Get class FQN and compose builder methods

getters-to-builder.groovy

import groovy.text.SimpleTemplateEngine

import java.lang.reflect.Method

def classFQN = args.length > 0? args[0]: System.exit(1)

Class<?> clazz = Class.forName(classFQN, false, getClass().getClassLoader())

class BuilderTemplateWrapper {
    final Class<?> clazz
    BuilderTemplateWrapper(Class<?> clazz) {
        this.clazz = clazz
    }
    def getShortName() {
        clazz.simpleName + 'Builder'
    }
    def getMethods() {
        clazz.methods.findAll { it.name.startsWith('get') || it.name.startsWith('is')}.collect { Method m ->
            def propName = m.name[3..-1]
            def propNameLower = propName[0].toLowerCase() + propName[1..-1]
            def propType = m.genericReturnType.typeName

"""public ${this.shortName} with$propName(${propType} $propNameLower) {
    this.$propNameLower = $propNameLower;
    return this;
}
"""
        }
    }

    def getProps() {
        clazz.methods.findAll { it.name.startsWith('get') || it.name.startsWith('is')}.collect { Method m ->
            def propName = m.name[3..-1]
            def propNameLower = propName[0].toLowerCase() + propName[1..-1]

            def propType = m.genericReturnType.typeName

            "private $propType $propNameLower;"
        }
    }
}

def text = '''
<% clazz.props.each { p-> %>
    $p
<% }  %>

<% clazz.methods.each { m-> %>
$m
<% }  %>
'''

def engine = new SimpleTemplateEngine()
def result = engine
    .createTemplate(text)
    .make(clazz: new BuilderTemplateWrapper(clazz))

if (args.contains('clip'))
    'xclip -selection clip'.execute().withWriter { Writer w ->
        result.writeTo(w)
    }

if (args.contains('print'))
    println result.toString()