An example Jenkinsfile that stops deployment if your method complexity is above 20, based on the static code analysis of PHPloc.

Jenkinsfile

pipeline {
    agent any

    tools {
        ant 'ant'
    }

    // Pull the repo first.
    stages {
        stage( 'Checkout Repo' ) {
            steps {
                checkout scm
            }
        }
        stage( 'Build' ) {
            steps {
                script {
                    // Define a function to count all comment lines
                    linesOfComments = sh(returnStdout: true,
                        script: "vendor/bin/phploc . --exclude vendor | grep CLOC").trim()
                    // Measure method complexity
                    complexityPerMethod = sh(returnStdout: true,
                        script: "vendor/bin/phploc . --exclude vendor | \
                                 grep \'Maximum Method Complexity\'| \
                                 tr -dc '0-9'").trim()
                    Let build fail if complexity is above a certain threshold                                 
                    if ( complexityPerMethod.toInteger() > 2000 ) {
                        error( "Build ${env.BUILD_NUMBER} failed because methods are too complex. ${env.BUILD_URL} - ${env.JOB_NAME}")
                    }
                }
                withAnt(installation: 'ant', jdk: 'jdk') {
                    sh "ant phploc"
                }
                echo "Lines of Comments: ${linesOfComments}"
                echo "Maximum complexity in method: ${complexityPerMethod}"
            }
        }
        stage( 'Deploy' ) {
            steps {
                // This is were Ant should run if I'm not mistaken
                // Run git status just to log anything outstanding.
                sh 'git status'
                script{
                    switch( env.BRANCH_NAME ) {
                        case "staging":
				                // Comment out the next line if the target directory
			    	            // does not exist on the server.
                                sh 'vendor/bin/phploy -s staging --list'
                                sh 'vendor/bin/phploy -s staging --force'
				            break
                        default:
                            // Doing nothing
                            break
                    }
                }
            }
        }
    }
    // Run items after pipeline completion/failure
    post {
        always {
            // Always clearn up the directory, regardless.
            deleteDir()
        }
    }
}