org.antlr.runtime.tree
Class CommonTreeNodeStream

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

All Implemented Interfaces:

IntStream, TreeNodeStream

public class CommonTreeNodeStream
extends java.lang.Object
implements TreeNodeStream

A buffered stream of tree nodes. Nodes can be from a tree of ANY kind. This node stream sucks all nodes out of the tree specified in the constructor during construction and makes pointers into the tree using an array of Object pointers. The stream necessarily includes pointers to DOWN and UP and EOF nodes. This stream knows how to mark/release for backtracking. This stream is most suitable for tree interpreters that need to jump around a lot or for tree parsers requiring speed (at cost of memory). There is some duplicated functionality here with UnBufferedTreeNodeStream but just in bookkeeping, not tree walking etc...

See Also:

UnBufferedTreeNodeStream

Nested Class Summary

protected class

CommonTreeNodeStream.StreamIterator

Field Summary

protected IntArray	calls Stack of indexes used for push/pop calls
static int	DEFAULT_INITIAL_BUFFER_SIZE
protected java.lang.Object	down
protected java.lang.Object	eof
static int	INITIAL_CALL_STACK_SIZE
protected int	lastMarker Track the last mark() call result value for use in rewind().
protected java.util.List	nodes The complete mapping from stream index to tree node.
protected int	p The index into the nodes list of the current node (next node to consume).
protected java.lang.Object	root Pull nodes from which tree?
protected TokenStream	tokens IF this tree (root) was created from a token stream, track it.
protected boolean	uniqueNavigationNodes Reuse same DOWN, UP navigation nodes unless this is true
protected java.lang.Object	up

Constructor Summary

CommonTreeNodeStream(CommonTreeNodeStream parent, int start, int stop)
Reuse an existing node stream's buffer of nodes.

CommonTreeNodeStream(java.lang.Object tree)

CommonTreeNodeStream(TreeAdaptor adaptor, java.lang.Object tree)

CommonTreeNodeStream(TreeAdaptor adaptor, java.lang.Object tree, int initialBufferSize)

Method Summary

protected void	addNavigationNode(int ttype) As we flatten the tree, we use UP, DOWN nodes to represent the tree structure.
void	consume()
protected void	fillBuffer() Walk tree with depth-first-search and fill nodes buffer.
void	fillBuffer(java.lang.Object t)
java.lang.Object	get(int i) Get a tree node at an absolute index i; 0..n-1.
java.lang.Object	getCurrentSymbol()
protected int	getNodeIndex(java.lang.Object node) What is the stream index for node? 0..n-1 Return -1 if node not found.
java.lang.String	getSourceName() Where are you getting symbols from? Normally, implementations will pass the buck all the way to the lexer who can ask its input stream for the file name or whatever.
TokenStream	getTokenStream() If the tree associated with this stream was created from a TokenStream, you can specify it here.
TreeAdaptor	getTreeAdaptor() What adaptor can tell me how to interpret/navigate nodes and trees.
java.lang.Object	getTreeSource() Where is this stream pulling nodes from? This is not the name, but the object that provides node objects.
boolean	hasUniqueNavigationNodes()
int	index() Return the current input symbol index 0..n where n indicates the last symbol has been read.
java.util.Iterator	iterator()
int	LA(int i) Get int at current input pointer + i ahead where i=1 is next int.
protected java.lang.Object	LB(int k) Look backwards k nodes
java.lang.Object	LT(int k) Get tree node at current input pointer + i ahead where i=1 is next node.
int	mark() Tell the stream to start buffering if it hasn't already.
int	pop() Seek back to previous index saved during last push() call.
void	push(int index) Make stream jump to a new location, saving old location.
void	release(int marker) You may want to commit to a backtrack but don't want to force the stream to keep bookkeeping objects around for a marker that is no longer necessary.
void	replaceChildren(java.lang.Object parent, int startChildIndex, int stopChildIndex, java.lang.Object t) Replace from start to stop child index of parent with t, which might be a list.
void	reset()
void	rewind() Rewind to the input position of the last marker.
void	rewind(int marker) Reset the stream so that next call to index would return marker.
void	seek(int index) Set the input cursor to the position indicated by index.
void	setTokenStream(TokenStream tokens)
void	setTreeAdaptor(TreeAdaptor adaptor)
void	setUniqueNavigationNodes(boolean uniqueNavigationNodes) As we flatten the tree, we use UP, DOWN nodes to represent the tree structure.
int	size() Only makes sense for streams that buffer everything up probably, but might be useful to display the entire stream or for testing.
java.lang.String	toString() Used for testing, just return the token type stream
java.lang.String	toString(java.lang.Object start, java.lang.Object stop) Return the text of all nodes from start to stop, inclusive.
java.lang.String	toTokenString(int start, int stop) Debugging

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_INITIAL_BUFFER_SIZE

public static final int DEFAULT_INITIAL_BUFFER_SIZE

See Also:

Constant Field Values

INITIAL_CALL_STACK_SIZE

public static final int INITIAL_CALL_STACK_SIZE

See Also:

Constant Field Values

down

protected java.lang.Object down

up

protected java.lang.Object up

eof

protected java.lang.Object eof

nodes

protected java.util.List nodes

The complete mapping from stream index to tree node. This buffer includes pointers to DOWN, UP, and EOF nodes. It is built upon ctor invocation. The elements are type Object as we don't what the trees look like. Load upon first need of the buffer so we can set token types of interest for reverseIndexing. Slows us down a wee bit to do all of the if p==-1 testing everywhere though.

root

protected java.lang.Object root

Pull nodes from which tree?

tokens

protected TokenStream tokens

IF this tree (root) was created from a token stream, track it.

uniqueNavigationNodes

protected boolean uniqueNavigationNodes

Reuse same DOWN, UP navigation nodes unless this is true

p

protected int p

The index into the nodes list of the current node (next node to consume). If -1, nodes array not filled yet.

lastMarker

protected int lastMarker

Track the last mark() call result value for use in rewind().

calls

protected IntArray calls

Stack of indexes used for push/pop calls

Constructor Detail

CommonTreeNodeStream

public CommonTreeNodeStream(java.lang.Object tree)

CommonTreeNodeStream

public CommonTreeNodeStream(TreeAdaptor adaptor,
                            java.lang.Object tree)

CommonTreeNodeStream

public CommonTreeNodeStream(TreeAdaptor adaptor,
                            java.lang.Object tree,
                            int initialBufferSize)

CommonTreeNodeStream

public CommonTreeNodeStream(CommonTreeNodeStream parent,
                            int start,
                            int stop)

Reuse an existing node stream's buffer of nodes. Do not point at a node stream that can change. Must have static node list. start/stop are indexes into the parent.nodes stream. We avoid making a new list of nodes like this.

Method Detail

fillBuffer

protected void fillBuffer()

Walk tree with depth-first-search and fill nodes buffer. Don't do DOWN, UP nodes if its a list (t is isNil).

fillBuffer

public void fillBuffer(java.lang.Object t)

getNodeIndex

protected int getNodeIndex(java.lang.Object node)

What is the stream index for node? 0..n-1 Return -1 if node not found.

addNavigationNode

protected void addNavigationNode(int ttype)

As we flatten the tree, we use UP, DOWN nodes to represent the tree structure. When debugging we need unique nodes so instantiate new ones when uniqueNavigationNodes is true.

get

public java.lang.Object get(int i)

Description copied from interface: TreeNodeStream

Get a tree node at an absolute index i; 0..n-1. If you don't want to buffer up nodes, then this method makes no sense for you.

Specified by:

get in interface TreeNodeStream

LT

public java.lang.Object LT(int k)

Description copied from interface: TreeNodeStream

Get tree node at current input pointer + i ahead where i=1 is next node. i<0 indicates nodes in the past. So LT(-1) is previous node, but implementations are not required to provide results for k < -1. LT(0) is undefined. For i>=n, return null. Return null for LT(0) and any index that results in an absolute address that is negative. This is analogus to the LT() method of the TokenStream, but this returns a tree node instead of a token. Makes code gen identical for both parser and tree grammars. :)

Specified by:

LT in interface TreeNodeStream

getCurrentSymbol

public java.lang.Object getCurrentSymbol()

LB

protected java.lang.Object LB(int k)

Look backwards k nodes

getTreeSource

public java.lang.Object getTreeSource()

Description copied from interface: TreeNodeStream

Where is this stream pulling nodes from? This is not the name, but the object that provides node objects.

Specified by:

getTreeSource in interface TreeNodeStream

getSourceName

public java.lang.String getSourceName()

Description copied from interface: IntStream

Where are you getting symbols from? Normally, implementations will pass the buck all the way to the lexer who can ask its input stream for the file name or whatever.

Specified by:

getSourceName in interface IntStream

getTokenStream

public TokenStream getTokenStream()

Description copied from interface: TreeNodeStream

If the tree associated with this stream was created from a TokenStream, you can specify it here. Used to do rule $text attribute in tree parser. Optional unless you use tree parser rule text attribute or output=template and rewrite=true options.

Specified by:

getTokenStream in interface TreeNodeStream

setTokenStream

public void setTokenStream(TokenStream tokens)

getTreeAdaptor

public TreeAdaptor getTreeAdaptor()

Description copied from interface: TreeNodeStream

What adaptor can tell me how to interpret/navigate nodes and trees. E.g., get text of a node.

Specified by:

getTreeAdaptor in interface TreeNodeStream

setTreeAdaptor

public void setTreeAdaptor(TreeAdaptor adaptor)

hasUniqueNavigationNodes

public boolean hasUniqueNavigationNodes()

setUniqueNavigationNodes

public void setUniqueNavigationNodes(boolean uniqueNavigationNodes)

Description copied from interface: TreeNodeStream

As we flatten the tree, we use UP, DOWN nodes to represent the tree structure. When debugging we need unique nodes so we have to instantiate new ones. When doing normal tree parsing, it's slow and a waste of memory to create unique navigation nodes. Default should be false;

Specified by:

setUniqueNavigationNodes in interface TreeNodeStream

consume

public void consume()

Specified by:

consume in interface IntStream

LA

public int LA(int i)

Description copied from interface: IntStream

Get int at current input pointer + i ahead where i=1 is next int. Negative indexes are allowed. LA(-1) is previous token (token just matched). LA(-i) where i is before first token should yield -1, invalid char / EOF.

Specified by:

LA in interface IntStream

mark

public int mark()

Description copied from interface: IntStream

Tell the stream to start buffering if it hasn't already. Return current input position, index(), or some other marker so that when passed to rewind() you get back to the same spot. rewind(mark()) should not affect the input cursor. The Lexer track line/col info as well as input index so its markers are not pure input indexes. Same for tree node streams.

Specified by:

mark in interface IntStream

release

public void release(int marker)

Description copied from interface: IntStream

You may want to commit to a backtrack but don't want to force the stream to keep bookkeeping objects around for a marker that is no longer necessary. This will have the same behavior as rewind() except it releases resources without the backward seek. This must throw away resources for all markers back to the marker argument. So if you're nested 5 levels of mark(), and then release(2) you have to release resources for depths 2..5.

Specified by:

release in interface IntStream

index

public int index()

Description copied from interface: IntStream

Return the current input symbol index 0..n where n indicates the last symbol has been read. The index is the symbol about to be read not the most recently read symbol.

Specified by:

index in interface IntStream

rewind

public void rewind(int marker)

Description copied from interface: IntStream

Reset the stream so that next call to index would return marker. The marker will usually be index() but it doesn't have to be. It's just a marker to indicate what state the stream was in. This is essentially calling release() and seek(). If there are markers created after this marker argument, this routine must unroll them like a stack. Assume the state the stream was in when this marker was created.

Specified by:

rewind in interface IntStream

rewind

public void rewind()

Description copied from interface: IntStream

Rewind to the input position of the last marker. Used currently only after a cyclic DFA and just before starting a sem/syn predicate to get the input position back to the start of the decision. Do not "pop" the marker off the state. mark(i) and rewind(i) should balance still. It is like invoking rewind(last marker) but it should not "pop" the marker off. It's like seek(last marker's input position).

Specified by:

rewind in interface IntStream

seek

public void seek(int index)

Description copied from interface: IntStream

Set the input cursor to the position indicated by index. This is normally used to seek ahead in the input stream. No buffering is required to do this unless you know your stream will use seek to move backwards such as when backtracking. This is different from rewind in its multi-directional requirement and in that its argument is strictly an input cursor (index). For char streams, seeking forward must update the stream state such as line number. For seeking backwards, you will be presumably backtracking using the mark/rewind mechanism that restores state and so this method does not need to update state when seeking backwards. Currently, this method is only used for efficient backtracking using memoization, but in the future it may be used for incremental parsing. The index is 0..n-1. A seek to position i means that LA(1) will return the ith symbol. So, seeking to 0 means LA(1) will return the first element in the stream.

Specified by:

seek in interface IntStream

push

public void push(int index)

Make stream jump to a new location, saving old location. Switch back with pop().

pop

public int pop()

Seek back to previous index saved during last push() call. Return top of stack (return index).

reset

public void reset()

size

public int size()

Description copied from interface: IntStream

Only makes sense for streams that buffer everything up probably, but might be useful to display the entire stream or for testing. This value includes a single EOF.

Specified by:

size in interface IntStream

iterator

public java.util.Iterator iterator()

replaceChildren

public void replaceChildren(java.lang.Object parent,
                            int startChildIndex,
                            int stopChildIndex,
                            java.lang.Object t)

Description copied from interface: TreeNodeStream

Replace from start to stop child index of parent with t, which might be a list. Number of children may be different after this call. The stream is notified because it is walking the tree and might need to know you are monkeying with the underlying tree. Also, it might be able to modify the node stream to avoid restreaming for future phases. If parent is null, don't do anything; must be at root of overall tree. Can't replace whatever points to the parent externally. Do nothing.

Specified by:

replaceChildren in interface TreeNodeStream

toString

public java.lang.String toString()

Used for testing, just return the token type stream

Overrides:

toString in class java.lang.Object

toTokenString

public java.lang.String toTokenString(int start,
                                      int stop)

Debugging

toString

public java.lang.String toString(java.lang.Object start,
                                 java.lang.Object stop)

Description copied from interface: TreeNodeStream

Return the text of all nodes from start to stop, inclusive. If the stream does not buffer all the nodes then it can still walk recursively from start until stop. You can always return null or "" too, but users should not access $ruleLabel.text in an action of course in that case.

Specified by:

toString in interface TreeNodeStream