Difference between revisions of "EclipseLink/UserGuide/MOXy/Runtime/Querying Objects by XPath"

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Line 12: Line 12:
  
 
<source lang="xml">
 
<source lang="xml">
<?xml version="1.0" encoding="UTF-8"?>
+
<customer id="1141">
<xsd:schema
+
  <first-name>Jon</first-name>
    xmlns:xsd="http://www.w3.org/2001/XMLSchema">
+
  <last-name>Smith</last-name>
+
  <phone-number>
    <xsd:element name="customer">
+
      <area-code>515</area code>
        <xsd:complexType>
+
      <number>2726652</number>
            <xsd:sequence>
+
  </phone-number>
                <xsd:element
+
</customer>
                    name="date-of-birth"
+
                    type="xsd:date"
+
                    minOccurs="0"/>
+
            </xsd:sequence>
+
        </xsd:complexType>
+
    </xsd:element>
+
+
</xsd:schema>
+
 
</source>
 
</source>
 +
 +
Your typical application code might look something like this:
  
 
<source lang="java">
 
<source lang="java">
 
Customer customer = (Customer) jaxbContext.createUnmarshaller().unmarshal(instanceDoc);
 
Customer customer = (Customer) jaxbContext.createUnmarshaller().unmarshal(instanceDoc);
 
+
...
 
int customerId = customer.getId();
 
int customerId = customer.getId();
 
customer.setFirstName("Bob");
 
customer.setFirstName("Bob");
 
customer.getPhoneNumber().setAreaCode("555");
 
customer.getPhoneNumber().setAreaCode("555");
 
+
...
 
jaxbContext.createMarshaller().marshal(customer, System.out);
 
jaxbContext.createMarshaller().marshal(customer, System.out);
 
</source>
 
</source>
  
You could use XPath to access these values:
+
You could instead use XPath to access these values:
  
 
<source lang="java">
 
<source lang="java">
 
Customer customer = (Customer) jaxbContext.createUnmarshaller().unmarshal(instanceDoc);
 
Customer customer = (Customer) jaxbContext.createUnmarshaller().unmarshal(instanceDoc);
 
+
...
 
int customerId = jaxbContext.getValueByXPath(customer, "@id", null, Integer.class);
 
int customerId = jaxbContext.getValueByXPath(customer, "@id", null, Integer.class);
 
jaxbContext.setValueByXPath(customer, "first-name/text()", null, "Bob");
 
jaxbContext.setValueByXPath(customer, "first-name/text()", null, "Bob");
 
jaxbContext.setValueByXPath(customer, "phone-number/area-code/text()", null, "555");
 
jaxbContext.setValueByXPath(customer, "phone-number/area-code/text()", null, "555");
 
+
...
 
jaxbContext.createMarshaller().marshal(customer, System.out);
 
jaxbContext.createMarshaller().marshal(customer, System.out);
 
</source>
 
</source>

Revision as of 14:28, 25 April 2011

EclipseLink MOXy

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Querying Objects by XPath

In addition to using conventional Java access methods to get and set your object's values, EclipseLink MOXy also allows you to access values using an XPath statement. There are special APIs on EclipseLink's JAXBContext to allow you to get and set values by XPath.

For example, consider the following XML document:

<customer id="1141">
   <first-name>Jon</first-name>
   <last-name>Smith</last-name>
   <phone-number>
      <area-code>515</area code>
      <number>2726652</number>
   </phone-number>
</customer>

Your typical application code might look something like this:

Customer customer = (Customer) jaxbContext.createUnmarshaller().unmarshal(instanceDoc);
...
int customerId = customer.getId();
customer.setFirstName("Bob");
customer.getPhoneNumber().setAreaCode("555");
...
jaxbContext.createMarshaller().marshal(customer, System.out);

You could instead use XPath to access these values:

Customer customer = (Customer) jaxbContext.createUnmarshaller().unmarshal(instanceDoc);
...
int customerId = jaxbContext.getValueByXPath(customer, "@id", null, Integer.class);
jaxbContext.setValueByXPath(customer, "first-name/text()", null, "Bob");
jaxbContext.setValueByXPath(customer, "phone-number/area-code/text()", null, "555");
...
jaxbContext.createMarshaller().marshal(customer, System.out);


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