Java chaincode

Note: This guide generally assumes you have followed the Chaincode development environment setup tutorial here.

To get started developing Java chaincode

  1. Ensure you have gradle
  2. Download the binary distribution from http://gradle.org/gradle-download/
  3. Unpack, move to the desired location, and add gradle’s bin directory to your system path
  4. Ensure gradle -v works from the command-line, and shows version 2.12 or greater
  5. Optionally, enable the gradle daemon for faster builds
  6. Ensure you have the Java 1.8 JDK installed. Also ensure Java’s directory is on your path with java -version
  7. Additionally, you will need to have the JAVA HOME variable set to your JDK installation in your system path

  8. From your command line terminal, move to the devenv subdirectory of your workspace environment. Log into a Vagrant terminal by executing the following command:

    vagrant ssh

  9. Build and run the peer process.

    cd $GOPATH/src/github.com/hyperledger/fabric make peer peer node start

  10. The following steps is for deploying chaincode in non-dev mode.

    • Deploy the chaincode,
    peer chaincode deploy -l java -n map -p /opt/gopath/src/github.com/hyperledger/fabric/core/chaincode/shim/java -c '{"Function": "init", "Args": ["a","100", "b", "200"]}'

6d9a704d95284593fe802a5de89f84e86fb975f00830bc6488713f9441b835cf32d9cd07b087b90e5cb57a88360f90a4de39521a5595545ad689cd64791679e9

    * This command will give the 'name' for this chaincode, and use this value in all the further commands with the -n (name) parameter


    * PS. This may take a few minutes depending on the environment as it deploys the chaincode in the container,
  • Invoke a transfer transaction,
    /opt/gopath/src/github.com/hyperledger/fabric/core/chaincode/shim/java$ peer chaincode invoke -l java \
    -n 6d9a704d95284593fe802a5de89f84e86fb975f00830bc6488713f9441b835cf32d9cd07b087b90e5cb57a88360f90a4de39521a5595545ad689cd64791679e9 \
    -c '{"Function": "transfer", "Args": ["a","b", "20"]}'

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  • Query the values of a and b after the transfer
    /opt/gopath/src/github.com/hyperledger/fabric/core/chaincode/shim/java$ peer chaincode query -l java \
    -n 6d9a704d95284593fe802a5de89f84e86fb975f00830bc6488713f9441b835cf32d9cd07b087b90e5cb57a88360f90a4de39521a5595545ad689cd64791679e9 \
    -c '{"Function": "query", "Args": ["a"]}'
    {"Name":"a","Amount":"80"}


    /opt/gopath/src/github.com/hyperledger/fabric/core/chaincode/shim/java$ peer chaincode query -l java \
    -n 6d9a704d95284593fe802a5de89f84e86fb975f00830bc6488713f9441b835cf32d9cd07b087b90e5cb57a88360f90a4de39521a5595545ad689cd64791679e9 \
    -c '{"Function": "query", "Args": ["b"]}'
    {"Name":"b","Amount":"220"}
  • To develop your own chaincodes, simply extend the Chaincode class (demonstrated in the SimpleSample Example under the examples package)

Java chaincode deployment in DEV Mode

  1. Follow the step 1 to 3 as above,
  2. Build and run the peer process
    cd $GOPATH/src/github.com/hyperledger/fabric
    make peer
    peer node start --peer-chaincodedev
  1. Open the second Vagrant terminal, and change to Java shim root folder and run gradle build,
    cd $GOPATH/src/github.com/hyperledger/fabric/core/chaincode/shim/java
    gradle build

  1. Run the SimpleSample chaincode using the gradle run

  2. Open the third Vagrant terminal to run init and invoke on the chaincode

    peer chaincode deploy -l java -n SimpleSample -c ‘{“Function”: “init”, “Args”: [“a”,”100”, “b”, “200”]}’

2016/06/28 19:10:15 Load docker HostConfig: %+v &{[] [] []  [] false map[] [] false [] [] [] [] host    { 0} [] { map[]} false []  0 0 0 false 0    0 0 0 []}
19:10:15.461 [crypto] main -> INFO 002 Log level recognized 'info', set to INFO
SimpleSample

peer chaincode invoke -l java -n SimpleSample -c '{"Function": "transfer", "Args": ["a", "b", "10"]}'

2016/06/28 19:11:13 Load docker HostConfig: %+v &{[] [] []  [] false map[] [] false [] [] [] [] host    { 0} [] { map[]} false []  0 0 0 false 0    0 0 0 []}
19:11:13.553 [crypto] main -> INFO 002 Log level recognized 'info', set to INFO
978ff89e-e4ef-43da-a9f8-625f2f6f04e5

peer chaincode query -l java -n SimpleSample -c '{"Function": "query", "Args": ["a"]}'

2016/06/28 19:12:19 Load docker HostConfig: %+v &{[] [] []  [] false map[] [] false [] [] [] [] host    { 0} [] { map[]} false []  0 0 0 false 0    0 0 0 []}
19:12:19.289 [crypto] main -> INFO 002 Log level recognized 'info', set to INFO
{"Name":"a","Amount":"90"}

peer chaincode query -l java -n SimpleSample -c '{"Function": "query", "Args": ["b"]}'

2016/06/28 19:12:25 Load docker HostConfig: %+v &{[] [] []  [] false map[] [] false [] [] [] [] host    { 0} [] { map[]} false []  0 0 0 false 0    0 0 0 []}
19:12:25.667 [crypto] main -> INFO 002 Log level recognized 'info', set to INFO
{"Name":"b","Amount":"210"}