stage ('UpstreamJob')\{ 
build job: 'DownstreamJob', parameters: [ 
string(name: 'ARTIFACT_NAME', value: "myArtifact_5.5.5.zip"), 
string(name: 'DEPLOY_PHASE', value: "Production"), 
string(name: 'DEPLOYMENT_COLOR', value: "purple"), 
string(name: 'SOMEEXTRAVAR', value: "Woohoo I can do whatever I want!") 
] 
}

properties([ 
parameters([ 
string( 
name: 'ARTIFACT_NAME', 
description: 'Name of the artifact to deploy', 
defaultValue: 'myArtifact_1.0.zip' 
), 
choice( 
choices: ["Development"].join("\n"), 
description: 'Only development is allowed!', 
name: 'DEPLOY_PHASE'), 
choice( 
choices: ["blue", "green"].join("\n"), 
description: 'Color of Blue/Green deployment option', 
name: 'DEPLOYMENT_COLOR') 
]) 
])

UserInput = "User Supplied Values:\n" 
params.each\{ 
k, v -> UserInput = UserInput + """ $\{k}\n $\{v}\n""" 
}

echo UserInput

stage ('DownstreamJob')\{ 

echo "The value of SOMEEXTRAVAR: $SOMEEXTRAVAR" 

}