com.goldencode.p2j.util

Class unknown

java.lang.Object

com.goldencode.p2j.util.LazyUndoable

com.goldencode.p2j.util.BaseDataType

com.goldencode.p2j.util.unknown

All Implemented Interfaces:

Undoable, java.io.Externalizable, java.io.Serializable, java.lang.Comparable

public class unknown
extends BaseDataType

A class that represents a Progress 4GL compatible unknown value literal.

Author:

GES

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class com.goldencode.p2j.util.BaseDataType

BaseDataType.Type, BaseDataType.WrapperHandler

Field Summary

Fields

Modifier and Type	Field and Description
static unknown	UNKNOWN Singleton instance (as this is immutable) which can be used in FWD runtime.

Constructor Summary

Constructors

Constructor and Description
unknown() Default constructor, creates an instance that represents the unknown value.

Method Summary

Modifier and Type	Method and Description
void	assign(BaseDataType value) Sets the state (data and unknown value) of this instance based on the state of the passed instance.
void	assign(Undoable old) Modify the contained data of the instance to copy the instance data from the given instance.
int	compareTo(java.lang.Object obj) Compares this instance with the specified instance and returns a 0 if the two instances are both unknown and 1 if the passed instance is not unknown.
java.lang.String	defaultFormatString() Return the default display format string for this type.
unknown	duplicate() Does the same as standard clone() method but returns an instance of BaseDataType and doesn't throw the CloneNotSupportedException.
BaseDataType.Type	getType() Get the type
int	hashCode() Hash code implementation which is consistent with BaseDataType.equals(java.lang.Object).
BaseDataType	instantiateDefault() Creates a new instance of the same type that represents the default initialized value.
BaseDataType	instantiateUnknown() Creates a new instance of the same type that represents the unknown value.
boolean	isUnknown() Determines if this instance represents the unknown value (which is always the case).
void	readExternal(java.io.ObjectInput in) Replacement for the default object reading method.
void	setUnknown() This instance always represents the unknown value so this method does nothing.
java.lang.String	toString() Creates a string representation of the unknown value which is always '?'.
java.lang.String	toString(java.lang.String fmt) Creates a string representation of the unknown value which is always '?'.
java.lang.String	toStringExport() Creates a string representation of the unknown value which is always '?'.
java.lang.String	toStringMessage() Creates a string representation of the instance data in a form that is compatible with the MESSAGE language statement.
void	writeExternal(java.io.ObjectOutput out) Replacement for the default object writing method.

Methods inherited from class com.goldencode.p2j.util.BaseDataType

assign, assign, calcFormatLength, createProxy, createProxy, deepCopy, elementsOfType, equals, fallback, formatLength, fromTypeName, generateDefault, generateUnknown, getAssigner, getSize, getTypeName, incompatibleTypesOnConversion, initialize, initializeDefaultExtent, instantiateDefaultExtent, invalidInitializer, isAllKnown, isAllKnown, isAssignDirect, isIncompatibleTypesOnConversion, isProxy, isUnknownValue, maximum, minimum, notUnknownValue, sameType, val, variable

Methods inherited from class com.goldencode.p2j.util.LazyUndoable

changed, checkUndoable, checkUndoable, checkUndoable, getTransLevel, isGlobal, isUndoable, markUndoable, popBlock, rollback, setGlobal

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

UNKNOWN

public static final unknown UNKNOWN

Singleton instance (as this is immutable) which can be used in FWD runtime.

Constructor Detail

unknown

public unknown()

Default constructor, creates an instance that represents the unknown value.

Method Detail

instantiateUnknown

public BaseDataType instantiateUnknown()

Creates a new instance of the same type that represents the unknown value.

Specified by:

instantiateUnknown in class BaseDataType

Returns:

An instance that represents the unknown value.

instantiateDefault

public BaseDataType instantiateDefault()

Creates a new instance of the same type that represents the default initialized value.

Specified by:

instantiateDefault in class BaseDataType

Returns:

An instance that represents the default value.

getType

public BaseDataType.Type getType()

Get the type

Specified by:

getType in class BaseDataType

Returns:

type

duplicate

public unknown duplicate()

Does the same as standard clone() method but returns an instance of BaseDataType and doesn't throw the CloneNotSupportedException.

Specified by:

duplicate in class BaseDataType

Returns:

A clone of this instance.

hashCode

public int hashCode()

Hash code implementation which is consistent with BaseDataType.equals(java.lang.Object).

Specified by:

hashCode in class BaseDataType

Returns:

Hash code value for this object instance. All instances of this class return the same hash code value, since all instances are inherently equal.

isUnknown

public boolean isUnknown()

Determines if this instance represents the unknown value (which is always the case).

Specified by:

isUnknown in class BaseDataType

Returns:

Always true.

setUnknown

public void setUnknown()

This instance always represents the unknown value so this method does nothing.

Specified by:

setUnknown in class BaseDataType

assign

public void assign(BaseDataType value)

Sets the state (data and unknown value) of this instance based on the state of the passed instance.

Specified by:

assign in class BaseDataType

Parameters:

value - The instance from which to copy state.

assign

public void assign(Undoable old)

Modify the contained data of the instance to copy the instance data from the given instance. Generally, the class of the given instance must match the class upon which the assign method is called, although this is not a strict requirement.

Parameters:

old - The backup instance from which to copy data.

compareTo

public int compareTo(java.lang.Object obj)

Compares this instance with the specified instance and returns a 0 if the two instances are both unknown and 1 if the passed instance is not unknown. This is the implementation of the Comparable interface, although the contract is not really correct. It is best NOT to use this method (it is required as a concrete subclass of BaseDataType.

Parameters:

obj - The instance to compare against.

Returns:

0 or 1 depending on if the passed instance is or is not unknown.

toString

public java.lang.String toString()

Creates a string representation of the unknown value which is always '?'.

Overrides:

toString in class java.lang.Object

Returns:

The formatted string.

toString

public java.lang.String toString(java.lang.String fmt)

Creates a string representation of the unknown value which is always '?'.

Specified by:

toString in class BaseDataType

Parameters:

fmt - Format string. Ignored at this time.

Returns:

The formatted string.

toStringMessage

public java.lang.String toStringMessage()

Creates a string representation of the instance data in a form that is compatible with the MESSAGE language statement. If the instance represents the unknown value, a '?' will be returned.

Specified by:

toStringMessage in class BaseDataType

Returns:

The 'message' formatted string.

toStringExport

public java.lang.String toStringExport()

Creates a string representation of the unknown value which is always '?'.

Specified by:

toStringExport in class BaseDataType

Returns:

The 'export' formatted string.

defaultFormatString

public java.lang.String defaultFormatString()

Return the default display format string for this type.

Specified by:

defaultFormatString in class BaseDataType

Returns:

The default format string.

readExternal

public void readExternal(java.io.ObjectInput in)
                  throws java.io.IOException,
                         java.lang.ClassNotFoundException

Replacement for the default object reading method. The latest state is read from the input source.

Parameters:

in - The input source from which fields will be restored.

Throws:

java.io.IOException - In case of I/O errors.

java.lang.ClassNotFoundException - If payload can't be instantiated.

writeExternal

public void writeExternal(java.io.ObjectOutput out)
                   throws java.io.IOException

Replacement for the default object writing method. The latest state is written to the output destination.

Parameters:

out - The output destination to which fields will be saved.

Throws:

java.io.IOException - In case of I/O errors.