Package com.blackrook.expression.struct

Class Lexer.ReaderStack

java.lang.Object

com.blackrook.expression.struct.Lexer.ReaderStack

Enclosing class:

Lexer

public static class Lexer.ReaderStack
extends Object

This holds a series of Reader streams such that the stream on top is the current active stream. This was separated out of Lexer to mix different Lexers on one stack (different lexers, same stream). It is the user's responsibility to pop() streams off of the stack when they reach an end.

Author:

Matthew Tropiano

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	Lexer.ReaderStack.Stream	Stream encapsulation of a single named Reader.

Constructor Summary

Constructors

Constructor	Description
ReaderStack()	Creates a new empty ReaderStack.
ReaderStack(String name, Reader reader)	Creates a new ReaderStack.

Method Summary

Modifier and Type	Method	Description
int	getCurrentLineCharacterIndex()
int	getCurrentLineNumber()
String	getCurrentStreamName()
boolean	isEmpty()
Lexer.ReaderStack.Stream	peek()	Gets the reference to the topmost (current) stream.
Lexer.ReaderStack.Stream	pop()	Pops a Lexer.ReaderStack.Stream off of the top of this stack.
void	push(String name, Reader reader)	Pushes another reader onto the stack.
int	readChar()	Reads the next character.
int	size()

Methods inherited from class java.lang.Object

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

Constructor Detail

ReaderStack

public ReaderStack()

Creates a new empty ReaderStack.

ReaderStack

public ReaderStack(String name,
                   Reader reader)

Creates a new ReaderStack.

Parameters:

name - the name to give the first reader.

reader - the reader itself (assumed open).

Method Detail

push

public final void push(String name,
                       Reader reader)

Pushes another reader onto the stack.

Parameters:

name - the name to give this reader.

reader - the reader itself (assumed open).

peek

public final Lexer.ReaderStack.Stream peek()

Gets the reference to the topmost (current) stream.

Returns:

the topmost stream.

pop

public final Lexer.ReaderStack.Stream pop()

Pops a Lexer.ReaderStack.Stream off of the top of this stack. The stream is closed automatically.

Returns:

the removed Lexer.ReaderStack.Stream, or null if empty.

See Also:

isEmpty()

getCurrentStreamName

public final String getCurrentStreamName()

Returns:

the current stream name, or null if empty.

See Also:

isEmpty()

getCurrentLineNumber

public final int getCurrentLineNumber()

Returns:

the current line number, or -1 if empty.

See Also:

isEmpty()

getCurrentLineCharacterIndex

public final int getCurrentLineCharacterIndex()

Returns:

the current line number, or -1 if empty.

See Also:

isEmpty()

size

public final int size()

Returns:

the amount of readers in the stack.

isEmpty

public final boolean isEmpty()

Returns:

if there are no readers in the stack.

readChar

public final int readChar()
                   throws IOException

Reads the next character.

Returns:

the character read, or null if end of current stream.

Throws:

IOException - if a line cannot be read by the topmost Reader.