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JavaCCͱSpring Expression Language
Λ༻͍ͨϢʔβఆ߲ٛ
Yuya Yamaguchi@rakus
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#RAKUSMeetup
Profile
⋅ SIerʹ5ࡏ੶ͨ͠ͷͪɺϥΫεʹೖࣾ
⋅ ָָۈଵνʔϜʹॴଐ
⋅ Backend Engineer + CI
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͓͢͠Δ͜ͱ
⋅ Ϣʔβఆ߲ٛͱ
⋅ Ϣʔβఆ߲ٛΛͲ͏࣮ͬͯݱͨ͠ͷ͔
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Ϣʔβఆ߲ٛͱ
⋅ ۈใΛར༻ͨ͠ҙͷܭࢉࣜΛ߲࣋ͬͨ
ΛఆٛͰ͖Δػೳ
⋅ ܭࢉ݁ՌΛۈใ͔Βࢀর
⋅ اۀಠࣗͷ༻ޠۀ࣌ؒͷࢉग़ͳͲΛఆ
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Ϣʔβఆ߲ٛͰॏཁͱߟ͑ͨ2ͭͷ͜ͱ
⋅ ܭࢉࣜΛͲ͏ධՁ͢Δͷ͔
− ࣜͱͯ͠ͷਖ਼͠͞ΛධՁ͠ͳ͍ͱ͍͚ͳ͍
− ΊΔܭࢉ͕ࣜ૿͑ͨ߹ʹ֦ுͰ͖Δඞཁ͕͋Δ
⋅ Ͳ͏ͬͯܭࢉ݁ՌΛࢉग़͢Δͷ͔
− ܭࢉ݁ՌʑมΘΔ
− ܭࢉ݁ՌΛग़͢ʹதؒܭࢉ͕Ͱ͖Δඞཁ͕͋Δ
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Ϣʔβఆ߲ٛͰॏཁͱߟ͑ͨ2ͭͷ͜ͱ
⋅ ܭࢉࣜΛͲ͏ධՁ͢Δͷ͔
− ࣜͱͯ͠ͷਖ਼͠͞ΛධՁ͠ͳ͍ͱ͍͚ͳ͍
− ΊΔܭࢉ͕ࣜ૿͑ͨ߹ʹ֦ுͰ͖Δඞཁ͕͋Δ
➢ JavaCC
⋅ Ͳ͏ͬͯܭࢉ݁ՌΛࢉग़͢Δͷ͔
− ܭࢉ݁ՌʑมΘΔ
− ܭࢉ݁ՌΛग़͢ʹதؒܭࢉ͕Ͱ͖Δඞཁ͕͋Δ
➢ SpEL(Spring Expression Language)
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ܭࢉࣜͷධՁͱܭࢉ݁Ռͷࢉग़
JavaCC
SpEL
JSON
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ܭࢉࣜͷධՁͱܭࢉ݁Ռͷࢉग़
JavaCC
SpEL
JSON
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ܭࢉࣜͷධՁͱܭࢉ݁Ռͷࢉग़
JavaCC
SpEL
ܭࢉࣜ
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ܭࢉࣜͷධՁͱܭࢉ݁Ռͷࢉग़
JavaCC
SpEL
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ܭࢉࣜͷධՁͱܭࢉ݁Ռͷࢉग़
JavaCC
SpEL
ܭࢉࣜͱม
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ܭࢉࣜͷධՁͱܭࢉ݁Ռͷࢉग़
JavaCC
SpEL
ܭࢉࣜ
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JavaCCͱ
⋅ Java Compiler Compiler
− https://javacc.github.io/javacc/
⋅ BSD License 2.0
⋅ ֦ுBNF͔ΒJavaͷύʔαΛੜ
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1 + 1͕ೖྗ͞ΕͨΒʮ2ʯΛग़ྗ͢Δαϯϓϧ
PARSER_BEGIN(Example)
public class Example {
public static void main(String args[]) {
Example parser = new Example(System.in);
parser.Start();
}
}
PARSER_END(Example)
SKIP: { " " }
TOKEN: { | | }
void Start():
{ int sum; int number; }
{
sum = number()
(
{}
number = number() { sum += number; }
)*
{ System.out.println("> " + sum); }
}
int number():
{ Token number; }
{
number = {}
{ return Integer.parseInt(number.image); }
}
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1 + 1͕ೖྗ͞ΕͨΒʮ2ʯΛग़ྗ͢Δαϯϓϧ
$ javacc example.jj
$ ls -l
-rw-r--r-- 1 user group 6290 1 2 12:34 Example.java
-rw-r--r-- 1 user group 457 1 2 12:34 ExampleConstants.java
-rw-r--r-- 1 user group 7228 1 2 12:34 ExampleTokenManager.java
-rw-r--r-- 1 user group 6171 1 2 12:34 ParseException.java
-rw-r--r-- 1 user group 12351 1 2 12:34 SimpleCharStream.java
-rw-r--r-- 1 user group 4058 1 2 12:34 Token.java
-rw-r--r-- 1 user group 4420 1 2 12:34 TokenMgrError.java
-rw-r--r-- 1 user group 375 1 2 12:34 example.jj
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ܭࢉࣜͷධՁͱܭࢉ݁Ռͷࢉग़
JavaCC
SpEL
ܭࢉࣜͱม
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SpEL(Spring Expression Language)ͱ
⋅ JSPͷELࣜΛSpringʹ֦ு
− ${name}
⋅ Spring 3.0͔Βಋೖ
⋅ @ValueΞϊςʔγϣϯͰར༻
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numberมͷ + 2000ͷܭࢉ݁ՌΛऔಘ͢Δαϯϓϧ
class Data {
public int number = 21;
}
ExpressionParser parser = new SpelExpressionParser();
EvaluationContext context = new StandardEvaluationContext(new Data());
Expression exp = parser.parseExpression("number + 2000");
// year = 2021
int year = exp.getValue(context, Integer.class);
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·ͱΊ
⋅ JavaCCͰܭࢉࣜΛධՁ͠ɺSpELͰܭࢉ݁Ռͷࢉग़͠·ͨ͠
⋅ JavaCCΛར༻͢Δ͜ͱͰܭࢉࣜΛಠཱͤ͞Δ͜ͱͰ֦ுੑ͕
Ͱ͖ͨ
⋅ JavaCCͷݺͼग़͠ίετ͕ߴ͍͕վળ՝Ͱ͢
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