PHP从抽象类动态访问常量

Question

I am stuck with a problem I thought was easily resolved, but at a loss. I have an abstract class which has several constants that define time increments which looks something like this.

abstract class DictionaryKeepAliveIncrements{

    CONST second        = 1;
    CONST quarterminute = 15;
    CONST halfminute    = 30;
    CONST minute        = 60;

I am trying to access them dynamically from another class like so

public function getKeepAliveByUnit($timeUnit){
    return constant('DictionaryKeepAliveIncrements::'.$timeUnit);
}

This is resulting in the error

Warning: constant(): Couldn't find constant DictionaryKeepAliveIncrements::minute in

The DictionaryKeepAliveIncrements is in the same namespace as the method getKeepAliveByUnit so should see it. I've also tried adding the full namespace but get the same result.

What am I missing?

Answer 1

You need to include namespace in the constant() call - see code @ 3v4l.org

EDIT To correct the problem adding namespace was the solution. The following solved the problem.

To better explain this solution here is what was needed.

public function getKeepAliveByUnit($timeUnit){
    return constant('root
amespace\DictionaryKeepAliveIncrements::'.$timeUnit);
}