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Process an XML document
Given the XML Document:
<shopping>
<item name=
<item name=
</shopping>
Print out the total cost of the items, e.g. $14.50
<shopping>
<item name=
"bread" quantity="3" price="2.50"/>
<item name=
"milk" quantity="2" price="3.50"/>
</shopping>
Print out the total cost of the items, e.g. $14.50
java
// solution uses JAXP and SAX included in Java API since version >= 1.5
class ShoppingContentHandler extends DefaultHandler {
Double priceSum = 0d;
@Override
public void startElement(String uri, String localName, String name,
Attributes attributes) throws SAXException {
if(name.equals("item")) {
String quantityString = attributes.getValue(attributes.getIndex("quantity"));
String priceString = attributes.getValue(attributes.getIndex("price"));
Integer quantity = Integer.parseInt(quantityString);
Double price = Double.parseDouble(priceString);
priceSum += (quantity * price);
}
}
public Double getPriceSum() {
return priceSum;
}
}
SAXParserFactory parserFactory = SAXParserFactory.newInstance();
try {
SAXParser parser = parserFactory.newSAXParser();
XMLReader reader = parser.getXMLReader();
ShoppingContentHandler contentHandler = new ShoppingContentHandler();
reader.setContentHandler(contentHandler);
reader.parse(new InputSource(new FileReader("shopping.xml")));
System.out.printf("$%.2f", contentHandler.getPriceSum());
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
class ShoppingContentHandler extends DefaultHandler {
Double priceSum = 0d;
@Override
public void startElement(String uri, String localName, String name,
Attributes attributes) throws SAXException {
if(name.equals("item")) {
String quantityString = attributes.getValue(attributes.getIndex("quantity"));
String priceString = attributes.getValue(attributes.getIndex("price"));
Integer quantity = Integer.parseInt(quantityString);
Double price = Double.parseDouble(priceString);
priceSum += (quantity * price);
}
}
public Double getPriceSum() {
return priceSum;
}
}
SAXParserFactory parserFactory = SAXParserFactory.newInstance();
try {
SAXParser parser = parserFactory.newSAXParser();
XMLReader reader = parser.getXMLReader();
ShoppingContentHandler contentHandler = new ShoppingContentHandler();
reader.setContentHandler(contentHandler);
reader.parse(new InputSource(new FileReader("shopping.xml")));
System.out.printf("$%.2f", contentHandler.getPriceSum());
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
csharp
System.Xml.XmlDocument doc = new System.Xml.XmlDocument();
doc.LoadXml(
@"<shopping>
<item name='bread' quantity='3' price='2.50'/>
<item name='milk' quantity='2' price='3.50'/>
</shopping>");
string decimalSeparator= System.Globalization.CultureInfo.CurrentCulture.NumberFormat.CurrencyDecimalSeparator;
double sum=0;
foreach(System.Xml.XmlNode nodo in doc.SelectNodes("/shopping/item")){
sum += int.Parse(nodo.Attributes["quantity"].InnerText) * double.Parse(nodo.Attributes["price"].InnerText.Replace(".",decimalSeparator));
}
Console.WriteLine("{0:#.00}",sum);
doc.LoadXml(
@"<shopping>
<item name='bread' quantity='3' price='2.50'/>
<item name='milk' quantity='2' price='3.50'/>
</shopping>");
string decimalSeparator= System.Globalization.CultureInfo.CurrentCulture.NumberFormat.CurrencyDecimalSeparator;
double sum=0;
foreach(System.Xml.XmlNode nodo in doc.SelectNodes("/shopping/item")){
sum += int.Parse(nodo.Attributes["quantity"].InnerText) * double.Parse(nodo.Attributes["price"].InnerText.Replace(".",decimalSeparator));
}
Console.WriteLine("{0:#.00}",sum);
clojure
(println (format "Total cost of items are $%#.2f"
(->> (xml-seq (parse *xml-input-stream*))
(filter #(= :item (:tag %))) ; Remove all but the item tags
(map :attrs) ; Keep the attributes
(map (fn [e] (str "(* " (:quantity e) " " (:price e) ")"))) ; Get the total price as a sexp
(map read-string) ; "(* quantity price)" -> (* quantity price)
(map eval) ; (* quantity price) -> quantity*price
(apply +)))) ; Sum all elements
(->> (xml-seq (parse *xml-input-stream*))
(filter #(= :item (:tag %))) ; Remove all but the item tags
(map :attrs) ; Keep the attributes
(map (fn [e] (str "(* " (:quantity e) " " (:price e) ")"))) ; Get the total price as a sexp
(map read-string) ; "(* quantity price)" -> (* quantity price)
(map eval) ; (* quantity price) -> quantity*price
(apply +)))) ; Sum all elements
fsharp
#r @"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\v3.5\System.Xml.Linq.dll"
open System
open System.Xml.Linq
//XElement Helper
let xname sname = XName.Get sname
let xmlsnippet =
let snippet = new XElement(xname "shopping")
//create bread
let bread = new XElement(xname "item")
bread.SetAttributeValue(xname "name","bread")
bread.SetAttributeValue(xname "quantity",3)
bread.SetAttributeValue(xname "price",2.50)
//add bread to snippet
snippet.Add(bread)
//create milk
let milk = new XElement(xname "item")
milk.SetAttributeValue(xname "name","milk")
milk.SetAttributeValue(xname "quantity",2)
milk.SetAttributeValue(xname "price",3.50)
//add milk to snippet
snippet.Add(milk)
snippet
let totalprice (xe: XElement) =
xe.Descendants(xname "item")
|> Seq.map(fun i -> Double.Parse(i.Attribute(xname "price").Value))
|> Seq.fold(fun acc x -> acc + x) 0.0
open System
open System.Xml.Linq
//XElement Helper
let xname sname = XName.Get sname
let xmlsnippet =
let snippet = new XElement(xname "shopping")
//create bread
let bread = new XElement(xname "item")
bread.SetAttributeValue(xname "name","bread")
bread.SetAttributeValue(xname "quantity",3)
bread.SetAttributeValue(xname "price",2.50)
//add bread to snippet
snippet.Add(bread)
//create milk
let milk = new XElement(xname "item")
milk.SetAttributeValue(xname "name","milk")
milk.SetAttributeValue(xname "quantity",2)
milk.SetAttributeValue(xname "price",3.50)
//add milk to snippet
snippet.Add(milk)
snippet
let totalprice (xe: XElement) =
xe.Descendants(xname "item")
|> Seq.map(fun i -> Double.Parse(i.Attribute(xname "price").Value))
|> Seq.fold(fun acc x -> acc + x) 0.0
let xname sname = XName.Get sname
let xattr (elem: XElement) sname = elem.Attribute(xname sname).Value
let xml = XDocument.Load("xml.txt")
let shoppingCost =
xml.Descendants(xname "item")
|> Seq.map (fun i -> Double.Parse(xattr i "quantity"), Double.Parse(xattr i "price"))
|> Seq.sumBy (fun (quantity, price) -> quantity * price)
let xattr (elem: XElement) sname = elem.Attribute(xname sname).Value
let xml = XDocument.Load("xml.txt")
let shoppingCost =
xml.Descendants(xname "item")
|> Seq.map (fun i -> Double.Parse(xattr i "quantity"), Double.Parse(xattr i "price"))
|> Seq.sumBy (fun (quantity, price) -> quantity * price)
// Alternative solution that uses XML Navigation, and XPath expressions to ensure that
// the items have the required attributes
let xname sname = XName.Get sname
let xattr (elem: XElement) sname = elem.Attribute(xname sname).Value
let navigator = XPathDocument("xml.txt").CreateNavigator()
let path = XPathExpression.Compile("/shopping/item[@price][@quantity]")
let names = XmlNamespaceManager(navigator.NameTable)
path.SetContext(names)
let shoppingCost =
match path.ReturnType with
| XPathResultType.NodeSet ->
navigator.Select(path)
|> Seq.cast
|> Seq.map (fun (i: XPathNavigator) ->
if i.IsNode then
let elem = XElement.Parse(i.OuterXml)
Double.Parse(xattr elem "quantity"), Double.Parse(xattr elem "price")
else
failwith "Error in expression, expecting to see a node"
)
|> Seq.sumBy (fun (quantity, price) -> quantity * price)
| _ -> failwith "Error in expression, expecting to see a node set"
// the items have the required attributes
let xname sname = XName.Get sname
let xattr (elem: XElement) sname = elem.Attribute(xname sname).Value
let navigator = XPathDocument("xml.txt").CreateNavigator()
let path = XPathExpression.Compile("/shopping/item[@price][@quantity]")
let names = XmlNamespaceManager(navigator.NameTable)
path.SetContext(names)
let shoppingCost =
match path.ReturnType with
| XPathResultType.NodeSet ->
navigator.Select(path)
|> Seq.cast
|> Seq.map (fun (i: XPathNavigator) ->
if i.IsNode then
let elem = XElement.Parse(i.OuterXml)
Double.Parse(xattr elem "quantity"), Double.Parse(xattr elem "price")
else
failwith "Error in expression, expecting to see a node"
)
|> Seq.sumBy (fun (quantity, price) -> quantity * price)
| _ -> failwith "Error in expression, expecting to see a node set"
create some XML programmatically
Given the following CSV:
bread,3,2.50
milk,2,3.50
Produce the equivalent information in XML, e.g.:
<shopping>
<item name=
<item name=
</shopping>
bread,3,2.50
milk,2,3.50
Produce the equivalent information in XML, e.g.:
<shopping>
<item name=
"bread" quantity="3" price="2.50" />
<item name=
"milk" quantity="2" price="3.50" />
</shopping>
java
// In this solution JAXB is used to created the xml output.
// JAXB is included in Java 1.6. Runs with 1.5 if you include JAXB Jars
// in the classpath.
class Item {
// Of course you use getters and setters and declare attributes private.
// In this sample a "dirty" way is chosen to keep LOC low.
@XmlAttribute
String name;
@XmlAttribute
Integer quantity;
@XmlAttribute
Double price;
}
@XmlRootElement
class Shopping {
@XmlElement
Set<Item> items = new HashSet<Item>();
}
String line = null;
Shopping shopping = new Shopping();
try {
BufferedReader reader = new BufferedReader(new FileReader("shopping.csv"));
while ((line = reader.readLine()) != null) {
String[] parts = line.split(",");
Item item = new Item();
item.name = parts[0];
item.quantity = Integer.parseInt(parts[1]);
item.price = Double.parseDouble(parts[2]);
shopping.items.add(item);
}
JAXB.marshal(shopping, "D:" + File.separatorChar + "shopping.auto.xml");
} catch (IOException e) {
e.printStackTrace();
}
// JAXB is included in Java 1.6. Runs with 1.5 if you include JAXB Jars
// in the classpath.
class Item {
// Of course you use getters and setters and declare attributes private.
// In this sample a "dirty" way is chosen to keep LOC low.
@XmlAttribute
String name;
@XmlAttribute
Integer quantity;
@XmlAttribute
Double price;
}
@XmlRootElement
class Shopping {
@XmlElement
Set<Item> items = new HashSet<Item>();
}
String line = null;
Shopping shopping = new Shopping();
try {
BufferedReader reader = new BufferedReader(new FileReader("shopping.csv"));
while ((line = reader.readLine()) != null) {
String[] parts = line.split(",");
Item item = new Item();
item.name = parts[0];
item.quantity = Integer.parseInt(parts[1]);
item.price = Double.parseDouble(parts[2]);
shopping.items.add(item);
}
JAXB.marshal(shopping, "D:" + File.separatorChar + "shopping.auto.xml");
} catch (IOException e) {
e.printStackTrace();
}
csharp
string cvs ="bread,3,2.50\nmilk,2,3.50";
IList<string> rows = cvs.Split('\n');
System.Text.StringBuilder sb = new System.Text.StringBuilder("<shopping>");
foreach(string row in rows){
IList<string> data = row.Split(',');
sb.AppendFormat("<item name='{0}' quantity='{1}' price='{2}' />",data[0],data[1],data[2]);
}
sb.Append("</shopping>");
IList<string> rows = cvs.Split('\n');
System.Text.StringBuilder sb = new System.Text.StringBuilder("<shopping>");
foreach(string row in rows){
IList<string> data = row.Split(',');
sb.AppendFormat("<item name='{0}' quantity='{1}' price='{2}' />",data[0],data[1],data[2]);
}
sb.Append("</shopping>");
clojure
(defn list->xml-item [lst]
(let [[name quantity price] (map str lst)]
{:tag :item
:attrs {:name name
:quantity quantity
:price price}}))
(defn cvs->xml [r]
(->> (map #(read-string (str "(" % ")")) (line-seq r))
(map list->xml-item)
(assoc {:tag :shopping} :content)
(emit)
(with-out-str)))
(println (cvs->xml *cvs-reader*))
(let [[name quantity price] (map str lst)]
{:tag :item
:attrs {:name name
:quantity quantity
:price price}}))
(defn cvs->xml [r]
(->> (map #(read-string (str "(" % ")")) (line-seq r))
(map list->xml-item)
(assoc {:tag :shopping} :content)
(emit)
(with-out-str)))
(println (cvs->xml *cvs-reader*))
fsharp
#r "System.Xml.dll"
#r "System.Xml.Linq.dll"
open System
open System.Xml
open System.Xml.Linq
let data = "bread,3,2.50
milk,2,3.50"
let X name =
XName.Get(name)
let lines = data.Split( [|"\n" |], StringSplitOptions.RemoveEmptyEntries)
let document = new XDocument()
let element = new XElement(X "shopping")
document.Add(element)
lines
|> Seq.iter (fun line ->
let items = line.Split([|','|])
let item = new XElement(X "item",
new XAttribute(X "name", items.[0]),
new XAttribute(X "quantity", items.[1]),
new XAttribute(X "price", items.[2]))
element.Add(item))
let output = document.ToString();;
#r "System.Xml.Linq.dll"
open System
open System.Xml
open System.Xml.Linq
let data = "bread,3,2.50
milk,2,3.50"
let X name =
XName.Get(name)
let lines = data.Split( [|"\n" |], StringSplitOptions.RemoveEmptyEntries)
let document = new XDocument()
let element = new XElement(X "shopping")
document.Add(element)
lines
|> Seq.iter (fun line ->
let items = line.Split([|','|])
let item = new XElement(X "item",
new XAttribute(X "name", items.[0]),
new XAttribute(X "quantity", items.[1]),
new XAttribute(X "price", items.[2]))
element.Add(item))
let output = document.ToString();;
