set _ORACLE_SCRIPT to be TRUE to create a new user
alter session set "_ORACLE_SCRIPT" = TRUE;
CREATE USER demo IDENTIFIED BY demo
grant dba to demo;
set _ORACLE_SCRIPT to be TRUE to create a new user
alter session set "_ORACLE_SCRIPT" = TRUE;
CREATE USER demo IDENTIFIED BY demo
grant dba to demo;
ByteBuddy is key framework used in Mockito, it will auto generated subclass and override default methods. Following code will print out “Hello ByteBuddy!”.
import net.bytebuddy.ByteBuddy;
import net.bytebuddy.dynamic.DynamicType;
import net.bytebuddy.implementation.FixedValue;
import net.bytebuddy.matcher.ElementMatchers;
public class ByteBuddyEntry {
public static void main(String[] args)
{
DynamicType.Unloaded unloadedType = new ByteBuddy()
.subclass(Object.class)
.method(ElementMatchers.isToString())
.intercept(FixedValue.value("Hello ByteBuddy!"))
.make();
Class<?> dynamicType = unloadedType.load(ByteBuddyEntry.class
.getClassLoader())
.getLoaded();
try {
System.out.println(dynamicType.newInstance().toString());
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
}
}
SQL lex files:
sql/sql_lex.h、sql/lex_token.h、sql/lex.h、sql/lex_symbol.h
sql/gen_lex_token.cc、sql/sql_lex.cc
SQL grammar parser file:
sql/sql_yacc.yy、sql/sql_yacc.cc、sql/sql_yacc.h
SQL hint grammar parser file:
sql/sql_hints.yy、sql/sql_hints.yy.cc
mysql use bison (lex/yacc) to token sql statement and parse it, take sql_yacc.yy for example, it is main file contains all parse sql rules.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | FROM ubuntu:18.04 ENV TZ=Australia/Sydney RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone RUN apt-get update RUN apt-get install -y bash git python3 g++ curl vim openssh-server sudo RUN addgroup --gid 9999 git && adduser --uid 9999 --gid 9999 --shell /usr/bin/git-shell git RUN addgroup --gid 9000 xxx && adduser --uid 9000 --gid 9000 --shell /bin/bash xxx RUN echo git:password | chpasswd RUN echo xxx:password | chpasswd RUN mkdir -p /home/git RUN mkdir -p /home/xxx RUN chown -Rh git:git /home/git COPY sshd_config /etc/ssh/sshd_config EXPOSE 22 ENTRYPOINT service ssh restart && bash CMD ["/bin/bash"] |
key idea is how to generate all subset of array.
take 3 elements of arrays for example,
[a, _, _] -> [1, 0, 0]
[_, b, _] -> [0, 1, 0]
[a, b, _] -> [1, 1, 0]
[_, _, c] -> [0, 0, 1]
[a, _, c] -> [1, 0, 1]
[_, b, c] -> [0, 1, 1]
[a, b, c] -> [1, 1, 1]
integer i is loop through 1 to Math.pow(2, nums.length) – 1, for each integer, we check how many 1 bit
i & 1, if it is 1, we get nums[index] out as elements for subarray.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | class Solution { public int subsetXORSum(int[] nums) { int result = 0; int x = (int)Math.pow(2, nums.length) - 1; for(int i=1;i<=x;i++) { int p = i; int r = 0; for(int j=0;j<nums.length;j++) { int t = p & 1; p >>= 1; if (t == 1) { r ^= nums[j]; } } result += r; } return result; } } |
git remote -v
git remote
git remote add pb https://github.com/paulboone/ticgit
$ git remote -v
origin https://github.com/schacon/ticgit (fetch)
origin https://github.com/schacon/ticgit (push)
pb https://github.com/paulboone/ticgit (fetch)
pb https://github.com/paulboone/ticgit (push)
$ git fetch pb
remote: Counting objects: 43, done.
remote: Compressing objects: 100% (36/36), done.
remote: Total 43 (delta 10), reused 31 (delta 5)
Unpacking objects: 100% (43/43), done.
From https://github.com/paulboone/ticgit
* [new branch] master -> pb/master
* [new branch] ticgit -> pb/ticgit
$ git checkout master
$ git merge upstream/master # important, merge fetch code and master
$ git push
There are 4 type of Mergeable Object in Spring
ManagedList
ManagedProperties
ManagedMap
ManagedSet
Take ManagedList as example
if mergeEnabled is set to be false, merge will stop
if parent is null, return itself.
and finally it will add parent firstly and then add children.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | @Override @SuppressWarnings("unchecked") public List<E> merge(@Nullable Object parent) { if (!this.mergeEnabled) { throw new IllegalStateException("Not allowed to merge when the 'mergeEnabled' property is set to 'false'"); } if (parent == null) { return this; } if (!(parent instanceof List)) { throw new IllegalArgumentException("Cannot merge with object of type [" + parent.getClass() + "]"); } List<E> merged = new ManagedList<>(); merged.addAll((List<E>) parent); merged.addAll(this); return merged; } |
java reflection could get all methods of a class.
isBridge() could check whether method is bridged or not.
when we override parent class general type method in child class, method will become bridged.
here is example:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 | package org.spring.main; import java.lang.reflect.Method; import org.springframework.core.BridgeMethodResolver; public class BridgeMethodResolverEntry { public class Node<T> { public T data; public Node(T data) { this.data = data; } public void setData(T data) { System.out.println("Node.setData"); this.data = data; } } public class MyNode extends Node<Integer> { public MyNode(Integer data) { super(data); } @Override public void setData(Integer data) { System.out.println("MyNode.setData"); super.setData(data); } } public static void main(String[] args) { // TODO Auto-generated method stub BridgeMethodResolverEntry x = new BridgeMethodResolverEntry(); MyNode resolver = x.new MyNode(5); Method[] declaredMethods = resolver.getClass().getDeclaredMethods(); for (int i = 0; i < declaredMethods.length; i++) { Method declaredMethod = declaredMethods[i]; String methodName = declaredMethod.getName(); Class<?> returnType = declaredMethod.getReturnType(); Class<?> declaringClass = declaredMethod.getDeclaringClass(); boolean bridge = declaredMethod.isBridge(); System.out.print((i+1) + " method name is" + methodName + ", return type is " + returnType + " "); System.out.print(bridge ? " is Bridge Method" : " is not Bridge Method"); System.out.println(" it is declared at "+declaringClass.getSimpleName()+""); } } } |
curl could be used as POSTMan CLI.
for PDF downloading restful API, curl actions better that postman
1 | curl -v -X GET -u username:password https://<url> |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | package com.dw.lib.test; public class StaticInitializationBlock { static { System.out.println("STATIC BLOCK"); } public StaticInitializationBlock() { System.out.println("constructor"); } public static void main(String[] args) { StaticInitializationBlock block = new StaticInitializationBlock(); System.out.println("MAIN METHOD"); } } |
output:
STATIC BLOCK
constructor
MAIN METHOD