionContext);
-
-    /**
-     * Creates the conversion string (opening and closing part) from target to source.
-     *
-     * @param conversionContext ConversionContext providing optional information required for creating
-     * the conversion.
-     *
-     * @return The open- and close parts of the conversion expression
-     */
-    protected abstract ConversionExpression getFromExpression( ConversionContext conversionContext );
 
     /**
      * Returns a set with imported types of the "from" conversion. Defaults to an empty set; can be overridden in
      * sub-classes to return the required types.
      *
      * @param conversionContext the conversion context
+     *
      * @return conversion types required in the "from" conversion
      */
     protected Set<Type> getFromConversionImportTypes(ConversionContext conversionContext) {
@@ -88,10 +91,10 @@ public abstract class SimpleConversion implements ConversionProvider {
      * sub-classes to return the required types.
      *
      * @param conversionContext the conversion context
+     *
      * @return conversion types required in the "to" conversion
      */
     protected Set<Type> getToConversionImportTypes(ConversionContext conversionContext) {
         return Collections.<Type>emptySet();
     }
-
 }

processor/src/main/java/org/mapstruct/ap/conversion/WrapperToStringConversion.java

@@ -42,13 +42,13 @@ public class WrapperToStringConversion extends SimpleConversion {
     }
 
     @Override
-    public ConversionExpression getToExpression(ConversionContext conversionContext) {
+    public String getToExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( "String.valueOf( ", " )" );
+        return "String.valueOf( <SOURCE> )";
     }
 
     @Override
-    public ConversionExpression getFromExpression(ConversionContext conversionContext) {
+    public String getFromExpression(ConversionContext conversionContext) {
-        return new ConversionExpression( sourceType.getSimpleName() + ".parse" +
+        return sourceType.getSimpleName() + ".parse" +
-                Strings.capitalize( primitiveType.getSimpleName() ) + "( ", " )" );
+            Strings.capitalize( primitiveType.getSimpleName() ) + "( <SOURCE> )";
     }
 }

processor/src/main/java/org/mapstruct/ap/conversion/WrapperToWrapperConversion.java

@@ -44,22 +44,22 @@ public class WrapperToWrapperConversion extends SimpleConversion {
     }
 
     @Override
-    public ConversionExpression getToExpression(ConversionContext conversionContext) {
+    public String getToExpression(ConversionContext conversionContext) {
         if ( sourceType == targetType ) {
-            return ConversionExpression.empty();
+            return "<SOURCE>";
         }
         else {
-            return new ConversionExpression( "", "." + targetType.getName() + "Value()" );
+            return "<SOURCE>." + targetType.getName() + "Value()";
         }
     }
 
     @Override
-    public ConversionExpression getFromExpression(ConversionContext conversionContext) {
+    public String getFromExpression(ConversionContext conversionContext) {
         if ( sourceType == targetType ) {
-            return ConversionExpression.empty();
+            return "<SOURCE>";
         }
         else {
-            return new ConversionExpression( "",  "." + sourceType.getName() + "Value()" );
+            return "<SOURCE>." + sourceType.getName() + "Value()";
         }
     }
 }

processor/src/main/java/org/mapstruct/ap/model/assignment/AssignmentFactory.java

@@ -20,6 +20,7 @@ package org.mapstruct.ap.model.assignment;
 
 import java.util.List;
 import java.util.Set;
+
 import org.mapstruct.ap.model.Assignment;
 import org.mapstruct.ap.model.FactoryMethod;
 import org.mapstruct.ap.model.MapperReference;
@@ -38,28 +39,25 @@ public class AssignmentFactory {
     private AssignmentFactory() {
     }
 
-    public static Assignment createTypeConversion( Set<Type> importTypes,
+    public static Assignment createTypeConversion(Set<Type> importTypes, List<Type> exceptionTypes, String expression) {
-            List<Type> exceptionTypes,
+        return new TypeConversion( importTypes, exceptionTypes, expression );
-            String openExpression,
-            String closeExpression ) {
-        return new TypeConversion( importTypes, exceptionTypes, openExpression, closeExpression );
     }
 
     public static FactoryMethod createFactory(SourceMethod method, MapperReference declaringMapper) {
-        return  new MethodReference( method, declaringMapper, null );
+        return new MethodReference( method, declaringMapper, null );
     }
 
     public static Assignment createMethodReference(SourceMethod method, MapperReference declaringMapper,
-            Type targetType) {
+                                                   Type targetType) {
-        return new  MethodReference(method, declaringMapper, targetType);
+        return new MethodReference( method, declaringMapper, targetType );
     }
 
-    public static Assignment createMethodReference( BuiltInMethod method, ConversionContext contextParam ) {
+    public static Assignment createMethodReference(BuiltInMethod method, ConversionContext contextParam) {
         return new MethodReference( method, contextParam );
     }
 
-    public static Simple createSimple( String sourceRef ) {
+    public static Simple createSimple(String sourceRef) {
-        return new Simple(sourceRef );
+        return new Simple( sourceRef );
     }
 
 }

processor/src/main/java/org/mapstruct/ap/model/assignment/TypeConversion.java

@@ -21,8 +21,8 @@ package org.mapstruct.ap.model.assignment;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
-import org.mapstruct.ap.model.Assignment;
 
+import org.mapstruct.ap.model.Assignment;
 import org.mapstruct.ap.model.common.ModelElement;
 import org.mapstruct.ap.model.common.Type;
 
@@ -33,6 +33,7 @@ import org.mapstruct.ap.model.common.Type;
  */
 public class TypeConversion extends ModelElement implements Assignment {
 
+    private static final String SOURCE_REFERENCE_PATTERN = "<SOURCE>";
 
     private final Set<Type> importTypes;
     private final List<Type> exceptionTypes;
@@ -46,16 +47,16 @@ public class TypeConversion extends ModelElement implements Assignment {
      */
     private Assignment assignment;
 
-
     TypeConversion( Set<Type> importTypes,
             List<Type> exceptionTypes,
-            String openExpression,
+            String expression ) {
-            String closeExpression ) {
         this.importTypes = new HashSet<Type>( importTypes );
         this.importTypes.addAll( exceptionTypes );
         this.exceptionTypes = exceptionTypes;
-        this.openExpression = openExpression;
+
-        this.closeExpression = closeExpression;
+        int patternIndex = expression.indexOf( SOURCE_REFERENCE_PATTERN );
+        this.openExpression = expression.substring( 0, patternIndex );
+        this.closeExpression = expression.substring( patternIndex + 8 );
     }
 
     @Override