BufferedTreeNodeStream (ANTLR 3 Runtime 3.5 API)

java.lang.Object
- org.antlr.runtime.tree.BufferedTreeNodeStream

All Implemented Interfaces:

IntStream, TreeNodeStream
```
public class BufferedTreeNodeStream
extends 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... TARGET DEVELOPERS: This is the old CommonTreeNodeStream that buffered up entire node stream. No need to implement really as new CommonTreeNodeStream is much better and covers what we need.

See Also:
CommonTreeNodeStream

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

protected class BufferedTreeNodeStream.StreamIterator

Nested Classes
Modifier and Type	Class and Description
`protected class`	`BufferedTreeNodeStream.StreamIterator`

Field Summary

Fields
Modifier and Type	Field and Description
`protected IntArray`	`calls` Stack of indexes used for push/pop calls
`static int`	`DEFAULT_INITIAL_BUFFER_SIZE`
`protected Object`	`down`
`protected Object`	`eof`
`static int`	`INITIAL_CALL_STACK_SIZE`
`protected int`	`lastMarker` Track the last mark() call result value for use in rewind().
`protected List<Object>`	`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 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 Object`	`up`

Constructor Summary

Constructors
Constructor and Description
`BufferedTreeNodeStream(Object tree)`
`BufferedTreeNodeStream(TreeAdaptor adaptor, Object tree)`
`BufferedTreeNodeStream(TreeAdaptor adaptor, Object tree, int initialBufferSize)`

Method Summary

Methods
Modifier and Type	Method and Description
`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(Object t)`
`Object`	`get(int i)` Get a tree node at an absolute index `i`; 0..n-1.
`Object`	`getCurrentSymbol()`
`protected int`	`getNodeIndex(Object node)` What is the stream index for node? 0..n-1 Return -1 if node not found.
`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.
`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.
`Iterator<Object>`	`iterator()`
`int`	`LA(int i)` Get int at current input pointer + i ahead where i=1 is next int.
`protected Object`	`LB(int k)` Look backwards k nodes
`Object`	`LT(int k)` Get tree node at current input pointer + `k` ahead where `k==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(Object parent, int startChildIndex, int stopChildIndex, Object t)` Replace children of `parent` from index `startChildIndex` to `stopChildIndex` with `t`, which might be a list.
`void`	`reset()` Reset the tree node stream in such a way that it acts like a freshly constructed stream.
`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 `Token.UP`, `Token.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.
`String`	`toString(Object start, Object stop)` Return the text of all nodes from `start` to `stop`, inclusive.
`String`	`toTokenString(int start, int stop)` Debugging
`String`	`toTokenTypeString()` Used for testing, just return the token type stream

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, 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 Object down
```
  - up
```
protected Object up
```
  - eof
```
protected Object eof
```
  - nodes
```
protected List<Object> 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 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
  - BufferedTreeNodeStream
```
public BufferedTreeNodeStream(Object tree)
```
  - BufferedTreeNodeStream
```
public BufferedTreeNodeStream(TreeAdaptor adaptor,
                      Object tree)
```
  - BufferedTreeNodeStream
```
public BufferedTreeNodeStream(TreeAdaptor adaptor,
                      Object tree,
                      int initialBufferSize)
```
- 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(Object t)
```
  - getNodeIndex
```
protected int getNodeIndex(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 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 Object LT(int k)
```
    Description copied from interface: TreeNodeStream
    
    Get tree node at current input pointer + k ahead where k==1 is next node. k<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 k<=n, return null. Return null for LT(0) and any index that results in an absolute address that is negative.
    This is analogous to TokenStream.LT(int), but this returns a tree node instead of a Token. Makes code generation identical for both parser and tree grammars.
    
    Specified by:
    
    LT in interface TreeNodeStream
  - getCurrentSymbol
```
public Object getCurrentSymbol()
```
  - LB
```
protected Object LB(int k)
```
    Look backwards k nodes
  - getTreeSource
```
public 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 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 Token.UP, Token.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()
```
    Description copied from interface: TreeNodeStream
    
    Reset the tree node stream in such a way that it acts like a freshly constructed stream.
    
    Specified by:
    
    reset in interface TreeNodeStream
  - 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 Iterator<Object> iterator()
```
  - replaceChildren
```
public void replaceChildren(Object parent,
                   int startChildIndex,
                   int stopChildIndex,
                   Object t)
```
    Description copied from interface: TreeNodeStream
    
    Replace children of parent from index startChildIndex to stopChildIndex 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
  - toTokenTypeString
```
public String toTokenTypeString()
```
    Used for testing, just return the token type stream
  - toTokenString
```
public String toTokenString(int start,
                   int stop)
```
    Debugging
  - toString
```
public String toString(Object start,
              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

Class BufferedTreeNodeStream

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

DEFAULT_INITIAL_BUFFER_SIZE

INITIAL_CALL_STACK_SIZE

down

up

eof

nodes

root

tokens

uniqueNavigationNodes

p

lastMarker

calls

Constructor Detail

BufferedTreeNodeStream

BufferedTreeNodeStream

BufferedTreeNodeStream

Method Detail

fillBuffer

fillBuffer

getNodeIndex

addNavigationNode

get

LT

getCurrentSymbol

LB

getTreeSource

getSourceName

getTokenStream

setTokenStream

getTreeAdaptor

setTreeAdaptor

hasUniqueNavigationNodes

setUniqueNavigationNodes

consume

LA

mark

release

index

rewind

rewind

seek

push

pop

reset

size

iterator

replaceChildren

toTokenTypeString

toTokenString

toString