Class BufferedTreeNodeStream

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:
  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    protected class 
     
  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    (package private) TreeAdaptor
    What tree adaptor was used to build these trees
    protected IntArray
    Stack of indexes used for push/pop calls
    static final int
     
    protected Object
     
    protected Object
     
    static final int
     
    protected int
    Track the last mark() call result value for use in rewind().
    protected List
    The complete mapping from stream index to tree node.
    protected int
    The index into the nodes list of the current node (next node to consume).
    protected Object
    Pull nodes from which tree?
    protected TokenStream
    IF this tree (root) was created from a token stream, track it.
    protected boolean
    Reuse same DOWN, UP navigation nodes unless this is true
    protected Object
     
  • Constructor Summary

    Constructors
    Constructor
    Description
     
     
    BufferedTreeNodeStream(TreeAdaptor adaptor, Object tree, int initialBufferSize)
     
  • Method Summary

    Modifier and Type
    Method
    Description
    protected void
    addNavigationNode(int ttype)
    As we flatten the tree, we use UP, DOWN nodes to represent the tree structure.
    void
     
    protected void
    Walk tree with depth-first-search and fill nodes buffer.
    void
     
    get(int i)
    Get a tree node at an absolute index i; 0..n-1.
     
    protected int
    What is the stream index for node? 0..n-1 Return -1 if node not found.
    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.
    If the tree associated with this stream was created from a TokenStream, you can specify it here.
    What adaptor can tell me how to interpret/navigate nodes and trees.
    Where is this stream pulling nodes from? This is not the name, but the object that provides node objects.
    boolean
     
    int
    Return the current input symbol index 0..n where n indicates the last symbol has been read.
     
    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
    LT(int k)
    Get tree node at current input pointer + i ahead where i=1 is next node.
    int
    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 from start to stop child index of parent with t, which might be a list.
    void
    Reset the tree node stream in such a way that it acts like a freshly constructed stream.
    void
    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
     
    void
     
    void
    setUniqueNavigationNodes(boolean uniqueNavigationNodes)
    As we flatten the tree, we use UP, DOWN nodes to represent the tree structure.
    int
    Only makes sense for streams that buffer everything up probably, but might be useful to display the entire stream or for testing.
    toString(Object start, Object stop)
    Return the text of all nodes from start to stop, inclusive.
    toTokenString(int start, int stop)
    Debugging
    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 Details

    • DEFAULT_INITIAL_BUFFER_SIZE

      public static final int DEFAULT_INITIAL_BUFFER_SIZE
      See Also:
    • INITIAL_CALL_STACK_SIZE

      public static final int INITIAL_CALL_STACK_SIZE
      See Also:
    • down

      protected Object down
    • up

      protected Object up
    • eof

      protected Object eof
    • nodes

      protected 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 Object root
      Pull nodes from which tree?
    • tokens

      protected TokenStream tokens
      IF this tree (root) was created from a token stream, track it.
    • adaptor

      TreeAdaptor adaptor
      What tree adaptor was used to build these trees
    • 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 Details

    • BufferedTreeNodeStream

      public BufferedTreeNodeStream(Object tree)
    • BufferedTreeNodeStream

      public BufferedTreeNodeStream(TreeAdaptor adaptor, Object tree)
    • BufferedTreeNodeStream

      public BufferedTreeNodeStream(TreeAdaptor adaptor, Object tree, int initialBufferSize)
  • Method Details

    • 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 + 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 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 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()
      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 iterator()
    • replaceChildren

      public void replaceChildren(Object parent, int startChildIndex, int stopChildIndex, 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
    • 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