com.google.gwt.thirdparty.streamhtmlparser.util
Class EntityResolver

java.lang.Object
  com.google.gwt.thirdparty.streamhtmlparser.util.EntityResolver

public class EntityResolver
extends java.lang.Object

Decodes (unescapes) HTML entities with the complication that these are received one character at a time hence must be stored temporarily. Also, we may receive some "junk" characters before the actual entity which we will discard.

This class is designed to be 100% compatible with the corresponding logic in the C-version of the com.google.security.streamhtmlparser.HtmlParser, found in htmlparser.c. There are however a few intentional differences outlines below:

• We accept lower and upper-case hex NCRs, the C-version accepts only lower-case ones.
• The output on some invalid inputs may be different. This is currently in the process of consolidation with Filipe.
• The API is a bit different, I find this one better suited for Java. In particular, the C method processChar returns the output String whereas in Java, we return a status code and then provide the String in a separate method getEntity. It is cleaner as it avoids the need to return empty Strings during incomplete processing.

Valid HTML entities have one of the following three forms:

• ⅆ where dd is a number in decimal (base 10) form.
• &x|Xyy; where yy is a hex-number (base 16).
• &<html-entity>; where <html-entity> is one of lt, gt, amp, quot or apos.

A reset method is provided to facilitate object re-use.

Nested Class Summary

static class

EntityResolver.Status Returned in processChar method.

Constructor Summary

EntityResolver()
Constructs an entity resolver that is initially empty and with status NOT_STARTED, see EntityResolver.Status.

EntityResolver(EntityResolver aEntityResolver)
Constructs an entity resolver that is an exact copy of the one provided.

Method Summary

java.lang.String	getEntity() Returns the decoded HTML Entity.
EntityResolver.Status	processChar(char input) Processes a character from the input stream and decodes any html entities from that processed input stream.
void	reset() Returns the object to its original state for re-use, deleting any stored characters that may be present.
java.lang.String	toString() Returns the full state of the StreamEntityResolver in a human readable form.

Methods inherited from class java.lang.Object

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

Constructor Detail

EntityResolver

public EntityResolver()

Constructs an entity resolver that is initially empty and with status NOT_STARTED, see EntityResolver.Status.

EntityResolver

public EntityResolver(EntityResolver aEntityResolver)

Constructs an entity resolver that is an exact copy of the one provided. In particular it has the same contents and status.

Parameters:

aEntityResolver - the entity resolver to copy

Method Detail

reset

public void reset()

Returns the object to its original state for re-use, deleting any stored characters that may be present.

toString

public java.lang.String toString()

Returns the full state of the StreamEntityResolver in a human readable form. The format of the returned String is not specified and is subject to change.

Overrides:

toString in class java.lang.Object

Returns:

full state of this object

getEntity

public java.lang.String getEntity()

Returns the decoded HTML Entity. Should only be called after processChar returned status COMPLETED.

Returns:

the decoded HTML Entity or an empty String if we were called with any status other than COMPLETED

processChar

public EntityResolver.Status processChar(char input)

Processes a character from the input stream and decodes any html entities from that processed input stream.

Parameters:

input - the char to process

Returns:

the processed String. Typically returns an empty String while awaiting for more characters to complete processing of the entity.