How to print an instance of some class in jenkins shared library without explicitly calling toString() method

I have jenkins shared library. It has some CustomClass.groovy with overridden toString() method:

package com.jenkins



class CustomClass {



    CustomClass(){

    }



    @Override

    String toString() {

        return "custom_class"

    }

}

And I have the Jenkinsfile:

@Library("sharedlib@to-string")

import com.jenkins.CustomClass



println("1")

println(new CustomClass())



println("2")

println("prefix: " + new CustomClass())



println("3")

println("prefix: " + new CustomClass().toString())

It produces following output:

[Pipeline] echo

1

[Pipeline] echo

2

[Pipeline] echo

custom_class

[Pipeline] echo

3

[Pipeline] echo

prefix: custom_class

[Pipeline] End of Pipeline

Finished: SUCCESS

I have some confusion about that output:

Why didn't the first example print anything?

Why didn't the first example print prefix? Why only instance?

Why are second and third examples different? Why here I see prefix, but don't see it in the second example. Why the first example it printed nothing, but third is okay as expected. After all, println() method uses toString() in second example implicitly.

edited Jan 1 at 4:47

Jayan

13.1k1065124

asked Dec 28 '18 at 22:41

grolegor

1265

in plain groovy all works as you expect. question to jenkins pipeline...

– daggett
Dec 29 '18 at 8:54

Yes. In plain groovy everything is ok. But running in jenkins environment shows strange results.

– grolegor
Dec 29 '18 at 10:46

what about echo "${new CustomClass()}"

– daggett
Dec 29 '18 at 11:12

same result - nothing.

– grolegor
Dec 29 '18 at 11:29

add a comment |

I have jenkins shared library. It has some CustomClass.groovy with overridden toString() method:

package com.jenkins



class CustomClass {



    CustomClass(){

    }



    @Override

    String toString() {

        return "custom_class"

    }

}

And I have the Jenkinsfile:

@Library("sharedlib@to-string")

import com.jenkins.CustomClass



println("1")

println(new CustomClass())



println("2")

println("prefix: " + new CustomClass())



println("3")

println("prefix: " + new CustomClass().toString())

It produces following output:

[Pipeline] echo

1

[Pipeline] echo

2

[Pipeline] echo

custom_class

[Pipeline] echo

3

[Pipeline] echo

prefix: custom_class

[Pipeline] End of Pipeline

Finished: SUCCESS

I have some confusion about that output:

Why didn't the first example print anything?

Why didn't the first example print prefix? Why only instance?

Why are second and third examples different? Why here I see prefix, but don't see it in the second example. Why the first example it printed nothing, but third is okay as expected. After all, println() method uses toString() in second example implicitly.

edited Jan 1 at 4:47

Jayan

13.1k1065124

asked Dec 28 '18 at 22:41

grolegor

1265

in plain groovy all works as you expect. question to jenkins pipeline...

– daggett
Dec 29 '18 at 8:54

Yes. In plain groovy everything is ok. But running in jenkins environment shows strange results.

– grolegor
Dec 29 '18 at 10:46

what about echo "${new CustomClass()}"

– daggett
Dec 29 '18 at 11:12

same result - nothing.

– grolegor
Dec 29 '18 at 11:29

add a comment |

I have jenkins shared library. It has some CustomClass.groovy with overridden toString() method:

package com.jenkins



class CustomClass {



    CustomClass(){

    }



    @Override

    String toString() {

        return "custom_class"

    }

}

And I have the Jenkinsfile:

@Library("sharedlib@to-string")

import com.jenkins.CustomClass



println("1")

println(new CustomClass())



println("2")

println("prefix: " + new CustomClass())



println("3")

println("prefix: " + new CustomClass().toString())

It produces following output:

[Pipeline] echo

1

[Pipeline] echo

2

[Pipeline] echo

custom_class

[Pipeline] echo

3

[Pipeline] echo

prefix: custom_class

[Pipeline] End of Pipeline

Finished: SUCCESS

I have some confusion about that output:

Why didn't the first example print anything?

Why didn't the first example print prefix? Why only instance?

Why are second and third examples different? Why here I see prefix, but don't see it in the second example. Why the first example it printed nothing, but third is okay as expected. After all, println() method uses toString() in second example implicitly.

edited Jan 1 at 4:47

Jayan

13.1k1065124

asked Dec 28 '18 at 22:41

grolegor

1265

I have jenkins shared library. It has some CustomClass.groovy with overridden toString() method:

package com.jenkins



class CustomClass {



    CustomClass(){

    }



    @Override

    String toString() {

        return "custom_class"

    }

}

And I have the Jenkinsfile:

@Library("sharedlib@to-string")

import com.jenkins.CustomClass



println("1")

println(new CustomClass())



println("2")

println("prefix: " + new CustomClass())



println("3")

println("prefix: " + new CustomClass().toString())

It produces following output:

[Pipeline] echo

1

[Pipeline] echo

2

[Pipeline] echo

custom_class

[Pipeline] echo

3

[Pipeline] echo

prefix: custom_class

[Pipeline] End of Pipeline

Finished: SUCCESS

I have some confusion about that output:

Why didn't the first example print anything?

Why didn't the first example print prefix? Why only instance?

Why are second and third examples different? Why here I see prefix, but don't see it in the second example. Why the first example it printed nothing, but third is okay as expected. After all, println() method uses toString() in second example implicitly.

jenkins jenkins-pipeline

edited Jan 1 at 4:47

Jayan

13.1k1065124

asked Dec 28 '18 at 22:41

grolegor

1265

edited Jan 1 at 4:47

Jayan

13.1k1065124

asked Dec 28 '18 at 22:41

grolegor

1265

edited Jan 1 at 4:47

Jayan

13.1k1065124

edited Jan 1 at 4:47

Jayan

13.1k1065124

edited Jan 1 at 4:47

Jayan

13.1k1065124

asked Dec 28 '18 at 22:41

grolegor

1265

asked Dec 28 '18 at 22:41

grolegor

1265

asked Dec 28 '18 at 22:41

grolegor

1265

in plain groovy all works as you expect. question to jenkins pipeline...

– daggett
Dec 29 '18 at 8:54

Yes. In plain groovy everything is ok. But running in jenkins environment shows strange results.

– grolegor
Dec 29 '18 at 10:46

what about echo "${new CustomClass()}"

– daggett
Dec 29 '18 at 11:12

same result - nothing.

– grolegor
Dec 29 '18 at 11:29

add a comment |

in plain groovy all works as you expect. question to jenkins pipeline...

– daggett
Dec 29 '18 at 8:54

Yes. In plain groovy everything is ok. But running in jenkins environment shows strange results.

– grolegor
Dec 29 '18 at 10:46

what about echo "${new CustomClass()}"

– daggett
Dec 29 '18 at 11:12

same result - nothing.

– grolegor
Dec 29 '18 at 11:29

in plain groovy all works as you expect. question to jenkins pipeline...

– daggett
Dec 29 '18 at 8:54

Yes. In plain groovy everything is ok. But running in jenkins environment shows strange results.

– grolegor
Dec 29 '18 at 10:46

what about echo "${new CustomClass()}"

– daggett
Dec 29 '18 at 11:12

same result - nothing.

– grolegor
Dec 29 '18 at 11:29

add a comment |

1 Answer
1

active

oldest

votes

according to the Pipeline Readme :-)

Note in particular that @Overrides of methods defined in binary classes, such as Object.toString(), should in general be marked @NonCPS since it will commonly be binary code calling them.

the following will work correctly:

class A{

    @NonCPS

    @Override

    public String toString(){

        return "A[123]"

    }

}



node {

    def a = new A()

    echo('1 >>>')

    echo(message: "Hello ${a}")

    echo('2 >>>')

    echo(message: "Hello " + a)

    echo('3 >>>')

    echo(message: "Hello " + a.toString())

}

answered Dec 30 '18 at 19:14

daggett

8,75521530

add a comment |

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1 Answer
1

active

oldest

votes

1 Answer
1

active

oldest

votes

according to the Pipeline Readme :-)

Note in particular that @Overrides of methods defined in binary classes, such as Object.toString(), should in general be marked @NonCPS since it will commonly be binary code calling them.

the following will work correctly:

class A{

    @NonCPS

    @Override

    public String toString(){

        return "A[123]"

    }

}



node {

    def a = new A()

    echo('1 >>>')

    echo(message: "Hello ${a}")

    echo('2 >>>')

    echo(message: "Hello " + a)

    echo('3 >>>')

    echo(message: "Hello " + a.toString())

}

answered Dec 30 '18 at 19:14

daggett

8,75521530

add a comment |

according to the Pipeline Readme :-)

Note in particular that @Overrides of methods defined in binary classes, such as Object.toString(), should in general be marked @NonCPS since it will commonly be binary code calling them.

the following will work correctly:

class A{

    @NonCPS

    @Override

    public String toString(){

        return "A[123]"

    }

}



node {

    def a = new A()

    echo('1 >>>')

    echo(message: "Hello ${a}")

    echo('2 >>>')

    echo(message: "Hello " + a)

    echo('3 >>>')

    echo(message: "Hello " + a.toString())

}

answered Dec 30 '18 at 19:14

daggett

8,75521530

add a comment |

according to the Pipeline Readme :-)

Note in particular that @Overrides of methods defined in binary classes, such as Object.toString(), should in general be marked @NonCPS since it will commonly be binary code calling them.

the following will work correctly:

class A{

    @NonCPS

    @Override

    public String toString(){

        return "A[123]"

    }

}



node {

    def a = new A()

    echo('1 >>>')

    echo(message: "Hello ${a}")

    echo('2 >>>')

    echo(message: "Hello " + a)

    echo('3 >>>')

    echo(message: "Hello " + a.toString())

}

answered Dec 30 '18 at 19:14

daggett

8,75521530

according to the Pipeline Readme :-)

Note in particular that @Overrides of methods defined in binary classes, such as Object.toString(), should in general be marked @NonCPS since it will commonly be binary code calling them.

the following will work correctly:

class A{

    @NonCPS

    @Override

    public String toString(){

        return "A[123]"

    }

}



node {

    def a = new A()

    echo('1 >>>')

    echo(message: "Hello ${a}")

    echo('2 >>>')

    echo(message: "Hello " + a)

    echo('3 >>>')

    echo(message: "Hello " + a.toString())

}

answered Dec 30 '18 at 19:14

daggett

8,75521530

answered Dec 30 '18 at 19:14

daggett

8,75521530

answered Dec 30 '18 at 19:14

daggett

8,75521530

answered Dec 30 '18 at 19:14

daggett

8,75521530

add a comment |

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