示例错误消息：

Question

更新：请参阅下面的答案，以解决此问题。还有第二个问题（宏现在无法找到Pojo），关于第二个问题的问题在这里：Scala macro can't find my java class

我正在创建一个scala宏来自动生成POJO中的case类（为了让avro更好一些）。

除了编译器在java.util.List和java.lang.Object等内置java类中阻塞外，所有东西都“有效”。

我的问题是：我如何在宏中生成代码，以便编译器解析java类？

示例错误消息：

（没有// Pojo.java中的coments）

[info] Compiling 1 Scala source to /Users/marcin/development/repo/problemdemo/target/scala-2.11/classes...
fieldType:java.util.List
fieldType:Int
fieldType:java.util.List
Expr[Any](case class Demo extends scala.Product with scala.Serializable {
  <caseaccessor> <paramaccessor> val baz: java.util.List[com.squarefoot.Pojo] = _;
  <caseaccessor> <paramaccessor> val bar: Int = _;
  <caseaccessor> <paramaccessor> val foo: java.util.List[java.lang.Integer] = _;
  def <init>(baz: java.util.List[com.squarefoot.Pojo], bar: Int, foo: java.util.List[java.lang.Integer]) = {
    super.<init>();
    ()
  }
})
[error] /Users/marcin/development/repos/problemdemo/src/main/scala/com/squarefoot/converters/problemdemo.scala:5: not found: type java.util.List
[error] @Caseify(classOf[com.squarefoot.Pojo])
[error]  ^
[error] one error found
[error] (root/compile:compileIncremental) Compilation failed
[error] Total time: 17 s, completed Dec 11, 2016 12:00:57 PM

（如图所示Pojo.java）

[info] Compiling 1 Scala source to /Users/marcin/development/repos/problemdemo/target/scala-2.11/classes...
fieldType:java.lang.Object
fieldType:Int
Expr[Any](case class Demo extends scala.Product with scala.Serializable {
  <caseaccessor> <paramaccessor> val qux: java.lang.Object = _;
  <caseaccessor> <paramaccessor> val bar: Int = _;
  def <init>(qux: java.lang.Object, bar: Int) = {
    super.<init>();
    ()
  }
})
[error] /Users/marcin/development/repos/problemdemo/src/main/scala/com/squarefoot/converters/problemdemo.scala:5: not found: type java.lang.Object
[error] @Caseify(classOf[com.squarefoot.Pojo])
[error]  ^
[error] one error found
[error] (root/compile:compileIncremental) Compilation failed
[error] Total time: 6 s, completed Dec 11, 2016 12:04:29 PM

编辑：showRaw的结果

showRaw给出这样的输出，对我来说很好看：

ValDef(Modifiers(DEFERRED), TermName("availablebuildouts"), AppliedTypeTree(Ident(TypeName("java.util.List")), List(Ident(TypeName("com.squarefoot.buildouttype")))), EmptyTree)

`problemdemo/avroschemas/src/main/java/com/squarefoot/Pojo.java`

package com.squarefoot;

public class Pojo {
    //public java.util.List<Integer> foo;
    public int bar;
    //public java.util.List<Pojo> baz;
    public java.lang.Object qux;
}

`problemdemo/src/main/scala/com/squarefoot/converters/problemdemo.scala`

package com.squarefoot.converters

import com.squarefoot.Pojo

class Foomin {
  val foobar: java.util.List[Int]
}

@Caseify(classOf[com.squarefoot.Pojo])
case class Demo()

`problemdemo/macros/src/main/scala/com/squarefoot/converters/Caseify.scala`

package com.squarefoot.converters

import scala.language.experimental.macros
import scala.annotation.StaticAnnotation
import scala.reflect.macros.Context

/** 
  *  Generate case class from POJO
  *  ex:
  *  @Caseify(classOf[com.squarefoot.incominglisting])
  *  case class Incominglisting()

  * NOTE that the type parameter to classOf must be provided as a fully
  * qualified name, otherwise the macro code here won't be able to find it.
  * 
  * Generates a case class with the same members as the public, non-static
  * members of the pojo
  * 
  * Note that you must have all types used in the POJO in scope where the macro
  * is invoked
  */

class Caseify[T](source: Class[T]) extends StaticAnnotation {
  def macroTransform(annottees: Any*) = macro CaseifyMacro.expand_impl[T]
}

object CaseifyMacro {
  /** generate case class from POJO */
  def expand_impl[T](c: Context)(annottees: c.Expr[Any]*) = {
    import c.universe._

    // macro expand the macro expression itself to extract param
    val source: Class[T] = c.prefix.tree match {
      case q"new Caseify($param)" => c.eval[Class[T]](c.Expr(param))
    }

    val rm = scala.reflect.runtime.currentMirror
    val vars =
      rm.classSymbol(source).toType.members.map(_.asTerm).
        filter(_.isVar).filter(_.isPublic)

    lazy val fields = vars.map({f=>
      val fieldName = TermName(f.name.toString)
      val fieldType = TypeName(f.typeSignature.typeConstructor.toString)
      val typeArgs = f.typeSignature.typeArgs.map(a=>TypeName(a.toString))
      println("fieldType:"+fieldType.toString)
      q"val $fieldName: $fieldType"
      if(typeArgs.size > 0)
        q"val $fieldName: $fieldType[..$typeArgs]"
      else
         q"val $fieldName: $fieldType"
    })

    annottees.map(_.tree) match {
      case List(q"case class $newname()") => {
        val q = c.Expr[Any](
        // Add your own logic here, possibly using arguments on the annotation.
          q"""
          case class $newname(..$fields)
        """)
        println(q.toString)
        q
      }
      // Add validation and error handling here.
    }
  }
}

Sbt文件：

`problemdemo/build.sbt`

name := "data-importer"


addCompilerPlugin("org.scalamacros" % "paradise" % "2.1.0" cross CrossVersion.full)

scalaVersion := "2.11.8"
val avroVersion = "1.8.1"

lazy val root =
        project.in( file(".") )
          .aggregate(avroschemas, macros).dependsOn(macros, avroschemas)

lazy val macros = project.dependsOn(avroschemas)

lazy val avroschemas = project



libraryDependencies ++= Seq(
  "org.scala-lang" % "scala-reflect" % scalaVersion.value
)


// better error reporting
scalacOptions in Test ++= Seq("-Yrangepos")

run in Compile := Defaults.runTask(fullClasspath in Compile, mainClass in (Compile, run), runner in (Compile, run))

`problemdemo/macros/build.sbt`

name := "data-importer-macros"


addCompilerPlugin("org.scalamacros" % "paradise" % "2.1.0" cross CrossVersion.full)

organization := "com.squarefoot"
scalaVersion := "2.11.3"



libraryDependencies ++= Seq(
  "org.scala-lang" % "scala-reflect" % scalaVersion.value
)

scalacOptions in Test ++= Seq("-Yrangepos")

`problemdemo/avroschemas/build.sbt`

name := "data-importer-avroschemas"

addCompilerPlugin("org.scalamacros" % "paradise" % "2.1.0" cross CrossVersion.full)

organization := "com.squarefoot"
scalaVersion := "2.11.8"


// better error reporting
scalacOptions in Test ++= Seq("-Yrangepos")

run in Compile := Defaults.runTask(fullClasspath in Compile, mainClass in (Compile, run), runner in (Compile, run))

Answer 1

基本上，您需要的是（{基于http://docs.scala-lang.org/overviews/reflection/symbols-trees-types.html#tree-creation-via-reify中的示例，而不是TypeName("java.util.List")，而不是Select(Select(This(TypeName("java")), TypeName("util")), TypeName("List"))。showRaw。如果您在输入树上执行TypeName(...toString)，则应该更准确地看到。因此，不是.，而是TypeName。也许只是删除val fieldType = f.typeSignature.typeConstructor val typeArgs = f.typeSignature.typeArgs：

<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
    <item>

        <shape
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:shape="rectangle"   >

            <solid
                android:width="1dp"
                android:color="#2B2B2D" >
            </solid>

            <stroke
                android:width="1dp"
                android:color="#666666" >
            </stroke>

            <padding
                android:left="2dp"
                android:top="2dp"
                android:right="2dp"
                android:bottom="2dp"    >
            </padding>

            <corners
                android:radius="2dp"   >
            </corners>

        </shape>
    </item>
    <item>
        <shape
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:shape="rectangle"   >



            <padding
                android:left="5dp"
                android:top="5dp"
                android:right="5dp"
                android:bottom="5dp"    >
            </padding>

            <corners
                android:radius="2dp"   >
            </corners>

            <gradient
                android:angle="180"
                android:endColor="#11B24A"
                android:centerColor="#fec804"
                android:startColor="#E3434B"
                android:type="linear" />

        </shape>
    </item>

</layer-list>

就够了吗？

Answer 2

所以，我还没有一个可行的宏，但我已经在Alexey Romanov的回答的帮助下解决了这个问题。此代码导致错误：

final Map<Polyline, String> polylines = new HashMap<>();

PolylineOptions polylineOptions = new PolylineOptions();
polylineOptions.addAll(coordinateList);
polylineOptions.width(10);
polylineOptions.color(Color.parseColor("#800080"));
polylineOptions.clickable(true);

polylines.put(mMap.addPolyline(polylineOptions), "Polyline data");

mMap.setOnPolylineClickListener(new GoogleMap.OnPolylineClickListener() {
    @Override
    public void onPolylineClick(Polyline polyline) {
        Toast.makeText(MapsActivity.this, polylines.get(polyline), Toast.LENGTH_SHORT).show();
    }
});

我即将打开一个关于该问题的单独问题。

[error] /Users/marcin/development/repos/problemdemo/src/main/scala/com/squarefoot/converters/problemdemo.scala:10: not found: type com.squarefoot.Pojo
[error] @Caseify(classOf[com.squarefoot.Pojo])

Scala宏找不到java.util.List，java.lang.Object

示例错误消息：

（没有// Pojo.java中的coments）

（如图所示Pojo.java）

编辑：showRaw的结果

`problemdemo/avroschemas/src/main/java/com/squarefoot/Pojo.java`

`problemdemo/src/main/scala/com/squarefoot/converters/problemdemo.scala`

`problemdemo/macros/src/main/scala/com/squarefoot/converters/Caseify.scala`

Sbt文件：

`problemdemo/build.sbt`

`problemdemo/macros/build.sbt`

`problemdemo/avroschemas/build.sbt`

2 个答案: