Following issues needs to be addressed regarding documentation:

• Since documentation is searched with selectSingleNode it will display wrong documentation if the tag remains same.
• namespace specific documentation. If elements belongs to different namespace, it should search documentation based on the namespace. Currently, it searches all the xsds files specified in schemaLocation.

Steps to reproduce:

• Open any of the complex pom.xml, such as this projects itself, in any editor supporting LSP, preferably VSCode.
• Hover over artifactId in dependency and parent pom itself, both displays same documentation.

Add contributing guidelines so that others can contribute.

Update contribution guidelines and README with steps to setup a complete dev environment.
This should be included in both xml-vscode-plugin as well as here.

Describe the bug
If XML is not well formed, but has schemaLocation defined in the root tag, it fails with following error.
This is because, in order to resolve schemas, it first tries to parse it and then tries to show the error. This should be avoided
i.e. if XML is malformed, first display those error and then if its not then display schema validations.

17:00:50.377 [pool-2-thread-1] ERROR io.github.handofgod94.schema.resolve.XsdSchemaResolver - Unable to parse or load schema
org.dom4j.DocumentException: Error on line 18 of document  : The element type "choice" must be terminated by the matching end-tag "</choice>".
	at org.dom4j.io.SAXReader.read(SAXReader.java:462) ~[xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.dom4j.io.SAXReader.read(SAXReader.java:345) ~[xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at io.github.handofgod94.schema.resolve.XsdSchemaResolver.resolve(XsdSchemaResolver.java:44) ~[xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at io.github.handofgod94.main.XmlDocumentService.didSave(XmlDocumentService.java:145) ~[xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_191]
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_191]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_191]
	at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_191]
	at org.eclipse.lsp4j.jsonrpc.services.GenericEndpoint.lambda$null$0(GenericEndpoint.java:65) ~[xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.eclipse.lsp4j.jsonrpc.services.GenericEndpoint.notify(GenericEndpoint.java:152) [xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.eclipse.lsp4j.jsonrpc.RemoteEndpoint.handleNotification(RemoteEndpoint.java:220) [xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.eclipse.lsp4j.jsonrpc.RemoteEndpoint.consume(RemoteEndpoint.java:187) [xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.eclipse.lsp4j.jsonrpc.json.StreamMessageProducer.handleMessage(StreamMessageProducer.java:192) [xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.eclipse.lsp4j.jsonrpc.json.StreamMessageProducer.listen(StreamMessageProducer.java:94) [xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.eclipse.lsp4j.jsonrpc.json.ConcurrentMessageProcessor.run(ConcurrentMessageProcessor.java:99) [xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_191]
	at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_191]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [?:1.8.0_191]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [?:1.8.0_191]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_191]
Caused by: org.xml.sax.SAXParseException: The element type "choice" must be terminated by the matching end-tag "</choice>".
	at org.apache.xerces.util.ErrorHandlerWrapper.createSAXParseException(Unknown Source) ~[xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.apache.xerces.util.ErrorHandlerWrapper.fatalError(Unknown Source) ~[xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.apache.xerces.impl.XMLErrorReporter.reportError(Unknown Source) ~[xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.apache.xerces.impl.XMLErrorReporter.reportError(Unknown Source) ~[xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.apache.xerces.impl.XMLErrorReporter.reportError(Unknown Source) ~[xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.apache.xerces.impl.XMLScanner.reportFatalError(Unknown Source) ~[xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.apache.xerces.impl.XMLNSDocumentScannerImpl.scanEndElement(Unknown Source) ~[xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown Source) ~[xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source) ~[xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source) ~[xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source) ~[xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.apache.xerces.parsers.XMLParser.parse(Unknown Source) ~[xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source) ~[xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.apache.xerces.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown Source) ~[xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	at org.dom4j.io.SAXReader.read(SAXReader.java:445) ~[xml-language-server-1.0-SNAPSHOT-jar-with-dependencies.jar:?]
	... 19 more

To Reproduce

Steps to reproduce the behavior:

1. Open any well formed XML File with valid schemaLocation
2. Add an extra element but just the starting tag and not the ending tag.
3. Save the file.

Expected behavior
It should first display malformed XML error in diagnostic report.

Desktop (please complete the following information):

• OS : Windows
• Editor : VSCode
• Editor Version : 1.30.1

Implement a cache repository, preferably using h2, to store XSD fetched from Remote
Future release should also handle DTD files.
The lookup for xsd will first take place in this cache and then will try to fetch it from the remote.
It should handle multiple versions of xsd too.

Enable checkstyle for java sources using google-checkstyle

Add required configs for travis CI to run.
A separate dev branch on which travis builds will be configured and a daily build needs to be configured on master branch.

When autocomplete requested for an element, it shows attribute already present in the element.
An xml can't have 2 same attributes for same element.
It should not display elements which are already present

Currently it displays, an error if the attributes are repeated for the current element.

Describe the bug
Currently, if user adds, removes or updates a schemaLocation for an XML, the file needs to be reopened
to load new XML Schema models from the XSD.

To Reproduce
Steps to reproduce the behavior:

1. Open any valid XML File
2. Modify the schemaLocation
3. Save it.

Expected behavior
It should load the metadata from new XSD location, and should provide hover information and
element/attribute completion accordingly.

Desktop (please complete the following information):

• OS : Windows
• Editor : VSCode
• Editor Version : 1.30.1

Need to implement integration test and ci integration with travis.
It should consider maximum possible xmls and xsd that users can have and the server
should not crash, unknowingly.

Utility classes currently are written as java 8 Function lambdas. This decreases readability and documentations. It needs to be changed to static final methods.

All the features of lsp for elements and attributes should only be activated in specific contexts.

For e.g.

  <foo fizz="buzz">bar</foo>

• The hover should not be activated for innerText
• The hover should not be activated for attributeValue
• The hover should not be activated for comments
• The completion invocation should not give suggestions inside comments..... and many more.

Certain unit tests written as part PR(#25) are failing because it checks these kind of scenarios.

Describe the bug
The completion suggestion is listing all the suggestions for a give parent, and is not honoring the
sequence in the elements should occur. The users gets notification after they modify the documet

To Reproduce
Steps to reproduce the behavior:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="
       http://www.springframework.org/schema/beans 
       http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
       http://www.springframework.org/schema/context 
       http://www.springframework.org/schema/context/spring-context-2.5.xsd
       http://camel.apache.org/schema/spring 
       http://camel.apache.org/schema/spring/camel-spring.xsd">

  <camelContext xmlns="http://camel.apache.org/schema/spring">
    <route>
      <from uri="seda:foo"/>
      <to uri="mock:results"/>
    </route>
  </camelContext>
</beans>

1. Open VSCode with attached XML
2. List down element suggestion after line 17 by typing <.
3. Select export element and add uri parameter to it since its required.
4. It throws an cvc error.

Expected behavior
It should not list export if it's after route element as per XSD, since it has to honor xsd:sequence.

Screenshots

• Wrong suggestions in autocomplete
  

Desktop (please complete the following information):

• OS : Windows
• Editor : VSCode
• Editor Version : 1.28.2

XSD files have xs:annotation which may contain documentation info for an element.
Support needed for providing documentation on hover of elements.

Google Guice is a nice Java library for dependency Injection.
Integrate it for better and more modular codebase for Language server.
Also document it that developer needs to follow.

Since now, documentation on hover and error detection is working. Probably screenshots can be attached for both these features to README.md for both xml-language-server and xml-vscode-plugin

Need to add coverage badge in README for unit test case using coveralls.

Add issues and PR templates

Describe the bug
If XML has a schemaLocation path relative to the current XML, then it's unable to resolve it

To Reproduce
Steps to reproduce the behavior:

1. Open any valid XML file, pointing to local XSD.
2. Displays an error, saying unable to load.

Expected behavior
If relative path is correct, then it should load it.

Desktop (please complete the following information):

• OS : Windows
• Editor : VSCode
• Editor Version : 1.30.1

Support for autocompletion of xml element tags and attributes.
For alpha release, focus will be on basic XSD schemas, DTD Support will be added later.
Also initial plan is to make it work for documents having namespace in the root element i.e. not prefix in the element tags.
Support for elements having namespace will be done at later stage.

Displays auto completion list out side xml elements.

To Reproduce
Steps to reproduce the behavior:

1. Open any XML document.
2. Go to any position which is out side of an element but in the same line.
3. Invoke suggestions by hitting Ctrl+Space.

Expected behavior
It should not display the list of attributes for that element.

Screenshot:

Desktop (please complete the following information):

• OS : Windows
• Editor :VSCode
• Editor Version :1.28.2

Upon saving, it resolves all the URI again from the schema Location. It should only resolve the schema URI once, and should only fetch for those who are newly added.

Add testcases and integrate coverage report as part of build and readme.

Currently it's written in Java 8.
Certain features, needs to evaluated first:

• new module system capabilities of java 9+. All the third party libs should have module support.
• Change the annotation to JSR-330 for dependency injections.
• Evaluate the size of heavy fat run time that will be created if we use jmod and jlink as packaging instead of jars.
• Update maven version
• Update travis build scripts

Preferably MIT or The Unlicense for the repo.

Currently validation is working for elements having just one xsd in the schemaLocation.
It should handle multiple schema for validating documents as well.