emfpath

EMFPath

Even more cool than what I

do with strawsMikaël Barbero

OBEO

public void demo(Library l) { List<Book> books = l.getBooks(); Set<Borrower> allBorrowers = new HashSet<Borrower>(); List<Writer> allWriters = new ArrayList<Writer>(); for (Book book : books) { List<Borrower> borrowers = book.getBorrowers(); allBorrowers.addAll(borrowers); allWriters.add(book.getAuthor()); } Set<Borrower> filteredBorowers = new HashSet<Borrower>(); for (Borrower borrower : allBorrowers) { if (borrower.getLastName().startsWith("B") && borrower.getBorrowed().contains(aSpecificBook)) { filteredBorowers.add(borrower); } } }

Java library used internally @ Google for years

Superset of Google Collections

About Guava

2007 2008 2009 2010 2011

Google Collec

tions

v0.5

Google Collec

tions

v1Guava

r03

Guava r0

8

About Guava

IO

About Guava

IO Networking

About Guava

IO Networking Concurrency

About Guava

IO Networking Concurrency

Primitive types

About Guava

IO Networking Concurrency

Primitive types Collections

About Guava

IO Networking Concurrency

Primitive types Collections

About Guava

in com.google.common.base package

Function<F, T> to transform a collection

Predicate<T> to filter out a collection

public interface Function<F, T> {

T apply(F from);

}

public interface Predicate<T> {boolean apply(T from);

}

in com.google.common.collect package

Iterables.filter()

Iterators.filter()

Collections2.filter()

Sets.filter()

4224 7 12813

4224 7 12813

public static void demo(Collection<Integer> c) { Predicate<Integer> isEven = new Predicate<Integer>() { @Override public boolean apply(Integer input) { return (input.intValue() % 2 == 0); } }; Collections2.filter(c, isEven); }

4224 128

4224 7 12813

public static void demo(Collection<Integer> c) { Predicate<Integer> isEven = new Predicate<Integer>() { @Override public boolean apply(Integer input) { return (input.intValue() % 2 == 0); } }; Collections2.filter(c, isEven); }

in com.google.common.collect package

Iterables.transform()

Iterators.transform()

Collections2.transform()

Lists.transform()

OrangeApple Kiwi PearBanana

OrangeApple Kiwi PearBanana

public void demo(Collection<String> c) { Function<String, String> toUpperCase = new Function<String, String>() { @Override public String apply(String input) { return input.toUpperCase(); } }; Collections2.transform(c, toUpperCase); }

ORANGEAPPLE KIWI PEARBANANA

OrangeApple Kiwi PearBanana

public void demo(Collection<String> c) { Function<String, String> toUpperCase = new Function<String, String>() { @Override public String apply(String input) { return input.toUpperCase(); } }; Collections2.transform(c, toUpperCase); }

Predicates

Functions

composeforPredicate

andornotcompose

Compose and combine

Beware of

Beware of

lazyness

Copy!

Lists.newArrayList() Lists.newLinkedList() Sets.newHashSet() Sets.newLinkedHashSet() Sets.newTreeSet()

ImmutableList.copyOf() ImmutableSet.copyOf()

and make it immutable...

Path

Set of functions and predicates for EMF objects

Code generators for your own Ecore models

and few other utility classes

public interface Function<F, T> {

T apply(F from);

}public interface Predicate<T> {

boolean apply(T from);}

‣ parent (eContainer)

‣ ancestor‣ ancestorOrSelf‣ child (eContents)

‣ descendant (eAllContents)

‣ descendantOrSelf‣ following‣ followingSibling‣ preceding‣ precedingSibling

Lazy EObjects containment tree walking

EObject myObject;Collection<EObject> fs = followingSibling.of(myObject);

HavingIsKind/IsTypeIsAncestor/IsChild

Common predicates

public static Collection<EObject> demoHaving(Collection<EObject> c) {

return Collections2.filter(c, Having.feature(EcorePackage.Literals.ENAMED_ELEMENT__NAME,

StringPredicates.firstUpperCase) ); }

non-EMF functions & predicates

length : Function<String, Integer>toL1Case : Function<String, String>toLowerCase : Function<String, String>toU1Case : Function<String, String>toUpperCase : Function<String, String>trim : Function<String, String>replaceAll(Pattern, String)replaceAll(String, String)replaceFirst(Pattern, String)replaceFirst(String, String)substring(int)substring(int, int)

Strings

Predicates to test ordering:equalless thangreater thanless or equalgreater or equal

Comparable

Ecore API has been Guava-ified

‣ EObject.eResource() is wrapped as a Function in EObjectPath.eResource

‣ EObject.eIsProxy() is wrapped as a Predicate in EObjectPath.eIsProxy

‣ EClass.getESuperTypes() is wrapped as a Function in EClass.eSuperTypes

‣ EReference.isContainment() is wrapped as a Predicate in ERefrencePath.isContainment

Ecore has been Guava-ified through a generator

that is available for your own Ecore model

+

time to play

public void demo(Library l) { List<Book> books = l.getBooks(); Set<Borrower> allBorrowers = new HashSet<Borrower>(); List<Writer> allWriters = new ArrayList<Writer>(); for (Book book : books) { List<Borrower> borrowers = book.getBorrowers(); allBorrowers.addAll(borrowers); allWriters.add(book.getAuthor()); } Set<Borrower> filteredBorowers = new HashSet<Borrower>(); for (Borrower borrower : allBorrowers) { if (borrower.getLastName().startsWith("B") && borrower.getBorrowed().contains(aSpecificBook)) { filteredBorowers.add(borrower); } } }

public void demo2(Library l) { List<Book> books = l.getBooks(); Set<Borrower> allBorrowers = ImmutableSet.copyOf( Iterables.concat( Collections2.transform(books, BookPath.borrowers)));

List<Writer> allWriters = Lists.transform(books, BookPath.author); Predicate<Borrower> predicate = new Predicate<Borrower>() { @Override public boolean apply(Borrower borrower) { return borrower.getLastName().startsWith("B") && borrower.getBorrowed().contains(aSpecificBook); } }; Set<Borrower> filteredBorrowers = Sets.filter(allBorrowers, predicate); }

public void demo2(Library l) { List<Book> books = l.getBooks(); Set<Borrower> allBorrowers = ImmutableSet.copyOf( Iterables.concat( Collections2.transform(books, BookPath.borrowers)));

List<Writer> allWriters = Lists.transform(books, BookPath.author); Predicate<Borrower> predicate = new Predicate<Borrower>() { @Override public boolean apply(Borrower borrower) { return borrower.getLastName().startsWith("B") && borrower.getBorrowed().contains(aSpecificBook); } }; Set<Borrower> filteredBorrowers = Sets.filter(allBorrowers, predicate); }

public void demo2(Library l) { List<Book> books = l.getBooks(); Set<Borrower> allBorrowers = ImmutableSet.copyOf( Iterables.concat( Collections2.transform(books, BookPath.borrowers)));

List<Writer> allWriters = Lists.transform(books, BookPath.author); Set<Borrower> filteredBorrowers = Sets.filter(allBorrowers, predicate); }

1. Function and Predicate2. Lazyness3. Walking EObjects containment tree along XPath-like axes4. Code generators for your own Ecore model

What you should remember

about this presentation

1. Guava is cool! 2. EMF is cool too!3. EMFPath bridges the gap between Guava and EMF4. EMFPath is cool - Q.E.D

What you should REALLY remember

about this presentation

http://code.google.com/a/eclipselabs.org/p/emfpath/

EMFPath v0.4.0 is available NOW!

Q&A