XQuery Functions

This function retrieves the value of an attribute from the current feature. It has two declarations:

fme:get-attribute( )

fme:get-attribute( , )

If a second parameter is provided, and the feature does not have a value for the given attribute name, the function will simply return the value of the second parameter. The second parameter may be any type of XQuery value: string, number, XML node, nested function call, etc.

If a second parameter is not provided, and the feature has no value for the given attribute, the function will simply return an empty sequence.

在使用它们的上下文中，将转换此函数返回的字符串值以序列化。特别是，如果将该值插入XML文档中，则任何XML语法都将被转义。例如，<characters will become<and>会变成>。Thefme:get-xml-attribute功能ion may be used to return XML nodes. Similarly, if the value is being inserted into a JSON document, the value will be enclosed in quotes, and reserved characters will be escaped. Thefme:get-json-attribute可用于返回JSON对象or arrays.

Example:

Consider a feature with the following attributes:

Attribute	Value
name	Oranjestad
location	-70.037 12.519

The fme:get-attribute function returns the following results:

XQuery	Result
{fme:get-attribute( "name" )}	Oranjestad
{fme:get-attribute( "point_type", "city" )}	city
{ “位置”:fme: get-attribute(“位置”) }	{ “地点” ："-70.037 12.519" }

This function retrieves the contents of a list attribute from the current feature. It also has two declarations:

fme:get-list-attribute( )

fme:get-list-attribute( , < delimiter > )

If no delimiter parameter is provided, the function will return the list attribute as a sequence of individual items. If a delimiter parameter is provided, the function will serialize the contents of the list attribute into a single string, using the value of the delimiter parameter as a delimiter.

As with thefme:get-attribute功能ion, all string values returned by this function will be converted to be valid XML or JSON strings, depending on the context of the function call. Thefme:get-xml-list-attribute功能ion may be used to retrieve a list of XML nodes, and thefme:get-json-list-attribute功能ion may be used to retrieve a list of JSON objects or arrays.

Example:

Consider a feature with the following attributes:

Attribute	Value
dates{0}	21-08-2010
dates{1}	22-08-2010
dates{2}	23-08-2010

The fme:get-list-attribute function returns the following results:

XQuery	Result
{fme:get-list-attribute( "dates" )}	21-08-2010 22-08-2010 23-08-2010
{fme:get-list-attribute( "dates", "," )}	21-08-2010,22-08-2010,23-08-2010
{ "dates" : fme:get-list-attribute("dates") }	{ "dates" : [ "21-08-2010", "22-08-2010", "23-08-2010" ] }

This function retrieves attributes containing XML nodes. It has only one declaration:

fme:get-xml-attribute( )

If the given attribute contains XML text, this function will parse the text and return an XML node. If the attribute does not contain XML text, the function will return an empty sequence.

Example:

Consider a feature with the following attributes:

Attribute	Value
name	Oranjestad
location	-70.037 12.519

FME：Get-XML-Attribute函数返回以下结果：

XQuery	Result
fme:get-xml-attribute("location" )	-70.037 12.519
fme:get-xml-attribute("name" )

This function is similar to the fme:get-xml-attribute function, but retrieves list attributes. It has two declarations:

fme：get-xml-list-attribute（<属性名称>）

fme:get-xml-list-attribute( , )

The function attempts to parse each value in the list attribute into an XML node. Values which are not valid XML will be skipped. If the delimiter parameter is provided, it will be copied into the return sequence between each parsed XML value.

Example:

Consider a feature with the following attributes:

Attribute	Value
person{0}	John Doe 25
person{1}	juan domingo 27
person{2}	johann deuter 29

The fme:get-xml-list-attribute function may be used as shown below:

XQuery	Result
<人们> {fme:get-xml-list-attribute("person{}")	<人们> John Doe 25 juan domingo 27 johann deuter 29

This function retrieves attributes containing JSON objects or arrays. It has only one declaration:

fme:get-json-attribute( )

If the given attribute contains JSON values, this function will parse the text and return a JSON object or array. If the attribute does not contain JSON text, the function will return an empty sequence.

Example:

Consider a feature with the following attributes:

Attribute	Value
name	Oranjestad
location	{ "type" : "point”, "x" : -70.037, "y" : 12.519 }

Thefme:get-json-attribute功能ion returns the following results:

XQuery	Result
{ "location" : fme:get-json-attribute( "location" ) }	{ “地点” ： { "type" : "point”, "x" : -70.037, "y" : 12.519 } }
fme:get-json-attribute( "name" )

此函数类似于fme：get-json-属性函数，但检索列表属性。它只有一个声明：

fme:get-json-list-attribute( )

The function attempts to parse each value in the list attribute into a JSON object or array. Values which are not valid JSON will be skipped.

Example:

Consider a feature with the following attributes:

Attribute	Value
person{0}	{ "name" : "John Doe", "age" : 25 }
person{1}	{ "name" : "Juan Domingo", "age" : 27 }
person{2}	{ "name" : "Johann Deuter", "age" : 29 }

Thefme:get-json-attribute功能ion may be used as shown below:

XQuery	Result
{ "people" : fme:get-json-list-attribute( "person{}" ) }	{ "people" : [ { "name" : "John Doe", "age" : 25 }, { "name" : "Juan Domingo", "age" : 27 }, { "name" : "Johann Deuter", "age" : 29 } ] }

This function allows access to a feature’s coordinate system. If a feature has a coordinate system, the function will return the name of the coordinate system. If the feature does not have a coordinate system, no value will be returned.

This function is very simple. It returns a boolean (true/false) value indicating whether or not an attribute exists on the current feature. It has one declaration:

fme:has-attribute( )

Example:

Consider a feature which has only one attribute: ‘name’. Thefme:has-attribute功能ion returns the following results:

XQuery	Result
fme:has-attribute("name")	true
fme:has-attribute("id")	false

This function returns a boolean (true/false) value indicating whether or not all of the attributes listed as parameters exist on the current feature. It has one declaration:

fme:has-all-attributes( )

Example:

Consider a feature which has a ‘name’ and an ‘id’ attribute. Thefme:has-all-attributes功能ion returns the following results:

XQuery	Result
fme:has-all-attributes( "name" )	true
fme:has-all-attributes( "name", "id" )	true
fme:has-all-attributes( "otherattr" )	false
fme:has-all-attributes( "name", "other", "id" )	false

This function returns a boolean (true/false) value indicating whether or not any of the attributes listed as parameters exist on the current feature. It has one declaration:

FME：具有任何属性（<属性名称>）

Example:

Consider a feature which has a ‘name’ and an ‘id’ attribute. Thefme:has-any-attributes功能ion returns the following results:

XQuery	Result
fme:has-any-attributes( "name" )	true
FME：具有任何属性（“名称”，“ID”）	true
fme:has-any-attributes( "otherattr" )	false
fme:has-any-attributes( "name", "other", "id" )	true

This function sets the value of a feature attribute. It has two declarations:

fme：set-attribute（<属性名称>，<值序列>）

fme:set-attribute( , , )

特征属性将被设置为序列化d value of the sequence of values. If the sequence contains more than one value, the values will be concatenated into a delimited string, and the attribute will be set to this concatenated value. The default delimiter is a comma, but the third parameter may be used to provide a different delimiter.

This function does not return a value.

Example

The following XML document is the context item for the examples in this section.

MONTSERRAT

<区域> 583.776

Plymouth

<城市>布雷德

After running the following query:

fme:set-attribute( "name_xml", /country/name ),

fme:set-attribute( "area", /country/area/text() ),

fme:set-attribute( "city_list", /country/cities/city/text() ),

fme:set-attribute( "city_list2", /country/cities/city/text(), "|" )

The feature has the following attributes:

Attribute	Value
name_xml	MONTSERRAT
area	583.776
city_list	Plymouth.Brades
city_list2	Plymouth|Brades

This function is very similar to thefme:append-attribute功能ion, but it appends to the value of a feature attribute, rather than replacing the attribute value. It has two declarations:

fme:append-attribute( , )

fme:append-attribute( , , )

The serialized value of the sequence of values will be appended to the feature attribute. If the sequence contains more than one value, the values will be concatenated into a delimited string before being appended to the attribute. The default delimiter is a comma, but the third parameter may be used to provide a different delimiter.

This function does not return a value.

This function sets the value of a feature list attribute. It has only one declaration:

fme:set-list-attribute( , )

The function serializes each value in the sequence into an element in the list attribute.

This function does not return a value.

Example:

The following XML document is the context item for the examples in this section.

Montserrat

Plymouth

Christmas Island

The Settlement

Aruba

Oranjestad

After running the following query:

fme:set-list-attribute( "names", /countries/country/name/text() ),

fme:set-list-attribute( "capitals", /countries/country/capital )

The feature has the following attributes:

Attribute	Value
names{0}	Montserrat
names{1}	Christmas Island
names{2}	Aruba
capitals{0}	Plymouth
capitals{1}	The Settlement
capitals{2}	Orangestad

This function is very similar to thefme:set-list-attribute功能ion, but it appends to the list attribute, rather than overwriting existing values. It has only one declaration:

FME：Append列表 - 属性（<属性名称>，<值序列>）

The function serializes each value in the sequence into an element in the list attribute. Existing list values will be preserved, with the new values appended to the end of the list.

This function does not return a value.

This function will evaluate a template, or set of templates, on features which enter the transformer through the corresponding input ports. The function will return the value of the sub-templates that get processed. This function has two declarations:

fme:process-features(