Top Description Fields Constructors Methods

org.antlr.runtime.tree

public abstract Class RewriteRuleElementStream

Class Inheritance

extends Object

java.lang.Object
org.antlr.runtime.tree.RewriteRuleElementStream

Known Direct Subclasses

org.antlr.runtime.tree.RewriteRuleNodeStream, org.antlr.runtime.tree.RewriteRuleSubtreeStream, org.antlr.runtime.tree.RewriteRuleTokenStream

Imports

java.util.ArrayList, .List

A generic list of elements tracked in an alternative to be used in a -> rewrite rule. We need to subclass to fill in the next() method, which returns either an AST node wrapped around a token payload or an existing subtree. Once you start next()ing, do not try to add more elements. It will break the cursor tracking I believe.

See Also: org.antlr.runtime.tree.RewriteRuleSubtreeStream, TODO: add mechanism to detect/puke on modification after reading from stream

Field Summary

Modifier and Type	Field and Description
protected TreeAdaptor	adaptor
protected int	cursor Cursor 0..n-1.
protected boolean	dirty Once a node / subtree has been used in a stream, it must be dup'd from then on.
protected String	elementDescription The element or stream description; usually has name of the token or rule reference that this list tracks.
protected List<Object>	elements The list of tokens or subtrees we are tracking
protected Object	singleElement Track single elements w/o creating a list.

Constructor Summary

Access	Constructor and Description
public	RewriteRuleElementStream(TreeAdaptor adaptor, String elementDescription)
public	RewriteRuleElementStream(TreeAdaptor adaptor, String elementDescription, Object oneElement) Create a stream with one element
public	RewriteRuleElementStream(TreeAdaptor adaptor, String elementDescription, List<Object> elements) Create a stream, but feed off an existing list

Method Summary

Modifier and Type	Method and Description
protected Object	_next() do the work of getting the next element, making sure that it's a tree node or subtree.
public void	add(Object el)
protected abstract Object	dup(Object el) When constructing trees, sometimes we need to dup a token or AST subtree.
public String	getDescription()
public boolean	hasNext()
public Object	nextTree() Return the next element in the stream.
public void	reset() Reset the condition of this stream so that it appears we have not consumed any of its elements.
public int	size()
protected Object	toTree(Object el) Ensure stream emits trees; tokens must be converted to AST nodes.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

adaptor	back to summary
protected TreeAdaptor adaptor

cursor	back to summary
protected int cursor Cursor 0..n-1. If singleElement!=null, cursor is 0 until you next(), which bumps it to 1 meaning no more elements.

dirty	back to summary
protected boolean dirty Once a node / subtree has been used in a stream, it must be dup'd from then on. Streams are reset after subrules so that the streams can be reused in future subrules. So, reset must set a dirty bit. If dirty, then next() always returns a dup. I wanted to use "naughty bit" here, but couldn't think of a way to use "naughty". TODO: unused?

elementDescription	back to summary
protected String elementDescription The element or stream description; usually has name of the token or rule reference that this list tracks. Can include rulename too, but the exception would track that info.

elements	back to summary
protected List<Object> elements The list of tokens or subtrees we are tracking

singleElement	back to summary
protected Object singleElement Track single elements w/o creating a list. Upon 2nd add, alloc list

Constructor Detail

RewriteRuleElementStream	back to summary
public RewriteRuleElementStream(TreeAdaptor adaptor, String elementDescription)

RewriteRuleElementStream

back to summary

public RewriteRuleElementStream(TreeAdaptor adaptor, String elementDescription, Object oneElement)

Create a stream with one element

Annotations

@SuppressWarnings:OverridableMethodCallInConstructor

RewriteRuleElementStream	back to summary
public RewriteRuleElementStream(TreeAdaptor adaptor, String elementDescription, List<Object> elements) Create a stream, but feed off an existing list

Method Detail

_next	back to summary
protected Object _next() do the work of getting the next element, making sure that it's a tree node or subtree. Deal with the optimization of single- element list versus list of size > 1. Throw an exception if the stream is empty or we're out of elements and size>1. protected so you can override in a subclass if necessary.

add	back to summary
public void add(Object el)

dup	back to summary
protected abstract Object dup(Object el) When constructing trees, sometimes we need to dup a token or AST subtree. Dup'ing a token means just creating another AST node around it. For trees, you must call the adaptor.dupTree() unless the element is for a tree root; then it must be a node dup.

getDescription	back to summary
public String getDescription()

hasNext	back to summary
public boolean hasNext()

nextTree	back to summary
public Object nextTree() Return the next element in the stream. If out of elements, throw an exception unless size()==1. If size is 1, then return elements[0]. Return a duplicate node/subtree if stream is out of elements and size==1. If we've already used the element, dup (dirty bit set).

reset	back to summary
public void reset() Reset the condition of this stream so that it appears we have not consumed any of its elements. Elements themselves are untouched. Once we reset the stream, any future use will need duplicates. Set the dirty bit.

size	back to summary
public int size()

toTree	back to summary
protected Object toTree(Object el) Ensure stream emits trees; tokens must be converted to AST nodes. AST nodes can be passed through unmolested.