org.htmlparser.filters
Class RegexFilter

java.lang.Object
  org.htmlparser.filters.RegexFilter

All Implemented Interfaces:

Serializable, Cloneable, NodeFilter

public class RegexFilter
extends Object
implements NodeFilter

This filter accepts all string nodes matching a regular expression. Because this searches Text nodes. it is only useful for finding small fragments of text, where it is unlikely to be broken up by a tag. To find large fragments of text you should convert the page to plain text with something like the StringBean and then apply the regular expression.

For example, to look for dates use:

   (19|20)\d\d([- \\/.](0[1-9]|1[012])[- \\/.](0[1-9]|[12][0-9]|3[01]))?
 

as in:

 Parser parser = new Parser ("http://cbc.ca");
 RegexFilter filter = new RegexFilter ("(19|20)\\d\\d([- \\\\/.](0[1-9]|1[012])[- \\\\/.](0[1-9]|[12][0-9]|3[01]))?");
 NodeIterator iterator = parser.extractAllNodesThatMatch (filter).elements ();
 

which matches a date in yyyy-mm-dd format between 1900-01-01 and 2099-12-31, with a choice of five separators, either a dash, a space, either kind of slash or a period. The year is matched by (19|20)\d\d which uses alternation to allow the either 19 or 20 as the first two digits. The round brackets are mandatory. The month is matched by 0[1-9]|1[012], again enclosed by round brackets to keep the two options together. By using character classes, the first option matches a number between 01 and 09, and the second matches 10, 11 or 12. The last part of the regex consists of three options. The first matches the numbers 01 through 09, the second 10 through 29, and the third matches 30 or 31. The day and month are optional, but must occur together because of the ()? bracketing after the year.

See Also:

Serialized Form

Field Summary

static int	FIND Use find() match strategy.
static int	LOOKINGAT Use lookingAt() match strategy.
static int	MATCH Use match() matching strategy.
protected Pattern	mPattern The compiled regular expression to search for.
protected String	mPatternString The regular expression to search for.
protected int	mStrategy The match strategy.

Constructor Summary

RegexFilter()
Creates a new instance of RegexFilter that accepts string nodes matching the regular expression ".*" using the FIND strategy.

RegexFilter(String pattern)
Creates a new instance of RegexFilter that accepts string nodes matching a regular expression using the FIND strategy.

RegexFilter(String pattern, int strategy)
Creates a new instance of RegexFilter that accepts string nodes matching a regular expression.

Method Summary

boolean	accept(Node node) Accept string nodes that match the regular expression.
String	getPattern() Get the search pattern.
int	getStrategy() Get the search strategy.
void	setPattern(String pattern) Set the search pattern.
void	setStrategy(int strategy) Set the search pattern.

Methods inherited from class java.lang.Object

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

Field Detail

MATCH

public static final int MATCH

Use match() matching strategy.

See Also:

Constant Field Values

LOOKINGAT

public static final int LOOKINGAT

Use lookingAt() match strategy.

See Also:

Constant Field Values

FIND

public static final int FIND

Use find() match strategy.

See Also:

Constant Field Values

mPatternString

protected String mPatternString

The regular expression to search for.

mPattern

protected Pattern mPattern

The compiled regular expression to search for.

mStrategy

protected int mStrategy

The match strategy.

See Also:

RegexFilter(String, int)

Constructor Detail

RegexFilter

public RegexFilter()

Creates a new instance of RegexFilter that accepts string nodes matching the regular expression ".*" using the FIND strategy.

RegexFilter

public RegexFilter(String pattern)

Creates a new instance of RegexFilter that accepts string nodes matching a regular expression using the FIND strategy.

Parameters:

pattern - The pattern to search for.

RegexFilter

public RegexFilter(String pattern,
                   int strategy)

Creates a new instance of RegexFilter that accepts string nodes matching a regular expression.

Parameters:

pattern - The pattern to search for.

strategy - The type of match:

1. MATCH use matches() method: attempts to match the entire input sequence against the pattern
2. LOOKINGAT use lookingAt() method: attempts to match the input sequence, starting at the beginning, against the pattern
3. FIND use find() method: scans the input sequence looking for the next subsequence that matches the pattern

Method Detail

getPattern

public String getPattern()

Get the search pattern.

Returns:

Returns the pattern.

setPattern

public void setPattern(String pattern)

Set the search pattern.

Parameters:

pattern - The pattern to set.

getStrategy

public int getStrategy()

Get the search strategy.

Returns:

Returns the strategy.

setStrategy

public void setStrategy(int strategy)

Set the search pattern.

Parameters:

strategy - The strategy to use. One of MATCH, LOOKINGAT or FIND.

accept

public boolean accept(Node node)

Accept string nodes that match the regular expression.

Specified by:

accept in interface NodeFilter

Parameters:

node - The node to check.

Returns:

true if the regular expression matches the text of the node, false otherwise.