URL produces too much garbage objects #3494
Description
- I have searched the issues of this repository and believe that this is not a duplicate.
- I have checked the FAQ of this repository and believe that this is not a duplicate.
PROBLEM
Most of the setXxxx and addParameter* in URL such as org.apache.dubbo.common.URL#addParameter and setXxxx will return a new URL object for chaining calls, and most of the "middle objects" are useless and unnecessary, example below:
class
org.apache.dubbo.config.spring.SimpleRegistryExporter
public static Exporter<RegistryService> export(int port, RegistryService registryService) {
return protocol.export(proxyFactory.getInvoker(registryService, RegistryService.class,
// HERE
new URL("dubbo", NetUtils.getLocalHost(), port, RegistryService.class.getName())
.setPath(RegistryService.class.getName()) // useless
.addParameter(Constants.INTERFACE_KEY, RegistryService.class.getName()) // useless
.addParameter(Constants.CLUSTER_STICKY_KEY, "true") // useless
.addParameter(Constants.CALLBACK_INSTANCES_LIMIT_KEY, "1000") // useless
.addParameter("ondisconnect", "disconnect") // useless
.addParameter("subscribe.1.callback", "true") // useless
.addParameter("unsubscribe.1.callback", "false")));
}class
org.apache.dubbo.config.ServiceConfig
@SuppressWarnings({"unchecked", "rawtypes"})
private void exportLocal(URL url) {
if (!Constants.LOCAL_PROTOCOL.equalsIgnoreCase(url.getProtocol())) {
// HERE
URL local = URL.valueOf(url.toFullString())
.setProtocol(Constants.LOCAL_PROTOCOL) // useless
.setHost(LOCALHOST_VALUE) // useless
.setPort(0);
Exporter<?> exporter = protocol.export(
proxyFactory.getInvoker(ref, (Class) interfaceClass, local));
exporters.add(exporter);
logger.info("Export dubbo service " + interfaceClass.getName() + " to local registry");
}
}SOLUTION
And I suggest refactoring the URL with Builder Pattern. And the possible usage may be:
URL url = ...;
URL newURL = new URLBuilder(url)
.addParameter(k, v)
.addParameter(k2, v2)
.setPath(yourPath)
.build();Though we cannot remove the original addXXX and setXxxx methods due to compability, we can mark them as deprecated and guide users to use the new URLBuilder.
I'd like to try refactoring this if it's good to the comunity :)