java 7 whats next

8/3/2019 Java 7 Whats Next

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Java 7:

Whats Next?

Alex Miller, BEA Systems


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http://tech.puredanger.com/java7

Java 7 Proposals Java Modularity

Superpackages

Java Module System

Java Kernel Swing

Swing App Framework

Bean Binding

Bean Validation

Generics and Types Generic Reification

Type Annotations

Short instance creation

NIO 2

XML Support

Property Support

Closures

invokedynamic

Date & Time API

Units & Quantities

JMX

JMX 2.0 Remote API Connector

Javadoc


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Java Modularity Superpackages (JSR 294)

Java Module System (JSR 277)

Java Kernel (no JSR)


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Superpackages (JSR 294)src/com/foo/super-package.java:

superpackage com.foo {

member package com.foo.api, com.foo.model,com.foo.util;

export com.foo.api; // Make api package public

}


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Java Module System (JSR 277)


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Module Definition Metadata/MODULE-INF/METADATA.module:

name=com.wombat.webservice

extensible-metadata=[@Version(1.0)]

members=[com.wombat.webservice.MainApp,

com.wombat.webservice.PrivateClassA,

com.wombat.webservice.PrivateInterfaceB]

imports=[ImportModule(org.foo.xml,@VersionConstraint(1.3.0)),

ImportModule(org.foo.soap,

@VersionConstraint(2.0.0+))]

class-exports=[com.wombat.webservice.MainApp]


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Java Kernel Reorganize JRE into kernel + optional

modules, load dynamically

Compete with Flex, Silverlight


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Swing Enhancements Swing Application Framework (JSR 296)

Bean Binding Framework (JSR 295)

Bean Validation Framework (JSR 303)


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Swing Application Framework

JSR 296

SingleFrame

Appliction

Application

initialize(String[] args)startup()shutdown()

exit()

ApplicationContext

getInstance()

Action

Manager

Resource

Manager

Session

Storage

Task

SwingWorker

Application

ActionMap

Task

MonitorTaskService

*

@Action

Local

Storage

Resource

Map

Resource

Converter


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Swing App Framework Demo


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Bean Binding Framework

JSR 295 Use a Binding to bind properties of two beans together:Binding binding = new Binding(source, "sourcePath",

target, "targetPath");

binding.bind();

Once bound, changes on either source or target arereflected on the other

Changes go through a BindingConverter and aBindingValidator along the way

The JSP expression language (EL) is used to specifyconversions


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Bean Validation

JSR 303 Heres an example from Hibnerate Validator that may be evocative (although I have

no idea what JSR 303 will actually look like:

public class Address {

@NotNullprivate String line1;

private String line2;

private String zip;

private String state;

@Length(max = 20)

@NotNullprivate String country;

@Range(min = -2, max = 50, message = "Floor out of range")

public int floor;

}


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Reification of Genericsclass NewCollection extends

Collection { ... }

class NewList extends

NewCollection, List { ... }


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Annotations on Java Types

JSR 308 for generic type arguments to parameterized classes:

Map files;

for generic type arguments in a generic method or constructor invocation:o.m("...");

for type parameter bounds and wildcards:class Folder { ... }Collection


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Short instance creationpublic static void main(String[] args) {

map := new HashMap();

for(word : args) {

freq := map.get(word);

map.put(word, (freq==null) ? 1 : freq+1);

}

System.out.println(map); }

public static void main(String[] args) {

final map = new HashMap();

for(final word : args) {final freq = map.get(word);

map.put(word, (freq==null) ? 1 : freq+1);

}

System.out.println(map); }


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NIO 2 (JSR 203) Major features:

New filesystem interface

Permissions File attributes

Pluggable implementations

Escape to filesystem-specific APIs

API for asynchronous I/O on sockets and files

Completion of socket channels (multicast, options,

etc)


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NIO 2 File System API

FileSystems FileSystem

FileReference

FileSystem

Provider

Watchable

WatchServiceCloseable

PathReference

BackingFile

System Path

FileSystem

AttributeViewFile

DiskSpace

AttributeView

Directory

WatchKey

FileId

WatchEvent

Files


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NIO 2: Copying a FilePathReference source =

PathReference.from(spongebob.jpg);

PathReference target =

PathReference.from(squarepants.jpg);int flags = CopyFlag.COPY_ATTRIBUTES |

CopyFlag.REPLACE_EXISTING;

source.copyTo(target, flags);


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NIO 2 Accessing file permissions

PathReference ref = PathReference.from("foo.txt");

PosixFileAttributeView view =ref.newFileAttributeView(PosixFileAttributeView.class);

PosixFileAttributes attrs = view.readAttributes();

int perms = attrs.getPermissions();

// prints "-rw-r--r-- alice bandits"System.out.format("%s\t%s\t%s%n",

PosixFilePermission.toString(perms), attrs.getOwner(),attrs.getGroup());

// deny others

perms &= ~OTHERS_READ & ~OTHERS_WRITE & ~OTHERS_EXECUTE;

view.updatePermissions(perms);

// change groupUserPrincipal cops = view.lookupPrincipalByGroupName("cops");

view.updateOwners(null, cops);


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XML Support: Constructionvoid addReviewer(XML feature,

String reviewer,

String time) {

feature.add(

{ reviewer }

{ time }

);

}


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XML Support: Data Coderpackage java.xml;

abstract class DataCoder {

String encode(Object o);

String encode(Object o, String type); T decode(String data, Class c);

T decode(String data, Class c, String type);

boolean supports(Class c);

boolean supports(Class c, String type);

static final DataCoder JAVA;static final DataCoder XSD;

}


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XML Support: Datacoder example

void addReviewer(XML feature,

String reviewer,

Timestamp time) {

DataCoder dc = DataCoder.XSD;

feature.add(

{ reviewer }

{ dc.encode(time) }

);}


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XML Support: Navigationvoid rejectOpenFeatures(XML featureList) {

List fs = featureList.findAll(feature[state!=approved]);

for(XML f : fs) {

f.get(state).set(rejected);

}

}


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Property SupportNew keyword proposal:public class Point {

property double x;

property double y;

}Point p = new Point(1, 2);

System.out.println(p.x + " " + p.y);

New accessor syntax proposal:Point p = new Point();

p->X = 56;

p->Y = 87;int z = p->X;

Also ideas around annotations, code gen, and various other syntaxes


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Closures - Abstractionvoid validateWithMax(Stat[] stats, final int max) throws InvalidStatException {

for(Stat stat : stats) {

if(! (stat.value() = min)) {

thrownew InvalidStatException();}

}

}


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Closures Inner Classesvoid validateWithMax(Stat[] stats, final int max) throws InvalidStatException {

validate( stats, new Validator() {

public boolean isValid(Stat stat) { return stat.value() = min; }

} ); }

interface Validator { boolean isValid(Stat stat); }

void validate(Stat[] stats, Validator validator) {for(Stat stat : stats) {

if(! validator.isValid(stat)) { throw new InvalidStatException(); }

}

}


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Closure Proposals BGGA Gilad Bracha, Neal Gafter, James

Gosling, Peter von der Ahe

CICE Concise Instance Creation Expressions Josh Bloch, Bob Lee, Doug Lea

FCM First Class Methods / JCA Java

Control Abstraction

Stephen Colebourne, Stefan Schulz, Ricky Clarkson


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Closures - CICEvoid validateWithMax(Stat[] stats, int max) throws InvalidStatException

{

validate( stats,

Validator(Stat stat) {

return stat.value()


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Closures - BGGAvoid validateWithMax(Stat[] stats, int max) throws InvalidStatException {

validate(stats, {Stat stat =>

stat.value() boolean} block) {

for(Stat stat : stats) {

if(! block.invoke(stat)) {

throw new InvalidStatException();

}}

}


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Closures - FCM

void validateWithMax(Stat[] stats, final int max) throws InvalidStatException {

validate( stats,

#(boolean(Stat stat)) {

return stat.value()


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Closures Control Constructs

File file = ...;

FileReader reader = null;

try {

reader = new FileReader(file);

reader.read

} finally {

if (reader != null) {

try {

reader.close();

} catch (IOException e) {// ignore

}

}


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Closures - JCA

File file = ...;

usingFileReader(FileReader reader : file) {

reader.read

}

public static void usingFileReader(#(void(FileReader)) block : File file) throwsIOException {


try {


block.invoke(reader);

} finally {if (reader != null) {

try {

reader.close();

} catch (IOException e) { }

}

}


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Closures - BGGA

File file = ...;

usingFileReader(FileReader reader : file) {

reader.read

}

public static

T usingFileReader(File file, {=>T throws E} block) throws E {


try {


return block.invoke(reader);

} finally {if (reader != null) {

try {

reader.close();

} catch (IOException e) { }

}

}


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invokedynamic


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Date / Time API


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Units and Quantities (JSR 275)Unit

DerivedUnit

ProductUnit

SI

BaseUnit

AlternateUnit TransformedUnit

UnitFormatter

NonSI

Converter

MultiplyConverter AddConverter LogConverter

Dimension


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Units Example

// Conversion between units.

KILO(METER).getConverterTo(MILE).convert(10)

6.2137119223733395

// Retrieval of system unit (identifies the measurement type).REVOLUTION.divide(MINUTE).getSystemUnit()

rad/s

// Dimension checking (allows/disallows conversions)

ELECTRON_VOLT.isCompatible(WATT.times(HOUR))

true

// Retrieval of unit dimension (depends upon the current model).ELECTRON_VOLT.getDimension()

[L][M]/[T]


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JMX

JMX 2.0 (JSR 255)

Retrofit with generics

Use annotations Make Open MBeans easier to use

Generalize monitors to support non-simpletypes

Cascaded/federated MBean servers

Web services connector (JSR 262)


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Javadoc (JSR 260)

New tags for examples, etc

New categorizations of method types,

bean properties, etc

Update the old school look


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Miscellaneous

BigDecimal operator supportBigDecimal a =

BigDecimal b =

BigDecimal s = a + b;

Allow String literals in switch case blocksswitch(stooge) {

case Moe:

Comparison support for enums

JACK < QUEEN


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Thanks!

My blog: http://tech.puredanger.com

Java 7: http://tech.puredanger.com/java7

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