sjm.parse
Class Assembly

java.lang.Object
  |
  +--sjm.parse.Assembly

All Implemented Interfaces:

java.lang.Cloneable, java.util.Enumeration, PubliclyCloneable

Direct Known Subclasses:

CharacterAssembly, TokenAssembly

public abstract class Assembly

extends java.lang.Object

implements java.util.Enumeration, PubliclyCloneable

An assembly maintains a stream of language elements along with stack and target objects. Parsers use assemblers to record progress at recognizing language elements from assembly's string.

Version:

1.0

Author:

Steven J. Metsker

Field Summary

protected int	index
protected java.util.Stack	stack
protected PubliclyCloneable	target

Constructor Summary

Assembly()

Method Summary

java.lang.Object	clone() Return a copy of this object.
abstract java.lang.String	consumed(java.lang.String delimiter) Returns the elements of the assembly that have been consumed, separated by the specified delimiter.
abstract java.lang.String	defaultDelimiter() Returns the default string to show between elements.
int	elementsConsumed() Returns the number of elements that have been consumed.
int	elementsRemaining() Returns the number of elements that have not been consumed.
java.util.Stack	getStack() Removes this assembly's stack.
java.lang.Object	getTarget() Returns the object identified as this assembly's "target".
boolean	hasMoreElements() Returns true if this assembly has unconsumed elements.
abstract int	length() Returns the number of elements in this assembly.
abstract java.lang.Object	peek() Shows the next object in the assembly, without removing it
java.lang.Object	pop() Removes the object at the top of this assembly's stack and returns it.
void	push(java.lang.Object o) Pushes an object onto the top of this assembly's stack.
abstract java.lang.String	remainder(java.lang.String delimiter) Returns the elements of the assembly that remain to be consumed, separated by the specified delimiter.
void	setTarget(PubliclyCloneable target) Sets the target for this assembly.
boolean	stackIsEmpty() Returns true if this assembly's stack is empty.
java.lang.String	toString() Returns a textual description of this assembly.
void	unget(int n) Put back n objects

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Enumeration

nextElement

Field Detail

stack

protected java.util.Stack stack

target

protected PubliclyCloneable target

index

protected int index

Constructor Detail

Assembly

public Assembly()

Method Detail

clone

public java.lang.Object clone()

Return a copy of this object.

Specified by:

clone in interface PubliclyCloneable

Overrides:

clone in class java.lang.Object

Returns:

a copy of this object

consumed

public abstract java.lang.String consumed(java.lang.String delimiter)

Returns the elements of the assembly that have been consumed, separated by the specified delimiter.

Parameters:

String - the mark to show between consumed elements

Returns:

the elements of the assembly that have been consumed

defaultDelimiter

public abstract java.lang.String defaultDelimiter()

Returns the default string to show between elements.

Returns:

the default string to show between elements

elementsConsumed

public int elementsConsumed()

Returns the number of elements that have been consumed.

Returns:

the number of elements that have been consumed

elementsRemaining

public int elementsRemaining()

Returns the number of elements that have not been consumed.

Returns:

the number of elements that have not been consumed

getStack

public java.util.Stack getStack()

Removes this assembly's stack.

Returns:

this assembly's stack

getTarget

public java.lang.Object getTarget()

Returns the object identified as this assembly's "target". Clients can set and retrieve a target, which can be a convenient supplement as a place to work, in addition to the assembly's stack. For example, a parser for an HTML file might use a web page object as its "target". As the parser recognizes markup commands like , it could apply its findings to the target.

Returns:

the target of this assembly

hasMoreElements

public boolean hasMoreElements()

Returns true if this assembly has unconsumed elements.

Specified by:

hasMoreElements in interface java.util.Enumeration

Returns:

true, if this assembly has unconsumed elements

length

public abstract int length()

Returns the number of elements in this assembly.

Returns:

the number of elements in this assembly

peek

public abstract java.lang.Object peek()

Shows the next object in the assembly, without removing it

Returns:

the next object

pop

public java.lang.Object pop()

Removes the object at the top of this assembly's stack and returns it.

Returns:

the object at the top of this assembly's stack

Throws:

java.util.EmptyStackException - if this stack is empty

push

public void push(java.lang.Object o)

Pushes an object onto the top of this assembly's stack.

Parameters:

object - the object to be pushed

remainder

public abstract java.lang.String remainder(java.lang.String delimiter)

Returns the elements of the assembly that remain to be consumed, separated by the specified delimiter.

Parameters:

String - the mark to show between unconsumed elements

Returns:

the elements of the assembly that remain to be consumed

setTarget

public void setTarget(PubliclyCloneable target)

Sets the target for this assembly. Targets must implement clone() as a public method.

Parameters:

target - a publicly cloneable object

stackIsEmpty

public boolean stackIsEmpty()

Returns true if this assembly's stack is empty.

Returns:

true, if this assembly's stack is empty

toString

public java.lang.String toString()

Returns a textual description of this assembly.

Overrides:

toString in class java.lang.Object

Returns:

a textual description of this assembly

unget

public void unget(int n)

Put back n objects