Scala xml power play part 1
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This document discusses how Scala allows for easy creation, loading, searching, and processing of XML content. Some key points: - Scala treats XML as a "first class citizen" and provides simple syntax for creating, saving, and loading XML. - XML content can be searched using methods like \ to find tags and text within tags. The \\ operator allows searching nested tags. - XML content can be processed and manipulated by looping through tags, finding lengths, slices of nodes, and more. Examples show printing names of members from India and all cities represented.
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Scala xml power play part 1
- 1. Scala – XML Power Play -Part 1 By VulcanMinds
- 2. Creating XML content Scala treats XML as ‘first class citizen’. Scala provides easy syntax for creating XML content for e.g. scala> var someXML = <candidate><name> Manish </name> <title> Consultant</title> <city> Pune </city></candidate> someXML: scala.xml.Elem = <candidate><name> Manish </name> <title> Consultant</title> <city> Pune </city></candidate> scala> var employee = <Employee><ID> 456789</ID> <Name> Mark Holland </Name><AGE>34</AGE></Employee> employee: scala.xml.Elem = <Employee><ID> 456789</ID> <Name> Mark Holland </Name><AGE>34</AGE></Employee> You can save the XML content to a file easily like below. You must import XML module in the REPL (console) for this example. scala> import scala.xml._; import scala.xml._ scala> XML.save("sample.xml", employee ); Also you can load XML directly from an XML file like below. scala> val xmlFromFile = XML.loadFile("sample.xml"); xmlFromFile: scala.xml.Elem = <candidate><name> Manish </name> <title> Scala Consultant</title> <city> Pune </city></candidate>
- 3. Searching in XML….. Scala provides easy syntax for searching in the XML content scala> var employee = <Employee><ID> 456789</ID> <Name> Mark Holland </Name><AGE>34</AGE></Employee> employee: scala.xml.Elem = <Employee><ID> 456789</ID> <Name> Mark Holland </Name><AGE>34</AGE></Employee> scala> var name = employee "Name" text name: String = " Mark Holland “ scala> var age = employee "age" text // String searches are case sensitive age: String = "" scala> var age = employee "AGE" text age: String = 34 Using wild card character ‘_’ will get everything within <employee> tag scala> var age = employee "_" age: scala.xml.NodeSeq = NodeSeq(<ID> 456789</ID>, <Name> Mark Holland </Name>, <AGE>34</AGE>) For deep diving search in the XML jungle which finds tags deep inside the XML jungle you can use ‘’ operator like below…. Note that <CITY> … </CITY> tag is inside the <ADDRESS> </ADDRESS> tag. scala> var employee = <Employee><ID> 456789</ID> <Name> Mark Holland </Name><AGE>34</AGE><ADDRESS><CITY>New York</CITY></ADDRESS></Employee> employee: scala.xml.Elem = <Employee><ID> 456789</ID> <Name> Mark Holland </Name><AGE>34</AGE><ADDRESS><CITY>New York</CITY></ADDRESS></Employee> scala> var city = employee “CITY“ city: scala.xml.NodeSeq = NodeSeq(<CITY>New York</CITY>)
- 4. Processing XML….. Scala provides elegant syntax for processing content in XML tags….. For e.g. For the example members.xml file <Members> <Member> <Name> THOMAS D'SILVA </Name> <Address>123 PARK AVENUE, GRANT ROAD </Address> <CITY> MUMBAI </CITY> <COUNTRY>INDIA </COUNTRY> </Member> <Member> <Name> ALVIN NAZARETH</Name> <Address> 524 ELEPHANT GRASS,BEDFORD DRIVE,</Address> <CITY>SASKATEN </CITY> <COUNTRY>INDIA </COUNTRY> </Member> <Member> <Name>ANTONIO ALVAREZ</Name> <Address>123 PARK AVENUE GRANT ROAD </Address> <CITY>MUMBAI</CITY> <COUNTRY>INDIA</COUNTRY> </Member> <Member> <Name>JONAS WHITTAKER</Name> <Address>B20345 ANDROMEDA HOUSE, PARAMOUNT ESTATE, </Address> <CITY>TIMBUKTU</CITY> <COUNTRY>EGYPTIA</COUNTRY> </Member> </Members>
- 5. Processing XML….. Following code prints the names of members from India. scala> var members=XML.loadFile("members2.xml") members: scala.xml.Elem = <Members> <Member> <Name> THOMAS D'SILVA </Name> <Address>123 PARK AVENUE, GRANT ROAD </Address> <CITY>MUMBAI</CITY> <COUNTRY>INDIA</COUNTRY> ……… ………. </Members> scala> for(val aMember <- members "Member") { if( (aMember "COUNTRY").text.trim.equals("INDIA") ) { println((aMember "Name").text); } } THOMAS D'SILVA ALVIN NAZARETH ANTONIO ALVAREZ
- 6. Processing XML….. Following code prints all the cities the members are from …. scala> var cities = members ”CITY” cities: scala.xml.NodeSeq = NodeSeq(<CITY> MUMBAI </CITY>, <CITY> SASKATEN</CITY>, <CITY> MUMBAI</CITY>, <CITY>TIMBUKTU</CITY>) Following code prints the total number of members scala> var memberElements = members ”Member” ………….. scala> println(memberElements.length) 4 Following code finds the first and the last member in the sequence scala> println(memberElements.first) <Member> <Name> THOMAS D'SILVA </Name> <Address>123 PARK AVENUE, GRANT ROAD </Address> <CITY> MUMBAI</CITY> <COUNTRY> INDIA </COUNTRY> </Member> scala> println(memberElements.last) <Member> <Name> JONAS WHITTAKER</Name> <Address> B20345 ANDROMEDA HOUSE, PARAMOUNT ESTATE, </Address> <CITY> TIMBUKTU</CITY> <COUNTRY> EGYPTIA</COUNTRY> </Member>
- 7. Processing XML….. Following code gets a slice of member nodes from all nodes with “from” index including to “toIndex” excluding. scala> println(memberElements.slice(0,2)) <Member> <Name> THOMAS D'SILVA </Name> <Address>123 PARK AVENUE, GRANT ROAD </Address> <CITY> MUMBAI</CITY> <COUNTRY> INDIA </COUNTRY> </Member> <Member> <Name> ALVIN NAZARETH</Name> <Address> 524 ELEPHANT GRASS, BEDFORD DRIVE,</Address> <CITY> SASKATEN </CITY> <COUNTRY> INDIA</COUNTRY> </Member>