[MPLUGIN-427] Expose generics information of parameter types in report

maven-plugin-tools-annotations/pom.xml

@@ -78,6 +78,10 @@
       <groupId>org.ow2.asm</groupId>
       <artifactId>asm</artifactId>
     </dependency>
+    <dependency>
+      <groupId>org.ow2.asm</groupId>
+      <artifactId>asm-util</artifactId>
+    </dependency>
     <!-- for HTML to plain text conversion -->
     <dependency>
       <groupId>org.jsoup</groupId>

maven-plugin-tools-annotations/src/main/java/org/apache/maven/tools/plugin/extractor/annotations/JavaAnnotationsMojoDescriptorExtractor.java

@@ -39,6 +39,7 @@
 import java.util.Set;
 import java.util.TreeMap;
 import java.util.TreeSet;
+import java.util.stream.Collectors;
 
 import com.thoughtworks.qdox.JavaProjectBuilder;
 import com.thoughtworks.qdox.library.SortedClassLibraryBuilder;
@@ -698,7 +699,13 @@ private List<MojoDescriptor> toMojoDescriptors( Map<String, MojoAnnotatedClass>
                             + property, null );
                 }
                 parameter.setExpression( StringUtils.isEmpty( property ) ? "" : "${" + property + "}" );
-                parameter.setType( parameterAnnotationContent.getClassName() );
+                StringBuilder type = new StringBuilder( parameterAnnotationContent.getClassName() );
+                if ( !parameterAnnotationContent.getTypeParameters().isEmpty() )
+                {
+                    type.append( parameterAnnotationContent.getTypeParameters().stream()
+                            .collect( Collectors.joining( ", ", "<", ">" ) ) );
+                }
+                parameter.setType( type.toString() );
                 parameter.setSince( parameterAnnotationContent.getSince() );
                 parameter.setRequired( parameterAnnotationContent.required() );
 

maven-plugin-tools-annotations/src/main/java/org/apache/maven/tools/plugin/extractor/annotations/datamodel/ParameterAnnotationContent.java

@@ -23,6 +23,7 @@
 import org.objectweb.asm.Type;
 
 import java.lang.annotation.Annotation;
+import java.util.List;
 import java.util.Objects;
 
 /**
@@ -50,16 +51,20 @@ public class ParameterAnnotationContent
 
     private String className;
 
-    public ParameterAnnotationContent( String fieldName, String className )
+    private final List<String> typeParameters;
+
+    public ParameterAnnotationContent( String fieldName, String className, List<String> typeParameters )
     {
         super( fieldName );
         this.className = className;
+        this.typeParameters = typeParameters;
     }
 
     public ParameterAnnotationContent( String fieldName, String alias, String property, String defaultValue,
-                                       Class<?> implementation, boolean required, boolean readonly, String className )
+                                       Class<?> implementation, boolean required, boolean readonly, String className,
+                                       List<String> typeParameters )
     {
-        this( fieldName, className );
+        this( fieldName, className, typeParameters );
         this.alias = alias;
         this.property = property;
         this.defaultValue = defaultValue;
@@ -177,6 +182,11 @@ public void setClassName( String className )
         this.className = className;
     }
 
+    public List<String> getTypeParameters()
+    {
+        return typeParameters;
+    }
+
     @Override
     public String toString()
     {
@@ -185,6 +195,7 @@ public String toString()
         sb.append( "ParameterAnnotationContent" );
         sb.append( "{fieldName='" ).append( getFieldName() ).append( '\'' );
         sb.append( ", className='" ).append( getClassName() ).append( '\'' );
+        sb.append( ", typeParameters='" ).append( getTypeParameters() ).append( '\'' );
         sb.append( ", name='" ).append( name ).append( '\'' );
         sb.append( ", alias='" ).append( alias ).append( '\'' );
         sb.append( ", alias='" ).append( alias ).append( '\'' );
@@ -230,6 +241,10 @@ public boolean equals( Object o )
             return false;
         }
 
+        if ( !Objects.equals( typeParameters, that.typeParameters ) )
+        {
+            return false;
+        }
         if ( !Objects.equals( alias, that.alias ) )
         {
             return false;
@@ -253,7 +268,7 @@ public boolean equals( Object o )
     @Override
     public int hashCode()
     {
-        return Objects.hash( alias, getFieldName(), property, defaultValue, required, readonly,
-                             implementationClassName );
+        return Objects.hash( alias, getFieldName(), getClassName(), typeParameters, property, defaultValue, required,
+                             readonly, implementationClassName );
     }
 }

maven-plugin-tools-annotations/src/main/java/org/apache/maven/tools/plugin/extractor/annotations/scanner/DefaultMojoAnnotationsScanner.java

@@ -302,7 +302,8 @@ protected void analyzeVisitors( MojoClassVisitor mojoClassVisitor )
             for ( MojoParameterVisitor parameterVisitor : mojoParameterVisitors )
             {
                 ParameterAnnotationContent parameterAnnotationContent =
-                    new ParameterAnnotationContent( parameterVisitor.getFieldName(), parameterVisitor.getClassName() );
+                    new ParameterAnnotationContent( parameterVisitor.getFieldName(), parameterVisitor.getClassName(),
+                                                    parameterVisitor.getTypeParameters() );
 
                 Map<String, MojoAnnotationVisitor> annotationVisitorMap = parameterVisitor.getAnnotationVisitorMap();
                 MojoAnnotationVisitor fieldAnnotationVisitor = annotationVisitorMap.get( Parameter.class.getName() );

maven-plugin-tools-annotations/src/main/java/org/apache/maven/tools/plugin/extractor/annotations/scanner/visitors/MojoClassVisitor.java

@@ -20,6 +20,8 @@
  */
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -36,6 +38,8 @@
 import org.objectweb.asm.MethodVisitor;
 import org.objectweb.asm.Opcodes;
 import org.objectweb.asm.Type;
+import org.objectweb.asm.signature.SignatureReader;
+import org.objectweb.asm.util.TraceSignatureVisitor;
 
 /**
  * Visitor for Mojo classes.
@@ -117,11 +121,49 @@ public AnnotationVisitor visitAnnotation( String desc, boolean visible )
     @Override
     public FieldVisitor visitField( int access, String name, String desc, String signature, Object value )
     {
-        MojoFieldVisitor mojoFieldVisitor = new MojoFieldVisitor( name, Type.getType( desc ).getClassName() );
+        List<String> typeParameters = extractTypeParameters( access, signature, true );
+        MojoFieldVisitor mojoFieldVisitor = new MojoFieldVisitor( name, Type.getType( desc ).getClassName(),
+                typeParameters );
         fieldVisitors.add( mojoFieldVisitor );
         return mojoFieldVisitor;
     }
 
+    /**
+     * Parses the signature according to 
+     * <a href="https://docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html#jvms-4.3.4">JVMS 4.3.4</a>
+     * and returns the type parameters.
+     * @param access
+     * @param signature
+     * @param isField
+     * @return the list of type parameters (may be empty)
+     */
+    private List<String> extractTypeParameters( int access, String signature, boolean isField )
+    {
+        if ( StringUtils.isEmpty( signature ) )
+        {
+            return Collections.emptyList();
+        }
+        TraceSignatureVisitor traceSignatureVisitor = new TraceSignatureVisitor( access );
+        SignatureReader signatureReader = new SignatureReader( signature );
+        if ( isField )
+        {
+            signatureReader.acceptType( traceSignatureVisitor );
+        }
+        else
+        {
+            signatureReader.accept( traceSignatureVisitor );
+        }
+        String declaration = traceSignatureVisitor.getDeclaration();
+        int startTypeParameters = declaration.indexOf( '<' );
+        if ( startTypeParameters == -1 )
+        {
+            return Collections.emptyList();
+        }
+        String typeParameters = declaration.substring( startTypeParameters + 1,
+                                                       declaration.lastIndexOf( '>' ) );
+        return Arrays.asList( typeParameters.split( ", " ) );
+    }
+
     @Override
     public MethodVisitor visitMethod( int access, String name, String desc, String signature, String[] exceptions )
     {
@@ -142,8 +184,9 @@ public MethodVisitor visitMethod( int access, String name, String desc, String s
         {
             String fieldName = StringUtils.lowercaseFirstLetter( name.substring( 3 ) );
             String className = type.getArgumentTypes()[0].getClassName();
+            List<String> typeParameters = extractTypeParameters( access, signature, false );
 
-            MojoMethodVisitor mojoMethodVisitor = new MojoMethodVisitor( fieldName, className );
+            MojoMethodVisitor mojoMethodVisitor = new MojoMethodVisitor( fieldName, className, typeParameters );
             methodVisitors.add( mojoMethodVisitor );
             return mojoMethodVisitor;
         }

maven-plugin-tools-annotations/src/main/java/org/apache/maven/tools/plugin/extractor/annotations/scanner/visitors/MojoFieldVisitor.java

@@ -20,6 +20,7 @@
  */
 
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import org.apache.maven.tools.plugin.extractor.annotations.scanner.MojoAnnotationsScanner;
@@ -43,11 +44,14 @@ public class MojoFieldVisitor
 
     private String className;
 
-    MojoFieldVisitor( String fieldName, String className )
+    private final List<String> typeParameters;
+
+    MojoFieldVisitor( String fieldName, String className, List<String> typeParameters )
     {
         super( Opcodes.ASM9 );
         this.fieldName = fieldName;
         this.className = className;
+        this.typeParameters = typeParameters;
     }
 
     @Override
@@ -62,6 +66,12 @@ public String getFieldName()
         return fieldName;
     }
 
+    @Override
+    public List<String> getTypeParameters()
+    {
+        return typeParameters;
+    }
+
     @Override
     public AnnotationVisitor visitAnnotation( String desc, boolean visible )
     {

maven-plugin-tools-annotations/src/main/java/org/apache/maven/tools/plugin/extractor/annotations/scanner/visitors/MojoMethodVisitor.java

@@ -20,6 +20,7 @@
  */
 
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import org.apache.maven.tools.plugin.extractor.annotations.scanner.MojoAnnotationsScanner;
@@ -37,14 +38,15 @@ public class MojoMethodVisitor extends MethodVisitor implements MojoParameterVis
 {
     private final String className;
     private final String fieldName;
-
+    private final List<String> typeParameters;
     private Map<String, MojoAnnotationVisitor> annotationVisitorMap = new HashMap<>();
 
-    public MojoMethodVisitor( String fieldName, String className )
+    public MojoMethodVisitor( String fieldName, String className, List<String> typeParameters )
     {
         super( Opcodes.ASM9 );
         this.fieldName = fieldName;
         this.className = className;
+        this.typeParameters = typeParameters;
     }
 
     @Override
@@ -73,6 +75,12 @@ public String getClassName()
         return className;
     }
 
+    @Override
+    public List<String> getTypeParameters()
+    {
+        return typeParameters;
+    }
+
     @Override
     public Map<String, MojoAnnotationVisitor> getAnnotationVisitorMap()
     {

maven-plugin-tools-annotations/src/main/java/org/apache/maven/tools/plugin/extractor/annotations/scanner/visitors/MojoParameterVisitor.java

@@ -19,6 +19,7 @@
  * under the License.
  */
 
+import java.util.List;
 import java.util.Map;
 
 /**
@@ -32,5 +33,7 @@ public interface MojoParameterVisitor
 
     String getClassName();
 
+    List<String> getTypeParameters();
+
     Map<String, MojoAnnotationVisitor> getAnnotationVisitorMap();
 }

maven-plugin-tools-annotations/src/test/java/org/apache/maven/tools/plugin/extractor/annotations/ParametersWithGenericsMojo.java

@@ -0,0 +1,66 @@
+package org.apache.maven.tools.plugin.extractor.annotations;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+
+@Mojo( name = "parameter-with-generics" )
+public class ParametersWithGenericsMojo
+    extends AbstractMojo
+{
+
+    @Parameter
+    private String string;
+
+    @Parameter
+    private Map<String, Boolean> stringBooleanMap;
+
+    @Parameter
+    private Collection<Integer> integerCollection;
+
+    @Parameter
+    private Collection<Collection<String>> nestedStringCollection;
+
+    @Parameter
+    private Collection<Integer[]> integerArrayCollection;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException {
+    }
+
+    @Parameter( name="numberList" )
+    public void setNumberList(List<Number> numberList) {
+    }
+
+    public static class NestedClass<E extends Number> {
+        /**
+         * Some field without type parameter but non-empty signature
+         */
+        protected E filter;
+    }
+}

maven-plugin-tools-annotations/src/test/java/org/apache/maven/tools/plugin/extractor/annotations/TestAnnotationsReader.java

@@ -98,25 +98,25 @@ void testReadMojoClass()
             .hasSize( 6 )
             .containsExactlyInAnyOrder(
                 new ParameterAnnotationContent( "bar", null, "thebar", "coolbar", null, true, false,
-                                                String.class.getName() ),
+                                                String.class.getName(), Collections.emptyList() ),
                 new ParameterAnnotationContent( "beer", null, "thebeer", "coolbeer", null, false, false,
-                                                String.class.getName() ),
+                                                String.class.getName(), Collections.emptyList() ),
                 new ParameterAnnotationContent( "fooInterface", null, "fooInterface", null,
                                                 FooInterfaceImpl.class,
                                                 false,
-                                                false, FooInterface.class.getName() ),
+                                                false, FooInterface.class.getName(), Collections.emptyList() ),
                 new ParameterAnnotationContent( "paramFromSetter", null, "props.paramFromSetter", null,
                                                 null,
                                                 false,
-                                                false, String.class.getName() ),
+                                                false, String.class.getName(), Collections.emptyList() ),
                 new ParameterAnnotationContent( "paramFromAdd", null, "props.paramFromAdd", null,
                                                 null,
                                                 false,
-                                                false, String.class.getName() ),
+                                                false, String.class.getName(), Collections.emptyList() ),
                 new ParameterAnnotationContent( "paramFromSetterDeprecated", null, "props.paramFromSetterDeprecated", null,
                                                 null,
                                                 false,
-                                                false, List.class.getName() )
+                                                false, List.class.getName(), Collections.singletonList("java.lang.String") )
             );
     }
 }