org.btrplace.btrpsl

Class SymbolsTable

java.lang.Object

org.btrplace.btrpsl.SymbolsTable

public class SymbolsTable
extends Object

A table of symbols to store variables in a script description. Variables can be declared as immutable. In this context, they can not be modified once declared. In addition, the table can be pushed or popped to simulate a context. Pushing a table create a new context. When it is popped, every variable created after the last push are automatically removed.

Author:

Fabien Hermenier

Field Summary

Fields

Modifier and Type	Field and Description
static String	ME

Constructor Summary

Constructors

Constructor and Description
SymbolsTable() Make a new table of symbols for a script.

Method Summary

Modifier and Type	Method and Description
boolean	declare(String label, BtrpOperand t) Declare a new variable.
boolean	declareImmutable(String label, BtrpOperand t) Declare an immutable variable.
BtrpOperand	getSymbol(String label) Get the content associated to a variable label.
boolean	isDeclared(String label) Check wether a variable is declared.
boolean	isImmutable(String label) Check if one variable is immutable.
boolean	popTable() Pop the table.
void	pushTable() Push the table.
boolean	remove(String label) Remove a symbol from the table.
String	toString() Textual representation of the table of symbol.

Methods inherited from class java.lang.Object

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

Field Detail

ME

public static final String ME

See Also:

Constant Field Values

Constructor Detail

SymbolsTable

public SymbolsTable()

Make a new table of symbols for a script.

Method Detail

declareImmutable

public boolean declareImmutable(String label,
                                BtrpOperand t)

Declare an immutable variable. The variable must not has been already declared.

Parameters:

label - the identifier of the variable

t - the operand associated to the identifier

Returns:

true if the variable as been declared. false otherwise

remove

public boolean remove(String label)

Remove a symbol from the table.

Parameters:

label - the symbol to remove

Returns:

true if the symbol was present then removed. false otherwise

isImmutable

public boolean isImmutable(String label)

Check if one variable is immutable.

Parameters:

label - the identifier of the variable

Returns:

true if the variable is immutable

declare

public final boolean declare(String label,
                             BtrpOperand t)

Declare a new variable. The variable is inserted into the current script.

Parameters:

label - the label of the variable

t - the content of the variable

Returns:

true if the declaration succeeds, false otherwise

getSymbol

public BtrpOperand getSymbol(String label)

Get the content associated to a variable label.

Parameters:

label - the label of the variable

Returns:

the content of the variable if exists. null otherwise

isDeclared

public boolean isDeclared(String label)

Check wether a variable is declared.

Parameters:

label - the label of the variable

Returns:

true if the variable is already declared, false otherwise

toString

public String toString()

Textual representation of the table of symbol.

Overrides:

toString in class Object

Returns:

all the variables and their content. One variable per line.

pushTable

public void pushTable()

Push the table. Every variables in the table are saved

popTable

public boolean popTable()

Pop the table. Every variable created after the last pushTable() are removed from the table. The table can not be poped if it was not at least pushed once earlier.

Returns:

true if the table has been popped successfully. false otherwise