| Protocol Buffers - Google's data interchange format |
| Copyright 2008 Google Inc. |
| |
| This directory contains the Java Protocol Buffers runtime library. |
| |
| Installation - With Maven |
| ========================= |
| |
| The Protocol Buffers build is managed using Maven. If you would |
| rather build without Maven, see below. |
| |
| 1) Install Apache Maven if you don't have it: |
| |
| http://maven.apache.org/ |
| |
| 2) Build the C++ code, or obtain a binary distribution of protoc. If |
| you install a binary distribution, make sure that it is the same |
| version as this package. If in doubt, run: |
| |
| $ protoc --version |
| |
| You will need to place the protoc executable in ../src. (If you |
| built it yourself, it should already be there.) |
| |
| 3) Run the tests: |
| |
| $ mvn test |
| |
| If some tests fail, this library may not work correctly on your |
| system. Continue at your own risk. |
| |
| 4) Install the library into your Maven repository: |
| |
| $ mvn install |
| |
| 5) If you do not use Maven to manage your own build, you can build a |
| .jar file to use: |
| |
| $ mvn package |
| |
| The .jar will be placed in the "target" directory. |
| |
| Installation - 'Lite' Version - With Maven |
| ========================================== |
| |
| Building the 'lite' version of the Java Protocol Buffers library is |
| the same as building the full version, except that all commands are |
| run using the 'lite' profile. (see |
| http://maven.apache.org/guides/introduction/introduction-to-profiles.html) |
| |
| E.g. to install the lite version of the jar, you would run: |
| |
| $ mvn install -P lite |
| |
| The resulting artifact has the 'lite' classifier. To reference it |
| for dependency resolution, you would specify it as: |
| |
| <dependency> |
| <groupId>com.google.protobuf</groupId> |
| <artifactId>protobuf-java</artifactId> |
| <version>${version}</version> |
| <classifier>lite</classifier> |
| </dependency> |
| |
| Installation - Without Maven |
| ============================ |
| |
| If you would rather not install Maven to build the library, you may |
| follow these instructions instead. Note that these instructions skip |
| running unit tests. |
| |
| 1) Build the C++ code, or obtain a binary distribution of protoc. If |
| you install a binary distribution, make sure that it is the same |
| version as this package. If in doubt, run: |
| |
| $ protoc --version |
| |
| If you built the C++ code without installing, the compiler binary |
| should be located in ../src. |
| |
| 2) Invoke protoc to build DescriptorProtos.java: |
| |
| $ protoc --java_out=src/main/java -I../src \ |
| ../src/google/protobuf/descriptor.proto |
| |
| 3) Compile the code in src/main/java using whatever means you prefer. |
| |
| 4) Install the classes wherever you prefer. |
| |
| Micro version |
| ============================ |
| |
| The runtime and generated code for MICRO_RUNTIME is smaller |
| because it does not include support for the descriptor, |
| reflection or extensions. Also, not currently supported |
| are packed repeated elements nor testing of java_multiple_files. |
| |
| To create a jar file for the runtime and run tests invoke |
| "mvn package -P micro" from the <protobuf-root>/java |
| directory. The generated jar file is |
| <protobuf-root>java/target/protobuf-java-2.2.0-micro.jar. |
| |
| If you wish to compile the MICRO_RUTIME your self, place |
| the 7 files below, in <root>/com/google/protobuf and |
| create a jar file for use with your code and the generated |
| code: |
| |
| ByteStringMicro.java |
| CodedInputStreamMicro.java |
| CodedOutputStreamMicro.java |
| InvalidProtocolBufferException.java |
| MessageMicro.java |
| StringUtf8Micro.java |
| WireFormatMicro.java |
| |
| If you wish to change on the code generator it is located |
| in /src/google/protobuf/compiler/javamicro. |
| |
| To generate code for the MICRO_RUNTIME invoke protoc with |
| --javamicro_out command line parameter. javamciro_out takes |
| a series of optional sub-parameters separated by comma's |
| and a final parameter, with a colon separator, which defines |
| the source directory. Sub-paraemeters begin with a name |
| followed by an equal and if that sub-parameter has multiple |
| parameters they are seperated by "|". The command line options |
| are: |
| |
| opt -> speed or space |
| java_use_vector -> true or false |
| java_package -> <file-name>|<package-name> |
| java_outer_classname -> <file-name>|<package-name> |
| |
| opt: |
| This change the code generation to optimize for speed, |
| opt=speed, or space, opt=space. When opt=speed this |
| changes the code generation for strings to use |
| StringUtf8Micro which eliminates multiple conversions |
| of the string to utf8. The default value is opt=space. |
| |
| java_use_vector: |
| Is a boolean flag either java_use_vector=true or |
| java_use_vector=false. When java_use_vector=true the |
| code generated for repeated elements uses |
| java.util.Vector and when java_use_vector=false the |
| java.util.ArrayList<> is used. When java.util.Vector |
| is used the code must be compiled with Java 1.3 and |
| when ArrayList is used Java 1.5 or above must be used. |
| The using javac the source parameter maybe used to |
| control the version of the srouce: "javac -source 1.3". |
| You can also change the <source> xml element for the |
| maven-compiler-plugin. Below is for 1.5 sources: |
| |
| <plugin> |
| <artifactId>maven-compiler-plugin</artifactId> |
| <configuration> |
| <source>1.5</source> |
| <target>1.5</target> |
| </configuration> |
| </plugin> |
| |
| When compiling for 1.5 java_use_vector=false or not |
| present where the default value is false. |
| |
| And below would be for 1.3 sources note when changing |
| to 1.3 you must also set java_use_vector=true: |
| |
| <plugin> |
| <artifactId>maven-compiler-plugin</artifactId> |
| <configuration> |
| <source>1.3</source> |
| <target>1.5</target> |
| </configuration> |
| </plugin> |
| |
| java_package: |
| The allows setting/overriding the java_package option |
| and associates allows a package name for a file to |
| be specified on the command line. Overriding any |
| "option java_package xxxx" in the file. The default |
| if not present is to use the value from the package |
| statment or "option java_package xxxx" in the file. |
| |
| java_outer_classname: |
| This allows the setting/overriding of the outer |
| class name option and associates a class name |
| to a file. An outer class name is required and |
| must be specified if there are multiple messages |
| in a single proto file either in the proto source |
| file or on the command line. If not present the |
| no outer class name will be used. |
| |
| Below are a series of examples for clarification of the |
| various javamicro_out parameters using |
| src/test/proto/simple-data.proto: |
| |
| package testprotobuf; |
| |
| message SimpleData { |
| optional fixed64 id = 1; |
| optional string description = 2; |
| optional bool ok = 3 [default = false]; |
| }; |
| |
| |
| Assuming you've only compiled and not installed protoc and |
| your current working directory java/, then a simple |
| command line to compile simple-data would be: |
| |
| ../src/protoc --javamicro_out=. src/test/proto/simple-data.proto |
| |
| This will create testprotobuf/SimpleData.java |
| |
| The directory testprotobuf is created because on line 1 |
| of simple-data.proto is "package testprotobuf;". If you |
| wanted a different package name you could use the |
| java_package option command line sub-parameter: |
| |
| ../src/protoc '--javamicro_out=java_package=src/test/proto/simple-data.proto|my_package:.' src/test/proto/simple-data.proto |
| |
| Here you see the new java_package sub-parameter which |
| itself needs two parameters the file name and the |
| package name, these are separated by "|". Now you'll |
| find my_package/SimpleData.java. |
| |
| If you wanted to also change the optimization for |
| speed you'd add opt=speed with the comma seperator |
| as follows: |
| |
| ../src/protoc '--javamicro_out=opt=speed,java_package=src/test/proto/simple-data.proto|my_package:.' src/test/proto/simple-data.proto |
| |
| Finally if you also wanted an outer class name you'd |
| do the following: |
| |
| ../src/protoc '--javamicro_out=opt=speed,java_package=src/test/proto/simple-data.proto|my_package,java_outer_classname=src/test/proto/simple-data.proto|OuterName:.' src/test/proto/simple-data.proto |
| |
| Now you'll find my_packate/OuterName.java. |
| |
| As mentioned java_package and java_outer_classname |
| may also be specified in the file. In the example |
| below we must define java_outer_classname because |
| there are multiple messages in |
| src/test/proto/two-messages.proto |
| |
| package testmicroruntime; |
| |
| option java_package = "com.example"; |
| option java_outer_classname = "TestMessages"; |
| |
| message TestMessage1 { |
| required int32 id = 1; |
| } |
| |
| message TestMessage2 { |
| required int32 id = 1; |
| } |
| |
| This could be compiled using: |
| |
| ../src/protoc --javamicro_out=. src/test/proto/two-message.proto |
| |
| With the result will be com/example/TestMessages.java |
| |
| |
| Usage |
| ===== |
| |
| The complete documentation for Protocol Buffers is available via the |
| web at: |
| |
| http://code.google.com/apis/protocolbuffers/ |