Java Execution Environment

How to Run

[NOTE] $JAVAEE_DIR indicates the top level directory that contains this repository. You need to replace it with your own directory path.

1. Compile SampleToken SCORE

$ cd $JAVAEE_DIR/samples
$ ./compile.sh sampletoken example.SampleToken
...
The jar has been generated at $JAVAEE_DIR/samples/sampletoken/build/dapp.jar

2. Optimize the dapp.jar with DAppCompiler

$ cd $JAVAEE_DIR
$ ./gradlew app:dappcomp:run --args='$JAVAEE_DIR/samples/sampletoken/build/dapp.jar -debug'
...
[main] INFO DAppCompiler - Generated $JAVAEE_DIR/samples/sampletoken/build/optimized-debug.jar

3. Deploy the optimized jar

If you use mock_server, copy the optimized jar into the target directory. If you use goloop, create a deploy transaction with the optimized jar and deploy it.

The counterpart SM server (mock_server or goloop) should be run first before executing the following step.

4. Run Executor Manager

$ ./gradlew app:execman:run --args='/tmp/ee.socket'

Java SCORE Structure

Comparison to Python SCORE

Name	Python	Java
External decorator	@external	@External
- (readonly)	@external(readonly=True)	@External(readonly=true)
Payable decorator	@payable	@Payable
Eventlog decorator	@eventlog	@EventLog
- (indexed)	@eventlog(indexed=1)	@EventLog(indexed=1)
fallback signature	def fallback	void fallback()
SCORE initialize	override on_install method	define a public constructor
Default parameters	native language support	@Optional

[NOTE] All external Java methods must have a public modifier, and should be instance methods.

How to invoke a external method of another SCORE

One SCORE can invoke a external method of another SCORE using the following APIs.

// [package score.Context]
public static Object call(Address targetAddress, String method, Object... params);

public static Object call(BigInteger value,
                          Address targetAddress, String method, Object... params);

Example of calling tokenFallback

if (_to.isContract()) {
    Context.call(_to, "tokenFallback", _from, _value, dataBytes);
}

Java SCORE Examples

• SampleToken
• SampleCrowdsale