Add bazel support for examples.

The example utilizes native bazel rules (proto_library, cc_proto_library,
java_proto_library, java_lite_proto_library) to show how easy it is to
build protobuf with bazel's native support. It also makes use of well
known types which was not possible until the latest bazel 0.5.4 release
and https://github.com/google/protobuf/pull/3594 .

README.md

@@ -68,9 +68,19 @@ how to install protobuf runtime for that specific language:
 | PHP                                  | [php](php)                                                  |
 | Dart                                 | [dart-lang/protobuf](https://github.com/dart-lang/protobuf) |
 
+Quick Start
+-----------
 
-Usage
------
+The best way to learn how to use protobuf is to follow the tutorials in our
+developer guide:
+
+https://developers.google.com/protocol-buffers/docs/tutorials
+
+If you want to learn from code examples, take a look at the examples in the
+[examples](examples) directory.
+
+Documentation
+-------------
 
 The complete documentation for Protocol Buffers is available via the
 web at:

examples/BUILD

+# This BUILD file shows how to use protobuf with bazel. Before you can use
+# proto_library/<lang>_proto_library rules in a BUILD file, you need to
+# include protobuf repo as remote repositories in your WORKSPACE file. See
+# the WORKSPACE file in the same directory with this BUILD file for an
+# example.
+
+# For each .proto file, a proto_library target should be defined. This target
+# is not bound to any particular language. Instead, it defines the dependency
+# graph of the .proto files (i.e., proto imports) and serves as the provider
+# of .proto source files to the protocol compiler.
+#
+# Remote repository "com_google_protobuf" must be defined to use this rule.
+proto_library(
+    name = "addressbook_proto",
+    srcs = ["addressbook.proto"],
+    deps = ["@com_google_protobuf//:timestamp_proto"],
+)
+
+# The cc_proto_library rule generates C++ code for a proto_library rule. It
+# must have exactly one proto_library dependency. If you want to use multiple
+# proto_library targets, create a separate cc_proto_library target for each
+# of them.
+#
+# Remote repository "com_google_protobuf_cc" must be defined to use this rule.
+cc_proto_library(
+    name = "addressbook_cc_proto",
+    deps = [":addressbook_proto"],
+)
+
+# cc_library/cc_binary targets can depend on cc_proto_library targets.
+cc_binary(
+    name = "add_person_cpp",
+    srcs = ["add_person.cc"],
+    deps = [":addressbook_cc_proto"],
+)
+
+cc_binary(
+    name = "list_people_cpp",
+    srcs = ["list_people.cc"],
+    deps = [":addressbook_cc_proto"],
+)
+
+# Similar to cc_proto_library but for Java.
+#
+# Remote repository "com_google_protobuf_java" must be defined to use this rule.
+java_proto_library(
+    name = "addressbook_java_proto",
+    deps = [":addressbook_proto"],
+)
+
+java_binary(
+    name = "add_person_java",
+    srcs = ["AddPerson.java"],
+    main_class = "AddPerson",
+    deps = [":addressbook_java_proto"],
+)
+
+java_binary(
+    name = "list_people_java",
+    srcs = ["ListPeople.java"],
+    main_class = "ListPeople",
+    deps = [":addressbook_java_proto"],
+)
+
+# Java lite.
+#
+# Remote repository "com_google_protobuf_javalite" must be defined to use this
+# rule.
+java_lite_proto_library(
+    name = "addressbook_java_lite_proto",
+    deps = [":addressbook_proto"],
+)
+
+# Java lite API is a subset of the regular Java API so if you only uses this
+# subset in your code, you can actually compile your code against both (i.e.,
+# share code between server build and Android build).
+#
+# The lite version has a smaller code size, and you can see that by comparing
+# the resulted .jar file:
+#
+#   $ bazel build :add_person_java_deploy.jar :add_person_java_lite_deploy.jar
+#   $ ls -l bazel-bin/*_deploy.jar
+#   -r-xr-xr-x 1 xiaofeng eng 1230797 Sep  8 12:24 bazel-bin/add_person_java_deploy.jar
+#   -r-xr-xr-x 1 xiaofeng eng  236166 Sep  8 12:24 bazel-bin/add_person_java_lite_deploy.jar
+#
+# In the above example, the lite .jar file is 6 times smaller. With proper
+# proguard inlining/stripping, the difference can be much more larger than
+# that.
+java_binary(
+    name = "add_person_java_lite",
+    srcs = ["AddPerson.java"],
+    main_class = "AddPerson",
+    deps = [":addressbook_java_lite_proto"],
+)
+
+java_binary(
+    name = "list_people_java_lite",
+    srcs = ["ListPeople.java"],
+    main_class = "ListPeople",
+    deps = [":addressbook_java_lite_proto"],
+)

examples/ListPeople.java

@@ -27,6 +27,9 @@ class ListPeople {
           case WORK:
             System.out.print("  Work phone #: ");
             break;
+          default:
+            System.out.println(" Unknown phone #: ");
+            break;
         }
         System.out.println(phoneNumber.getNumber());
       }

examples/Makefile

@@ -51,7 +51,7 @@ list_people_gotest: list_people.go list_people_go
 	go test list_people.go list_people_test.go
 
 javac_middleman: AddPerson.java ListPeople.java protoc_middleman
-	javac -cp ../java/core/target/*.jar AddPerson.java ListPeople.java com/example/tutorial/AddressBookProtos.java
+	javac -cp $$CLASSPATH AddPerson.java ListPeople.java com/example/tutorial/AddressBookProtos.java
 	@touch javac_middleman
 
 add_person_java: javac_middleman

examples/README.md

+# Protocol Buffers - Code Example
+
+This directory contains example code that uses Protocol Buffers to manage an
+address book. Two programs are provided for each supported language. The
+add_person example adds a new person to an address book, prompting the user to
+input the person's information. The list_people example lists people already in
+the address book. The examples use the exact same format in all three languages,
+so you can, for example, use add_person_java to create an address book and then
+use list_people_python to read it.
+
+These examples are part of the Protocol Buffers tutorial, located at:
+  https://developers.google.com/protocol-buffers/docs/tutorials
+
+## Build the example using bazel
+
+The example requires bazel 0.5.4 or newer to build. You can download/install
+the latest version of bazel from bazel's release page:
+
+    https://github.com/bazelbuild/bazel/releases
+
+Once you have bazel installed, simply run the following command in this examples
+directory to build the code:
+
+    $ bazel build :all
+
+Then you can run the built binary:
+
+    $ bazel-bin/add_person_cpp addressbook.data
+
+To use protobuf in your own bazel project, please follow instructions in the
+[BUILD](BUILD) file and [WORKSPACE](WORKSPACE) file.
+
+## Build the example using make
+
+You must install the protobuf package before you can build it using make. The
+minimum requirement is to install protocol compiler (i.e., the protoc binary)
+and the protobuf runtime for the language you want to build.
+
+You can simply run "make" to build the example for all languages (except for
+Go). However, since different language has different installation requirement,
+it will likely fail. It's better to follow individual instrutions below to
+build only the language you are interested in.
+
+### C++
+
+You can follow instructions in [../src/README.md](../src/README.md) to install
+protoc and protobuf C++ runtime from source.
+
+Then run "make cpp" in this examples directory to build the C++ example. It
+will create two executables: add_person_cpp and list_people_cpp. These programs
+simply take an address book file as their parameter. The add_person_cpp
+programs will create the file if it doesn't already exist.
+
+To run the examples:
+
+    $ ./add_person_cpp addressbook.data
+    $ ./list_people_cpp addressbook.data
+
+Note that on some platforms you may have to edit the Makefile and remove
+"-lpthread" from the linker commands (perhaps replacing it with something else).
+We didn't do this automatically because we wanted to keep the example simple.
+
+### Python
+
+Follow instructions in [../README.md](../README.md) to install protoc and then
+follow [../python/README.md](../python/README.md) to install protobuf python
+runtime from source. You can also install python runtime using pip:
+
+    $ pip install protobuf
+
+Make sure the runtime version is the same as protoc binary, or it may not work.
+
+After you have install both protoc and python runtime, run "make python" to
+build two executables (shell scripts actually): add_person_python and
+list_people_python. They work the same way as the C++ executables.
+
+### Java
+
+Follow instructions in [../README.md](../README.md) to install protoc and then
+download protobuf Java runtime .jar file from maven:
+
+    https://mvnrepository.com/artifact/com.google.protobuf/protobuf-java
+
+Then run the following:
+
+    $ export CLASSPATH=/path/to/protobuf-java-[version].jar
+    $ make java
+
+This will create the add_person_java/list_people_java executables (shell
+scripts) and can be used to create/display an address book data file.
+
+### Go
+
+The Go example requires a plugin to the protocol buffer compiler, so it is not
+build with all the other examples.  See:
+
+    https://github.com/golang/protobuf
+
+for more information about Go protocol buffer support.
+
+First, install the Protocol Buffers compiler (protoc).
+
+Then, install the Go Protocol Buffers plugin ($GOPATH/bin must be in your $PATH
+for protoc to find it):
+
+    go get github.com/golang/protobuf/protoc-gen-go
+
+Build the Go samples in this directory with "make go".  This creates the
+following executable files in the current directory:
+
+    add_person_go      list_people_go
+
+To run the example:
+
+    ./add_person_go addressbook.data
+
+to add a person to the protocol buffer encoded file addressbook.data.  The file
+is created if it does not exist.  To view the data, run:
+
+    ./list_people_go addressbook.data
+
+Observe that the C++, Python, and Java examples in this directory run in a
+similar way and can view/modify files created by the Go example and vice
+versa.

examples/README.txt

-This directory contains example code that uses Protocol Buffers to manage an
-address book.  Two programs are provided, each with three different
-implementations, one written in each of C++, Java, and Python.  The add_person
-example adds a new person to an address book, prompting the user to input
-the person's information.  The list_people example lists people already in the
-address book.  The examples use the exact same format in all three languages,
-so you can, for example, use add_person_java to create an address book and then
-use list_people_python to read it.
-
-You must install the protobuf package before you can build these.
-
-To build all the examples (on a unix-like system), simply run "make".  This
-creates the following executable files in the current directory:
-  add_person_cpp     list_people_cpp
-  add_person_java    list_people_java
-  add_person_python  list_people_python
-
-If you only want to compile examples in one language, use "make cpp"*,
-"make java", or "make python".
-
-All of these programs simply take an address book file as their parameter.
-The add_person programs will create the file if it doesn't already exist.
-
-These examples are part of the Protocol Buffers tutorial, located at:
-  https://developers.google.com/protocol-buffers/docs/tutorials
-
-* Note that on some platforms you may have to edit the Makefile and remove
-"-lpthread" from the linker commands (perhaps replacing it with something else).
-We didn't do this automatically because we wanted to keep the example simple.
-
-## Java ##
-
-protobuf-java-*.jar can be generated by:
-  cd ../java
-  mvn package
-and will be used by "make java"
-
-## Go ##
-
-The Go example requires a plugin to the protocol buffer compiler, so it is not
-build with all the other examples.  See:
-  https://github.com/golang/protobuf
-for more information about Go protocol buffer support.
-
-First, install the Protocol Buffers compiler (protoc).
-Then, install the Go Protocol Buffers plugin
-($GOPATH/bin must be in your $PATH for protoc to find it):
-  go get github.com/golang/protobuf/protoc-gen-go
-
-Build the Go samples in this directory with "make go".  This creates the
-following executable files in the current directory:
-  add_person_go      list_people_go
-To run the example:
-  ./add_person_go addressbook.data
-to add a person to the protocol buffer encoded file addressbook.data.  The file
-is created if it does not exist.  To view the data, run:
-  ./list_people_go addressbook.data
-
-Observe that the C++, Python, and Java examples in this directory run in a
-similar way and can view/modify files created by the Go example and vice
-versa.

examples/WORKSPACE

+# This com_google_protobuf repository is required for proto_library rule.
+# It provides the protocol compiler binary (i.e., protoc).
+http_archive(
+    name = "com_google_protobuf",
+    strip_prefix = "protobuf-master",
+    urls = ["https://github.com/google/protobuf/archive/master.zip"],
+)
+
+# This com_google_protobuf_cc repository is required for cc_proto_library
+# rule. It provides protobuf C++ runtime. Note that it actually is the same
+# repo as com_google_protobuf but has to be given a different name as
+# required by bazel.
+http_archive(
+    name = "com_google_protobuf_cc",
+    strip_prefix = "protobuf-master",
+    urls = ["https://github.com/google/protobuf/archive/master.zip"],
+)
+
+# Similar to com_google_protobuf_cc but for Java (i.e., java_proto_library).
+http_archive(
+    name = "com_google_protobuf_java",
+    strip_prefix = "protobuf-master",
+    urls = ["https://github.com/google/protobuf/archive/master.zip"],
+)
+
+# Similar to com_google_protobuf_cc but for Java lite. If you are building
+# for Android, the lite version should be prefered because it has a much
+# smaller code size.
+http_archive(
+    name = "com_google_protobuf_javalite",
+    strip_prefix = "protobuf-javalite",
+    urls = ["https://github.com/google/protobuf/archive/javalite.zip"],
+)

examples/add_person.cc

 // See README.txt for information and build instructions.
 
-#include <iostream>
+#include <ctime>
 #include <fstream>
+#include <google/protobuf/util/time_util.h>
+#include <iostream>
 #include <string>
+
 #include "addressbook.pb.h"
+
 using namespace std;
 
+using google::protobuf::util::TimeUtil;
+
 // This function fills in a Person message based on user input.
 void PromptForAddress(tutorial::Person* person) {
   cout << "Enter person ID number: ";
@@ -48,6 +54,7 @@ void PromptForAddress(tutorial::Person* person) {
       cout << "Unknown phone type.  Using default." << endl;
     }
   }
+  *person->mutable_last_updated() = TimeUtil::SecondsToTimestamp(time(NULL));
 }
 
 // Main function:  Reads the entire address book from a file,

examples/addressbook.proto

@@ -9,6 +9,8 @@
 // [START declaration]
 syntax = "proto3";
 package tutorial;
+
+import "google/protobuf/timestamp.proto";
 // [END declaration]
 
 // [START java_declaration]
@@ -38,6 +40,8 @@ message Person {
   }
 
   repeated PhoneNumber phones = 4;
+
+  google.protobuf.Timestamp last_updated = 5;
 }
 
 // Our address book file is just one of these.

examples/list_people.cc

 // See README.txt for information and build instructions.
 
-#include <iostream>
 #include <fstream>
+#include <google/protobuf/util/time_util.h>
+#include <iostream>
 #include <string>
+
 #include "addressbook.pb.h"
+
 using namespace std;
 
+using google::protobuf::util::TimeUtil;
+
 // Iterates though all people in the AddressBook and prints info about them.
 void ListPeople(const tutorial::AddressBook& address_book) {
   for (int i = 0; i < address_book.people_size(); i++) {
@@ -30,9 +35,15 @@ void ListPeople(const tutorial::AddressBook& address_book) {
         case tutorial::Person::WORK:
           cout << "  Work phone #: ";
           break;
+        default:
+          cout << "  Unknown phone #: ";
+          break;
       }
       cout << phone_number.number() << endl;
     }
+    if (person.has_last_updated()) {
+      cout << "  Updated: " << TimeUtil::ToString(person.last_updated()) << endl;
+    }
   }
 }