Invocation Mode
Each proxy has an invocation mode that configures its invocation behavior. You can choose between the following invocation modes:
Invocation mode | Stringified proxy option | Meaning |
|---|---|---|
twoway (the default) |
| An invocation sends a request and expects/waits for a reply. |
oneway |
| An invocation sends a request but does not expect/wait for a reply. |
batch oneway |
| An invocation sends requests in batches. It does not expect or wait for any reply. |
datagram |
| An invocation sends a request but does not expect/wait for a reply. It’s just like oneway, but for proxies with UDP endpoints. |
batch datagram |
| An invocation sends requests in batches. It does not expect or wait for any reply. It’s just like batch oneway, but for proxies with UDP endpoints. |
For example, if you create a proxy from the stringified proxy greeter:tcp -h localhost -p 4061, you’ll get a two-way proxy, just like if you created this proxy from greeter -t:tcp -h -localhost -p 4061. And if you create a proxy from greeter -O:tcp - localhost -p 4061, you’ll get a batch one-way proxy.
You can also set the invocation method on a proxy programmatically using a proxy factory method: ice_twoway, ice_oneway, ice_batchOneway, etc.
Keep in mind that proxies are immutable and all proxy factory methods create new proxies - they don’t change the source proxy.
Twoway, Oneway, Batch Oneway
These invocation modes are only applicable to proxies with non-UDP endpoints, such as tcp, ssl, wss.
If you select oneway or batch oneway for a proxy with a UDP endpoint, you won’t get an error - you’ll just made this proxy unusable. If you later make an invocation with such a proxy, you’ll receive a NoEndpointException.
Datagram and Batch Datagram
These invocation modes are only applicable to proxies with UDP endpoints.
If you select datagram or batch datagram for a proxy with a TCP endpoint, you won’t get an error - you’ll just made this proxy unusable. If you later make an invocation with such a proxy, you’ll receive a NoEndpointException.
In theory, the datagram and batch datagram invocation modes are applicable to any datagram transport. In practice, Ice provides a single datagram transport, UDP, and we don’t anticipate ever adding another datagram transport.