org.htmlparser.nodeDecorators
Class AbstractNodeDecorator

java.lang.Object
  org.htmlparser.nodeDecorators.AbstractNodeDecorator

All Implemented Interfaces:

Node

Direct Known Subclasses:

DecodingNode, EscapeCharacterRemovingNode, NonBreakingSpaceConvertingNode

public abstract class AbstractNodeDecorator

extends Object

implements Node

Field Summary

protected Node

delegate

Constructor Summary

protected

AbstractNodeDecorator(Node delegate)

Method Summary

void	accept(Object visitor) Apply the visitor object (of type NodeVisitor) to this node.
void	collectInto(NodeList list, NodeFilter filter) Collect this node and its child nodes (if-applicable) into the collectionList parameter, provided the node satisfies the filtering criteria.
void	doSemanticAction() Perform the meaning of this tag.
int	elementBegin() Returns the beginning position of the tag.
int	elementEnd() Returns the ending position fo the tag deprecated Use getEndPosition()
boolean	equals(Object arg0)
NodeList	getChildren() Get the children of this node.
int	getEndPosition() Gets the ending position of the node.
Node	getParent() Get the parent of this node.
int	getStartPosition() Gets the starting position of the node.
String	getText() Returns the text of the node.
void	setChildren(NodeList children) Set the children of this node.
void	setEndPosition(int position) Sets the ending position of the node.
void	setParent(Node node) Sets the parent of this node.
void	setStartPosition(int position) Sets the starting position of the node.
void	setText(String text) Sets the string contents of the node.
String	toHtml() This method will make it easier when using html parser to reproduce html pages (with or without modifications) Applications reproducing html can use this method on nodes which are to be used or transferred as they were recieved, with the original html
String	toPlainTextString() Returns a string representation of the node.
String	toString() Return the string representation of the node.

Methods inherited from class java.lang.Object

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

Field Detail

delegate

protected Node delegate

Constructor Detail

AbstractNodeDecorator

protected AbstractNodeDecorator(Node delegate)

Method Detail

accept

public void accept(Object visitor)

Description copied from interface: Node

Apply the visitor object (of type NodeVisitor) to this node.

Specified by:

accept in interface Node

collectInto

public void collectInto(NodeList list,
                        NodeFilter filter)

Description copied from interface: Node

Collect this node and its child nodes (if-applicable) into the collectionList parameter, provided the node satisfies the filtering criteria.

This mechanism allows powerful filtering code to be written very easily, without bothering about collection of embedded tags separately. e.g. when we try to get all the links on a page, it is not possible to get it at the top-level, as many tags (like form tags), can contain links embedded in them. We could get the links out by checking if the current node is a CompositeTag, and going through its children. So this method provides a convenient way to do this.

Using collectInto(), programs get a lot shorter. Now, the code to extract all links from a page would look like:

 NodeList collectionList = new NodeList();
 NodeFilter filter = new TagNameFilter ("A");
 for (NodeIterator e = parser.elements(); e.hasMoreNodes();)
      e.nextNode().collectInto(collectionList, filter);
 

Thus, collectionList will hold all the link nodes, irrespective of how deep the links are embedded.

Another way to accomplish the same objective is:

 NodeList collectionList = new NodeList();
 NodeFilter filter = new TagClassFilter (LinkTag.class);
 for (NodeIterator e = parser.elements(); e.hasMoreNodes();)
      e.nextNode().collectInto(collectionList, filter);
 

This is slightly less specific because the LinkTag class may be registered for more than one node name, e.g. <LINK> tags too.

Specified by:

collectInto in interface Node

elementBegin

public int elementBegin()

Description copied from interface: Node

Returns the beginning position of the tag.
deprecated Use Node.getStartPosition()

Specified by:

elementBegin in interface Node

elementEnd

public int elementEnd()

Description copied from interface: Node

Returns the ending position fo the tag
deprecated Use Node.getEndPosition()

Specified by:

elementEnd in interface Node

getStartPosition

public int getStartPosition()

Gets the starting position of the node.

Specified by:

getStartPosition in interface Node

Returns:

The start position.

setStartPosition

public void setStartPosition(int position)

Sets the starting position of the node.

Specified by:

setStartPosition in interface Node

Parameters:

position - The new start position.

getEndPosition

public int getEndPosition()

Gets the ending position of the node.

Specified by:

getEndPosition in interface Node

Returns:

The end position.

setEndPosition

public void setEndPosition(int position)

Sets the ending position of the node.

Specified by:

setEndPosition in interface Node

Parameters:

position - The new end position.

equals

public boolean equals(Object arg0)

getParent

public Node getParent()

Description copied from interface: Node

Get the parent of this node. This will always return null when parsing without scanners, i.e. if semantic parsing was not performed. The object returned from this method can be safely cast to a CompositeTag.

Specified by:

getParent in interface Node

Returns:

The parent of this node, if it's been set, null otherwise.

getText

public String getText()

Description copied from interface: Node

Returns the text of the node.

Specified by:

getText in interface Node

setParent

public void setParent(Node node)

Description copied from interface: Node

Sets the parent of this node.

Specified by:

setParent in interface Node

Parameters:

node - The node that contains this node. Must be a CompositeTag.

getChildren

public NodeList getChildren()

Get the children of this node.

Specified by:

getChildren in interface Node

Returns:

The list of children contained by this node, if it's been set, null otherwise.

setChildren

public void setChildren(NodeList children)

Set the children of this node.

Specified by:

setChildren in interface Node

Parameters:

children - The new list of children this node contains.

setText

public void setText(String text)

Description copied from interface: Node

Sets the string contents of the node.

Specified by:

setText in interface Node

Parameters:

text - The new text for the node.

toHtml

public String toHtml()

Description copied from interface: Node

This method will make it easier when using html parser to reproduce html pages (with or without modifications) Applications reproducing html can use this method on nodes which are to be used or transferred as they were recieved, with the original html

Specified by:

toHtml in interface Node

toPlainTextString

public String toPlainTextString()

Description copied from interface: Node

Returns a string representation of the node. This is an important method, it allows a simple string transformation of a web page, regardless of a node.
Typical application code (for extracting only the text from a web page) would then be simplified to :

 Node node;
 for (Enumeration e = parser.elements();e.hasMoreElements();) {
    node = (Node)e.nextElement();
    System.out.println(node.toPlainTextString()); // Or do whatever processing you wish with the plain text string
 }
 

Specified by:

toPlainTextString in interface Node

toString

public String toString()

Description copied from interface: Node

Return the string representation of the node. Subclasses must define this method, and this is typically to be used in the manner

System.out.println(node)

Specified by:

toString in interface Node

doSemanticAction

public void doSemanticAction()
                      throws ParserException

Description copied from interface: Node

Perform the meaning of this tag. This is defined by the tag, for example the bold tag <B> may switch bold text on and off. Only a few tags have semantic meaning to the parser. These have to do with the character set to use (<META>), the base URL to use (<BASE>). Other than that, the semantic meaning is up to the application and it's custom nodes.

Specified by:

doSemanticAction in interface Node

Throws:

ParserException