Subscribe to an account
public BigInteger listenAccount(Identity id, IEventCallback handler, EventModelType type)
Parameter |
Required |
Type |
Description |
id |
true |
Identity |
The account’s business ID. |
handler |
true |
IEventCallback |
Performs callback when a response is received or a timeout or an error occurs. |
type |
true |
EventModelType |
The event model type. 1 indicates PULL, and 2 indicates PUSH. |
Response field |
Field type |
Description |
result |
BigInteger |
The returned result. If the result is 0, the listening failed. |
// event handler
IEventCallback handler = new IEventCallback() {
@Override
public void onEvent(Message message) {
PushAccountEvent accountEvent = (PushAccountEvent) message;
//code
}
};
// account: Tester001
Identity identity = new Identity("c60a9d48105950a0cca07a4c6320b98c303ad42d694a634529e8e1a0a16fcdb5");
// listen account
BigInteger eventId = sdk.getEventService().listenAccount(identity, handler, EventModelType.PUSH)
if (eventId.longValue() == 0) {
System.out.println("listen failed");
}
Subscribe to a contract
public BigInteger listenContract(Identity id, IEventCallback handler, EventModelType type)
Parameter |
Required |
Type |
Description |
id |
true |
Identity |
The account’s business ID. |
handler |
true |
IEventCallback |
Performs callback when a response is received or a timeout or an error occurs. |
type |
true |
EventModelType |
The event model type. 1 indicates PULL, and 2 indicates PUSH. |
Response field |
Field type |
Description |
result |
BigInteger |
The returned result. If the result is 0, the listening failed. |
/event handler
IEventCallback handler = new IEventCallback() {
@Override
public void onEvent(Message message) {
PushContractEvent eventContractMessage = (PushContractEvent) message;
// code
}
};
Identity identity = new Identity("a7937b64b8caa58f03721bb6bacf5c78cb235febe0e70b1b84cd99541461a08e");
//listen contract
BigInteger result = sdk.getEventService().listenContract(identity, handler, EventModelType.PUSH)
Subscribe to a topic event
public BigInteger listenTopics(List<String> topics, IEventCallback handler, VMTypeEnum vmType, EventModelType type)
Parameter |
Required |
Type |
Description |
topics |
true |
List |
The list of subscribed topics. |
handler |
true |
IEventCallback |
Performs callback when a response is received or a timeout or an error occurs. |
vmType |
true |
VMTypeEnum |
The contract type. 1 indicates EVM, and 2 indicates WASM. |
type |
true |
EventModelType |
The event model type. 1 indicates PULL, and 2 indicates PUSH. |
Response field |
Field type |
Description |
result |
BigInteger |
The returned result. If the result is 0, the listening failed. |
//Evm contract
contract logAndPrecomileContract {
event TEST(identity id, uint a, uint b);
...
function test(identity id, uint ba) public payable returns(uint) {
if (!id.send(ba / 2))
throw; // also reverts the transfer to Sharer
emit TEST(id, ba, id.balance);
return id.balance;
}
...
}
//deploy Evm contract
// evnet handler
IEventCallback handler = new IEventCallback() {
@Override
public void onEvent(Message message) {
PushTopicsEvent eventTopicsMessage = (PushTopicsEvent) message;
//code
}
};
// add contract
List<String> topics = new ArrayList<>();
// The system contract. An event will be returned when any contract is called.
topics.add("call_contract");
// The EVM contract. Calling the contract triggers an internal TEST event of the contract.
IHash hashTool = HashFactory.getHash();
byte[] sha256 = hashTool.hash("TEST(identity,uint256,uint256)".getBytes());
topics.add(ByteUtils.toHexString(sha256));
// listen topics
BigInteger result = sdk.getEventService().listenTopics(topics, handler, VMTypeEnum.EVM, EventModelType.PUSH)
// Calling the EVM contract triggers two topic events: call_contract and TEST.
EVMParameter parameters = new EVMParameter("test(identity,uint256)");
parameters.addIdentity(identity);
parameters.addUint(value);
CallContractRequest request = new CallContractRequest(accId, contractId, parameters, BigInteger.ZERO, VMTypeEnum.EVM);
sdk.getContractService().callContract(request);
// Unsubscribe from the topic.
sdk.getEventService().unListenTopics(result);
//Wasm contract
class logAndPrecomileContract : public Contract {
public:
INTERFACE test(const Identity& id, uint64_t ba){
uint64_t balance = 0;
bool ret = GetBalance(id, balance);
Log(pack(id), {String2Bytes("hello"), String2Bytes("abc")});
Result(pack(balance));
}
}
//deploy Wasm contract
// evnet handler
IEventCallback handler = new IEventCallback() {
@Override
public void onEvent(Message message) {
PushTopicsEvent eventTopicsMessage = (PushTopicsEvent) message;
//code
}
};
// add contract
List<String> topics = new ArrayList<>();
// The system contract. An event will be returned when any contract is called.
topics.add("call_contract");
topics.add("hello"); // Listen to a hello event.
topics.add("abc"); // Listen to an abc event.
// listen topics
BigInteger result = sdk.getEventService().listenTopics(topics, handler, VMTypeEnum.WASM, EventModelType.PUSH)
// Calling the WASM contract triggers call_contract.
WASMParameter parameters = new WASMParameter("test");
parameters.addIdentity(identity);
parameters.addUInt64(value);
CallContractRequest request = new CallContractRequest(accId, contractId, parameters, BigInteger.ZERO, VMTypeEnum.WASM);
sdk.getContractService().callContract(request);
// Unsubscribe from the topic.
sdk.getEventService().unListenTopics(result);
Subscribe to a block event
public BigInteger listenBlock(IEventCallback handler, EventModelType type)
Parameter |
Required |
Type |
Description |
handler |
true |
IEventCallback |
Performs callback when a response is received or a timeout or an error occurs. |
type |
true |
EventModelType |
The event model type. 1 indicates PULL, and 2 indicates PUSH. |
Response field |
Field type |
Description |
result |
BigInteger |
The returned result. If the result is 0, the listening failed. |
// event handler
IEventCallback handler = new IEventCallback() {
@Override
public void onEvent(Message message) {
// code
}
};
// listen block
BigInteger result = sdk.getEventService().listenBlock(handler, EventModelType.PUSH)
Unsubscribe from an account event
public boolean unListenAccount(BigInteger eventId)
Parameter |
Required |
Type |
Description |
eventId |
true |
BigInteger |
The ID of the event to unsubscribe from. |
Unsubscribe from a contract event
public boolean unListenContract(BigInteger eventId)
Parameter |
Required |
Type |
Description |
eventId |
true |
BigInteger |
The ID of the event to unsubscribe from. |
Unsubscribe from a topic event
public boolean unListenTopics(BigInteger eventId)
Parameter |
Required |
Type |
Description |
eventId |
true |
BigInteger |
The ID of the event to unsubscribe from. |
Unsubscribe from a block event
public boolean unListenBlock(BigInteger eventId)
Parameter |
Required |
Type |
Description |
eventId |
true |
BigInteger |
The ID of the event to unsubscribe from. |