Source printer import ordering strategy

[4everTheOne]

Hello!

This PR adds support for custom import ordering.
Previously, the user could not define the "template" to be used for imports, only having the option to have imports like this:

import java.util.List;
import com.github.javaparser.ast.NodeList;
import com.github.javaparser.ast.ImportDeclaration;

What if the user wants to separate the static imports from the others? What if the user wants to group all java imports into a single group?

Example:

import com.github.javaparser.ast.NodeList;
import com.github.javaparser.ast.ImportDeclaration;

import java.util.List;

With this PR this can now be achieve Included in this PR, there are 3 implementation of import ordering.

• DefaultImportOrderingStrategy: The logic that existed previously in JavaParser.
• IntelliJImportOrderingStrategy: Implements the ordering like IntelliJ does;
• EclipseImportOrderingStrategy: Implements the ordering like Eclipse does;

An example of code that makes the printer use a custom formatitng can be seen below:

CompilationUnit cu = ...;

IntelliJImportOrderingStrategy strategy = new IntelliJImportOrderingStrategy();
DefaultConfigurationOption option = new DefaultConfigurationOption(ConfigOption.SORT_IMPORTS_STRATEGY, strategy);
printerConfiguration.addOption(option);

Printer printer = new DefaultPrettyPrinter(printerConfiguration);
String actualCode = printer.print(cu);

This design is flexible, so if the user wants to create their own implementation they can also do it.

Feedback is welcome! :)

[codecov]

Codecov Report

Merging #3807 (4d2d1be) into master (b9301ef) will increase coverage by 0.083%.
The diff coverage is 94.318%.

@@               Coverage Diff               @@
##              master     #3807       +/-   ##
===============================================
+ Coverage     57.490%   57.574%   +0.083%     
  Complexity      2182      2182               
===============================================
  Files            635       638        +3     
  Lines          33802     33878       +76     
  Branches        5837      5850       +13     
===============================================
+ Hits           19433     19505       +72     
- Misses         12290     12293        +3     
- Partials        2079      2080        +1     

Flag	Coverage Δ
AlsoSlowTests	57.574% <94.318%> (+0.083%)	⬆️
javaparser-core	50.334% <94.318%> (+0.127%)	⬆️
javaparser-symbol-solver	36.610% <1.136%> (-0.080%)	⬇️
jdk-10	57.570% <94.318%> (+0.086%)	⬆️
jdk-11	57.567% <94.318%> (+0.080%)	⬆️
jdk-12	57.570% <94.318%> (+0.083%)	⬆️
jdk-13	57.570% <94.318%> (+0.083%)	⬆️
jdk-14	57.564% <94.318%> (+0.077%)	⬆️
jdk-15	57.570% <94.318%> (+0.083%)	⬆️
jdk-16	57.570% <94.318%> (+0.089%)	⬆️
jdk-8	57.571% <94.318%> (+0.089%)	⬆️
jdk-9	57.570% <94.318%> (+0.086%)	⬆️
macos-latest	57.565% <94.318%> (+0.083%)	⬆️
ubuntu-latest	57.559% <94.318%> (+0.083%)	⬆️
windows-latest	57.556% <94.318%> (+0.083%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...uration/imports/DefaultImportOrderingStrategy.java	90.000% <90.000%> (ø)
...ration/imports/IntelliJImportOrderingStrategy.java	91.304% <91.304%> (ø)
...avaparser/printer/DefaultPrettyPrinterVisitor.java	92.897% <94.736%> (+0.040%)	⬆️
...uration/imports/EclipseImportOrderingStrategy.java	97.142% <97.142%> (ø)
...ter/configuration/DefaultPrinterConfiguration.java	87.500% <100.000%> (+0.403%)	⬆️

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[jlerbsc]

As usual it is a very nice contribution.
Nevertheless, would it be possible to rename the "strategy" classes so as not to refer to a solution (eclipse, intelliJ) but rather to an order. If it's too complex to describe the order other than by the name of the solution, that's okay.

[4everTheOne]

Hi @jlerbsc. Thanks for your feedback!
I'm not sure how to name it, because they are a little complex.

For example, in intellij the order is:

• Other Imports;
• Java and Javax:
• Static Imports

On eclipse the order is:

• Static Imports
• Java
• JavaX
• org
• com
• Other

If you have any suggestion, please let me know! I would be happy to integrate it.

[jlerbsc]

No I have no idea that's why I asked you for yours. Have you finished this PR?

[4everTheOne]

Yes I have finished it :)
Thanks