org.htmlparser.beans
Class StringBean

java.lang.Object
  org.htmlparser.visitors.NodeVisitor
      org.htmlparser.beans.StringBean

All Implemented Interfaces:

Serializable

public class StringBean
extends NodeVisitor
implements Serializable

Extract strings from a URL.

Text within <SCRIPT></SCRIPT> tags is removed.

The text within <PRE></PRE> tags is not altered.

The property Strings, which is the output property is null until a URL is set. So a typical usage is:

     StringBean sb = new StringBean ();
     sb.setLinks (false);
     sb.setReplaceNonBreakingSpaces (true);
     sb.setCollapse (true);
     sb.setURL ("http://www.netbeans.org"); // the HTTP is performed here
     String s = sb.getStrings ();
 

You can also use the StringBean as a NodeVisitor on your own parser, in which case you have to refetch your page if you change one of the properties because it resets the Strings property:

     StringBean sb = new StringBean ();
     Parser parser = new Parser ("http://cbc.ca");
     parser.visitAllNodesWith (sb);
     String s = sb.getStrings ();
     sb.setLinks (true);
     parser.reset ();
     parser.visitAllNodesWith (sb);
     String sl = sb.getStrings ();
 

According to Nick Burch, who contributed the patch, this is handy if you don't want StringBean to wander off and get the content itself, either because you already have it, it's not on a website etc.

See Also:

Serialized Form

Field Summary

protected StringBuffer	mBuffer The buffer text is stored in while traversing the HTML.
protected boolean	mCollapse If true sequences of whitespace characters are replaced with a single space character.
protected int	mCollapseState The state of the collapse processiung state machine.
protected boolean	mIsPre Set true when traversing a PRE tag.
protected boolean	mIsScript Set true when traversing a SCRIPT tag.
protected boolean	mIsStyle Set true when traversing a STYLE tag.
protected boolean	mLinks If true the link URLs are embedded in the text output.
protected Parser	mParser The parser used to extract strings.
protected PropertyChangeSupport	mPropertySupport Bound property support.
protected boolean	mReplaceSpace If true regular space characters are substituted for non-breaking spaces in the text output.
protected String	mStrings The strings extracted from the URL.
static String	PROP_COLLAPSE_PROPERTY Property name in event where the 'collapse whitespace' state changes.
static String	PROP_CONNECTION_PROPERTY Property name in event where the connection changes.
static String	PROP_LINKS_PROPERTY Property name in event where the 'embed links' state changes.
static String	PROP_REPLACE_SPACE_PROPERTY Property name in event where the 'replace non-breaking spaces' state changes.
static String	PROP_STRINGS_PROPERTY Property name in event where the URL contents changes.
static String	PROP_URL_PROPERTY Property name in event where the URL changes.

Constructor Summary

StringBean()
Create a StringBean object.

Method Summary

void	addPropertyChangeListener(PropertyChangeListener listener) Add a PropertyChangeListener to the listener list.
protected void	carriageReturn() Appends a newline to the buffer if there isn't one there already.
protected void	collapse(StringBuffer buffer, String string) Add the given text collapsing whitespace.
protected String	extractStrings() Extract the text from a page.
boolean	getCollapse() Get the current 'collapse whitespace' state.
URLConnection	getConnection() Get the current connection.
boolean	getLinks() Get the current 'include links' state.
boolean	getReplaceNonBreakingSpaces() Get the current 'replace non breaking spaces' state.
String	getStrings() Return the textual contents of the URL.
String	getURL() Get the current URL.
static void	main(String[] args) Unit test.
void	removePropertyChangeListener(PropertyChangeListener listener) Remove a PropertyChangeListener from the listener list.
void	setCollapse(boolean collapse) Set the current 'collapse whitespace' state.
void	setConnection(URLConnection connection) Set the parser's connection.
void	setLinks(boolean links) Set the 'include links' state.
void	setReplaceNonBreakingSpaces(boolean replace) Set the 'replace non breaking spaces' state.
protected void	setStrings() Fetch the URL contents.
void	setURL(String url) Set the URL to extract strings from.
protected void	updateStrings(String strings) Assign the Strings property, firing the property change.
void	visitEndTag(Tag tag) Resets the state of the PRE and SCRIPT flags.
void	visitStringNode(Text string) Appends the text to the output.
void	visitTag(Tag tag) Appends a NEWLINE to the output if the tag breaks flow, and possibly sets the state of the PRE and SCRIPT flags.

Methods inherited from class org.htmlparser.visitors.NodeVisitor

beginParsing, finishedParsing, shouldRecurseChildren, shouldRecurseSelf, visitRemarkNode

Methods inherited from class java.lang.Object

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

Field Detail

PROP_STRINGS_PROPERTY

public static final String PROP_STRINGS_PROPERTY

Property name in event where the URL contents changes.

See Also:

Constant Field Values

PROP_LINKS_PROPERTY

public static final String PROP_LINKS_PROPERTY

Property name in event where the 'embed links' state changes.

See Also:

Constant Field Values

PROP_URL_PROPERTY

public static final String PROP_URL_PROPERTY

Property name in event where the URL changes.

See Also:

Constant Field Values

PROP_REPLACE_SPACE_PROPERTY

public static final String PROP_REPLACE_SPACE_PROPERTY

Property name in event where the 'replace non-breaking spaces' state changes.

See Also:

Constant Field Values

PROP_COLLAPSE_PROPERTY

public static final String PROP_COLLAPSE_PROPERTY

Property name in event where the 'collapse whitespace' state changes.

See Also:

Constant Field Values

PROP_CONNECTION_PROPERTY

public static final String PROP_CONNECTION_PROPERTY

Property name in event where the connection changes.

See Also:

Constant Field Values

mPropertySupport

protected PropertyChangeSupport mPropertySupport

Bound property support.

mParser

protected Parser mParser

The parser used to extract strings.

mStrings

protected String mStrings

The strings extracted from the URL.

mLinks

protected boolean mLinks

If true the link URLs are embedded in the text output.

mReplaceSpace

protected boolean mReplaceSpace

If true regular space characters are substituted for non-breaking spaces in the text output.

mCollapse

protected boolean mCollapse

If true sequences of whitespace characters are replaced with a single space character.

mCollapseState

protected int mCollapseState

The state of the collapse processiung state machine.

mBuffer

protected StringBuffer mBuffer

The buffer text is stored in while traversing the HTML.

mIsScript

protected boolean mIsScript

Set true when traversing a SCRIPT tag.

mIsPre

protected boolean mIsPre

Set true when traversing a PRE tag.

mIsStyle

protected boolean mIsStyle

Set true when traversing a STYLE tag.

Constructor Detail

StringBean

public StringBean()

Create a StringBean object. Default property values are set to 'do the right thing':

Links is set false so text appears like a browser would display it, albeit without the colour or underline clues normally associated with a link.

ReplaceNonBreakingSpaces is set true, so that printing the text works, but the extra information regarding these formatting marks is available if you set it false.

Collapse is set true, so text appears compact like a browser would display it.

Method Detail

carriageReturn

protected void carriageReturn()

Appends a newline to the buffer if there isn't one there already. Except if the buffer is empty.

collapse

protected void collapse(StringBuffer buffer,
                        String string)

Add the given text collapsing whitespace. Use a little finite state machine:

 state 0: whitepace was last emitted character
 state 1: in whitespace
 state 2: in word
 A whitespace character moves us to state 1 and any other character
 moves us to state 2, except that state 0 stays in state 0 until
 a non-whitespace and going from whitespace to word we emit a space
 before the character:
    input:     whitespace   other-character
 state\next
    0               0             2
    1               1        space then 2
    2               1             2
 

Parameters:

buffer - The buffer to append to.

string - The string to append.

extractStrings

protected String extractStrings()
                         throws ParserException

Extract the text from a page.

Returns:

The textual contents of the page.

Throws:

ParserException - If a parse error occurs.

updateStrings

protected void updateStrings(String strings)

Assign the Strings property, firing the property change.

Parameters:

strings - The new value of the Strings property.

setStrings

protected void setStrings()

Fetch the URL contents. Only do work if there is a valid parser with it's URL set.

addPropertyChangeListener

public void addPropertyChangeListener(PropertyChangeListener listener)

Add a PropertyChangeListener to the listener list. The listener is registered for all properties.

Parameters:

listener - The PropertyChangeListener to be added.

removePropertyChangeListener

public void removePropertyChangeListener(PropertyChangeListener listener)

Remove a PropertyChangeListener from the listener list. This removes a registered PropertyChangeListener.

Parameters:

listener - The PropertyChangeListener to be removed.

getStrings

public String getStrings()

Return the textual contents of the URL. This is the primary output of the bean.

Returns:

The user visible (what would be seen in a browser) text.

getLinks

public boolean getLinks()

Get the current 'include links' state.

Returns:

true if link text is included in the text extracted from the URL, false otherwise.

setLinks

public void setLinks(boolean links)

Set the 'include links' state. If the setting is changed after the URL has been set, the text from the URL will be reacquired, which is possibly expensive.

Parameters:

links - Use true if link text is to be included in the text extracted from the URL, false otherwise.

getURL

public String getURL()

Get the current URL.

Returns:

The URL from which text has been extracted, or null if this property has not been set yet.

setURL

public void setURL(String url)

Set the URL to extract strings from. The text from the URL will be fetched, which may be expensive, so this property should be set last.

Parameters:

url - The URL that text should be fetched from.

getReplaceNonBreakingSpaces

public boolean getReplaceNonBreakingSpaces()

Get the current 'replace non breaking spaces' state.

Returns:

true if non-breaking spaces (character '\u00a0', numeric character reference &#160; or character entity reference &nbsp;) are to be replaced with normal spaces (character '\u0020').

setReplaceNonBreakingSpaces

public void setReplaceNonBreakingSpaces(boolean replace)

Set the 'replace non breaking spaces' state. If the setting is changed after the URL has been set, the text from the URL will be reacquired, which is possibly expensive.

Parameters:

replace - true if non-breaking spaces (character '\u00a0', numeric character reference &#160; or character entity reference &nbsp;) are to be replaced with normal spaces (character '\u0020').

getCollapse

public boolean getCollapse()

Get the current 'collapse whitespace' state. If set to true this emulates the operation of browsers in interpretting text where user agents should collapse input white space sequences when producing output inter-word space. See HTML specification section 9.1 White space http://www.w3.org/TR/html4/struct/text.html#h-9.1.

Returns:

true if sequences of whitespace (space '\u0020', tab '\u0009', form feed '\u000C', zero-width space '\u200B', carriage-return '\r' and NEWLINE '\n') are to be replaced with a single space.

setCollapse

public void setCollapse(boolean collapse)

Set the current 'collapse whitespace' state. If the setting is changed after the URL has been set, the text from the URL will be reacquired, which is possibly expensive. The internal state of the collapse state machine can be reset with code like this: setCollapse (getCollapse ());

Parameters:

collapse - If true, sequences of whitespace will be reduced to a single space.

getConnection

public URLConnection getConnection()

Get the current connection.

Returns:

The connection that the parser has or null if it hasn't been set or the parser hasn't been constructed yet.

setConnection

public void setConnection(URLConnection connection)

Set the parser's connection. The text from the URL will be fetched, which may be expensive, so this property should be set last.

Parameters:

connection - New value of property Connection.

visitStringNode

public void visitStringNode(Text string)

Appends the text to the output.

Overrides:

visitStringNode in class NodeVisitor

Parameters:

string - The text node.

visitTag

public void visitTag(Tag tag)

Appends a NEWLINE to the output if the tag breaks flow, and possibly sets the state of the PRE and SCRIPT flags.

Overrides:

visitTag in class NodeVisitor

Parameters:

tag - The tag to examine.

visitEndTag

public void visitEndTag(Tag tag)

Resets the state of the PRE and SCRIPT flags.

Overrides:

visitEndTag in class NodeVisitor

Parameters:

tag - The end tag to process.

main

public static void main(String[] args)

Unit test.

Parameters:

args - Pass arg[0] as the URL to process.