MetaBuilder

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Code Block

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title	Step 1


import groovytools.builder.*

MetaBuilder mb = new MetaBuilder(getClass().getClassLoader())

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Code Block

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title	Step 2


class Customer {
    def name
    def dateOfBirth
    def ssn
    def phone
}

mb.define {
    customer(factory: Customer) {
        properties {
            name()
            dateOfBirth()
            ssn()
        }
    }
}

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Code Block

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title	Step 3


def aCustomer = mb.build {
    customer {
        name = 'J. Doe'
        dateOfBirth  = '1/1/1900'
        ssn  = '555-55-5555'
    }
}

// this is equivalent
aCustomer = mb.build {
    customer ( name: 'J. Doe', dateOfBirth: '1/1/1900', ssn: '555-55-5555')
}

// you can even mix up the styles:
aCustomer = mb.build {
    customer ( name: 'J. Doe', dateOfBirth: '1/1/1900') {
        ssn = '555-55-5555'
    }
}

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Code Block

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title	Catching Errors


aCustomer = mb.build {
    customer {
        name = 'J. Doe'
        dob  = '1/1/1900'      // should have been 'dataOfBirth'
        ssn  = '555-55-5555'
        phone = '1-555-555-5555' // not allowed
    }
}

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Despite the fact that phone is a an actual property of your class, MetaBuilder only goes by what's in your the schema. That kind of checking is nice to have and can protect private or sensitive properties. Read on to see how MetaBuilder can do even more with some additional information.

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This next example demonstrates how one might use closure to create
Customer objects:

Code Block

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title	Specifying a Factory using a Closure


mb.define {
    customer2(factory: { new Customer() } )) {
        properties {
            name()
            dateOfBirth()
            ssn()
        }
    }
}

def aCustomer2 = mb.build {
    customer2 {
        name = 'J. Doe'
        dateOfBirth  = '1/1/1900'
        ssn  = '555-55-5555'
    }
}

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def: the default value or a Closure to produce the default value, as needed
req: if true, a value must be specfied (it could be null though)
property: an alternative property name or Closure to use to set the value
min: the minimum length for a property value
max: the maximum length for a property value

check: causes an exception if the value fails the following test:

Code Block

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switch(value) {
    case check: return true
}
return false

Tip

title	Tip

The check attribute accepts the following types of objects which makes enforcing constraints easy:

Closures
Patterns
Classes
Numbers
Strings
Ranges
Collections

Here's an example showing combinations of some of the above:

Code Block

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title	MetaBuilder Property Attributes in Action


mb.define {
customer3(factory: Customer) {
    properties {
        name(req: true, min: 1)
        dob(property: 'dateOfBirth')
        ssn(check: ~/\d{3}-\d{2}-\d{4}/)
    }
}

def aCustomer3 = mb.build {
    customer4 {
        name = 'J. Doe'
        dob = '1/1/1900'
        ssn  = '555-55-5555'
    }
}

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Code Block

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title	Adding a Phone Class and Schema


class Phone {
    def type
    def number
}

mb.define {
    phone (factory: Phone) {
        properties {
            type(check: ['home','cell','work'], def: 'home')
            number(req: true, check: ~/\d{3}-\d{3}-\d{4}/)
        }
    }
}

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Code Block

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title	Using the Phone Schema


mb.define {
    customer4(factory: Customer) {
        properties {
            name(req: true, min: 1)
            dob(property: 'dateOfBirth')
            ssn(check: ~/\d{3}-\d{2}-\d{4}/)
            phone(schema: 'phone', req: true)
        }
    }
}

def aCustomer4 = mb.build {
    customer4 {
        name = 'J. Doe'
        dob  = '1/1/1900'
        ssn  = '555-55-5555'
        phone {
            type = 'home'
            number = '123-456-7890'
        }
    }
}

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Code Block

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title	Defining Schema with Indexed and Non-Indexed Collections


class Customer2 extends Customer {
    def phoneList = []
    def addresses = [:]
}

mb.define {
    customer5(factory: Customer2) {
        properties {
            name(req: true, min: 1)
            dob(property: 'dateOfBirth')
            ssn(check: ~/\d{3}-\d{2}-\d{4}/)
            phone(schema: 'phone', req: true)
        }
        collections {
            phoneList(min: 1) {
                phone(schema: phone)
            }
            addresses (key: 'type', min: 1, max:2) {
                address() {
                    properties {
                        type(check: ['billto', 'shipto'], def: 'billto')
                        street()
                        city()
                        state()
                        zip()
                    }
                }
            }
        }
    }
}

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Another thing to note is the use of the key attribute in the addresses collection. Presenece Presence of the key attribute tells MetaBuilder that the parent-child relationship is indexed. In the following example, you can see that customer5 has both a list of phone and map of addresses using the address's type
and the key.

Code Block

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title	Building Objects with Indexed and Non-Indexed Collections


def aCustomer5 = mb.build {
    customer5 {
        name = 'J. Doe'
        dob  = '1/1/1900'
        ssn  = '555-55-5555'
        phone {
            type = 'home'
            number = '123-456-7890'
        }
        phoneList {
            phone(type: 'work', number: '111-222-3333')
            phone(type: 'cell', number: '444-555-6666')
        }
        address {
            type   = 'billto'
            street = '1234 Some St.'
            city   = 'Some City'
            zip    = '12345'
        }
        address {
            type   = 'shipto'
            street = '1234 Some Other St.'
            city   = 'Some Other City'
            zip    = '12345'
        }
    }
}

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MetaBuilder

Versions Compared

Old Version 4

New Version 5

Key