CODEWITHSUNDEEP
javagroovy
Gideon
Gideon

Reputation: 1517

Get the type of a Class property in Java/Groovy

I'm creating a dynamic query on Grails. The UI will pass a JSON Object that holds all the criteria. I manage to do that:

def criteria = params.criteria

def l = DomainClass.createCriteria().list {
    for(int k = 0; k < criteria.names().length(); k++) {
        def names = list[x].names()
        if(DomainClass.hasProperty(names[k])) {
            eq(names[k], list[x][names[k]])
        }
    }
}

This works already if all the properties of DomainClass is type String, but I also use other types such as Long and Date so I want to implement something like this:

def criteria = params.criteria

def l = DomainClass.createCriteria().list {
    for(int k = 0; k < criteria.names().length(); k++) {
        def names = list[x].names()
        if(DomainClass.hasProperty(names[k])) {
            if(/* DomainClass.getProperty(names[k]).getClass() == Long */) {
                // Parse first string to long before actually using it to the criteria
                eq(names[k], Long.valueOf(list[x][names[k]]).longValue()))
            }
            else if(/* DomainClass.getProperty(names[k]).getClass() == Date */) {
                // parse first date
                ...
            }
            else {
                // The default criteria
                eq(names[k], list[x][names[k]])
            }
        }
    }
}

But I don't know in Java nor in Groovy what to use to the condition in the if statements.

Upvotes: 1

Views: 3614

Answers (2)

Mathias Begert
Mathias Begert

Reputation: 2471

Exact match

new Long(1L).getClass().equals(Long.class)
> true

or

new Long(1L) instanceof Number
> true
new Long(1L) instanceof Long
> true

Your == approach (with added .class), should also work, since it is unlikely, that there are two different Long classes are loaded but I would prefer the equals way. 

new Long(1L).getClass() == Long.class
> true (most likely)

Upvotes: 1

Pumphouse
Pumphouse

Reputation: 2053

There are a couple of ways that you could approach this

instanceof

or 

object.getClass().equals(Float.class);

With your example you could do something similar

if(DomainClass.getProperty(names[k]).getClass().equals(Date.class))

Previous post

Upvotes: 2

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