com.jcabi.xml

Interface XML

All Known Implementing Classes:

StrictXML, XMLDocument

@Immutable
public interface XML

XML document.

Set of convenient XML manipulations:

 XML xml = new XMLDocument(content);
 for (XML employee : xml.nodes("//Employee")) {
   String name = employee.xpath("name/text()").get(0);
   // ...
 }

You can always get DOM node out of this abstraction using node() method.

toString() must produce a full XML.

Implementation of this interface must be immutable and thread-safe.

Since:

0.1

Version:

$Id$

Author:

Yegor Bugayenko (yegor@tpc2.com)

See Also:

XMLDocument

Method Summary

Methods

Modifier and Type	Method and Description
XML	merge(NamespaceContext context) Append this namespace context to the existing one.
Node	node() Retrieve DOM node, represented by this wrapper.
List<XML>	nodes(String query) Retrieve DOM nodes from the XML response.
XML	registerNs(String prefix, Object uri) Register additional namespace prefix for XPath.
List<String>	xpath(String query) Find and return text elements or attributes matched by XPath address.

Method Detail

xpath

@NotNull(message="list of texts is never NULL")
List<String> xpath(@NotNull(message="query can\'t be NULL")
                                String query)

Find and return text elements or attributes matched by XPath address.

The XPath query should point to text elements or attributes in the XML document. If any nodes of different types (elements, comments, etc.) are found in result node list - a RuntimeException will be thrown.

Alternatively, the XPath query can be a function or expression that returns a single value instead of pointing to a set of nodes. In this case, the result will be a List containing a single String, the content of which is the result of the evaluation. If the expression result is not a String, it will be converted to a String representation and returned as such. For example, a document containing three <a> elements, the input query "count(//a)", will return a singleton List with a single string value "3".

This is a convenient method, which is used (according to our experience) in 95% of all cases. Usually you don't need to get anything else but a text value of some node or an attribute. And in most cases you are interested to get just the first value (use xpath(..).get(0)). But when/if you need to get more than just a plain text - use nodes(String).

The List returned will throw IndexOutOfBoundsException if you try to access a node which wasn't found by this XPath query.

An IllegalArgumentException is thrown if the parameter passed is not a valid XPath expression.

Parameters:

query - The XPath query

Returns:

The list of string values (texts) or single function result

nodes

@NotNull(message="list of nodes is never NULL")
List<XML> nodes(@NotNull(message="query can\'t be NULL")
                             String query)

Retrieve DOM nodes from the XML response.

The List returned will throw IndexOutOfBoundsException if you try to access a node which wasn't found by this XPath query.

An IllegalArgumentException is thrown if the parameter passed is not a valid XPath expression.

Parameters:

query - The XPath query

Returns:

Collection of DOM nodes

registerNs

@NotNull(message="XML is never NULL")
XML registerNs(@NotNull(message="prefix can\'t be NULL")
                            String prefix,
                            @NotNull(message="URI can\'t be NULL")
                            Object uri)

Register additional namespace prefix for XPath.

For example:

 String name = new XMLDocument("...")
   .registerNs("ns1", "http://example.com")
   .registerNs("foo", "http://example.com/foo")
   .xpath("/ns1:root/foo:name/text()")
   .get(0);
 

A number of standard namespaces are registered by default in instances of XML. Their full list is in XMLDocument.XMLDocument(String).

If a namespace prefix is already registered an IllegalArgumentException will be thrown.

Parameters:

prefix - The XPath prefix to register

uri - Namespace URI

Returns:

A new XML document, with this additional namespace registered

merge

@NotNull(message="XML is never NULL")
XML merge(@NotNull(message="context can\'t be NULL")
                       NamespaceContext context)

Append this namespace context to the existing one.

The existing context (inside this object) and the new one provided will be merged together. The existing context will be have higher priority.

Parameters:

context - The context to append

Returns:

A new XML document, with a merged context on board

node

@NotNull(message="node is never NULL")
Node node()

Retrieve DOM node, represented by this wrapper.

Returns:

DOM node