Add support for external Eclipse formatter settings

[fbricon]

We should expose (wrapped) jdt formatter options

[gorkem]

related to redhat-developer/vscode-java#2

[fbricon]

So the idea would be to

• map java.formatting.* options to org.eclipse.jdt.core.formatter.*
• same default values as corresponding jdt options
• formatter configuration would be received during startup or workspace/didChangeConfiguration requests, as part of the java settings
• Formatting options should be held in a dedicated class.

We need a way to gather all properties keys, default values and descriptions, by scripting something that'd extract all the info from JDT's DefaultCodeFormatterOptions , FormatterMessages and FormatterMessages.properties

That'll be a LOT of keys to expose. So we'll start small with a small subset of 10 sensible options

[snjeza]

@fbricon We could enable importing an Eclipse formatter xml file and define two following properties:

• java.formatter.fileName - a URL to the formatter xml file; if it isn't set, we would set JDT default formatting options
• java.formatter.profileName - a profile name; if it isn't set we would choose the first profile from the formatter xml file

I have attached the jdtls formatting options as an example.

jdtls.xml.zip

[fbricon]

I can't get line wrapping to work for some reason (<setting id="org.eclipse.jdt.core.formatter.lineSplit" value="100"/> and <setting id="org.eclipse.jdt.core.formatter.comment.line_length" value="100"/> are ignored).

Seems referencing "java.formatter.url": "eclipse-java-google-style.xml" with eclipse-java-google-style.xml present at the root of my project is ignored

[snjeza]

Seems referencing "java.formatter.url": "eclipse-java-google-style.xml" with eclipse-java-google-style.xml present at the root of my project is ignored
"org.eclipse.jdt.core.formatter.lineSplit"

I can't reproduce the issue.

"org.eclipse.jdt.core.formatter.comment.line_length"

Java LS doesn't format comments.
See https://github.com/eclipse/eclipse.jdt.ls/blob/master/org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/handlers/FormatterHandler.java#L88
To format comments, we would need to use:

TextEdit format = formatter.format(CodeFormatter.K_COMPILATION_UNIT | CodeFormatter.F_INCLUDE_COMMENTS, sourceToFormat, region.getOffset(), region.getLength(), 0, lineDelimiter);

We could also add the "java.format.comments" property, false by default.

[fbricon]

Changing eclipse-java-google-style.xml definitely does not trigger a workspace/didChangeWatchedFiles event

[fbricon]

To format comments, we would need to use:
TextEdit format = formatter.format(CodeFormatter.K_COMPILATION_UNIT | CodeFormatter.F_INCLUDE_COMMENTS, sourceToFormat, region.getOffset(), region.getLength(), 0, lineDelimiter);
We could also add the "java.format.comments" property, false by default.

ok let's do that, but with java.format.comments:true by default, same as eclipse

[fbricon]

Any idea why <setting id="org.eclipse.jdt.core.formatter.blank_lines_after_package" value="1"/> is not applied if current blank lines after package is bigger than org.eclipse.jdt.core.formatter.blank_lines_after_package's value?

[snjeza]

Any idea why is not applied if current blank lines after packages is bigger than org.eclipse.jdt.core.formatter.blank_lines_after_package's value?

Does it work in Eclipse?

[fbricon]

yes, it works fine in Eclipse. Say if you have

package foo.bar;










public class Foo

with <setting id="org.eclipse.jdt.core.formatter.blank_lines_after_package" value="1"/>, this is actually formatted into

package foo.bar;



public class Foo

instead of

package foo.bar;

public class Foo

[snjeza]

@fbricon I think you have used the standard Eclipse formatter in Eclipse and the Google formatter in VS Code.

I have updated the PR. Could you, please, test again.

[snjeza]

In order to use the formatter, you need an Eclipse formatter file like https://raw.githubusercontent.com/google/styleguide/gh-pages/eclipse-java-google-style.xml

Set the following property:

"java.format.settings.url": "https://raw.githubusercontent.com/google/styleguide/gh-pages/eclipse-java-google-style.xml",

The property can point to an URL or a local file path.
If the formatter xml file contains more profiles you will be able set a profile name as:

"java.format.settings.profile": "GoogleStyle",