Union (J2Native API Documentation)

com.smardec

j2native

AnsiString

FunctionExecutionException

FunctionNotFoundException

IllegalMemoryAccessException

LibraryNotFoundException

com.smardec.j2native
Class Union

java.lang.Object
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+--com.smardec.j2native.Argument
|
+--com.smardec.j2native.Union

All Implemented Interfaces:: java.lang.Cloneable

public abstract class Union
extends Argument

The Union class represents a C union type. Function arguments of this type are initialized with several parameters representing the union members. The length of the union is equal to that of its longest member. A union represents only one of its members at a time. Users of this class should define which member the union represents by calling one of the setActiveMember methods.

Field Summary

Fields inherited from class com.smardec.j2native.Argument

JAVA_SIDE, NATIVE_SIDE

Constructor Summary

protected Union()
Preconstructs a union.

protected Union(Argument[] members)
Constructs a union with a given set of members.

Method Summary

void fromBytesValue(byte[] bytes, int offset)
Restores itself from provided array of bytes.

Argument getActiveMember()
Returns currently active member.

int getLength()
Returns length in bytes.

Argument[] getMembers()
Returns union members.

protected void initialize(Argument[] members)
Initialize union and sets union members.

protected boolean isFixedLength()
Identify if Argument is a fixed length variable.

protected void read(long handle, int offset)
Reads itself from the memory.

protected void readFromStack(byte[] stack, int offset)
Read itself from stack.

void setActiveMember(Argument active)
Defines the member of this union that is currently used.

void setActiveMember(Argument active, boolean update)
Defines the member of this union that is currently used.

void setActiveMember(int index)
Selects a new active member of the union by its index in the array passed on the initialization.

void setActiveMember(int index, boolean update)
Selects a new active member of the union by its index in the array passed on the initialization.

byte[] toBytesValue()
Encodes itself and returns it's representation as array of bytes.

protected void toBytesValue(byte[] bytes, int offset)
Encodes itself to the provided array of bytes.

protected void update(byte side)
This method is used to synchronize Java side and native part.

protected void write(long handle, int offset)
Writes itself to the memory.

protected void writeToStack(byte[] stack, int offset)
Writes itself to stack.

Methods inherited from class com.smardec.j2native.Argument

clone, finalize, free, getAlignedLength, getResultFlags, readFromRAM, restoreFromRAM, storeToRAM, writeToRAM

Methods inherited from class java.lang.Object

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

Constructor Detail

Union
protected Union()

Preconstructs a union. Unions constructed with this constructor should be initialized using the initialize() method

Union
protected Union(Argument[] members)

Constructs a union with a given set of members. A constructed union initially has 0-index active member.

Method Detail

initialize
protected void initialize(Argument[] members)

Initialize union and sets union members.

Parameters:: members - union members

getMembers
public Argument[] getMembers()

Returns union members. WARNING: Do not modify contents of the returned array.

setActiveMember
public void setActiveMember(Argument active)

Defines the member of this union that is currently used. This method should be called before a value is assigned to that member.

Parameters:: active - a new active member

setActiveMember
public void setActiveMember(Argument active, boolean update) throws java.lang.IllegalStateException

Defines the member of this union that is currently used. This method should be called before a value is assigned to that member. If the update parameter is true, this member is read from the last value of this union. This is for the case when an active member can be determined only after the function call is completed. If the union contains pointers, it is recommended to set an active member to null before making such calls.

Parameters:: active - a new active member; update - if true, this member is read from the last value of this union
Throws:: java.lang.IllegalStateException - if internal structure is wrong

setActiveMember
public void setActiveMember(int index)

Selects a new active member of the union by its index in the array passed on the initialization.

Parameters:: index - the index of the new active member.

setActiveMember
public void setActiveMember(int index, boolean update)

Selects a new active member of the union by its index in the array passed on the initialization. If the update parameter is true, this member is read from the last value of this union. This is for the case when an active member can be determined only after the function call is completed. If the union contains pointers, it is recommended to set an active member to null before making such calls.

Parameters:: index - the index of the new active member.; update - if true, this member is read from the last value of this union
Throws:: java.lang.IllegalStateException - if internal structure is wrong

getActiveMember
public Argument getActiveMember()

Returns currently active member.