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Tij generic 170527 #2

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Merged
OneCodeOneTime merged 2 commits into from
May 27, 2017
Merged

Tij generic 170527 #2

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e9b0698
170537-Generic
OneCodeOneTime May 27, 2017
44243e0
Merge pull request #1 from OneCodeOneTime/master
OneCodeOneTime May 27, 2017
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22 changes: 22 additions & 0 deletions src/btp/oneP/GenericErase.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,22 @@
package btp.oneP;

import java.lang.reflect.Method;
import java.util.ArrayList;

public class GenericErase {

public static void main(String[] args) {
ArrayList<String> sl = new ArrayList<String>();
sl.add("Magic");
Class<? extends ArrayList> clazz = sl.getClass();
try{
Method method = clazz.getMethod("add", Object.class);
method.invoke(sl, 1);
System.out.println(sl);
//out:[Magic, 1]
}catch(Exception e){
e.printStackTrace();
}
}

}
29 changes: 29 additions & 0 deletions src/btp/oneP/GenericEvaluate.java
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package btp.oneP;

import java.util.ArrayList;
import java.util.Collection;

public class GenericEvaluate {

public static void main(String[] args) {
Collection<Pair<String,Long>> c1 = new ArrayList<Pair<String,Long>>();
Collection<Pair<String,Long>> c2 = c1;
//Collection<Pair<String,?>> c3 = c1;
Collection<? extends Pair<String,?>> c4 = c1;

Collection<SubTypeOfPair<String,Long>> c5 = new ArrayList<SubTypeOfPair<String,Long>>();
//Collection<Pair<String,Long>> c6 = c5;
Collection<SubTypeOfPair<String,Long>> c7 = c5;
//Collection<Pair<String,?>> c8 = c5;
Collection<? extends Pair<String,?>> c9 = c5;
}

}

class Pair<K,V>{

}

class SubTypeOfPair<K,V> extends Pair<K, V>{

}
24 changes: 24 additions & 0 deletions src/btp/oneP/ListCopy.java
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package btp.oneP;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class ListCopy {

public static <T> void copy(List<? extends T> src,List<? super T> dest){
for(T t:src){
dest.add(t);
}
}

public static void main(String[] args) {
List<String> sList = new ArrayList<String>(Arrays.<String>asList(new String[]{"hehe","xixi","caca"}));
List<Object> oList = new ArrayList<Object>();
copy(sList,oList);
for(Object o:oList){
System.out.println(o);
}
}

}