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## org.htmlparser.scanners
Class CompositeTagScanner

    java.lang.Object
      org.htmlparser.scanners.TagScanner
          org.htmlparser.scanners.CompositeTagScanner

All Implemented Interfaces:
  Scanner, Serializable

Direct Known Subclasses:
  ScriptScanner, StyleScanner

public class CompositeTagScanner
extends TagScanner

The main scanning logic for nested tags. When asked to scan, this class gathers nodes into a heirarchy of tags.

See Also:
  Serialized Form

Constructor Summary
`CompositeTagScanner()` Create a composite tag scanner.

Method Summary
`protected void` | `addChild(Tag parent, Node child)` Add a child to the given tag.
`protected Tag` | `createVirtualEndTag(Tag tag, Page page, int position)` Creates an end tag with the same name as the given tag.
`protected void` | `finishTag(CompositeTag tag, Lexer lexer)` Finish off a tag.
`boolean` | `isTagToBeEndedFor(Tag current, Tag tag)` Determine if the current tag should be terminated by the given tag.
`Tag` | `scan(Tag tag, Lexer lexer, NodeList stack)` Collect the children.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### CompositeTagScanner

    public CompositeTagScanner()

  Create a composite tag scanner.

Method Detail

### scan

    public Tag scan(Tag tag,
                    Lexer lexer,
                    NodeList stack)
             throws ParserException

  Collect the children.

  An initial test is performed for an empty XML tag, in which case the start tag and end tag of the returned tag are the same and it has no children.

  If it's not an empty XML tag, the lexer is repeatedly asked for subsequent nodes until an end tag is found or a node is encountered that matches the tag ender set or end tag ender set. In the latter case, a virtual end tag is created. Each node found that is not the end tag is added to the list of children. The end tag is special and not a child.

  Nodes that also have a CompositeTagScanner as their scanner are recursed into, which provides the nested structure of an HTML page. This method operates in two possible modes, depending on a private boolean. It can recurse on the JVM stack, which has caused some overflow problems in the past, or it can use the supplied stack argument to nest scanning of child tags within itself. The former is left as an option in the code, mostly to help subsequent modifiers visualize what the internal nesting is doing.

  Specified by:
    `scan` in interface `Scanner`
  Overrides:
    `scan` in class `TagScanner`
  Parameters:
    `tag` - The tag this scanner is responsible for.
    `lexer` - The source of subsequent nodes.
    `stack` - The parse stack. May contain pending tags that enclose this tag.
  Returns:
    The resultant tag (may be unchanged).
  Throws:
    `ParserException`

### addChild

    protected void addChild(Tag parent,
                            Node child)

  Add a child to the given tag.

  Parameters:
    `parent` - The parent tag.
    `child` - The child node.

### finishTag

    protected void finishTag(CompositeTag tag,
                             Lexer lexer)
                      throws ParserException

  Finish off a tag. Perhap add a virtual end tag. Set the end tag parent as this tag. Perform the semantic acton.

  Parameters:
    `tag` - The tag to finish off.
    `lexer` - A lexer positioned at the end of the tag.
  Throws:
    `ParserException`

### createVirtualEndTag

    protected Tag createVirtualEndTag(Tag tag,
                                      Page page,
                                      int position)

  Creates an end tag with the same name as the given tag.

  Parameters:
    `tag` - The tag to end.
    `page` - The page the tag is on (virtually).
    `position` - The offset into the page at which the tag is to be anchored.
  Returns:
    An end tag with the name '"/" + tag.getTagName()' and a start and end position at the given position. The fact these positions are equal may be used to distinguish it as a virtual tag later on.

### isTagToBeEndedFor

    public final boolean isTagToBeEndedFor(Tag current,
                                           Tag tag)

  Determine if the current tag should be terminated by the given tag. Examines the 'enders' or 'end tag enders' lists of the current tag for a match with the given tag. Which list is chosen depends on whether tag is an end tag ('end tag enders') or not ('enders').

  Parameters:
    `current` - The tag that might need to be ended.
    `tag` - The candidate tag that might end the current one.
  Returns:
    `true` if the name of the given tag is a member of the appropriate list.

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| © 2004 Somik Raha Mar 14, 2004
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HTML Parser is an open source library released under LGPL.