Develop Reference

Is it possible to create an enum with parameters using an .txt or .xml file?

I would like to create an enum class using a file.
I hope to make maintenance easier.
txt example:
//name of the enum instance and devided by a '-' are the parameter values:
JOHN-23
ANNA-19
xml example:
<friends>
<friend name="JOHN">
<age>23</age>
</friend>
<friend name="ANNA">
<age>19</age>
</friend>
</friends>
I would like to have an enum akting like this one:
enum Friends {
JOHN(23),
ANNA(19);
private int age;
Friends(int age) {
this.age = age;
}
}

You can do it with an XSLT transformation and call out to SAXON via a task in your build system.
e.g. applying this to your example XML will result in your example enum code
<xsl:stylesheet
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="2.0">
<xsl:output method="text" indent="no"/>
<xsl:variable name="classname"><xsl:sequence select="concat(upper-case(substring(/*/local-name(),1,1)), substring(/*/local-name(), 2), ' '[not(last())])"/> </xsl:variable>
<xsl:template match="/*">
enum <xsl:value-of select="$classname"/>
{<xsl:for-each select="*"><xsl:if test="position()!=1">,</xsl:if><xsl:text>
</xsl:text><xsl:value-of select="#name"/>(<xsl:for-each select="*"><xsl:if test="position()!=1">, </xsl:if><xsl:value-of select="text()"/></xsl:for-each>)</xsl:for-each>;
<xsl:for-each select="*[1]/*"> private int <xsl:value-of select="local-name()"/>;
</xsl:for-each><xsl:text>
</xsl:text><xsl:value-of select="$classname"/>(<xsl:for-each select="*[1]/*"><xsl:if test="position()!=1">, </xsl:if>int <xsl:value-of select="local-name()"/></xsl:for-each>)
{
<xsl:for-each select="*[1]/*"> this.<xsl:value-of select="local-name()"/> = <xsl:value-of select="local-name()"/>;
</xsl:for-each> }
}
</xsl:template>
</xsl:stylesheet>
However,
it would break if the XML didn't have the same number of parameters for each enum value.
your input is encoding type names and field names as element names, whereas it's easier for metamodels to encode them as attributes
it's easier to write transforms for explicit rather than implicit information (i.e. say that you have an int age parameter rather than just happening to have age elements whose content is a string of decimal digits)
if you move on to anything a bit more complicated, such as generating hierarchies of classes, the queries to resolve overloads and inheritance rapidly go past simple XSLT

Here an example how you can generate the enum with StAX in java:
package codegen;
import java.io.FileWriter;
import java.io.IOException;
import java.net.URL;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
public class GenCode {
public static void main(String[] args) throws XMLStreamException, IOException {
URL xmlFile = GenCode.class.getResource("Friends.xml");
XMLInputFactory inFactory = XMLInputFactory.newFactory();
XMLStreamReader reader = inFactory.createXMLStreamReader(xmlFile.openStream());
try (FileWriter out = new FileWriter("generated/codegen/Friends.java")) {
out.write("package codegen;\n");
out.write("\n");
out.write("public enum Friends {\n");
String friendName = null;
boolean inAge = false;
String sep = "\t";
while (reader.hasNext()) {
switch (reader.next()) {
case XMLStreamReader.START_ELEMENT:
if (reader.getLocalName().equals("friend"))
friendName = reader.getAttributeValue(null, "name");
if (reader.getLocalName().equals("age"))
inAge = true;
break;
case XMLStreamReader.CHARACTERS:
if (inAge) {
out.write(sep + friendName + "_" + reader.getText());
sep = ",\n\t";
}
break;
case XMLStreamReader.END_ELEMENT:
if (reader.getLocalName().equals("age"))
inAge = false;
break;
}
}
out.write("\n}");
}
}
}
You might need to change some paths.
You have to compile this file, invoke it with java, which will create the Friends.java with the enum and then compile the rest.

Extract a block of XML into another XML file in java

I have a XML file called word.xml containing
<A>
<Answer>How was you day</Answer>
<Question>Happy day </Question>
<Biased> good morning </Biased>
<abc>..............</abc>
.
. // few more tags here
.
</A>
Now i want to extract another XML file called word1.xml containing part of word1.xml
<A>
<Answer>How was you day</Answer>
<Question>Happy day </Question>
</A>
Java Code which I tried so far
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public class ReadXMLFile {
public static void main(String args[]) {
try {
File stocks = new File("word.xml");
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(stocks);
doc.getDocumentElement().normalize();
System.out.println("root of xml file" + doc.getDocumentElement().getNodeName());
NodeList nodes = doc.getElementsByTagName("A");
System.out.println("==========================");
for (int i = 0; i < nodes.getLength(); i++) {
Node node = nodes.item(i);
System.out.println("i value---"+i);
System.out.println(nodes.getLength());
if (node.getNodeType() == Node.ELEMENT_NODE) {
Element element = (Element) node;
System.out.println(element.getTextContent());
//element.getElementsByTagName(name)
File statText = new File(i+".txt");
FileOutputStream is = new FileOutputStream(statText);
OutputStreamWriter osw = new OutputStreamWriter(is);
Writer w = new BufferedWriter(osw);
w.write("<Answer>");
w.write(element.getElementsByTagName("Answer").item(0).getTextContent());
w.write("</Answer>");
w.write("Question");
w.write(element.getElementsByTagName("Question").item(0).getTextContent());
w.write("</Question>");
w.close();
}
}
}
catch (Exception ex) {
ex.printStackTrace();
}
private static String getValue(String tag, Element element) {
NodeList nodes = element.getElementsByTagName(tag).item(0).getChildNodes();
Node node = (Node) nodes.item(0);
return node.getNodeValue();
}
}
}
I just want to include tags in my results. This is the DIRTY way of doing. Can you please suggest me the best way.Need help. Thanks in advance.

If Java is not a mandatory constraint here, you can achieve this by using XSLT. It's pretty easy to follow. You can find some guidance here: Link
An example of my own practice:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<xsl:for-each select="//title">
<article>
<title>
<xsl:value-of select="./name/>
<xsl:text> : </xsl:text>
<xsl:value-of select = "./number/>
</title>
<references>
<xsl:value-of select = "reference"/>
</references>
</article>
</xsl:for-each>
</xsl:template>
Hope it helps!

Just like BeginnerJava explained XSL is the most appropriate technology here as you are transforming one XML tree to another XML tree and XSL is meant for that.
in XSL the code needed to achieve what you describe would be (I skipped some bits):
<xsl:template match="A">
<xsl:copy>
<xsl:apply-templates select="Answer|Question"/>
</xsl:copy>
</xsl:template>
You can invoke XSL transfomation from you Java code or from command line like this:
java net.sf.saxon.Transform [options] source-document stylesheet [ params…]

Parse the xml into DOM using a DocumentParser. remove the elements that you don't need from the resulting Document. write the modified Document to a new File using a Transformer. (note, the details for each of these steps can be found in any of the thousands of java xml tutorials online).

Modify XML file with xPath

I want to modify an existing XML file using xPath. If the node doesn't exist, it should be created (along with it's parents if neccessary). An example:
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<param0>true</param0>
<param1>1.0</param1>
</configuration>
And here are a couple of xPaths I want to insert/modify:
/configuration/param1/text() -> 4.0
/configuration/param2/text() -> "asdf"
/configuration/test/param3/text() -> true
The XML file should look like this afterwards:
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<param0>true</param0>
<param1>4.0</param1>
<param2>asdf</param2>
<test>
<param3>true</param3>
</test>
</configuration>
I tried this:
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
try {
DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
Document doc = domFactory.newDocumentBuilder().parse(file.getAbsolutePath());
XPath xpath = XPathFactory.newInstance().newXPath();
String xPathStr = "/configuration/param1/text()";
Node node = ((NodeList) xpath.compile(xPathStr).evaluate(doc, XPathConstants.NODESET)).item(0);
System.out.printf("node value: %s\n", node.getNodeValue());
node.setNodeValue("4.0");
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
transformer.transform(new DOMSource(doc), new StreamResult(file));
} catch (Exception e) {
e.printStackTrace();
}
The node is changed in the file after running this code. Exactly what I wanted. But if I use one of the below paths, node is null (and therefore a NullPointerException is thrown):
/configuration/param2/text()
/configuration/test/param3/text()
How can I change this code so that the node (and non existing parent nodes as well) are created?
EDIT: Ok, to clarify: I have a set of parameters that I want to save to XML. During development, this set can change (some parameters get added, some get moved, some get removed). So I basically want to have a function to write the current set of parameters to an already existing file. It should override the parameters that already exist in the file, add new parameters and leave old parameters in there.
The same for reading, I could just have the xPath or some other coordinates and get the value from the XML. If it doesn't exist, it returns the empty string.
I don't have any constraints on how to implement it, xPath, DOM, SAX, XSLT... It should just be easy to use once the functionality is written (like BeniBela's solution).
So if I have the following parameters to set:
/configuration/param1/text() -> 4.0
/configuration/param2/text() -> "asdf"
/configuration/test/param3/text() -> true
the result should be the starting XML + those parameters. If they already exist at that xPath, they get replaced, otherwise they get inserted at that point.

If you want a solution without dependencies, you can do it with just DOM and without XPath/XSLT.
Node.getChildNodes|getNodeName / NodeList.* can be used to find the nodes, and Document.createElement|createTextNode, Node.appendChild to create new ones.
Then you can write your own, simple "XPath" interpreter, that creates missing nodes in the path like that:
public static void update(Document doc, String path, String def){
String p[] = path.split("/");
//search nodes or create them if they do not exist
Node n = doc;
for (int i=0;i < p.length;i++){
NodeList kids = n.getChildNodes();
Node nfound = null;
for (int j=0;j<kids.getLength();j++)
if (kids.item(j).getNodeName().equals(p[i])) {
nfound = kids.item(j);
break;
}
if (nfound == null) {
nfound = doc.createElement(p[i]);
n.appendChild(nfound);
n.appendChild(doc.createTextNode("\n")); //add whitespace, so the result looks nicer. Not really needed
}
n = nfound;
}
NodeList kids = n.getChildNodes();
for (int i=0;i<kids.getLength();i++)
if (kids.item(i).getNodeType() == Node.TEXT_NODE) {
//text node exists
kids.item(i).setNodeValue(def); //override
return;
}
n.appendChild(doc.createTextNode(def));
}
Then, if you only want to update text() nodes, you can use it as:
DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
Document doc = domFactory.newDocumentBuilder().parse(file.getAbsolutePath());
update(doc, "configuration/param1", "4.0");
update(doc, "configuration/param2", "asdf");
update(doc, "configuration/test/param3", "true");

Here is a simple XSLT solution:
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:template match="node()|#*">
<xsl:copy>
<xsl:apply-templates select="node()|#*"/>
</xsl:copy>
</xsl:template>
<xsl:template match="param1/text()">4.0</xsl:template>
<xsl:template match="/*">
<xsl:copy>
<xsl:apply-templates select="#*|node()"/>
<param2>asdf</param2>
<test><param3>true</param3></test>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
When this transformation is applied on the provided XML document:
<configuration>
<param0>true</param0>
<param1>1.0</param1>
</configuration>
the wanted, correct result is produced:
<configuration>
<param0>true</param0>
<param1>4.0</param1>
<param2>asdf</param2>
<test><param3>true</param3></test>
</configuration>
Do Note:
An XSLT transformation never "updates in-place". It always creates a new result tree. Therefore, if one wants to modify the same file, typically the result of the transformation is saved under another name, then the original file is deleted and the result is renamed to have the original name.

I've created a small project for using XPATH to create/update XML: https://github.com/shenghai/xmodifier
the code to change your xml is like:
DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
builderFactory.setNamespaceAware(true);
DocumentBuilder documentBuilder = builderFactory.newDocumentBuilder();
Document document = documentBuilder.parse(xmlfile);
XModifier modifier = new XModifier(document);
modifier.addModify("/configuration/param1", "asdf");
modifier.addModify("/configuration/param2", "asdf");
modifier.addModify("/configuration/test/param3", "true");
modifier.modify();

I would point you to a new/novel way of doing what you described, by using VTD-XML... there are numerous reasons why VTD-XML is far better than all other solutions provided for this question... here are a few links ...
Simplify XML processing with vtd-xml
Manipulate XML the Ximple Way
Processing XML with Java – A Performance Benchmark
dfs
import com.ximpleware.*;
import java.io.*;
public class modifyXML {
public static void main(String[] s) throws VTDException, IOException{
VTDGen vg = new VTDGen();
if (!vg.parseFile("input.xml", false))
return;
VTDNav vn = vg.getNav();
AutoPilot ap = new AutoPilot(vn);
ap.selectXPath("/configuration/param1/text()");
XMLModifier xm = new XMLModifier(vn);
// using XPath
int i=ap.evalXPath();
if(i!=-1){
xm.updateToken(i, "4.0");
}
String s1 ="<param2>asdf</param2>/n<test>/n<param3>true</param3>/n</test>";
xm.insertAfterElement(s1);
xm.output("output.xml");
}
}

How to Generate an XML File from a set of XPath Expressions?

I want to be able to generate a complete XML file, given a set of XPath mappings.
The input could specified in two mappings: (1) One which lists the XPath expressions and values; and (2) the other which defines the appropriate namespaces.
/create/article[1]/id => 1
/create/article[1]/description => bar
/create/article[1]/name[1] => foo
/create/article[1]/price[1]/amount => 00.00
/create/article[1]/price[1]/currency => USD
/create/article[2]/id => 2
/create/article[2]/description => some name
/create/article[2]/name[1] => some description
/create/article[2]/price[1]/amount => 00.01
/create/article[2]/price[1]/currency => USD
For namespaces:
/create => xmlns:ns1='http://predic8.com/wsdl/material/ArticleService/1/
/create/article => xmlns:ns1='http://predic8.com/material/1/‘
/create/article/price => xmlns:ns1='http://predic8.com/common/1/‘
/create/article/id => xmlns:ns1='http://predic8.com/material/1/'
Note also, that it is important that I also deal with XPath Attributes expressions as well. For example: I should also be able to handle attributes, such as:
/create/article/#type => richtext
The final output should then look something like:
<ns1:create xmlns:ns1='http://predic8.com/wsdl/material/ArticleService/1/'>
<ns1:article xmlns:ns1='http://predic8.com/material/1/‘ type='richtext'>
<name>foo</name>
<description>bar</description>
<ns1:price xmlns:ns1='http://predic8.com/common/1/'>
<amount>00.00</amount>
<currency>USD</currency>
</ns1:price>
<ns1:id xmlns:ns1='http://predic8.com/material/1/'>1</ns1:id>
</ns1:article>
<ns1:article xmlns:ns1='http://predic8.com/material/2/‘ type='richtext'>
<name>some name</name>
<description>some description</description>
<ns1:price xmlns:ns1='http://predic8.com/common/2/'>
<amount>00.01</amount>
<currency>USD</currency>
</ns1:price>
<ns1:id xmlns:ns1='http://predic8.com/material/2/'>2</ns1:id>
</ns1:article>
</ns1:create>
PS: This is a more detailed question to a previous question asked, although due to a series of further requirements and clarifications, I was recommended to ask a more broader question in order to address my needs.
Note also, I am implementing this in Java. So either a Java-based or XSLT-based solution would both be perfectly acceptable. thnx.
Further note: I am really looking for a generic solution. The XML shown above is just an example.

This problem has an easy solution if one builds upon the solution of the previous problem:
<xsl:stylesheet version="2.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:my="my:my">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:key name="kNSFor" match="namespace" use="#of"/>
<xsl:variable name="vStylesheet" select="document('')"/>
<xsl:variable name="vPop" as="element()*">
<item path="/create/article/#type">richtext</item>
<item path="/create/article/#lang">en-us</item>
<item path="/create/article[1]/id">1</item>
<item path="/create/article[1]/description">bar</item>
<item path="/create/article[1]/name[1]">foo</item>
<item path="/create/article[1]/price[1]/amount">00.00</item>
<item path="/create/article[1]/price[1]/currency">USD</item>
<item path="/create/article[1]/price[2]/amount">11.11</item>
<item path="/create/article[1]/price[2]/currency">AUD</item>
<item path="/create/article[2]/id">2</item>
<item path="/create/article[2]/description">some name</item>
<item path="/create/article[2]/name[1]">some description</item>
<item path="/create/article[2]/price[1]/amount">00.01</item>
<item path="/create/article[2]/price[1]/currency">USD</item>
<namespace of="create" prefix="ns1:"
url="http://predic8.com/wsdl/material/ArticleService/1/"/>
<namespace of="article" prefix="ns1:"
url="xmlns:ns1='http://predic8.com/material/1/"/>
<namespace of="#lang" prefix="xml:"
url="http://www.w3.org/XML/1998/namespace"/>
<namespace of="price" prefix="ns1:"
url="xmlns:ns1='http://predic8.com/material/1/"/>
<namespace of="id" prefix="ns1:"
url="xmlns:ns1='http://predic8.com/material/1/"/>
</xsl:variable>
<xsl:template match="/">
<xsl:sequence select="my:subTree($vPop/#path/concat(.,'/',string(..)))"/>
</xsl:template>
<xsl:function name="my:subTree" as="node()*">
<xsl:param name="pPaths" as="xs:string*"/>
<xsl:for-each-group select="$pPaths" group-adjacent=
"substring-before(substring-after(concat(., '/'), '/'), '/')">
<xsl:if test="current-grouping-key()">
<xsl:choose>
<xsl:when test=
"substring-after(current-group()[1], current-grouping-key())">
<xsl:variable name="vLocal-name" select=
"substring-before(concat(current-grouping-key(), '['), '[')"/>
<xsl:variable name="vNamespace"
select="key('kNSFor', $vLocal-name, $vStylesheet)"/>
<xsl:choose>
<xsl:when test="starts-with($vLocal-name, '#')">
<xsl:attribute name=
"{$vNamespace/#prefix}{substring($vLocal-name,2)}"
namespace="{$vNamespace/#url}">
<xsl:value-of select=
"substring(
substring-after(current-group(), current-grouping-key()),
2
)"/>
</xsl:attribute>
</xsl:when>
<xsl:otherwise>
<xsl:element name="{$vNamespace/#prefix}{$vLocal-name}"
namespace="{$vNamespace/#url}">
<xsl:sequence select=
"my:subTree(for $s in current-group()
return
concat('/',substring-after(substring($s, 2),'/'))
)
"/>
</xsl:element>
</xsl:otherwise>
</xsl:choose>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="current-grouping-key()"/>
</xsl:otherwise>
</xsl:choose>
</xsl:if>
</xsl:for-each-group>
</xsl:function>
</xsl:stylesheet>
When this transformation is applied on any XML document (not used), the wanted, correct result is produced:
<ns1:create xmlns:ns1="http://predic8.com/wsdl/material/ArticleService/1/">
<ns1:article xmlns:ns1="xmlns:ns1='http://predic8.com/material/1/" type="richtext"
xml:lang="en-us"/>
<ns1:article xmlns:ns1="xmlns:ns1='http://predic8.com/material/1/">
<ns1:id>1</ns1:id>
<description>bar</description>
<name>foo</name>
<ns1:price>
<amount>00.00</amount>
<currency>USD</currency>
</ns1:price>
<ns1:price>
<amount>11.11</amount>
<currency>AUD</currency>
</ns1:price>
</ns1:article>
<ns1:article xmlns:ns1="xmlns:ns1='http://predic8.com/material/1/">
<ns1:id>2</ns1:id>
<description>some name</description>
<name>some description</name>
<ns1:price>
<amount>00.01</amount>
<currency>USD</currency>
</ns1:price>
</ns1:article>
</ns1:create>
Explanation:
A reasonable assumption is made that throughout the generated document any two elements with the same local-name() belong to the same namespace -- this covers the predominant majority of real-world XML documents.
The namespace specifications follow the path specifications. A nsmespace specification has the form: <namespace of="target element's local-name" prefix="wanted prefix" url="namespace-uri"/>
Before generating an element with xsl:element, the appropriate namespace specification is selected using an index created by an xsl:key. From this namespace specification the values of its prefix and url attributes are used in specifying in the xsl:element instruction the values of the full element name and the element's namespace-uri.

Interesting question. Let's assume that your input set of XPath expressions satisfies some reasonsable constraints, for example if there is an X/article[2] then there also (preceding it) an X/article[1]. And let's put the namespace part of the problem to one side for the moment.
Let's go for an XSLT 2.0 solution: we'll start with the input in the form
<paths>
<path value="1">/create/article[1]/id</path>
<path value="bar">/create/article[1]/description</path>
</paths>
and then we'll turn this into
<paths>
<path value="1"><step>create</step><step>article[1]</step><step>id</step></path>
...
</paths>
Now we'll call a function which does a grouping on the first step, and calls itself recursively to do grouping on the next step:
<xsl:function name="f:group">
<xsl:param name="paths" as="element(path)*"/>
<xsl:param name="step" as="xs:integer"/>
<xsl:for-each-group select="$paths" group-by="step[$step]">
<xsl:element name="{replace(current-grouping-key(), '\[.*', '')}">
<xsl:choose>
<xsl:when test="count(current-group) gt 1">
<xsl:sequence select="f:group(current-group(), $step+1)"/>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="current-group()[1]/#value"/>
</xsl:otherwise>
</xsl:choose>
</xsl:element>
</xsl:for-each-group>
</xsl:function>
That's untested, and there may well be details you have to adjust to get it working. But I think the basic approach should work.
The namespace part of the problem is perhaps best tackled by preprocessing the list of paths to add a namespace attribute to each step element; this can then be used in the xsl:element instruction to put the element in the right namespace.

i came across a similar situation where i had to convert Set of XPath/FQN - value mappings to XML. A generic simple solution can be using the following code, which can be enhanced to specific requirements.
public class XMLUtils {
static public String transformToXML(Map<String, String> pathValueMap, String delimiter)
throws ParserConfigurationException, TransformerException {
DocumentBuilderFactory documentFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder documentBuilder = documentFactory.newDocumentBuilder();
Document document = documentBuilder.newDocument();
Element rootElement = null;
Iterator<Entry<String, String>> it = pathValueMap.entrySet().iterator();
while (it.hasNext()) {
Entry<String, String> pair = it.next();
if (pair.getKey() != null && pair.getKey() != "" && rootElement == null) {
String[] pathValuesplit = pair.getKey().split(delimiter);
rootElement = document.createElement(pathValuesplit[0]);
break;
}
}
document.appendChild(rootElement);
Element rootNode = rootElement;
Iterator<Entry<String, String>> iterator = pathValueMap.entrySet().iterator();
while (iterator.hasNext()) {
Entry<String, String> pair = iterator.next();
if (pair.getKey() != null && pair.getKey() != "" && rootElement != null) {
String[] pathValuesplit = pair.getKey().split(delimiter);
if (pathValuesplit[0].equals(rootElement.getNodeName())) {
int i = pathValuesplit.length;
Element parentNode = rootNode;
int j = 1;
while (j < i) {
Element child = null;
NodeList childNodes = parentNode.getChildNodes();
for (int k = 0; k < childNodes.getLength(); k++) {
if (childNodes.item(k).getNodeName().equals(pathValuesplit[j])
&& childNodes.item(k) instanceof Element) {
child = (Element) childNodes.item(k);
break;
}
}
if (child == null) {
child = document.createElement(pathValuesplit[j]);
if (j == (i - 1)) {
child.appendChild(
document.createTextNode(pair.getValue() == null ? "" : pair.getValue()));
}
}
parentNode.appendChild(child);
parentNode = child;
j++;
}
} else {
// ignore any other root - add logger
System.out.println("Data not processed for node: " + pair.getKey());
}
}
}
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
DOMSource domSource = new DOMSource(document);
// to return a XMLstring in response to an API
StringWriter writer = new StringWriter();
StreamResult result = new StreamResult(writer);
StreamResult resultToFile = new StreamResult(new File("C:/EclipseProgramOutputs/GeneratedXMLFromPathValue.xml"));
transformer.transform(domSource, resultToFile);
transformer.transform(domSource, result);
return writer.toString();
}
public static void main(String args[])
{
Map<String, String> pathValueMap = new HashMap<String, String>();
String delimiter = "/";
pathValueMap.put("create/article__1/id", "1");
pathValueMap.put("create/article__1/description", "something");
pathValueMap.put("create/article__1/name", "Book Name");
pathValueMap.put("create/article__1/price/amount", "120" );
pathValueMap.put("create/article__1/price/currency", "INR");
pathValueMap.put("create/article__2/id", "2");
pathValueMap.put("create/article__2/description", "something else");
pathValueMap.put("create/article__2/name", "Book name 1");
pathValueMap.put("create/article__2/price/amount", "2100");
pathValueMap.put("create/article__2/price/currency", "USD");
try {
XMLUtils.transformToXML(pathValueMap, delimiter);
} catch (ParserConfigurationException | TransformerException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}}
Output:
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<create>
<article__1>
<id>1</id>
<name>Book Name</name>
<description>something</description>
<price>
<currency>INR</currency>
<amount>120</amount>
</price>
</article__1>
<article__2>
<description>something else</description>
<name>Book name 1</name>
<id>2</id>
<price>
<currency>USD</currency>
<amount>2100</amount>
</price>
</article__2>
To remove __%num , can use regular expressions on final string. like:
resultString = resultString.replaceAll("(__[0-9][0-9])|(__[0-9])", "");
This would do the cleaning job

Generate/get xpath from XML node java

I'm interested in advice/pseudocode code/explanation rather than actual implementation.
I'd like to go through XML document, all of its nodes
Check the node for attribute existence
Case if node doesn't have attribute, get/generate String with value of its xpath
Case if node does have attributes, iterate through attribute list and create xpath for each attribute including the node as well.
Edit
My reason for doing this is: I'm writing automated tests in Jmeter, so for every request I need to verify that request actually did its job so I'm asserting results by getting nodes values with Xpath.
When the request is small it's not a problem to create asserts by hand, but for larger ones it's really a pain.
I'm looking for Java approach.
Goal
My goal is to achieve following from this example XML file :
<root>
<elemA>one</elemA>
<elemA attribute1='first' attribute2='second'>two</elemA>
<elemB>three</elemB>
<elemA>four</elemA>
<elemC>
<elemB>five</elemB>
</elemC>
</root>
to produce the following :
//root[1]/elemA[1]='one'
//root[1]/elemA[2]='two'
//root[1]/elemA[2][#attribute1='first']
//root[1]/elemA[2][#attribute2='second']
//root[1]/elemB[1]='three'
//root[1]/elemA[3]='four'
//root[1]/elemC[1]/elemB[1]='five'
Explained :
If node value/text is not null/zero, get xpath , add = 'nodevalue' for assertion purpose
If node has attributes create assert for them too
Update
I found this example, it doesn't produce the correct results, but I'm looking something like this:
http://www.coderanch.com/how-to/java/SAXCreateXPath

Update:
#c0mrade has updated his question. Here is a solution to it:
This XSLT transformation:
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="text"/>
<xsl:strip-space elements="*"/>
<xsl:variable name="vApos">'</xsl:variable>
<xsl:template match="*[#* or not(*)] ">
<xsl:if test="not(*)">
<xsl:apply-templates select="ancestor-or-self::*" mode="path"/>
<xsl:value-of select="concat('=',$vApos,.,$vApos)"/>
<xsl:text>
</xsl:text>
</xsl:if>
<xsl:apply-templates select="#*|*"/>
</xsl:template>
<xsl:template match="*" mode="path">
<xsl:value-of select="concat('/',name())"/>
<xsl:variable name="vnumPrecSiblings" select=
"count(preceding-sibling::*[name()=name(current())])"/>
<xsl:if test="$vnumPrecSiblings">
<xsl:value-of select="concat('[', $vnumPrecSiblings +1, ']')"/>
</xsl:if>
</xsl:template>
<xsl:template match="#*">
<xsl:apply-templates select="../ancestor-or-self::*" mode="path"/>
<xsl:value-of select="concat('[#',name(), '=',$vApos,.,$vApos,']')"/>
<xsl:text>
</xsl:text>
</xsl:template>
</xsl:stylesheet>
when applied on the provided XML document:
<root>
<elemA>one</elemA>
<elemA attribute1='first' attribute2='second'>two</elemA>
<elemB>three</elemB>
<elemA>four</elemA>
<elemC>
<elemB>five</elemB>
</elemC>
</root>
produces exactly the wanted, correct result:
/root/elemA='one'
/root/elemA[2]='two'
/root/elemA[2][#attribute1='first']
/root/elemA[2][#attribute2='second']
/root/elemB='three'
/root/elemA[3]='four'
/root/elemC/elemB='five'
When applied to the newly-provided document by #c0mrade:
<root>
<elemX serial="kefw90234kf2esda9231">
<id>89734</id>
</elemX>
</root>
again the correct result is produced:
/root/elemX[#serial='kefw90234kf2esda9231']
/root/elemX/id='89734'
Explanation:
Only elements that have no children elements, or have attributes are matched and processed.
For any such element, if it doesn't have children-elements all of its ancestor-or self elements are processed in a specific mode, named 'path'. Then the "='theValue'" part is output and then a NL character.
All attributes of the matched element are then processed.
Then finally, templates are applied to all children-elements.
Processing an element in the 'path' mode is simple: A / character and the name of the element are output. Then, if there are preceding siblings with the same name, a "[numPrecSiblings+1]` part is output.
Processing of attributes is simple: First all ancestor-or-self:: elements of its parent are processed in 'path' mode, then the [attrName=attrValue] part is output, followed by a NL character.
Do note:
Names that are in a namespace are displayed without any problem and in their initial readable form.
To aid readability, an index of [1] is never displayed.
Below is my initial answer (may be ignored)
Here is a pure XSLT 1.0 solution:
Below is a sample xml document and a stylesheet that takes a node-set parameter and produces one valid XPath expression for every member-node.
stylesheet (buildPath.xsl):
<xsl:stylesheet version='1.0'
xmlns:xsl='http://www.w3.org/1999/XSL/Transform'
xmlns:msxsl="urn:schemas-microsoft-com:xslt"
>
<xsl:output method="text"/>
<xsl:variable name="theParmNodes" select="//namespace::*[local-name() =
'myNamespace']"/>
<xsl:template match="/">
<xsl:variable name="theResult">
<xsl:for-each select="$theParmNodes">
<xsl:variable name="theNode" select="."/>
<xsl:for-each select="$theNode |
$theNode/ancestor-or-self::node()[..]">
<xsl:element name="slash">/</xsl:element>
<xsl:choose>
<xsl:when test="self::*">
<xsl:element name="nodeName">
<xsl:value-of select="name()"/>
<xsl:variable name="thisPosition"
select="count(preceding-sibling::*[name(current()) =
name()])"/>
<xsl:variable name="numFollowing"
select="count(following-sibling::*[name(current()) =
name()])"/>
<xsl:if test="$thisPosition + $numFollowing > 0">
<xsl:value-of select="concat('[', $thisPosition +
1, ']')"/>
</xsl:if>
</xsl:element>
</xsl:when>
<xsl:otherwise> <!-- This node is not an element -->
<xsl:choose>
<xsl:when test="count(. | ../#*) = count(../#*)">
<!-- Attribute -->
<xsl:element name="nodeName">
<xsl:value-of select="concat('#',name())"/>
</xsl:element>
</xsl:when>
<xsl:when test="self::text()"> <!-- Text -->
<xsl:element name="nodeName">
<xsl:value-of select="'text()'"/>
<xsl:variable name="thisPosition"
select="count(preceding-sibling::text())"/>
<xsl:variable name="numFollowing"
select="count(following-sibling::text())"/>
<xsl:if test="$thisPosition + $numFollowing > 0">
<xsl:value-of select="concat('[', $thisPosition +
1, ']')"/>
</xsl:if>
</xsl:element>
</xsl:when>
<xsl:when test="self::processing-instruction()">
<!-- Processing Instruction -->
<xsl:element name="nodeName">
<xsl:value-of select="'processing-instruction()'"/>
<xsl:variable name="thisPosition"
select="count(preceding-sibling::processing-instruction())"/>
<xsl:variable name="numFollowing"
select="count(following-sibling::processing-instruction())"/>
<xsl:if test="$thisPosition + $numFollowing > 0">
<xsl:value-of select="concat('[', $thisPosition +
1, ']')"/>
</xsl:if>
</xsl:element>
</xsl:when>
<xsl:when test="self::comment()"> <!-- Comment -->
<xsl:element name="nodeName">
<xsl:value-of select="'comment()'"/>
<xsl:variable name="thisPosition"
select="count(preceding-sibling::comment())"/>
<xsl:variable name="numFollowing"
select="count(following-sibling::comment())"/>
<xsl:if test="$thisPosition + $numFollowing > 0">
<xsl:value-of select="concat('[', $thisPosition +
1, ']')"/>
</xsl:if>
</xsl:element>
</xsl:when>
<!-- Namespace: -->
<xsl:when test="count(. | ../namespace::*) =
count(../namespace::*)">
<xsl:variable name="apos">'</xsl:variable>
<xsl:element name="nodeName">
<xsl:value-of select="concat('namespace::*',
'[local-name() = ', $apos, local-name(), $apos, ']')"/>
</xsl:element>
</xsl:when>
</xsl:choose>
</xsl:otherwise>
</xsl:choose>
</xsl:for-each>
<xsl:text>
</xsl:text>
</xsl:for-each>
</xsl:variable>
<xsl:value-of select="msxsl:node-set($theResult)"/>
</xsl:template>
</xsl:stylesheet>
xml source (buildPath.xml):
<!-- top level Comment -->
<root>
<nodeA>textA</nodeA>
<nodeA id="nodeA-2">
<?myProc ?>
xxxxxxxx
<nodeB/>
<nodeB xmlns:myNamespace="myTestNamespace">
<!-- Comment within /root/nodeA[2]/nodeB[2] -->
<nodeC/>
<!-- 2nd Comment within /root/nodeA[2]/nodeB[2] -->
</nodeB>
yyyyyyy
<nodeB/>
<?myProc2 ?>
</nodeA>
</root>
<!-- top level Comment -->
Result:
/root/nodeA[2]/nodeB[2]/namespace::*[local-name() = 'myNamespace']
/root/nodeA[2]/nodeB[2]/nodeC/namespace::*[local-name() =
'myNamespace']

Here is how this can be done with SAX:
import java.util.HashMap;
import java.util.Map;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;
public class FragmentContentHandler extends DefaultHandler {
private String xPath = "/";
private XMLReader xmlReader;
private FragmentContentHandler parent;
private StringBuilder characters = new StringBuilder();
private Map<String, Integer> elementNameCount = new HashMap<String, Integer>();
public FragmentContentHandler(XMLReader xmlReader) {
this.xmlReader = xmlReader;
}
private FragmentContentHandler(String xPath, XMLReader xmlReader, FragmentContentHandler parent) {
this(xmlReader);
this.xPath = xPath;
this.parent = parent;
}
#Override
public void startElement(String uri, String localName, String qName, Attributes atts) throws SAXException {
Integer count = elementNameCount.get(qName);
if(null == count) {
count = 1;
} else {
count++;
}
elementNameCount.put(qName, count);
String childXPath = xPath + "/" + qName + "[" + count + "]";
int attsLength = atts.getLength();
for(int x=0; x<attsLength; x++) {
System.out.println(childXPath + "[#" + atts.getQName(x) + "='" + atts.getValue(x) + ']');
}
FragmentContentHandler child = new FragmentContentHandler(childXPath, xmlReader, this);
xmlReader.setContentHandler(child);
}
#Override
public void endElement(String uri, String localName, String qName) throws SAXException {
String value = characters.toString().trim();
if(value.length() > 0) {
System.out.println(xPath + "='" + characters.toString() + "'");
}
xmlReader.setContentHandler(parent);
}
#Override
public void characters(char[] ch, int start, int length) throws SAXException {
characters.append(ch, start, length);
}
}
It can be tested with:
import java.io.FileInputStream;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;
public class Demo {
public static void main(String[] args) throws Exception {
SAXParserFactory spf = SAXParserFactory.newInstance();
SAXParser sp = spf.newSAXParser();
XMLReader xr = sp.getXMLReader();
xr.setContentHandler(new FragmentContentHandler(xr));
xr.parse(new InputSource(new FileInputStream("input.xml")));
}
}
This will produce the desired output:
//root[1]/elemA[1]='one'
//root[1]/elemA[2][#attribute1='first]
//root[1]/elemA[2][#attribute2='second]
//root[1]/elemA[2]='two'
//root[1]/elemB[1]='three'
//root[1]/elemA[3]='four'
//root[1]/elemC[1]/elemB[1]='five'

With jOOX (a jquery API port to Java, disclaimer - I work for the company behind the library), you can almost achieve what you want in a single statement:
// I'm assuming this:
import static org.joox.JOOX.$;
// And then...
List<String> coolList = $(document).xpath("//*[not(*)]").map(
context -> $(context).xpath() + "='" + $(context).text() + "'"
);
If document is your sample document:
<root>
<elemA>one</elemA>
<elemA attribute1='first' attribute2='second'>two</elemA>
<elemB>three</elemB>
<elemA>four</elemA>
<elemC>
<elemB>five</elemB>
</elemC>
</root>
This will produce
/root[1]/elemA[1]='one'
/root[1]/elemA[2]='two'
/root[1]/elemB[1]='three'
/root[1]/elemA[3]='four'
/root[1]/elemC[1]/elemB[1]='five'
By "almost", I mean that jOOX does not (yet) support matching/mapping attributes. Hence, your attributes will not produce any output. This will be implemented in the near future, though.

private static void buildEntryList( List<String> entries, String parentXPath, Element parent ) {
NamedNodeMap attrs = parent.getAttributes();
for( int i = 0; i < attrs.getLength(); i++ ) {
Attr attr = (Attr)attrs.item( i );
//TODO: escape attr value
entries.add( parentXPath+"[#"+attr.getName()+"='"+attr.getValue()+"']");
}
HashMap<String, Integer> nameMap = new HashMap<String, Integer>();
NodeList children = parent.getChildNodes();
for( int i = 0; i < children.getLength(); i++ ) {
Node child = children.item( i );
if( child instanceof Text ) {
//TODO: escape child value
entries.add( parentXPath+"='"+((Text)child).getData()+"'" );
} else if( child instanceof Element ) {
String childName = child.getNodeName();
Integer nameCount = nameMap.get( childName );
nameCount = nameCount == null ? 1 : nameCount + 1;
nameMap.put( child.getNodeName(), nameCount );
buildEntryList( entries, parentXPath+"/"+childName+"["+nameCount+"]", (Element)child);
}
}
}
public static List<String> getEntryList( Document doc ) {
ArrayList<String> entries = new ArrayList<String>();
Element root = doc.getDocumentElement();
buildEntryList(entries, "/"+root.getNodeName()+"[1]", root );
return entries;
}
This code works with two assumptions: you aren't using namespaces and there are no mixed content elements. The namespace limitation isn't a serious one, but it'd make your XPath expression much harder to read, as every element would be something like *:<name>[namespace-uri()='<nsuri>'][<index>], but otherwise it's easy to implement. Mixed content on the other hand would make the use of xpath very tedious, as you'd have to be able to individually address the second, third and so on text node within an element.

use w3c.dom
go recursively down
for each node there is easy way to get it's xpath: either by storing it as array/list while #2, or via function which goes recursively up until parent is null, then reverses array/list of encountered nodes.
something like that.
UPD:
and concatenate final list in order to get final xpath.
don't think attributes will be a problem.

I've done a similar task once. The main idea used was that you can use indexes of the element in the xpath. For example in the following xml
<root>
<el />
<something />
<el />
</root>
xpath to the second <el/> will be /root[1]/el[2] (xpath indexes are 1-based). This reads as "take the first root, then take the second one from all elements with the name el". So element something does not affect indexing of elements el. So you can in theory create an xpath for each specific element in your xml. In practice I've accomplished this by walking the tree recursevely and remembering information about elements and their indexes along the way.
Creating xpath referencing specific attribute of the element then was just adding '/#attrName' to element's xpath.

I have written a method to return the absolute path of an element in the Practical XML library. To give you an idea of how it works, here's an extract form one of the unit tests:
assertEquals("/root/wargle[2]/zargle",
DomUtil.getAbsolutePath(child3a));
So, you could recurse through the document, apply your tests, and use this to return the XPath. Or, what is probably better, is that you could use the XPath-based assertions from that same library.

I did the exact same thing last week for processing my xml to solr compliant format.
Since you wanted a pseudo code: This is how I accomplished that.
// You can skip the reference to parent and child.
1_ Initialize a custom node object: NodeObjectVO {String nodeName, String path, List attr, NodeObjectVO parent, List child}
2_ Create an empty list
3_ Create a dom representation of xml and iterate thro the node. For each node, get the corresponding information. All the information like Node name,attribute names and value should be readily available from dom object. ( You need to check the dom NodeType, code should ignore processing instruction and plain text nodes.)
// Code Bloat warning.
4_ The only tricky part is get path. I created an iterative utility method to get the xpath string from NodeElement. (While(node.Parent != null ) { path+=node.parent.nodeName}.
(You can also achieve this by maintaining a global path variable, that keeps track of the parent path for each iteration.)
5_ In the setter method of setAttributes (List), I will append the object's path with all the available attributes. (one path with all available attributes. Not a list of path with each possible combination of attributes. You might want to do someother way. )
6_ Add the NodeObjectVO to the list.
7_ Now we have a flat (not hierrarchial) list of custom Node Objects, that have all the information I need.
(Note: Like I mentioned, I maintain parent child relationship, you should probably skip that part. There is a possibility of code bloating, especially while getparentpath. For small xml this was not a problem, but this is a concern for large xml).