turn lsp4xml cache on by default

[fbricon]

Need to set "xml.useCache":true in the extension preferences. See eclipse-lemminx/lemminx#159

[angelozerr]

@fridex I have set it as default in server side, see eclipse-lemminx/lemminx@db41997

[fridex]

@angelozerr wrong nick? :)

[angelozerr]

Sorry @fridex -( with my mistake.

@fbricon I have set it as default in server side, see eclipse-lemminx/lemminx@db41997

[fbricon]

@angelozerr I don't see anything downloaded/cached when opening an actual schema:

<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <xs:complexType name="property">
        <xs:attribute name="name" type="xs:string" />
        <xs:attribute name="value" type="xs:string" />
    </xs:complexType>

    <xs:complexType name="resource">
        <xs:sequence>
            <xs:element name="property" type="property" minOccurs="0" maxOccurs="unbounded" />
        </xs:sequence>
        <xs:attribute name="name" type="xs:string" use="required" />
    </xs:complexType>

    <xs:element name="resources">
        <xs:complexType>
            <xs:sequence>
                <xs:element name="resource" type="resource" minOccurs="0" maxOccurs="unbounded" />
            </xs:sequence>
            <xs:attribute name="variant" type="xs:string" use="required"/>
        </xs:complexType>
    </xs:element>
</xs:schema>

[angelozerr]

@angelozerr I don't see anything downloaded/cached when opening an actual schema:

Yes it's normal. The cache download is done when Xerces XMLEntityResolver#resolveEntity is done.

This resolveEntity method is called when:

• XML Schema uses import (not in your case of resource.xsd)
• XML declares use of XML Schema with xsi:schemaLocation or xsi:noNamespaceSchemaLocation which have uri which start with http or ftp.