How to parse an equation?
Here's my problem:
The user enters an equation into a TextField. The app reads the TextField and records the equation into a String.
Say the user enters 3x + 5. Now, I need to convert the String into an algorithm that will be able to calculate the value of 3x + 5 for any x.
It might sound simple for 3x + 5, but consider an equation like this:
(sin(x)^2 * 3cos(x)) / (e^(tan(x)) * sinh(4x) - x^x^x^345.55)
How would I parse something like that?
Well, I looked at the source code, and it uses several
dozen classes with some kind of nodes and so forth
I need something simple. Effective, but simple.
The programme I am writing will be working as an
applet, so I wouldn't want to have people first
download Jep, then run the applet ...Just how simple is your "simple"?
Every mathematical formula parser requires nodes and stuff to represent the equation in a tree and so forth; you'd be re-writing all that and that is effectively much more complex than just using a parser that is there. You don't have to know how or why JEP works to use it.
JEP is fairly simple to use... did happen to you see the sample applet and its source?
http://jep.sourceforge.net/sampleapplet.htm
what about the usage doc: http://jep.sourceforge.net/doc_usage.htm
Doesn't seem that complex to me... but if you really want to build a parser of your own, be my guest... btw, if you're into that, I know a great open source expression parser from which you might want to pick ideas! :)
Similar Messages
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How to parse crystal report query prompt value via url parameters
HI All,
I am creating a employee detail report in crystal report. The recordset is huge and i have created a parameter prompts in the query and thinking to parse the prompt value via url parameters. Not sure why i still could not make it works.
for example, in my query panel i have created a prompt called "pwwid"
and this is how i parse the prompt value via open document url.
OpenDocument/opendoc/openDocument.jsp?sIDType=CUID&iDocID=AV8U6HlIq4FBl_MhcBwHqGI&lsSpwwid=12345678
I read the sap documentation, this is how it parse the prompt value via url parameter. but it is not working for me and i am getting prompt to fill in the wwid whenever i run the reports.
any idea why i am not getting this works?
Regards,
KeatAunCould you try:
OpenDocument/opendoc/openDocument.jsp?sIDType=CUID&iDocID=AV8U6HlIq4FBl_MhcBwHqGI&lsSpspwwid=12345678
-Abhilash -
hei evryone!!!
I'm a newbie in java, i just wanna know how to parse an xml file in JSP wherein i could remove nodes / modify certain nodes on the xml.
Any suggestions / codes/ ideas would be much appreciatedOn my jsp page the default screen would be the list of traders. The user of the said application has the option to make some changes on the list either, add more trader/s on the list , remove specified trader/s on the list or edit certain trader/s. Furthermore, the user can also cancel the changes he made by clicking the cancel button or commit the modification he made by clicking the save button. When the application altered something, the changes must be reflected on the front end right away, but not on the database yet. In doing so, I intend to have two xml files , (1) the original xml file that is send to a CmsServlet (the servlet code that does the database commit) and (2) the temporary xml file that the page loads, which is initially just a copy of the original xml file. So whenever changes made at the frontend the temporary file is also altered, and when the save button is clicked, the temporary file is copied to original xml file to send the changes on the CmsServlet. But when the application user withdraws the changes he made at the frontend by clicking the cancel button , the original xml file is then copied to temporary xml file to reload the page.
The access/modification on the temporary xml file is done in default.jsp. -
How to parse XML file with namesapce?
Hi,
I am trying to parse an xml file having namespace. But no data is returned.
Sample Code:
public class XMLFileLoader
var xml:XML = new XML();
var myXML:XML = new XML();
var XML_URL:String = "file:///C:/Documents and Settings/Administrator/Desktop/MyData.xml";
var myLoader:URLLoader = null;
public function XMLFileLoader()
var myXMLURL:URLRequest = new URLRequest(XML_URL);
myLoader= new URLLoader(myXMLURL);
myLoader.addEventListener(Event.COMPLETE,download);
public function download(event:Event):void
myXML = XML(myLoader.data);
var ns:Namespace=myXML.namespace("xsi");
for(var prop:String in myXML)
trace(prop);
//Alert.show(myXML..Parameters);
//trace("Data loadedww."+myXML.toString());
//Alert.show(myXML.DocumentInfo.attributes()+"test","Message");
The XML Contains the following format.
<Network xmlns="http://www.test.com/2005/test/omc/conf"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.test.com/2005/test/omc/conf/TestConfigurationEdition3proposal4.xsd">
<TestDomain>
<WAC>
<!--Release Parameter -->
<Parameters ParameterName="ne_release" OutageType="None"
accessRight="CreateOnly" isMandatory="true"
Planned="false"
Reference="true" Working="true">
<DataType>
<StringType/>
</DataType>
<GUIInfo graphicalName="Release"
tabName="All"
description="Describes the release version of the managed object"/>
</Parameters>
</TestDomain>
</Network>
Any sample code how to parse this kind of xml file with namespaces...
Regards,
Purushothami have exactly the same problem with KXml2, but using a j2me-polish netbeans project.
i've tried to work around with similar ways like you, but none of them worked. now i've spent 3 days for solving this problem, i'm a bit disappointed :( what is wrong with setting the downloaded kxml2 jar path in libraries&resources?
screenshot -
How to parse XML for internal table
hi guys, I would like to know how to parse xml for an internal table. I explain myself.
Let's say you have a purchase order form where you have header data & items data. In my interactive form, the user can change the purchase order quantity at the item level. When I received back the pdf completed by mail, I need to parse the xml and get the po qty that has been entered.
This is how I do to get header data from my form
lr_ixml_node = lr_ixml_document->find_from_name( name = ''EBELN ).
lv_ebeln = lr_ixml_node->get_value( ).
How do we do to get the table body??
Should I used the same method (find_from_name) and passing the depth parameter inside a do/enddo?
thanks
Alexandre GiguereAlexandre,
Here is an example. Suppose your internal table is called 'ITEMS'.
lr_node = lr_document->find_from_name('ITEMS').
lv_num_of_children = lr_node->num_children( ).
lr_nodechild = lr_node->get_first_child( ).
do lv_num_of_children times.
lv_num_of_attributes = lr_nodechild->num_children( ).
lr_childchild = lr_nodechild->get_first_child( ).
do lv_num_of_attributes times.
lv_value = lr_childchild->get_value( ).
case sy-index.
when 1.
wa_item-field1 = lv_value
when 2.
wa_item-field2 = lv_value.
endcase.
lr_childchild = lr_childchild->get_next( ).
enddo.
append wa_item to lt_item.
lr_nodechild = lr_nodechild->get_next( ).
enddo. -
How to parse XML against XSD,DTD, etc.. locally (no internet connection) ?
i've searched on how to parse xml against xsd,dtd,etc.. without the needs of internet connection..
but unfortunately, only the xsd file can be set locally and still there needs the internet connection for the other features, properties.
XML: GML file input from gui
XSD: input from gui
javax.xml
package demo;
import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import javax.xml.XMLConstants;
import javax.xml.transform.Source;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;
import javax.xml.validation.Validator;
import org.xml.sax.SAXException;
public class Sample1WithJavaxXML {
public static void main(String[] args) {
URL schemaFile = null;
try {
//schemaFile = new URL("http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd");
File file0 = new File("AppSchema-C01-v1_0.xsd");
schemaFile = new URL(file0.toURI().toString());
} catch (MalformedURLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
//Source xmlFile = new StreamSource(new File("web.xml"));
Source xmlFile = new StreamSource(new File("C01.xml"));
SchemaFactory schemaFactory = SchemaFactory
.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
//File file1 = new File("XMLSchema.dtd");
//SchemaFactory schemaFactory = SchemaFactory
//.newInstance("javax.xml.validation.SchemaFactory:XMLSchema.dtd");
Schema schema = null;
try {
schema = schemaFactory.newSchema(schemaFile);
} catch (SAXException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
Validator validator = schema.newValidator();
try {
validator.validate(xmlFile);
System.out.println(xmlFile.getSystemId() + " is valid");
} catch (SAXException e) {
System.out.println(xmlFile.getSystemId() + " is NOT valid");
System.out.println("Reason: " + e.getLocalizedMessage());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}Xerces
package demo;
import java.io.File;
import java.util.Date;
import org.apache.xerces.parsers.DOMParser;
public class SchemaTest {
private String xmlFile = "";
private String xsdFile = "";
public SchemaTest(String xmlFile, String xsdFile) {
this.xmlFile = xmlFile;
this.xsdFile = xsdFile;
public static void main (String args[]) {
File file0 = new File("AppSchema-C01-v1_0.xsd");
String xsd = file0.toURI().toString();
SchemaTest testXml = new SchemaTest("C01.xml",xsd);
testXml.process();
public void process() {
File docFile = new File(xmlFile);
DOMParser parser = new DOMParser();
try {
parser.setFeature("http://xml.org/sax/features/validation", true);
parser.setFeature("http://apache.org/xml/features/validation/schema", true);
parser.setProperty("http://apache.org/xml/properties/schema/external-noNamespaceSchemaLocation",
xsdFile);
ErrorChecker errors = new ErrorChecker();
parser.setErrorHandler(errors);
System.out.println(new Date().toString() + " START");
parser.parse(docFile.toString());
} catch (Exception e) {
System.out.print("Problem parsing the file.");
System.out.println("Error: " + e);
System.out.println(new Date().toString() + " ERROR");
return;
System.out.println(new Date().toString() + " END");
}Thanks a lot Sir DrClap..
I tried to use and implement the org.w3c.dom.ls.LSResourceResolver Interface which is based on the SAX2 EntityResolver.
please give comments the way I implement it. Here's the code:
LSResourceResolver Implementation
import org.w3c.dom.ls.LSInput;
import org.w3c.dom.ls.LSResourceResolver;
import abc.xml.XsdConstant.Path.DTD;
import abc.xml.XsdConstant.Path.XSD;
public class LSResourceResolverImpl implements LSResourceResolver {
public LSResourceResolverImpl() {
* {@inheritDoc}
@Override
public LSInput resolveResource(String type, String namespaceURI, String publicId, String systemId, String baseURI) {
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
LSInput input = new LSInputImpl(publicId, systemId, baseURI);
if ("http://www.w3.org/2001/xml.xsd".equals(systemId)) {
input.setByteStream(classLoader.getResourceAsStream(XSD.XML));
} else if (XsdConstant.PUBLIC_ID_XMLSCHEMA.equals(publicId)) {
input.setByteStream(classLoader.getResourceAsStream(DTD.XML_SCHEMA));
} else if (XsdConstant.PUBLIC_ID_DATATYPES.equals(publicId)) {
input.setByteStream(classLoader.getResourceAsStream(DTD.DATATYPES));
return input;
}I also implement org.w3c.dom.ls.LSInput
import java.io.InputStream;
import java.io.Reader;
import org.w3c.dom.ls.LSInput;
public class LSInputImpl implements LSInput {
private String publicId;
private String systemId;
private String baseURI;
private InputStream byteStream;
private String stringData;
public LSInputImpl(String publicId, String systemId, String baseURI) {
super();
this.publicId = publicId;
this.systemId = systemId;
this.baseURI = baseURI;
//getters & setters
}Then, here's the usage/application:
I create XMLChecker class (SchemaFactory implementation is Xerces)
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import javax.xml.XMLConstants;
import javax.xml.stream.FactoryConfigurationError;
import javax.xml.transform.Source;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;
import javax.xml.validation.Validator;
import org.xml.sax.ErrorHandler;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import abc.xml.XsdConstant.Path.XSD;
public class XMLChecker {
private ErrorMessage errorMessage = new ErrorMessage();
public boolean validate(String filePath){
final ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
List<Source> schemas = new ArrayList<Source>();
schemas.add(new StreamSource(classLoader.getResourceAsStream(XSD.XML_SCHEMA)));
schemas.add(new StreamSource(classLoader.getResourceAsStream(XSD.XLINKS)));
schemas.add(new StreamSource(classLoader.getResourceAsStream("abc/xml/AppSchema.xsd")));
SchemaFactory schemaFactory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
schemaFactory.setResourceResolver(new LSResourceResolverImpl());
try {
Schema schema = schemaFactory.newSchema(schemas.toArray(new Source[schemas.size()]));
Validator validator = schema.newValidator();
validator.setErrorHandler(new ErrorHandler() {
@Override
public void error(SAXParseException e) throws SAXException {
errorMessage.setErrorMessage(e.getMessage());
errorMessage.setLineNumber(e.getLineNumber());
errorMessage.setColumnNumber(e.getLineNumber());
throw e;
@Override
public void fatalError(SAXParseException e) throws SAXException {
errorMessage.setErrorMessage(e.getMessage());
errorMessage.setLineNumber(e.getLineNumber());
errorMessage.setColumnNumber(e.getLineNumber());
throw e;
@Override
public void warning(SAXParseException e) throws SAXException {
errorMessage.setErrorMessage(e.getMessage());
errorMessage.setLineNumber(e.getLineNumber());
errorMessage.setColumnNumber(e.getLineNumber());
throw e;
StreamSource source = new StreamSource(new File(filePath));
validator.validate(source);
} catch (SAXParseException e) {
return false;
} catch (SAXException e) {
errorMessage.setErrorMessage(e.getMessage());
return false;
} catch (FactoryConfigurationError e) {
errorMessage.setErrorMessage(e.getMessage());
return false;
} catch (IOException e) {
errorMessage.setErrorMessage(e.getMessage());
return false;
return true;
public ErrorMessage getErrorMessage() {
return errorMessage;
}Edited by: erossy on Aug 31, 2010 1:56 AM -
How to parse xml file, containing image, generaged from JAX-RS connector?
Hi,
We are using JAX-RS connector and just want to call getBusinessObjects() directly using JerseyMe (basically bypassing sync engine). We have used sync engine so far and want to try as how to bypass it. The method produces the text/xml and verified the xml file in the web by giving the full url. The plan is to call the same URL from the Java Me Client using JerseyMe. When I print the bytes at the client I receive the same xml that I have seen in the web. Actually, I am passing an image that I can see in a different character format in xml (assuming this is bcos of UTF-8 encoding). I am wondering as how to parse this xml file and how to decode the "UTF-8" format? Do we need to use SGMP for this or use kxml or java me webservices spec.
I would really appreciate if somebody can answer this one.
I have been observing in this forum that SGMP team is not at all active in answering the questions. Please let us know whether Oracle is keeping this product and we can continue using SGMP1.1. Please let us know so that we can plan accordingly as we are building a product based on SGMP.Hi Rajiv,
The client library is using org.apache.commons.codec.binary.Base64 internally. We don't have the full Commons Codec library bundled, but you can look up the javadoc for the Base64 class online. All you need to do is call Base64.decode(obj.getBytes()) on the objects you get out of the XML.
In general it isn't a good idea to depend on implementation details of the client library, but in this case, I think it is pretty safe to expect org.apache.commons.codec.binary.Base64 to remain in our library.
--Ryan -
How to parse XML files from normal FTP Servers?
I want to parse xml files from a normal FTP Servers , NOT the sap application severs itself. How can i do that?
I know how to use the SAPFTP getting and putting files ,but I don't want to download and then parse it.
Who knows how to parse it directly? I Just need to read the contents into a database.
Thanks.I want to parse xml files from a normal FTP Servers , NOT the sap application severs itself. How can i do that?
I know how to use the SAPFTP getting and putting files ,but I don't want to download and then parse it.
Who knows how to parse it directly? I Just need to read the contents into a database.
Thanks. -
How to use DOMParser from an Applet / Or, how to parse XML from an Applet?
Hey,
As stating in the subject line, I wonder how to do it without getting an �Access Denied� error.
I would like to parse a XML file that has external DTD pointing to a SYSTEM location. Yes, I can change it to a public location. However, in either way, I have problems to use DOMBuilder to parse the xml file. The application always throws the security exception.
I tried to use the DOMParser from org.apache.xerces.parsers to parse the xml file. I set the DOMParser to ignore parsing the external DTD, and use the DOMParser.parse(InputSource) to parse the xml file from a giving URL. However, I get null of the result document.
Does anyone know how to parse the XML from an Applet? Or, does anyone know how to use the DOMParser from an Applet?
Thank you very much,If the document resides on the local filesystem, you will need to sign a CAB or JAR for the applet to circumvent the sandbox's security restrictions. There are dozens of posts on how to do this. Basically, that will turn the applet into an application, from a Java security perspective.
- Saish
"My karma ran over your dogma." - Anon -
How to parse xml string using JSTL
Suppose this is my string:-----
<books>
<book>
<title id=1>Book Title A</title>
<author>A. B. C.</author>
<price>17.95</price>
</book>
<book>
<title id=2>Book Title B</title>
<author>X. Y. Z.</author>
<price>24.99</price>
</book>
</books>
and I want to read title id = 1 then, how to parse it, I found tutorials regarding parsing simple xml document but how to parse attributes of a given XMLBut both of them either parse a file or data from an input source. I don't think they handle strings.An InputSource can be constructed with a Reader as input. One useful subclass of Reader is StringReader, so you'd use something likeDocument doc = documentBuilder.parse(new InputSource(new StringReader(myXMLString)));
-
Hi! I'm having problems parsing an xml string. I've done DOM and SAX parsing before. But both of them either parse a file or data from an input source. I don't think they handle strings. I also don't want to write the string into a file just so I can use DOM or SAX.
I'm looking for something where I could simply do:
Document doc = documentBuilder.parse( myXMLString );
So the heirarchy is automatically established for me. Then I could just do
Element elem = doc.getElement();
String name = elem.getTagName();
These aren't the only methods I would want to use. Again, my main problem is how to parse xml if it is stored in a string, not a file, nor comming from a stream.
thanks!But both of them either parse a file or data from an input source. I don't think they handle strings.An InputSource can be constructed with a Reader as input. One useful subclass of Reader is StringReader, so you'd use something likeDocument doc = documentBuilder.parse(new InputSource(new StringReader(myXMLString)));
-
How to parse contents from XML file in Java
Hi All,
I have a scenario like this . I have one xml file with key value pairs of ( name , URL ) . I have retrieved contents from XML file , now I want to parse these contents and store in a bean object.
How to parse Contents of XML file??
Thanks in advance,
Rajendra.Hi All,
I have a scenario like this . I have one xml file with key value pairs of ( name , URL ) . I have retrieved contents from XML file , now I want to parse these contents and store in a bean object.
How to parse Contents of XML file??
Thanks in advance,
Rajendra. -
I am a new learner to XML & JAVA,I dont't know how to parse the XML file using JAXP,Who can tell me,Who can write an Example?
thx
Best Regards.Using the SAXParser in JAXP the parsing of the XML file is event driven.
Instantiate the parser:
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser parser = factory.newSAXParser();
InputSource is = new InputSource(new FileReader(theXML));call the parse method:
parser.parse(is, this);The following events are fired as the parser works through the XML public void startElement(String namespaceURI, String localName, String qName, Attributes atts) throws org.xml.sax.SAXException
public void endElement(String namespaceURI, String localName, String qName) throws org.xml.sax.SAXException
characters(char[] ch, int start, int length)etc.
You write what you want within each of these sections to handle the structure of your data. Keep in mind SAX is useful only when you know the structure of your XML. -
Hi Folks,
Can anyone help me out on how to parse the characters in data services. Here is the example:
Rule: Parse first three characters MU_1000008 to 1000008
What is the function I can use?
Any help is appreciated.
Thank youHi,Dear All,
I am Trying to go from
Id
LS001
LS003
NT006
LS007
ES009
LS004
TO OUTPUT
Col ID
T1 LS001,ES009,LS003
T2 NT006
T3 LS007,LS004
pls help me out or give me hint or idea so i can use that.
Regards
Varsha -
Hi,experts:
In below thread:
Receiving .Net dataset with deployed proxies
i asked how to create a external definition in IR base on above XML data.
Now,i have created a XSD file base on the XML data.And importing it into IR successfully.
<?xml version="1.0" encoding="utf-8"?>
<xs:schema id="NewDataSet" xmlns="" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
<xs:element name="NewDataSet" msdata:IsDataSet="true" msdata:Locale="zh-CN">
<xs:complexType>
<xs:choice maxOccurs="unbounded">
<xs:element name="Status">
<xs:complexType>
<xs:attribute name="Result" type="xs:string"/>
</xs:complexType>
</xs:element>
</xs:choice>
</xs:complexType>
</xs:element>
</xs:schema>
And now,the question is how to parse the XML data in diffgr:diffgram segment.It seems a MS-XML syntax.Can it be parsed by XI?
I tried,but the following error occurs:
com.sap.aii.utilxi.misc.api.BaseRuntimeException: RuntimeException in Message-Mapping transformation: Cannot produce target element /ns0:ZMT_SD_ORDER01_RESULT. Check xml instance is valid for source xsd and target-field mapping fulfills requirements of target xsd at com.sap.aii.mappingtool.tf3.AMappingProgram.startHi,
The above Exception seems to be because of mapping error.
Check your mapping for all the mandatory 1-1 mapping, also the 1-unbounded parent node mapping.
Once when you import the XSD and activate your External Definition if it does without any error then there is no problem with your External Definition.
If this error occurs only when you test your mapping then this is mapping error and not because of XSD.
Please check the parent node mapping like 1-unbounded.
Reward Points if useful
Regards
Ashmi.
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