com.singularsys.jep
Class VariableTable

java.lang.Object
  java.util.Observable
      com.singularsys.jep.VariableTable

All Implemented Interfaces:

JepComponent, java.io.Serializable

Direct Known Subclasses:

CaseInsensitiveVariableTable, StandardVariableTable

public class VariableTable
extends java.util.Observable
implements JepComponent

A table of variables. This class implements Observable and observers will be notified when new variables are added, or removed, but not when their values are changed. Use Variable.addObserver() to monitor individual variables.

See Also:

for a base class for monotoring a VariableTable., Serialized Form

Field Summary

protected java.util.HashMap<java.lang.String,Variable>	table
protected VariableFactory	vf

Constructor Summary

VariableTable()

VariableTable(VariableTable tbl)

Method Summary

Variable	addConstant(java.lang.String name, java.lang.Object value) Adds a new variable which is marked as a constant.
Variable	addVariable(java.lang.String name) Adds a new variable with no value specified.
Variable	addVariable(java.lang.String name, java.lang.Object value) Adds a new variable with specified value.
void	clear() Clears all variables from the table.
void	clearValues() Clears the values of all non constant variables.
boolean	containsKey(java.lang.String key)
boolean	containsVariable(Variable value)
void	copyConstantsFrom(VariableTable vt) Copies all the constants from a variable table into this table
void	copyVariablesFrom(VariableTable vt) Copies all the variables from a variable table into this table
JepComponent	getLightWeightInstance() Returns a new empty VariableTable.
Variable	getVariable(java.lang.String name) Gets an existing variable, returns null if variable is not found.
VariableFactory	getVariableFactory()
java.util.Collection<Variable>	getVariables() Returns all the variable in the table.
void	init(Jep j) Initialize the component.
boolean	isEmpty()
java.util.Set<java.lang.String>	keySet() Returns the names of all the variables.
Variable	remove(java.lang.String varname) Remove a variable with a given name from the table.
Variable	remove(Variable var) Remove a variable from the table.
void	setVariableFactory(VariableFactory vf)
int	size()
java.lang.String	toString()
java.util.Collection<Variable>	values() Deprecated.

Methods inherited from class java.util.Observable

addObserver, clearChanged, countObservers, deleteObserver, deleteObservers, hasChanged, notifyObservers, notifyObservers, setChanged

Methods inherited from class java.lang.Object

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

Field Detail

table

protected java.util.HashMap<java.lang.String,Variable> table

vf

protected transient VariableFactory vf

Constructor Detail

VariableTable

public VariableTable()

VariableTable

public VariableTable(VariableTable tbl)

Method Detail

init

public void init(Jep j)

Description copied from interface: JepComponent

Initialize the component. This methods is called whenever a component is added to Jep. Hence it allows components to keep track of the other components they may rely on.

Specified by:

init in interface JepComponent

Parameters:

j - the current Jep instance

setVariableFactory

public void setVariableFactory(VariableFactory vf)

getVariableFactory

public VariableFactory getVariableFactory()

addVariable

public Variable addVariable(java.lang.String name)

Adds a new variable with no value specified. If the variable already exists in the table, that variable instance is returned. Otherwise a new Variable instance is created with the variable factory.

Parameters:

name - the variable's name

Returns:

the variable

addVariable

public Variable addVariable(java.lang.String name,
                            java.lang.Object value)
                     throws JepException

Adds a new variable with specified value. If the variable already exists, its value is updated with the new value. If the variable exists and is a constant, the value is not updated and no error is reported. If the variable does not exist, it is created using the variable factory of the jep instance specified with the init(Jep j) method.

Parameters:

name - the name of the variable

value - the value for the variable to be set to

Returns:

the variable added or updated

Throws:

JepException - if an attempt is made to set the value of a constant variable

addConstant

public Variable addConstant(java.lang.String name,
                            java.lang.Object value)
                     throws JepException

Adds a new variable which is marked as a constant. Its value will also be marked as valid, in particular a null value is valid for a constant.

Parameters:

name -

value -

Returns:

the corresponding Variable object

Throws:

JepException - if an attempt is made to set the value of an existing constant variable

getVariable

public Variable getVariable(java.lang.String name)

Gets an existing variable, returns null if variable is not found.

Parameters:

name -

Returns:

the variable

clear

public void clear()

Clears all variables from the table.

isEmpty

public boolean isEmpty()

keySet

public java.util.Set<java.lang.String> keySet()

Returns the names of all the variables.

Returns:

a collection Strings with the variable names.

getVariables

public java.util.Collection<Variable> getVariables()

Returns all the variable in the table.

remove

public Variable remove(java.lang.String varname)

Remove a variable with a given name from the table.

Parameters:

varname - name of the variable to remove

Returns:

the removed variable or null if the variable does not exist in the table.

remove

public Variable remove(Variable var)

Remove a variable from the table.

Parameters:

var - the variable to remove

Returns:

the removed variable or null if the variable does not exist in the table.

values

@Deprecated
public java.util.Collection<Variable> values()

Deprecated.

A collection of all the variables

size

public int size()

containsKey

public boolean containsKey(java.lang.String key)

containsVariable

public boolean containsVariable(Variable value)

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getLightWeightInstance

public JepComponent getLightWeightInstance()

Returns a new empty VariableTable.

Specified by:

getLightWeightInstance in interface JepComponent

Returns:

a new VariableTable

See Also:

copyConstantsFrom(VariableTable), copyVariablesFrom(VariableTable)

copyConstantsFrom

public void copyConstantsFrom(VariableTable vt)

Copies all the constants from a variable table into this table

Parameters:

vt - source variable table

copyVariablesFrom

public void copyVariablesFrom(VariableTable vt)

Copies all the variables from a variable table into this table

Parameters:

vt - source variable table

clearValues

public void clearValues()

Clears the values of all non constant variables. This will set the Variable.setValidValue(boolean) to false.

Since:

3.4.0