UnbufferedTokenStream (ANTLR 4 Runtime 4.1 API)

java.lang.Object
- org.antlr.v4.runtime.UnbufferedTokenStream<T>

All Implemented Interfaces:: IntStream, TokenStream

public class UnbufferedTokenStream<T extends Token>
extends Object
implements TokenStream

Field Summary

Fields
Modifier and Type	Field and Description
`protected int`	`currentTokenIndex` Absolute token index.
`protected Token`	`lastToken` This is the `LT(-1)` token for the current position.
`protected Token`	`lastTokenBufferStart` When `numMarkers > 0`, this is the `LT(-1)` token for the first token in `tokens`.
`protected int`	`n` The number of tokens currently in `tokens`.
`protected int`	`numMarkers` Count up with `mark()` and down with `release()`.
`protected int`	`p` 0..n-1 index into `tokens` of next token.
`protected Token[]`	`tokens` A moving window buffer of the data being scanned.
`protected TokenSource`	`tokenSource`

Fields inherited from interface org.antlr.v4.runtime.IntStream
EOF, UNKNOWN_SOURCE_NAME

Constructor Summary

Constructors
Constructor and Description

UnbufferedTokenStream(TokenSource tokenSource)

UnbufferedTokenStream(TokenSource tokenSource, int bufferSize)

Constructors
Constructor and Description
`UnbufferedTokenStream(TokenSource tokenSource)`
`UnbufferedTokenStream(TokenSource tokenSource, int bufferSize)`

Method Summary

Methods
Modifier and Type	Method and Description
`protected void`	`add(Token t)`
`void`	`consume()` Consumes the current symbol in the stream.
`protected int`	`fill(int n)` Add `n` elements to the buffer.
`Token`	`get(int i)` Gets the `Token` at the specified `index` in the stream.
`protected int`	`getBufferStartIndex()`
`String`	`getSourceName()` Gets the name of the underlying symbol source.
`String`	`getText()` Return the text of all tokens in the stream.
`String`	`getText(Interval interval)` Return the text of all tokens within the specified `interval`.
`String`	`getText(RuleContext ctx)` Return the text of all tokens in the source interval of the specified context.
`String`	`getText(Token start, Token stop)` Return the text of all tokens in this stream between `start` and `stop` (inclusive).
`TokenSource`	`getTokenSource()` Gets the underlying `TokenSource` which provides tokens for this stream.
`int`	`index()` Return the index into the stream of the input symbol referred to by `LA(1)`.
`int`	`LA(int i)` Gets the value of the symbol at offset `i` from the current position.
`Token`	`LT(int i)` Get the `Token` instance associated with the value returned by `LA(k)`.
`int`	`mark()` Return a marker that we can release later.
`void`	`release(int marker)` This method releases a marked range created by a call to `mark()`.
`void`	`seek(int index)` Set the input cursor to the position indicated by `index`.
`int`	`size()` Returns the total number of symbols in the stream, including a single EOF symbol.
`protected void`	`sync(int want)` Make sure we have 'need' elements from current position `p`.

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

- Field Detail
  - tokenSource
```
protected TokenSource tokenSource
```
  - tokens
```
protected Token[] tokens
```
    A moving window buffer of the data being scanned. While there's a marker, we keep adding to buffer. Otherwise, consume() resets so we start filling at index 0 again.
  - n
```
protected int n
```
    The number of tokens currently in tokens.
    This is not the buffer capacity, that's tokens.length.
  - p
```
protected int p
```
    0..n-1 index into tokens of next token.
    The LT(1) token is tokens[p]. If p == n, we are out of buffered tokens.
  - numMarkers
```
protected int numMarkers
```
    Count up with mark() and down with release(). When we release() the last mark, numMarkers reaches 0 and we reset the buffer. Copy tokens[p]..tokens[n-1] to tokens[0]..tokens[(n-1)-p].
  - lastToken
```
protected Token lastToken
```
    This is the LT(-1) token for the current position.
  - lastTokenBufferStart
```
protected Token lastTokenBufferStart
```
    When numMarkers > 0, this is the LT(-1) token for the first token in tokens. Otherwise, this is null.
  - currentTokenIndex
```
protected int currentTokenIndex
```
    Absolute token index. It's the index of the token about to be read via LT(1). Goes from 0 to the number of tokens in the entire stream, although the stream size is unknown before the end is reached.
    This value is used to set the token indexes if the stream provides tokens that implement WritableToken.
- Constructor Detail
  - UnbufferedTokenStream
```
public UnbufferedTokenStream(TokenSource tokenSource)
```
  - UnbufferedTokenStream
```
public UnbufferedTokenStream(TokenSource tokenSource,
                     int bufferSize)
```
- Method Detail
  - get
```
public Token get(int i)
```
    Description copied from interface: TokenStream
    
    Gets the Token at the specified index in the stream. When the preconditions of this method are met, the return value is non-null.
    The preconditions for this method are the same as the preconditions of IntStream.seek(int). If the behavior of seek(index) is unspecified for the current state and given index, then the behavior of this method is also unspecified.
    The symbol referred to by index differs from seek() only in the case of filtering streams where index lies before the end of the stream. Unlike seek(), this method does not adjust index to point to a non-ignored symbol.
    
    Specified by:
    
    get in interface TokenStream
  - LT
```
public Token LT(int i)
```
    Description copied from interface: TokenStream
    
    Get the Token instance associated with the value returned by LA(k). This method has the same pre- and post-conditions as IntStream.LA(int). In addition, when the preconditions of this method are met, the return value is non-null and the value of LT(k).getType()==LA(k).
    
    Specified by:
    
    LT in interface TokenStream
    
    See Also:
    IntStream.LA(int)
  - LA
```
public int LA(int i)
```
    Description copied from interface: IntStream
    Gets the value of the symbol at offset i from the current position. When i==1, this method returns the value of the current symbol in the stream (which is the next symbol to be consumed). When i==-1, this method returns the value of the previously read symbol in the stream. It is not valid to call this method with i==0, but the specific behavior is unspecified because this method is frequently called from performance-critical code.
    This method is guaranteed to succeed if any of the following are true:
    - i>0
    - i==-1 and index() returns a value greater than the value of index() after the stream was constructed and LA(1) was called in that order. Specifying the current index() relative to the index after the stream was created allows for filtering implementations that do not return every symbol from the underlying source. Specifying the call to LA(1) allows for lazily initialized streams.
    - LA(i) refers to a symbol consumed within a marked region that has not yet been released.
    If i represents a position at or beyond the end of the stream, this method returns IntStream.EOF.
    The return value is unspecified if i<0 and fewer than -i calls to consume() have occurred from the beginning of the stream before calling this method.
    Specified by:
    
    LA in interface IntStream
  - getTokenSource
```
public TokenSource getTokenSource()
```
    Description copied from interface: TokenStream
    
    Gets the underlying TokenSource which provides tokens for this stream.
    
    Specified by:
    
    getTokenSource in interface TokenStream
  - getText
```
@NotNull
public String getText()
```
    Description copied from interface: TokenStream
    Return the text of all tokens in the stream. This method behaves like the following code, including potential exceptions from the calls to IntStream.size() and TokenStream.getText(Interval), but may be optimized by the specific implementation.
```
 TokenStream stream = ...;
 String text = stream.getText(new Interval(0, stream.size()));
 
```
    Specified by:
    
    getText in interface TokenStream
    
    Returns:
    The text of all tokens in the stream.
  - getText
```
@NotNull
public String getText(RuleContext ctx)
```
    Description copied from interface: TokenStream
    Return the text of all tokens in the source interval of the specified context. This method behaves like the following code, including potential exceptions from the call to TokenStream.getText(Interval), but may be optimized by the specific implementation.
    If ctx.getSourceInterval() does not return a valid interval of tokens provided by this stream, the behavior is unspecified.
```
 TokenStream stream = ...;
 String text = stream.getText(ctx.getSourceInterval());
 
```
    Specified by:
    
    getText in interface TokenStream
    
    Parameters:
    ctx - The context providing the source interval of tokens to get text for.
    
    Returns:
    The text of all tokens within the source interval of ctx.
  - getText
```
@NotNull
public String getText(Token start,
                     Token stop)
```
    Description copied from interface: TokenStream
    Return the text of all tokens in this stream between start and stop (inclusive).
    If the specified start or stop token was not provided by this stream, or if the stop occurred before the start token, the behavior is unspecified.
    For streams which ensure that the Token.getTokenIndex() method is accurate for all of its provided tokens, this method behaves like the following code. Other streams may implement this method in other ways provided the behavior is consistent with this at a high level.
```
 TokenStream stream = ...;
 String text = "";
 for (int i = start.getTokenIndex(); i <= stop.getTokenIndex(); i++) {
   text += stream.get(i).getText();
 }
 
```
    Specified by:
    
    getText in interface TokenStream
    
    Parameters:
    start - The first token in the interval to get text for.
    stop - The last token in the interval to get text for (inclusive).
    
    Returns:
    The text of all tokens lying between the specified start and stop tokens.
  - consume
```
public void consume()
```
    Description copied from interface: IntStream
    Consumes the current symbol in the stream. This method has the following effects:
    - Forward movement: The value of index() before calling this method is less than the value of index() after calling this method.
    - Ordered lookahead: The value of LA(1) before calling this method becomes the value of LA(-1) after calling this method.
    Note that calling this method does not guarantee that index() is incremented by exactly 1, as that would preclude the ability to implement filtering streams (e.g. CommonTokenStream which distinguishes between "on-channel" and "off-channel" tokens).
    Specified by:
    
    consume in interface IntStream
  - sync
```
protected void sync(int want)
```
    Make sure we have 'need' elements from current position p. Last valid p index is tokens.length-1. p+need-1 is the tokens index 'need' elements ahead. If we need 1 element, (p+1-1)==p must be less than tokens.length.
  - fill
```
protected int fill(int n)
```
    Add n elements to the buffer. Returns the number of tokens actually added to the buffer. If the return value is less than n, then EOF was reached before n tokens could be added.
  - add
```
protected void add(@NotNull
       Token t)
```
  - mark
```
public int mark()
```
    Return a marker that we can release later.
    The specific marker value used for this class allows for some level of protection against misuse where seek() is called on a mark or release() is called in the wrong order.
    
    Specified by:
    
    mark in interface IntStream
    
    Returns:
    An opaque marker which should be passed to release() when the marked range is no longer required.
  - release
```
public void release(int marker)
```
    Description copied from interface: IntStream
    
    This method releases a marked range created by a call to mark(). Calls to release() must appear in the reverse order of the corresponding calls to mark(). If a mark is released twice, or if marks are not released in reverse order of the corresponding calls to mark(), the behavior is unspecified.
    For more information and an example, see IntStream.mark().
    
    Specified by:
    
    release in interface IntStream
    
    Parameters:
    marker - A marker returned by a call to mark().
    See Also:
    IntStream.mark()
  - index
```
public int index()
```
    Description copied from interface: IntStream
    
    Return the index into the stream of the input symbol referred to by LA(1).
    The behavior of this method is unspecified if no call to an initializing method has occurred after this stream was constructed.
    
    Specified by:
    
    index in interface IntStream
  - seek
```
public void seek(int index)
```
    Description copied from interface: IntStream
    Set the input cursor to the position indicated by index. If the specified index lies past the end of the stream, the operation behaves as though index was the index of the EOF symbol. After this method returns without throwing an exception, the at least one of the following will be true.
    - index() will return the index of the first symbol appearing at or after the specified index. Specifically, implementations which filter their sources should automatically adjust index forward the minimum amount required for the operation to target a non-ignored symbol.
    - LA(1) returns IntStream.EOF
    This operation is guaranteed to not throw an exception if index lies within a marked region. For more information on marked regions, see IntStream.mark(). The behavior of this method is unspecified if no call to an initializing method has occurred after this stream was constructed.
    Specified by:
    
    seek in interface IntStream
    
    Parameters:
    index - The absolute index to seek to.
  - size
```
public int size()
```
    Description copied from interface: IntStream
    
    Returns the total number of symbols in the stream, including a single EOF symbol.
    
    Specified by:
    
    size in interface IntStream
  - getSourceName
```
public String getSourceName()
```
    Description copied from interface: IntStream
    
    Gets the name of the underlying symbol source. This method returns a non-null, non-empty string. If such a name is not known, this method returns IntStream.UNKNOWN_SOURCE_NAME.
    
    Specified by:
    
    getSourceName in interface IntStream
  - getText
```
@NotNull
public String getText(Interval interval)
```
    Description copied from interface: TokenStream
    Return the text of all tokens within the specified interval. This method behaves like the following code (including potential exceptions for violating preconditions of TokenStream.get(int), but may be optimized by the specific implementation.
```
 TokenStream stream = ...;
 String text = "";
 for (int i = interval.a; i <= interval.b; i++) {
   text += stream.get(i).getText();
 }
 
```
    Specified by:
    
    getText in interface TokenStream
    
    Parameters:
    interval - The interval of tokens within this stream to get text for.
    
    Returns:
    The text of all tokens within the specified interval in this stream.
  - getBufferStartIndex
```
protected final int getBufferStartIndex()
```

Class UnbufferedTokenStream<T extends Token>

Field Summary

Fields inherited from interface org.antlr.v4.runtime.IntStream

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

tokenSource

tokens

n

p

numMarkers

lastToken

lastTokenBufferStart

currentTokenIndex

Constructor Detail

UnbufferedTokenStream

UnbufferedTokenStream

Method Detail

get

LT

LA

getTokenSource

getText

getText

getText

consume

sync

fill

add

mark

release

index

seek

size

getSourceName

getText

getBufferStartIndex