org.apache.jackrabbit.core.util
Class DOMWalker

java.lang.Object
  org.apache.jackrabbit.core.util.DOMWalker

public final class DOMWalker

extends Object

Document walker class. This class provides an intuitive interface for traversing a parsed DOM document.

Constructor Summary

DOMWalker(InputStream xml)
Creates a walker for traversing a DOM document read from the given input stream.

Method Summary

boolean	enterElement(String name) Enters the named child element.
String	getAttribute(String name) Returns the value of the named attribute of the current element.
String	getContent() Returns the text content of the current element.
String	getName() Returns the name of the current element.
Properties	getNamespaces() Returns the namespace mappings defined in the current element.
boolean	iterateElements(String name) Iterates through the named child elements over multiple calls.
void	leaveElement() Leaves the current element.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DOMWalker

public DOMWalker(InputStream xml)
          throws IOException

Creates a walker for traversing a DOM document read from the given input stream. The root element of the document is set as the current element.

Parameters:

xml - XML input stream

Throws:

IOException - if a document cannot be read from the stream

Method Detail

getNamespaces

public Properties getNamespaces()

Returns the namespace mappings defined in the current element. The returned property set contains the prefix to namespace mappings specified by the xmlns attributes of the current element.

Returns:

prefix to namespace mappings of the current element

getName

public String getName()

Returns the name of the current element.

Returns:

element name

getAttribute

public String getAttribute(String name)

Returns the value of the named attribute of the current element.

Parameters:

name - attribute name

Returns:

attribute value, or null if not found

getContent

public String getContent()

Returns the text content of the current element.

Returns:

text content

enterElement

public boolean enterElement(String name)

Enters the named child element. If the named child element is found, then it is made the current element and true is returned. Otherwise the current element is not changed and false is returned.

The standard call sequence for this method is show below.

     DOMWalker walker = ...;
     if (walker.enterElement("...")) {
         ...;
         walker.leaveElement();
     }
 

Parameters:

name - child element name

Returns:

true if the element was entered, false otherwise

leaveElement

public void leaveElement()

Leaves the current element. The parent element is set as the new current element.

See Also:

enterElement(String)

iterateElements

public boolean iterateElements(String name)

Iterates through the named child elements over multiple calls. This method makes it possible to use the following code to walk through all the child elements with the given name.

     DOMWalker walker = ...;
     while (walker.iterateElements("...")) {
         ...;
     }
 

WARNING: This method should only be used when walker.getName() does not equal name when the while loop is started. Otherwise the walker will not be positioned at the same node when the while loop ends.

Parameters:

name - name of the iterated elements

Returns:

true if another iterated element was entered, or false if no more iterated elements were found and the original element is restored as the current element