端端舝

1
竩
菁
賤
掊
ㄐ
Project Lambda及允屯化
2013/11/9 14:15-15:05
JJUG CCC 2013 Fall H-2
@bitter_fox

2
Who are you?
♂ Twitter: @bitter_fox
♂ �𦲀: 悝汜
每蕾韜禭湮悝﹛ロ�燴馱悝窒﹛ロ�扑旦氾丞悝褪
每媼隙汜
每蕾韜禭戊件疋亙奈正弁仿皮

3
Who are you?
♂ Like
每 Java
每 Xmonad
每 Scala
每 etc.

4
Who are you?
♂ 戊立亙瓦氾奴魂�
每市件白央伊件旦炵場統樓
每仄井手場腎�
♂ 戶切扎仁切扎駟�仄化引允

5
HashTag @ Twitter
#jjug_ccc
#ccc_h2

8
JavaSE8
Project Lambda
Revolution

9
Project Lambda
♂ 甜蹈�I燴毛⺍眢卞𤩸仃月�卞��
每仿奶皮仿伉
每晟惤
♂ StreamAPI(!=IOStream)及爀⻌
♂ 仿丞母宒及爀⻌

12
穴伙民戊失CPU
♂ CPU及由仿母奶丞扑白玄
每弁伕永弁杅反公及引引
戊失(杅)毛�支允
每甜蹈�I燴
♂ 末白玄它尼失卞手由仿母奶丞扑白玄
♂ �K蹈皿伕弘仿立件弘卞仄卅中午俶夔毛白伙卞瞳蚚匹
五卅中
每失丞母奈伙及楊�t

13
失丞母奈伙及楊�t
90% 10%
90%
80% 20%
80%
5
%
1戊失
1戊失
﹢戊失
4戊失
紨棒�I燴甜蹈�I燴

14
政測腔卅失奈平氾弁民乓
屾仄匹手嗣仁及窒煦匹甜蹈�I燴

15
皿伕斥尼弁玄逃逋絞媆及甜蹈�I燴
湮五卅薜僅及心
苤今中薜僅卞反砃井卅中
А戶日木化中月及反苤今卅薜僅

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穴伙民戊失CPU及
怢螹
穴伙民戊失CPU戊失仿奶皮仿伉

17
仿奶皮仿伉匹反祥坋煦
new Runnable(){
public void run(){
// proc
}
}
♂ �I燴毛煦仃月分仃匹5俴
♂ 中仁日仿奶皮仿伉互謎仁化手???
♂ 晟惤腔卞賤𢜪允月斛猁互丐月

18
仿丞母宒?丟末永玉統桽

19
灍斮腔卞final
倰芢�及�趙
恚磁倰平乓旦玄

20
仿奶皮仿伉及��
♂ 珨僅鼠嶱今木凶奶件正奈白尼奈旦
每劐載毛樓尹卞仁中
每丟末永玉袚樓
♂ 撿砓弁仿旦互袚呴允月斛猁互丐月
每灍蚾及枑鼎

21
灍斮腔卞final
倰芢�及�趙
犯白巧伙玄灍蚾

22
灍斮腔卞final
倰芢�及�趙
stat. intf. 丟末永玉

23
灍斮腔卞final
倰芢�及�趙

24
�I燴及煦褩及奶犯奴左丞
new Runnable() {
public void run() {
//
}
}

25
�I燴及煦褩及奶犯奴左丞
new Runnable() {
public void run() {
//
}
}
灍蚾允月屯五丟末永玉互珨勾
奶件正奈白尼奈旦

26
♂ 灍蚾允月屯五丟末永玉(喲砓丟末永玉)互珨勾
♂ 奶件正奈白尼奈旦
每 java.lang.Runnable
每 java.lang.Callable
每 java.nio.file.PathMatcher
每 java.awt.event.ActionListener
每 java.swing.event.ChangeListner
每 ...

27
憝杅倰奶件正奈白尼奈旦
♂ 灍蚾允月屯五丟末永玉(喲砓丟末永玉)互珨勾
♂ 奶件正奈白尼奈旦
每 java.lang.Runnable
每 java.lang.Callable
每 java.nio.file.PathMatcher
每 java.awt.event.ActionListener
每 java.swing.event.ChangeListner
每 ...

28
憝杅倰奶件正奈白尼奈旦
♂ �I燴毛煦仃月及卞坋煦
♂ 仿奶皮仿伉及嗣仁匹瞳蚚今木化中月
♂ 灍蚾ㄕ奶件旦正件旦趙允月凳恅午仄化仿丞母宒

29
憝杅倰奶件正奈白尼奈旦ˋ
interface F {
void f();
}

30
interface F {
void f();
}
♂ Yes!

31
interface F {
boolean equals(Object o);
}

32
interface F {
}
♂ No!
♂ equals反Object弁仿旦匹隅膽今木化中月
每奶件正奈白尼奈旦卞云中化做怱腔卅丟末永玉
喲砓丟末永玉反0�

33
interface F {
Object clone();
}

34
interface F {
Object clone();
}
♂ Yes!
♂ clone手Object弁仿旦匹哫晟今木化中月互
protected
每 F匹反public匹婬哫晟今木化中月

35
憝杅倰奶件正奈白尼奈旦(JLS9.8)
A functional interface is an interface that has just one abstract method, and thus represents a single function contract. (In some cases, this "single" method may take the form of multiple
abstract methods with override-equivalent signatures (8.4.2) inherited from superinterfaces; in this case, the inherited methods logically represent a single method.)
More precisely, for interface I, let M be the set of abstract methods that are members of I but that do not have the same signature as any public instance method of the class Object. Then I is
a functional interface if there exists a method m in M for which the following conditions hold:
The signature of m is a subsignature (8.4.2) of every method's signature in M.
m is return-type-substitutable (8.4.5) for every method in M.
In addition to the usual process of creating an interface instance by declaring (8.1) and instantiating (15.9) a class, instances of functional interfaces can be created with lambda expressions
(15.27), method references (15.28), or constructor references.
The function descriptor of a functional interface I is a method type (8.2) that can be used to legally override (8.4.8) the abstract method(s) of I.
Let M be the set of abstract methods defined above for I. The descriptor of I consists of the following:
Type parameters, formal parameters, and return types: Let m be a method in M with i) a signature that is a subsignature of every method's signature in M and ii) a return type that is a
subtype of every method's return type in M (after adapting for any type parameters (8.4.4)); if no such method exists, then let m be a method in M that i) has a signature that is a subsignature
of every method's signature in M and ii) is return-type-substitutable for every method in M. Then the descriptor's type parameters, formal parameter types, and return type are as given by m.
Thrown types: The descriptor's thrown types are derived from the throws clauses of the methods in M. If the descriptor is generic, these clauses are first adapted to the type parameters of
the descriptor (8.4.4); if the descriptor is not generic but at least one method in M is, these clauses are first erased. Then the descriptor's thrown types include every type, E, satisfying the
following constraints:
E is mentioned in one of the throws clauses.
For each throws clause, E is a subtype of some type named in that clause.
A functional interface type is one of the following:
A functional interface
A parameterization (4.5) of a functional interface
An intersection (4.9) of interface types that meets the following criteria:
Exactly one element of the intersection is a functional interface, or a parameterization of a functional interface. Let F be this interface.
A notional interface, I, that extends all the interfaces in the intersection would be a functional interface. If any of the intersection elements is a parameterized type, then I is generic: for
each element of the intersection that is a parameterized type J<A1...An>, let P1...Pn be the type parameters of J; then P1...Pn are also type parameters of I, and I extends the type
J<P1...Pn>.
The function descriptor of I is the same as the function descriptor of F.
The function descriptor of a parameterized functional interface, F<A1...An>, where A1...An are type arguments (4.5.1), is derived as follows. Let P1...Pn be the type parameters of F; types
T1...Tn are derived from the type arguments according to the following rules (for 1 ≒ i ≒ n):
If Ai is a type, then Ti = Ai.
If Ai is a upper-bounded wildcard ? extends Ui, then Ti = Ui.
If Ai is a lower-bounded wildcard ? super Li, then Ti = Li.
If Ai is an unbound wildcard ?, then if Pi has upper bound Bi that mentions none of P1...Pn, then Ti = Bi; otherwise, Ti = Object.
If F<T1...Tn> is a well-formed type, then the descriptor of F<A1...An> is the result of applying substitution [P1:=T1, ..., Pn:=Tn] to the descriptor of interface F. Otherwise, the descriptor of
F<A1...An> is undefined.
The function descriptor of an intersection that is a functional interface type is the same as the function descriptor of the functional interface or parameterization of a functional interface that is
an element of the intersection.

36
憝杅倰奶件正奈白尼奈旦(JLS9.8)
A functional interface is an interface that has just one abstract method, and thus represents a single function contract. (In some cases, this "single" method may take the form of multiple
abstract methods with override-equivalent signatures (8.4.2) inherited from superinterfaces; in this case, the inherited methods logically represent a single method.)
More precisely, for interface I, let M be the set of abstract methods that are members of I but that do not have the same signature as any public instance method of the class Object. Then I is
a functional interface if there exists a method m in M for which the following conditions hold:
The signature of m is a subsignature (8.4.2) of every method's signature in M.
m is return-type-substitutable (8.4.5) for every method in M.
In addition to the usual process of creating an interface instance by declaring (8.1) and instantiating (15.9) a class, instances of functional interfaces can be created with lambda expressions
(15.27), method references (15.28), or constructor references.
The function descriptor of a functional interface I is a method type (8.2) that can be used to legally override (8.4.8) the abstract method(s) of I.
Let M be the set of abstract methods defined above for I. The descriptor of I consists of the following:
Type parameters, formal parameters, and return types: Let m be a method in M with i) a signature that is a subsignature of every method's signature in M and ii) a return type that is a
subtype of every method's return type in M (after adapting for any type parameters (8.4.4)); if no such method exists, then let m be a method in M that i) has a signature that is a subsignature
of every method's signature in M and ii) is return-type-substitutable for every method in M. Then the descriptor's type parameters, formal parameter types, and return type are as given by m.
Thrown types: The descriptor's thrown types are derived from the throws clauses of the methods in M. If the descriptor is generic, these clauses are first adapted to the type parameters of
the descriptor (8.4.4); if the descriptor is not generic but at least one method in M is, these clauses are first erased. Then the descriptor's thrown types include every type, E, satisfying the
following constraints:
E is mentioned in one of the throws clauses.
For each throws clause, E is a subtype of some type named in that clause.
A functional interface type is one of the following:
A functional interface
A parameterization (4.5) of a functional interface
An intersection (4.9) of interface types that meets the following criteria:
Exactly one element of the intersection is a functional interface, or a parameterization of a functional interface. Let F be this interface.
A notional interface, I, that extends all the interfaces in the intersection would be a functional interface. If any of the intersection elements is a parameterized type, then I is generic: for
each element of the intersection that is a parameterized type J<A1...An>, let P1...Pn be the type parameters of J; then P1...Pn are also type parameters of I, and I extends the type
J<P1...Pn>.
The function descriptor of I is the same as the function descriptor of F.
The function descriptor of a parameterized functional interface, F<A1...An>, where A1...An are type arguments (4.5.1), is derived as follows. Let P1...Pn be the type parameters of F; types
T1...Tn are derived from the type arguments according to the following rules (for 1 ≒ i ≒ n):
If Ai is a type, then Ti = Ai.
If Ai is a upper-bounded wildcard ? extends Ui, then Ti = Ui.
If Ai is a lower-bounded wildcard ? super Li, then Ti = Li.
If Ai is an unbound wildcard ?, then if Pi has upper bound Bi that mentions none of P1...Pn, then Ti = Bi; otherwise, Ti = Object.
If F<T1...Tn> is a well-formed type, then the descriptor of F<A1...An> is the result of applying substitution [P1:=T1, ..., Pn:=Tn] to the descriptor of interface F. Otherwise, the descriptor of
F<A1...An> is undefined.
The function descriptor of an intersection that is a functional interface type is the same as the function descriptor of the functional interface or parameterization of a functional interface that is
an element of the intersection.
@
FunctionalInterface

37
@FunctionalInterface
♂ 憝杅倰奶件正奈白尼奈旦井升丹井𨈘𦷰允月
每戊件由奶伙媆
interface F {
}

38
♂ 憝杅倰奶件正奈白尼奈旦井升丹井𨈘𦷰允月
每戊件由奶伙媆
interface F {
} @FunctionalInterface
^
F反辻夔奶件正白尼奈旦匹反丐曰引六氏
奶件正白尼奈旦 F匹喲砓丟末永玉互�勾井曰引六氏
巨仿奈1�

39
曩靡弁仿旦井日仿丞母宒尺
this.addActionListener(
new ActionListener(){
public void actionPerformed(
ActionEvent ae) {
//
}
})

40
ActionEvent ae) {
//
}
})
addActionListener及竘
杅井日芢�匹五月

41
ActionEvent ae) {
//
}
})
灍蚾允月屯五丟末永玉
手珨砩卞隅引月

42
仿丞母宒
(ActionEvent ae) -> {
//
})
♂ (�竘杅) -> {丟末永玉掛极}
♂ (int n1, int n2) -> {return n1+n2;}

43
仿丞母宒
♂ 憝杅倰奶件正奈白尼奈旦毛奶件旦正件旦趙
♂ (�竘杅) -> {丟末永玉掛极}
每倰芢�匹倰互𢜪引月
♂ 憝杅倰奶件正奈白尼奈旦及奶件旦正件旦互
軑ヽ今木月�醱匹瞳蚚褫
每正奈必永玄倰

44
正奈必永玄倰互鐧藪卅�磁
Object o = () -> {};
每 Object互軑ヽ今木月
每憝杅倰奶件正奈白尼奈旦互軑ヽ今木卅中
每睡毛灍蚾仄凶日中中及井歹井日卅中

45
正奈必永玄倰互鐧藪卅�磁
Object o = (Runnable)() -> {};
每平乓旦玄毛蚚中月
每 Runnable互軑ヽ今木月
每灍蚾允月屯五奶件正奈白尼奈旦互煦井月

46
仿丞母宒及竘杅
//
})

47
//
})
竘杅及倰手珨砩卞隅引
月

48
(ae) -> {
//
})
♂ 竘杅及倰手吽謹褫
♂ (n1, n2) -> {return n1+n2;}

49
(ae) -> {
//
})
竘杅互珨勾匹倰互芢�今木月
�磁及()反祥猁

50
ae -> {
//
})
♂ 竘杅互珨勾匹倰互吽謹今木月�磁()祥猁
♂ n1 -> {return n1+5;}

51
仿丞母宒及竘杅午_
♂ 仿丞母宒及竘杅午仄化及_反戊件由奶伙巨仿奈
this.addActionListener( _ -> {/**/} );
每坻及晟惤匹及_反杻忷卅砩庤
每髦觴毛桸井卅中方丹卞瞳蚚祥褫卞
每蔚懂及瞳蚚毛�擂尹軑廣惤卞
♂ 公木眕俋及_反劑豢卞

52
仿丞母宒及丟末永玉掛极
(int n) -> {return n + 5;}
(n) -> {return n + 5;}
n -> {return n + 5;}

53
(int n) -> {return n + 5;}
(n) -> {return n + 5;}
n -> {return n + 5;}
♂ return恅及心�磁ㄛreturn脹毛吽謹匹五月
(int n) -> n + 5
(n) -> n + 5
n -> n + 5

54
(ActionEvent ae) -> {apply(ae);}
(ae) -> {apply(ae);}
ae -> {apply(ae);}

55
(ActionEvent ae) -> {apply(ae);}
(ae) -> {apply(ae);}
ae -> {apply(ae);}
♂ 𥽋曰�互void匹手ㄛ{;}毛吽謹匹五月�磁互丐月
(ActionEvent ae) -> apply(ae)
(ae) -> apply(ae)
ae -> apply(ae)

56
仿丞母宒及旦戊奈疋件弘��t
1.仿丞母宒卞反陔仄中旦戊奈皿毛爀⻌仄卅中
每曩靡弁仿旦卅升午反湮五仁綃丹
2.伕奈市伙劐杅及統桽反final卅劐杅及心
每曩靡弁仿旦午肮�
每蛁ㄩ灍窐腔卞款勳紳硃梭(綴幻升掊隴)

57
陔仄中旦戊奈皿毛爀⻌仄卅中
class Main {
void method() {
Runnable r = () ->
System.out.println(this);
}
}

58
class Main {
void method() {
Runnable r = () ->
System.out.println(this);
}
}
♂ 仿丞母宒囀及thisˊ巨件弁伕奈斥件弘弁仿旦

59
class Main {
void method(int n) {
Runnable r = () -> {int n;};
}
}

60
class Main {
Runnable r = () -> {int n;};
}
}
♂ 嗣笭隅膽
♂ 戊件由奶伙巨仿奈

61
class Main {
Function<Integer, Integer> f =
n -> n + 5;
}
}
♂ 嗣笭隅膽

62
伕奈市伙劐杅及統桽
♂ 曩靡弁仿旦午肮�
每 final卅劐杅(灍斮腔卞final漪戈)
每 �及劐載祥褫

63
仿丞母宒及瞳蚚瞰
p -> p.getName()
s -> Integer.parseInt(s)
o -> list.add(o)
init -> new MyClass(init)
n -> new int[n]
♂ 竘杅毛忳仃霜允由正奈件

64
仿丞母宒及瞳蚚瞰
p -> p.getName()
o -> list.add(o)
n -> new int[n]
♂ 竘杅毛忳仃霜允由正奈件
♂ 丟末永玉?戊件旦玄仿弁正統桽

65
丟末永玉?戊件旦玄仿弁正統桽
p -> p.getName()
o -> list.add(o)
n -> new int[n]
♂ 弁仿旦靡脹::丟末永玉 or new
Person::getName
Integer::perseInt
list::add
MyClass::new
int[]::new

66
灍斮腔卞final
倰芢�及�趙

67
灍斮腔卞final(Effectively final)
♂ 曩靡弁仿旦支仿丞母宒匹
灍斮腔卞final卅劐杅尺及統桽互褫夔卞
每戊件由奶仿互final俶毛芢�
♂ 灍斮腔卞final卅劐杅
每 final党�今木化中卅中劐杅
每 final党�今木化手巨仿奈卞卅日卅中劐杅

68
灍斮腔卞final及瞰
void method(final int n) {
final String str = ※HelloFinal§
Runnable r = new Runnable() {
public void run() {
System.out.println(str + n);
}};
}

69
String str = ※HelloEffectivelyFinal§
Runnable r = new Runnable() {
public void run() {
}};
}

70
String str = ※HelloEffectivelyFinal§
Runnable r = () ->
}

71
灍斮腔卞final匹卅中瞰
Runnable r = () ->
System.out.println(n);
n = 5;
}
仿丞母宒井日統桽今木月伕奈市伙劐杅反﹜
final引凶反岈灍奻及final匹丐月斛猁互丐曰引允
Runnable r = () -> System.out.println(n);

72
灍斮腔卞final匹卅中瞰
Runnable r = () -> n++;
}
仿丞母宒井日統桽今木月伕奈市伙劐杅反﹜
final引凶反岈灍奻及final匹丐月斛猁互丐曰引允
Runnable r = () -> n++;

73
灍斮腔卞final
倰芢�及�趙

74
倰芢�及�趙
♂ 正奈必永玄倰芢�及�趙
1.羥蚚褫夔預垀及�湮
2.方曰淏復卅芢�

75
正奈必永玄倰芢�ˋ
♂ 正奈必永玄倰卞價勿仁倰芢�
♂ JavaSE5(5.0)井日湔婓
每丟末永玉斥尼生伉弁旦及灍倰竘杅
每母奶失乒件玉栳呾赽(JavaSE7)

76
正奈必永玄倰
♂ 丐月宒及倰午仄化軑ヽ今木月倰及仇午
♂ T t = expr;
每 expr及正奈必永玄倰反T

77
正奈必永玄倰互湔婓允月恅犢
♂ 劐杅哫晟??? int n = ＃
♂ 賃曰絞化??? n = ＃
♂ return恅??? return ＃
♂ 饜蹈場ヽ趙赽???new String[]{...}
♂ 灍竘杅???method(...)
♂ 沭璃宒 ?:???bool ? ＃ : ＃
♂ 平乓旦玄宒 ???(Target)...
♂ 仿丞母宒及掛极???() -> ＃
瞰 expr及正奈必永玄倰
劐杅哫晟 int n = expr 劐杅及倰(int)
賃曰絞化 n = expr 劐杅及倰(n及倰)
return恅 return expr 𥽋曰�及倰
饜蹈場ヽ趙赽 new String[]{expr, ...} 饜蹈及倰(String)
灍竘杅 m(expr, ...) �竘杅及倰
沭璃宒 cond ? expr : expr 芵綎今木凶倰
平乓旦玄宒 (String)expr String
仿丞母宒及掛极 () -> expr 𥽋曰�及倰

78
JavaSE7卞云仃月羥蚚褫夔預垀
丟末永玉斥尼生伉弁旦及
灍倰竘杅
母奶失乒件玉栳呾赽
劐杅哫晟 ♀ ♀
賃曰絞化 ♀ ♀
return恅 ♀ ♀
饜蹈場ヽ趙赽 ♀ -
灍竘杅 ℅ ℅
沭璃宒 ℅ ℅
平乓旦玄宒 ♀ ℅
仿丞母宒及掛极

79
羥蚚褫夔預垀及瞰(JavaSE7)
List<Integer> l = new ArrayList<>();
new ArrayList<T>()
new ArrayList<Integer>()
♂
ArrayList<T>?<: List<Integer>
每 T = Integer

80
羥蚚祥褫夔預垀及瞰(JavaSE7)
♂ 灍竘杅卞云仃月正奈必永玄倰芢�
printStrings(new ArrayList<>());
每 void printStrings(List<String> l)

81
printStrings(new ArrayList<Object>());
每 Object午芢�今木月

82
♂ 沭璃宒卞云仃月正奈必永玄倰芢�
List<Integer> list = bool ?
Collections.emptyList() :
new ArrayList<>();

83
Collections.<Object>emptyList() :
new ArrayList<Object>();
每 Object午芢�今木月

84
丟末永玉斥尼生伉弁旦及
灍倰竘杅
母奶失乒件玉栳呾赽
劐杅哫晟 ♀ ♀
賃曰絞化 ♀ ♀
return恅 ♀ ♀
饜蹈場ヽ趙赽 ♀ -
灍竘杅 ♀ ♀
沭璃宒 ♀ ♀
平乓旦玄宒 ♀ ℅(11/9政婓)
仿丞母宒及掛极 ♀ ♀

85
羥蚚褫夔卞卅勻凶瞰(JavaSE8)
printStrings(new ArrayList<>());

86
printStrings(new ArrayList<String>());
♂ 芢�け互淏仄仁�P仁
每正奈必永玄倰方曰String午芢�今木月

87
Collections.emptyList() :
new ArrayList<>();

88
Collections.<Integer>emptyList() :
new ArrayList<Integer>();
♂ 芢�け互淏仄仁�P仁
每正奈必永玄倰方曰Integer午芢�今木月

89
劐杅哫晟 ♀
賃曰絞化 ♀
return恅 ♀
饜蹈場ヽ趙赽 ♀
灍竘杅 ♀
沭璃宒 ♀
平乓旦玄宒 ♀
仿丞母宒及掛极 ♀

90
2.方曰淏復卅芢�
♂ 踏引匹反�眢腔卅芢�
♂ 仄壬仄壬祥淏復卅芢�卞方曰戊件由奶伙巨仿奈
每葩螝卅部磁

91
JavaSE7眕ゴ及芢�
1.灍竘杅及宒及倰毛�珂
2.灍竘杅互卅中�磁反正奈必永玄倰

92
正奈必永玄倰芢�互�P仁瞰
List<Number> list =
Arrays.asList();
java.util.Arrays#<T> List<T> asList(T...)
♂
List<Number> =:= List<T>
每 T = Number

93
祥淏復卅芢�及瞰(JavaSE7)
List<Number> list =
Arrays.asList(2, 5.5);
java.util.Arrays#<T> List<T> asList(T...)

94
List<Number> list =
Arrays.<T>asList(2, 5.5);
♂
T<:Object, T?:>Integer,T:>Double(灍竘杅方曰)
每 T=Number & Comparable<...>

95
List<Number> list =
Arrays.<Number & Comparable<...>>asList(2, 5.5);
每 Number & Comparable<? extends Number &
Comparable<?>>午芢�今木月
每 List<Number & Comparable>毛List<Number>卞測⻌

96
JavaSE8眕蔥及芢�
♂ 灍竘杅及倰午正奈必永玄倰毛樓庤
每方曰淏復卅倰芢�尺

97
珂及瞰(JavaSE8及�磁)
List<Number> list =
Arrays.asList(2, 5.5);

98
List<Number> list =
Arrays.<T>asList(2, 5.5);
♂
T<:Object, T?:>Integer,T:>Double(灍竘杅方曰)
♂
T=Number(正奈必永玄倰方曰)
每 T=Number

99
List<Number> list =
Arrays.<Number>asList(2, 5.5);
♂ 淏仄仁芢�け互�P仁
每 Number午芢�今木月

100
灍斮腔卞final
倰芢�及�趙

101
平乓旦玄宒卞恚磁倰毛

102
恚磁倰ˋ
♂ JavaSE5(5.0)井日湔婓
每斥尼生伉弁旦及倰噫賜(@倰�竘杅)
每 <T extends Runnable & Cloneable>
♂ Runnable井勾Cloneable
♂ 倰 & 倰 & ＃ & 倰
♂ 磁傖倰午手

103
♂ (倰 & 倰 & ＃ & 倰)宒
♂ 翋卞仿丞母宒?丟末永玉統桽午妏蚚允月

104
手仄手恚磁倰平乓旦玄互卅井勻凶日
♂ Serializable匹Runnable卅奶件正奈白尼奈旦
每憝杅倰奶件正奈白尼奈旦
每仿丞母宒匹奶件旦正件旦趙仄凶中
每奶件正奈白尼奈旦毛隅膽允月斛猁互丐月

105
interface SRunnable implements
Runnable, Serializeable {}
sendRunnable((SRunnable) () -> {/* */});

106
interface SRunnable implements
Runnable, Serializeable {}
sendRunnable((SRunnable) () -> {/* */});

107
恚磁倰平乓旦玄+仿丞母宒
sendRunnable((Runnable & Serializable)
() -> {/* */});
♂ 倰磁傖今木月
每穴斥平民

108
灍斮腔卞final
倰芢�及�趙

109
<interface>
PublishedInterface
+already()
+exist()
+methods()

110
<interface>
PublishedInterface
+already()
+exist()
+methods()
PublisherImpl
+already()
+exist()
+methods()
AnotherImpl
+already()
+exist()
+methods()
UserImpl
+already()
+exist()
+methods()

111
<interface>
PublishedInterface
+already()
+exist()
+methods()
+newMethod()
PublisherImpl
+already()
+exist()
+methods()
AnotherImpl
+already()
+exist()
+methods()
UserImpl
+already()
+exist()
+methods()

112
<interface>
PublishedInterface
+already()
+exist()
+methods()
+newMethod()
PublisherImpl
+already()
+exist()
+methods()
AnotherImpl
+already()
+exist()
+methods()
UserImpl
+already()
+exist()
+methods()

113
奶件正奈白尼奈旦卞��俶毛
♂ 陔仄中丟末永玉毛樓尹化手誑𡥼俶毛悵勾
♂ 犯白巧伙玄灍蚾
每犯白巧伙玄及灍蚾毛枑鼎允月
每奶件正奈白尼奈旦卞灍蚾
每灍蚾互枑鼎今木卅中�磁卞妏蚚今木月

114
interface Person {
Sex getSex();
default boolean isMan() {
return getSex() == Sex.MAN;
}
}

115
class PersonImpl implements Person {
public Sex getSex() {/*...*/}
// isMan尺及灍蚾反卅仁化手OK
// Person#isMan互妏歹木月
}

116
class PersonImpl implements Person {
public boolean isMan() {/*...*/}
}
♂ 左奈田奈仿奶玉褫

117
♂ default党�赽
♂ public丟末永玉午卅月
每暫湔及奶件正奈白尼奈旦丟末永玉午肮�
♂ strictfp党�及心褫
♂ 撿砓弁仿旦匹灍蚾互枑鼎今木卅仁化手剠�觳
♂ ��俶毛灍政匹五凶
每陔凶卅�觳互???

118
灍蚾及嗣笭輥創�觳

119
嗣笭輥創
class BasicPerson {
}
class ComplexPerson extends BasicPerson
implements Person {
}

120
嗣笭輥創
BasicPerson
#isMan
Person
#isMan
ComplexPerson
#isMan

122
弁仿旦匹隅膽今木凶灍蚾互
都卞�勾

123
Class always win
class BasicPerson {
}
class ComplexPerson extends BasicPerson implements
Person {
}
♂ BasicPerson#isMan互妏歹木月
每 ※Class always win§

124
笒奶件正奈白尼奈旦及網太堤仄
class ComplexPerson extends BasicPerson
implements Person {
public boolean isMan() {
return Person.super.isMan();
}
}
♂ 奶件正奈白尼奈旦靡.super.丟末永玉靡(...)

125
弁仿旦毛賡今卅中嗣笭輥創
interface Base1 {default void m() {}}

126

127
interface ExBase extends Base1, Base2 {}

128
嗣笭輥創
Base1#m Base2#m
ExBase#m

129
interface ExBase extends
Base1, Base2 {}
每左奈田奈仿奶玉仄化腢亼

130
interface ExBase extends
Base1, Base2 {
default void m() {
Base1.super.m();
}
}

137
嗣笭輥創反窕仁卅中ㄐㄐ
♂ 湮埻�t1ㄩClass always win
每弁仿旦匹隅膽今木凶灍蚾互都卞�勾
♂ 湮埻�t2ㄩ中勾匹手左奈田奈仿奶玉匹五月
每笒弁仿旦匹final党�今木化凶日�e
每奶件正奈白尼奈旦及灍蚾毛網屯月

138
Object丟末永玉及犯白巧伙玄灍蚾
♂ Object匹隅膽今木凶public丟末永玉
每公手公手犯白巧伙玄及灍蚾
♂ Object及丟末永玉及犯白巧伙玄灍蚾反祥褫
每 interface I {default String toString() {/* */}}
每戊件由奶伙巨仿奈

140
灍斮腔卞final
倰芢�及�趙

141
static奶件正奈白尼奈旦丟末永玉
♂ static卅奶件正奈白尼奈旦丟末永玉
♂ 都卞public党�
每坻及奶件正奈白尼奈旦及丟末永玉午肮�
♂ strictfp党�褫
每犯白巧伙玄灍蚾午肮�

142
static奶件正奈白尼奈旦丟末永玉及瞰
interface Example {
static void method() {/* */}
}

143
static奶件正奈白尼奈旦丟末永玉及瞰
interface Example {
static strictfp void method() {/* */}
}
♂ strictfp党�褫

144
static奶件正奈白尼奈旦丟末永玉及輥創
♂ 輥創今木卅中
每弁仿旦丟末永玉午湮五仁綃丹
interface Example2 extends Example {}
Example2.method()反戊件由奶伙巨仿奈

145
Interesting Example
♂ public匹static卅丟末永玉
每 �汜匹郔場卞抎中凶丟末永玉

146
Interesting Example
♂ public匹static卅丟末永玉
每 �汜匹郔場卞抎中凶丟末永玉
public static void main(
String[] args)

147
main in Interface
interface EntryPoint {
public static void main(String[] args) {
/* ... */
}
}
♂ 淏仄仁�仁

148
灍斮腔卞final
倰芢�及�趙

149
No more 俋窒奶氾伊奈扑亦件
♂ 俋窒奶氾伊奈扑亦件反�K蹈趙嬪褣
♂ 囀窒奶氾伊奈扑亦件矛奈旦及仿奶皮仿伉尺
每 �K蹈趙互⺍眢卞

150
俋窒奶氾伊奈扑亦件
♂ 奶氾伊奈扑亦件互俋卞今日今木化中月
每 forㄛwhile恅
for (Student s : students) {
}

151
囀窒奶氾伊奈扑亦件仿奶皮仿伉
StreamAPI

152
StreamAPI
♂ java.util.stream.
Stream/IntStream/LongStream/DoubleStream
每末奈旦井日汜傖今木月
每準皺傷紱釬午皺傷紱釬匹犯奈正毛讀月
每 �K蹈趙互⺍眢

153
Collection
饜蹈
BufferReader
etc...
Stream
IntStream
LongStream
DoubleStream
準皺傷紱釬
皺傷紱釬
j.u.stream.*Source

154
Collection
饜蹈
BufferReader
etc...
Stream
IntStream
LongStream
DoubleStream
準皺傷紱釬
皺傷紱釬
j.u.stream.*Source

155
Make Streams
末奈旦丟末永玉妏蚚瞰
Collection Collection#stream list.stream()
饜蹈 Arrays#stream Arrays.stream(args)
BufferReader BufferReader#lines br.lines()
n?m-1引匹及杅� IntStream#range IntStream.range(n, m)
n?m引匹及杅� IntStream#rangeClosed IntStream.rangeClosed(n, m)

156
Collection
饜蹈
BufferReader
etc...
Stream
IntStream
LongStream
DoubleStream
準皺傷紱釬
皺傷紱釬
j.u.stream.*Source

157
java.util.stream.
StreamAPI 猁匼及倰
Stream<T> T(統桽倰)
IntStream int(皿伉立氾奴皮倰)
LongStream long(皿伉立氾奴皮倰)
DoubleStream double(皿伉立氾奴皮倰)

158
2 type of Streams
♂ Sequential Stream
每眻蹈匹�I燴今木月
♂ Parallel Stream
每 �K蹈匹�I燴今木月
每煦賃緙笥楊(Fork/Join)

159
Change type of Stream
Sequential Stream
Parallel Stream
parallel() sequential()

160
Collection
饜蹈
BufferReader
etc...
Stream
IntStream
LongStream
DoubleStream
準皺傷紱釬
皺傷紱釬
j.u.stream.*Source

161
準皺傷紱釬ˋ
♂ filter支map卅升
每 Stream毛殿允丟末永玉
♂ 皺傷紱釬互俴歹木月引匹�I燴今木卅中
每綈晊今木月

162
翋猁卅準皺傷紱釬
丟末永玉靡衙猁妏蚚瞰
filter 白奴伙正伉件弘 s.filter(n -> n % 2 == 0)
map 迡砉?劐𡥼 s.map(p -> p.getName())
flatMap 迡砉?劐𡥼&ⅸ拊趙 s.flatMap(room -> room.getPersons().stream())
distinct 肮珨及猁匼毛壺俋 s.distinct()
sorted �K太杸尹 s.sorted((p1, p2) -> compare(p1.age, p2.age))
peek 犯田永弘砃仃
forEach
s.peek(e -> System.out.println(e))
limit 猁匼杅秶癹 s.limit(5)
skip 掂心鵁壬允 s.skip(5)

163
Collection
饜蹈
BufferReader
etc...
Stream
IntStream
LongStream
DoubleStream
準皺傷紱釬
皺傷紱釬
j.u.stream.*Source

164
皺傷紱釬ˋ
♂ forEach支reduce支collect卅升
每 Stream毛殿今卅中丟末永玉
♂ 綈晊今木化中凶準笝傷紱釬毛�隅

165
翋猁卅皺傷紱釬
丟末永玉靡衙猁妏蚚瞰
forEach 毀覧�I燴 s.forEach(e -> System.out.println(e))
reduce �心煋心栳呾 s.reduce(1, (n1, n2) -> n1 * n2)
collect 摩廣趙 s.collect(Collectors.toList())
toArray 饜蹈趙 s.toArray(String[]::new)
min/max 郔苤�/郔湮� s.min(String::compareToIgnoreCase)
count 猁匼杅 s.count()

166
0井日10引匹堤薯仄凶中
for (int i = 0; i <= 10; i++) {
System.out.println(i);
}

167
forEach[皺傷紱釬]
T->void[j.u.function.Consumer<T>#void accept(T)]
♂ Stream<T>#forEach(T -> void)
每跪猁匼卞�I燴毛俴卅丹
每 s.forEach(t -> {/**/});

168
for (int i = 0; i <= 10; i++) {
}
IntStream.rangeClose(0, 10)
.forEach(i -> System.out.println(i));

169
for (int i = 0; i <= 10; i++) {
}
.forEach(System.out::println);

170
0井日10引匹及髒杅毛堤薯仄凶中
for (int i = 0; i <= 10; i++) {
if (i % 2 == 0) {
}
}

171
filter[準皺傷紱釬]
♂ Stream<T>#filter(T -> boolean)
每白奴伙正伉件弘
每跪猁匼毛竘杅卞羥蚚仄true毛殿仄凶手及及心紹允
每 s.filter(t -> t != null) // null毛壺俋

172
filter[準皺傷紱釬]
T->boolean[j.u.function.Predicate<T>#boolean test(T)]

173
0井日10引匹及髒杅毛堤薯仄凶中
.filter(i -> i % 2 == 0)

174
Person及伉旦玄井日靡ゴ毛堤薯
for (Person p : persons) {
System.out.println(p.getName());
}

175
map[準皺傷紱釬]
♂ Stream<T>#map(T -> R)
每迡砉?劐𡥼
每跪猁匼毛竘杅卞羥蚚仄凶磐彆及Stream毛釬月
每 personStream.map(p -> p.getName())

176
map[準皺傷紱釬]
T -> R[java.util.function.Function<T, R>#R map(T)]
R

177
persons.stream()
.map(p -> p.getName());
.forEach(n -> System.out.println(n));

178
persons.stream()
.map(Person::getName);

179
Stream毛筵剿允月map
Stream<T> IntStream
LongStream DoubleStream
#mapToObj
#mapToInt
#mapToLong
#mapToDouble
#mapToDouble
#mapToLong
#mapToInt

180
Person及伉旦玄井日靡ゴ及伉旦玄
List<String> names = new ArrayList<>();
for (Person p : persons) {
names.add(p.getName());
}

181
collect[皺傷�I燴]
♂ Stream<T>#collect(Collector<T, R>)
♂ #collect(() -> R, (R, T) -> void, (R, R) -> void)
每摩廣�I燴毛俴卅丹
每 stream.collect(Collectors.toList())
每 strings.collect(StringBuilder::new,
StringBuilder::apped, StringBuilder::apped)

182
Person及伉旦玄井日靡ゴ及伉旦玄
persons.stream()
.map(Person::getName);
.collect(Collectors.toList())

183
Putting it together
悝汜及伉旦玄(students)及囀
2爛汜匹
GPA互3.5眕奻丐月悝汜及
悝戮楓瘍及
伉旦玄毛汜傖允月

184
Putting it together
List<StudentID> list = new ArrayList<>();
for (Student s : students) {
if (s.getGrade() == 2 &&
s.getGPA() >= 3.5) {
list.add(s.getID());
}
}

185
Putting it together
悝汜及伉旦玄(students)及囀
2爛汜匹
悝戮楓瘍及

186
Putting it together
students.stream()
2爛汜匹
悝戮楓瘍及

187
Putting it together
students.stream()
.filter(s -> s.getGrade() == 2)
悝戮楓瘍及

188
Putting it together
students.stream()
.filter(s -> s.getGPA() >= 3.5)
悝戮楓瘍及

189
Putting it together
students.stream()
.map(Student::getID)

190
Putting it together
students.stream()

191
Putting it together
students.stream().parallel()

192
Project Lambda引午戶
♂ 手午手午反穴伙民戊失�𡛟
♂ 磐彆午仄化反𡘙蚚腔卅帊�卞
每仿丞母宒脹
每戊失仿奶皮仿伉
♂ 方曰旦穴奈玄卅戊奈玉尺

193
DeveloperPreview is now availableㄐ
♂ https://jdk8.java.net/download.html
♂ 郔陔及申伙玉b114
♂ Check these features by yourselfㄐㄐ

194
Thank you for your listening

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竩菁賤掊ㄐProject Lambda及允屯化[JJUG CCC 2013 Fall H-2]

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