[Language] Playing with protocol buffer

1. Install Protocal Buffer
1. Please read the readmes.  Running "make install" in the root directory installs the C++ libraries only.  You need to install the Java and Python versions separately by following the instructions in the corresponding directories. 
2. https://groups.google.com/forum/#!topic/protobuf/60-OFrBXlAE
2. How to start from protocol buffer


1. Check example code from source code package. 
2. https://github.com/google/protobuf/tree/master/examples
3. Including source for java, c++, and python
3. Examples
1. CPP
• protoc_middleman: addressbook.proto
• protoc --cpp_out=. --java_out=. --python_out=. addressbook.proto
• @touch protoc_middleman
• 
  
• protoc_middleman_go: addressbook.proto
• mkdir tutorial # make directory for go package
• protoc --go_out=tutorial addressbook.proto
• @touch protoc_middleman_go
• 
  
• add_person_cpp: add_person.cc protoc_middleman
• pkg-config --cflags protobuf  # fails if protobuf is not installed
• c++ add_person.cc addressbook.pb.cc -o add_person_cpp `pkg-config --cflags --libs protobuf`
• 
  
1. pkg-config --cflags --libs protobuf 
• pkg-config - Return metainformation about installed libraries
• The  pkg-config program is used to retrieve information about installed libraries in
•        the system.  It is typically used to compile and link against one or more libraries.
•        Here is a typical usage scenario in a Makefile:
• 
  
•        program: program.c
•             cc program.c 'pkg-config --cflags --libs gnomeui'
2. `pkg-config --cflags --libs protobuf ` returns
1.  -lprotobuf -lz -lpthread on centos
2.  -pthread  -pthread -lprotobuf -lpthread on ubuntu 14.04
3. "Package protobuf was not found in the pkg-config search path." if it is not installed
3. Generated: 
1. add_person_cpp
1. Run this file, saved it to an address book following prompt
2. File looks like something like this
2. list_people_cpp
1. Run this file, returned with:
• Person ID: 1
•   Name: Charles
•   E-mail address: charles@gmail.com
•   Home phone #: 541 346 1380
4. Python
1. Error： ImportError: No module named google.protobuf
1. sudo pip install protobuf
5. Java
1. make Error:  package com.google.protobuf does not exist
2. need protobuf-java-*.jar