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forEach lambda support? #11

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prashanthsadasivan opened this issue Mar 19, 2014 · 3 comments
Closed

forEach lambda support? #11

prashanthsadasivan opened this issue Mar 19, 2014 · 3 comments

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@prashanthsadasivan
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Hey, I'm using this library along with the gradle plugin and I was wondering if this library supports the Iterable#forEach method? I know that it provides lambdas, but my IDE/javac doesn't recognize when i use the forEach java 8 convention. is this supported?

Thanks!
@Mart-Bogdan
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Hello @prashanthsadasivan
I have a retrolambda aware library https://bitbucket.org/mart_bogdan/collectionsquery/src which implements lots of useful functions to work with Iterables.
I've just Implemented forEeach method, but I haven't uploaded new version to Maven Central yet. Will do that soon. But you can download sources and execute gradle install to install into local maven repo, and then use:

repositories {
    mavenLocal()
    mavenCentral()
}

@Mart-Bogdan
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I've released version 0.2.1 which supports forEach in followg way

Itragable iter=....
Queryable.from(iter).forEachR(x->d.doSomething());

I had to use *R suffix to make method not overlapping with java8's method, which isn't available in java <8

@luontola
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Backporting Java 8's new APIs is outside the scope of Retrolambda. However, you can use the various 3rd party Java libraries that have such methods, as mentioned by Mart-Bogdan (some other libraries that do similar things are Google Guava and Functional Java).

Arneball added a commit to Arneball/retrolambda that referenced this issue Aug 11, 2014
@Arneball
package testpackage;
8e13c80 
public interface MyInterface {
    default String def() {
        return "[" + toString() + ", " + "def]";
    }

    default String join(MyInterface other) {
        return def() + other.def();
    }
}

class C implements MyInterface{}  compiles to:

public class testpackage.MyClass implements testpackage.MyInterface {
  public testpackage.MyClass();
    Code:
       0: aload_0
       1: invokespecial luontola#16                 // Method java/lang/Object."<init>":()V
       4: return

  public java.lang.String join(testpackage.MyInterface);
    Code:
       0: aload_0
       1: aload_1
       2: invokestatic  luontola#46                 // Method testpackage/MyInterfacehelper.join:(Ltestpackage/MyInterface;Ltestpackage/MyInterface;)Ljava/lang/String;
       5: areturn

  public java.lang.String def();
    Code:
       0: aload_0
       1: invokestatic  luontola#49                 // Method testpackage/MyInterfacehelper.def:(Ltestpackage/MyInterface;)Ljava/lang/String;
       4: areturn
}

Where testpackage.MyInterfacehelper is compiled to
public class testpackage.MyInterfacehelper {
  private testpackage.MyInterfacehelper();
    Code:
       0: aload_0
       1: invokespecial luontola#9                  // Method java/lang/Object."<init>":()V
       4: return

  public static java.lang.String def(testpackage.MyInterface);
    Code:
       0: new           luontola#13                 // class java/lang/StringBuilder
       3: dup
       4: invokespecial luontola#14                 // Method java/lang/StringBuilder."<init>":()V
       7: ldc           luontola#16                 // String [
       9: invokevirtual luontola#20                 // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
      12: aload_0
      13: invokevirtual luontola#24                 // Method java/lang/Object.toString:()Ljava/lang/String;
      16: invokevirtual luontola#20                 // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
      19: ldc           luontola#26                 // String ,
      21: invokevirtual luontola#20                 // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
      24: ldc           luontola#28                 // String def]
      26: invokevirtual luontola#20                 // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
      29: invokevirtual luontola#29                 // Method java/lang/StringBuilder.toString:()Ljava/lang/String;
      32: areturn

  public static java.lang.String join(testpackage.MyInterface, testpackage.MyInterface);
    Code:
       0: new           luontola#13                 // class java/lang/StringBuilder
       3: dup
       4: invokespecial luontola#14                 // Method java/lang/StringBuilder."<init>":()V
       7: aload_0
       8: invokeinterface luontola#35,  1           // InterfaceMethod testpackage/MyInterface.def:()Ljava/lang/String;
      13: invokevirtual luontola#20                 // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
      16: aload_1
      17: invokeinterface luontola#35,  1           // InterfaceMethod testpackage/MyInterface.def:()Ljava/lang/String;
      22: invokevirtual luontola#20                 // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
      25: invokevirtual luontola#29                 // Method java/lang/StringBuilder.toString:()Ljava/lang/String;
      28: areturn
}

==============
interface StaticTest {
    static <T> T staticMethod(T t) {
        return t;
    }
}
compiles to
public class testpackage.StaticTesthelper {
  private testpackage.StaticTesthelper();
    Code:
       0: aload_0
       1: invokespecial luontola#9                  // Method java/lang/Object."<init>":()V
       4: return

  public static <T> T staticMethod$static(T);
    Code:
       0: aload_0
       1: areturn
}

========

Brigde methods are generated properly in example:
public interface BridgeParent<T> {
    T get();
}
public interface StringBridges extends BridgeParent<String> {
    @OverRide
    default String get() {
        return "default method";
    }

    default String concrete() {
        return "concrete";
    }
}
public class testpackage.StringBridgeshelper
  SourceFile: "testpackage/StringBridges.java"
  minor version: 0
  major version: 50
  flags: ACC_PUBLIC, ACC_SUPER
Constant pool:
   luontola#1 = Utf8               testpackage/StringBridgeshelper
   luontola#2 = Class              luontola#1             //  testpackage/StringBridgeshelper
   luontola#3 = Utf8               java/lang/Object
   luontola#4 = Class              luontola#3             //  java/lang/Object
   luontola#5 = Utf8               testpackage/StringBridges.java
   luontola#6 = Utf8               <init>
   luontola#7 = Utf8               ()V
   luontola#8 = NameAndType        luontola#6:luontola#7          //  "<init>":()V
   luontola#9 = Methodref          luontola#4.luontola#8          //  java/lang/Object."<init>":()V
  luontola#10 = Utf8               get
  luontola#11 = Utf8               (Ltestpackage/StringBridges;)Ljava/lang/String;
  luontola#12 = Utf8               default method
  luontola#13 = String             luontola#12            //  default method
  luontola#14 = Utf8               concrete
  luontola#15 = String             luontola#14            //  concrete
  luontola#16 = Utf8               (Ltestpackage/StringBridges;)Ljava/lang/Object;
  luontola#17 = Utf8               testpackage/StringBridges
  luontola#18 = Class              luontola#17            //  testpackage/StringBridges
  luontola#19 = Utf8               ()Ljava/lang/String;
  luontola#20 = NameAndType        luontola#10:luontola#19        //  get:()Ljava/lang/String;
  luontola#21 = InterfaceMethodref luontola#18.luontola#20        //  testpackage/StringBridges.get:()Ljava/lang/String;
  luontola#22 = Utf8               Code
  luontola#23 = Utf8               LineNumberTable
  luontola#24 = Utf8               SourceFile
{
  private testpackage.StringBridgeshelper();
    descriptor: ()V
    flags: ACC_PRIVATE
    Code:
      stack=1, locals=1, args_size=1
         0: aload_0
         1: invokespecial luontola#9                  // Method java/lang/Object."<init>":()V
         4: return

  public static java.lang.String get(testpackage.StringBridges);
    descriptor: (Ltestpackage/StringBridges;)Ljava/lang/String;
    flags: ACC_PUBLIC, ACC_STATIC
    Code:
      stack=1, locals=1, args_size=1
         0: ldc           luontola#13                 // String default method
         2: areturn
      LineNumberTable:
        line 9: 0

  public static java.lang.String concrete(testpackage.StringBridges);
    descriptor: (Ltestpackage/StringBridges;)Ljava/lang/String;
    flags: ACC_PUBLIC, ACC_STATIC
    Code:
      stack=1, locals=1, args_size=1
         0: ldc           luontola#15                 // String concrete
         2: areturn
      LineNumberTable:
        line 13: 0

  public static java.lang.Object get(testpackage.StringBridges);
    descriptor: (Ltestpackage/StringBridges;)Ljava/lang/Object;
    flags: ACC_PUBLIC, ACC_STATIC, ACC_BRIDGE, ACC_SYNTHETIC
    Code:
      stack=1, locals=1, args_size=1
         0: aload_0
         1: invokeinterface luontola#21,  1           // InterfaceMethod testpackage/StringBridges.get:()Ljava/lang/String;
         6: areturn
      LineNumberTable:
        line 6: 0
}
@Arneball Arneball mentioned this issue Aug 11, 2014
Closed
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3 participants
@luontola @prashanthsadasivan @Mart-Bogdan