More Related Content Similar to Let's go Developer 2011 sendai Let's go Java Developer (Programming Language Groovy Part) (20) More from Uehara Junji (20) 2. Java
2011 05/28
Slide # 2
2011 5 28
3. Java
2011 05/28
Slide # 3
2011 5 28
4. $ cat input.txt
That that is is that that is
not is not is that it it is
$ java WordCount input.txt
1: [That]
2: [not]
2: [it]
4: [that]
6: [is] Java
2011 05/28
Slide # 4
2011 5 28
5. Java WordCount:48 Set<Map.Entry<String, Integer>> entrySet =
import java.util.Comparator; map.entrySet();
import java.util.HashMap; Object[] list = entrySet.toArray();
import java.util.Map; Comparator comp = new Comparator(){
import java.util.Set; public int compare(Object o1, Object o2)
import java.util.List; {
import java.util.Arrays; Map.Entry<String, Integer> e1 =
import java.io.FileReader; (Map.Entry<String, Integer>) o1;
import java.io.BufferedReader; Map.Entry<String, Integer> e2 =
import java.io.FileNotFoundException; (Map.Entry<String, Integer>) o2;
import java.io.IOException; return e1.getValue() - e2.getValue();
}
public class WordCount { };
@SuppressWarnings(value = "unchecked") Arrays.sort(list, comp);
public static void main(String[] args) { for (Object it: list) {
FileReader fis = null; Map.Entry<String, Integer> entry =
BufferedReader br = null; (Map.Entry<String, Integer>)it;
try { System.out.println(entry.getValue() + ":
HashMap<String, Integer> map = new ["+entry.getKey()+"]");
HashMap<String, Integer>(); }
fis = new FileReader(args[0]); }
br = new BufferedReader(fis); catch (IOException e) {
String line; try {if (br != null) br.close();}catch
while ((line = br.readLine()) != null) { (IOException ioe){}
for (String it: line.split("s+")) { try {if (fis != null)fis.close();}catch
map.put(it, (map.get(it)==null) ? 1 : (IOException ioe){}
(map.get(it) + 1)); e.printStackTrace();
} }
Java
} }
}
2011 05/28
Slide # 5
2011 5 28
6. Groovy WordCount(9 )
def map = [:].withDefault{0}
new File(args[0]).eachLine {
it.split(/s+/).each {
map[it]++
}
}
map.entrySet().sort{it.value}.each {
println "${it.value}: [${it.key}]"
}
Java
2011 05/28
Slide # 6
2011 5 28
7. Java
Set<Map.Entry<String, Integer>>
import java.util.Comparator; entrySet = map.entrySet();
import java.util.HashMap; Object[] list = entrySet.toArray();
import java.util.Map; Comparator comp = new Comparator(){
import java.util.Set; public int compare(Object o1,
import java.util.List; Object o2) {
import java.util.Arrays; Map.Entry<String, Integer> e1
import java.io.FileReader; = (Map.Entry<String, Integer>) o1;
import java.io.BufferedReader; Map.Entry<String, Integer> e2
import java.io.FileNotFoundException; = (Map.Entry<String, Integer>) o2;
import java.io.IOException; return e1.getValue() -
e2.getValue();
public class WordCount { }
@SuppressWarnings(value = "unchecked") };
public static void main(String[] args) { Arrays.sort(list, comp);
FileReader fis = null; for (Object it: list) {
BufferedReader br = null; Map.Entry<String, Integer> entry
try { = (Map.Entry<String, Integer>)it;
HashMap<String, Integer> map = new System.out.println(entry.getValue
HashMap<String, Integer>(); () + ": ["+entry.getKey()+"]");
fis = new FileReader(args[0]); }
br = new BufferedReader(fis); }
String line; catch (IOException e) {
while ((line = br.readLine()) != try {if (br != null) br.close();}
null) { catch(IOException ioe){}
for (String it: line.split("s try {if (fis != null)fis.close();}
+")) { catch(IOException ioe){}
map.put(it, (map.get(it) e.printStackTrace();
==null) ? 1 : (map.get(it) + 1));
}
}
}
Java
} } 2011 05/28
Slide # 7
2011 5 28
8. Groovy WordCount(9 )
def map = [:].withDefault{0} // value 0 map
new File(args[0]).eachLine { //
it.split(/s+/).each { // /s+/
map[it]++ // map 1
}
}
map.entrySet().sort{it.value}.each {// map entrySet value
println "${it.value}: [${it.key}]"// key,value
}
Java
2011 05/28
Slide # 8
2011 5 28
9. Groovy WordCount(9 )
def map = [:].withDefault{0} // value 0 map
new File(args[0]).eachLine { //
it.split(/s+/).each { // /s+/
map[it]++ // map 1
}
}
map.entrySet().sort{it.value}.each {// map entrySet value
println "${it.value}: [${it.key}]"// key,value
}
Java
2011 05/28
Slide # 9
2011 5 28
10. Groovy WordCount(9 )
def map = [:].withDefault{0} // value 0 map
new File(args[0]).eachLine { //
it.split(/s+/).each { // /s+/
map[it]++ // map 1
}
}
map.entrySet().sort{it.value}.each {// map entrySet value
println "${it.value}: [${it.key}]"// key,value
}
Java
2011 05/28
Slide # 10
2011 5 28
11. Groovy WordCount(9 )
def map = [:].withDefault{0} // value 0 map
new File(args[0]).eachLine { //
it.split(/s+/).each { // /s+/
map[it]++ // map 1
}
}
map.entrySet().sort{it.value}.each {// map entrySet value
println "${it.value}: [${it.key}]"// key,value
}
Java
2011 05/28
Slide # 11
2011 5 28
12. Groovy WordCount(9 )
def map = [:].withDefault{0} // value 0 map
new File(args[0]).eachLine { //
it.split(/s+/).each { // /s+/
map[it]++ // map 1
}
}
map.entrySet().sort{it.value}.each {// map entrySet value
println "${it.value}: [${it.key}]"// key,value
}
Java
2011 05/28
Slide # 12
2011 5 28
13. Groovy WordCount(9 )
def map = [:].withDefault{0} // value 0 map
new File(args[0]).eachLine { //
it.split(/s+/).each { // /s+/
map[it]++ // map 1
}
}
map.entrySet().sort{it.value}.each {// map entrySet value
println "${it.value}: [${it.key}]"// key,value
}
Java
2011 05/28
Slide # 13
2011 5 28
14. Groovy WordCount(9 )
def map = [:].withDefault{0} // value 0 map
new File(args[0]).eachLine { //
it.split(/s+/).each { // /s+/
map[it]++ // map 1
}
}
map.entrySet().sort{it.value}.each {// map entrySet value
println "${it.value}: [${it.key}]"// key,value
}
Java
2011 05/28
Slide # 14
2011 5 28
15. Java
2011 05/28
Slide # 15
2011 5 28
16. public final class Person { if (obj == null)
private final String firstName; return false;
private final String lastName; if (getClass() != obj.getClass())
return false;
public Person(String firstName, String lastName) { Person other = (Person) obj;
this.firstName = firstName; if (firstName == null) {
this.lastName = lastName; if (other.firstName != null)
} return false;
} else if (!firstName.equals(other.firstName))
public String getFirstName() { return false;
return firstName; if (lastName == null) {
} if (other.lastName != null)
return false;
public String getLastName() { } else if (!lastName.equals(other.lastName))
return lastName; return false;
} return true;
}
@Override
public int hashCode() { @Override
final int prime = 31; public String toString() {
int result = 1; return "Person(firstName:" + firstName
result = prime * result + ((firstName == null) + ", lastName:" + lastName + ")";
? 0 : firstName.hashCode()); }
result = prime * result + ((lastName == null)
? 0 : lastName.hashCode()); }
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
Java
2011 05/28
Slide # 16
2011 5 28
17. public final class Person { if (obj == null)
private final String firstName; return false;
private final String lastName; if (getClass() != obj.getClass())
return false;
public Person(String firstName, String lastName) { Person other = (Person) obj;
this.firstName = firstName; if (firstName == null) {
this.lastName = lastName; if (other.firstName != null)
} return false;
} else if (!firstName.equals(other.firstName))
public String getFirstName() { return false;
return firstName; if (lastName == null) {
} if (other.lastName != null)
return false;
public String getLastName() { } else if (!lastName.equals(other.lastName))
return lastName; return false;
} return true;
}
@Override
public int hashCode() { @Override
final int prime = 31; public String toString() {
int result = 1; return "Person(firstName:" + firstName
result = prime * result + ((firstName == null) + ", lastName:" + lastName + ")";
? 0 : firstName.hashCode()); }
result = prime * result + ((lastName == null)
? 0 : lastName.hashCode()); }
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
Java
2011 05/28
Slide # 16
2011 5 28
18. Groovy :4
@Immutable
class Person {
String firstName, lastName
}
Java
2011 05/28
Slide # 17
2011 5 28
19. Groovy :4
@Immutable
class Person {
String firstName, lastName
}
x = new Person("Junji","Uehara")
assert x.lastName == "Uehara"
x.firstName = "abc"
//==>
groovy.lang.ReadOnlyPropertyException:
Cannot set readonly property: firstName
Java
for class: Person 2011 05/28
Slide # 17
2011 5 28
20. Groovy :4
@Immutable
class Person {
String firstName, lastName
}
x = new Person("Junji","Uehara")
assert x.lastName == "Uehara"
x.firstName = "abc"
Java
2011 05/28
Slide # 18
2011 5 28
21. Groovy :4
@Immutable
class Person {
String firstName, lastName
}
x = new Person("Junji","Uehara")
assert x.lastName == "Uehara"
x.firstName = "abc"
Java
2011 05/28
Slide # 19
2011 5 28
22. Groovy :4
@Immutable
class Person {
String firstName, lastName
}
x = new Person("Junji","Uehara")
assert x.lastName == "Uehara"
x.firstName = "abc"
Java
2011 05/28
Slide # 20
2011 5 28
23. Java
2011 05/28
Slide # 21
2011 5 28
24. Java
2011 05/28
Slide # 21
2011 5 28
25. Java
2011 05/28
Slide # 21
2011 5 28
26. Java
2011 05/28
Slide # 21
2011 5 28
27. Java
2011 05/28
Slide # 21
2011 5 28
28. DSL
OS
PHP Haskel
C++
Python
C Ruby
Java
Java + Groovy
Java
2011 05/28
Slide # 22
2011 5 28
29. Groovy
Java
Java
2011 05/28
Slide # 23
2011 5 28
