Golang implementation of channel with priority

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The general Go language uses multiple channel methods simultaneously using the select / case statement mate <- operators, such as

select {case <- chan1:    // do somethingcase <- chan2:    // do something}

But this implementation is the chan1 same as the chan2 priority level. If you want to implement a priority, you channel need to use the defalut statement.

In the Go language, if select case there is no clause in/, the default program blocks in select until one of the case statements receives the data.
If there is a default statement, it will not block, if the case data received, the execution case of the statement, if the case signal is not received, will execute defalut the statement in, and then jump out of the select block.

Use this feature to implement a queue with priority channel . A 2-priority channel example is achieved by using multiple layers select , placing high priority channel behind the outermost select statement case , and following a default statement to avoid blocking when high-priority channel data is not available.
defalutis still a statement in which the select select high-priority and low-priority case are placed and no default statements are in the statement. This will block the inner layer select until one of the data is case received.

This implementation is equivalent to the high priority of the channel lower priority than the opportunity to be processed once, that is, the outer select layer, only the high priority without data, will only execute the inner layers select , when the first generation of data channel is executed.

That is, when high-priority and low-priority have data, high-priority is processed first, that is, the priority is achieved. Examples are as follows:

for  {select  {case  data: = <-highchan:handlehigh (data) default : select  {case  data: = <-highchan:handlehigh (data) case  data: = <-lowchan:handlelow (data)}}}