Package com.sun.jna

Klasse Union

java.lang.Object

com.sun.jna.Structure

com.sun.jna.Union

Bekannte direkte Unterklassen:

Kstat2.Kstat2NV.UNION, LibKstat.KstatNamed.UNION, Ntifs.REPARSE_DATA_BUFFER.REPARSE_UNION, NTSecApi.LSA_FOREST_TRUST_RECORD.UNION, OaIdl.BINDPTR, OaIdl.CURRENCY, OaIdl.DECIMAL._DECIMAL1, OaIdl.DECIMAL._DECIMAL2, OaIdl.ELEMDESC._ELEMDESC, OaIdl.TYPEDESC._TYPEDESC, OaIdl.VARDESC._VARDESC, Perfstat.perfstat_protocol_t.AnonymousUnionPayload, ShTypes.STRRET.UNION, Variant.VARIANT, Variant.VARIANT._VARIANT.__VARIANT, WinBase.SYSTEM_INFO.UNION, Wincon.INPUT_RECORD.Event, WinCrypt.CERT_STRONG_SIGN_PARA.DUMMYUNION, Winevt.EVT_VARIANT.field1_union, Wininet.INTERNET_CACHE_ENTRY_INFO.UNION, WinNT.LARGE_INTEGER.UNION, WinNT.SYSTEM_LOGICAL_PROCESSOR_INFORMATION.AnonymousUnionPayload, WinRas.RASTUNNELENDPOINT.UNION, Winspool.NOTIFY_DATA, WinUser.INPUT.INPUT_UNION, X11.XClientMessageEvent.Data, X11.XEvent

public abstract class Union
extends Structure

Represents a native union. When writing to native memory, the field corresponding to the type passed to setType(java.lang.Class<?>) will be written to native memory. Upon reading from native memory, Structure, String, or WString fields will not be initialized unless they are the current field as identified by a call to setType(java.lang.Class<?>). The current field is always unset by default to avoid accidentally attempting to read a field that is not valid. In the case of a String, for instance, an invalid pointer may result in a memory fault when attempting to initialize the String.

Verschachtelte Klassen - Übersicht

Von Klasse geerbte verschachtelte Klassen/Schnittstellen com.sun.jna.Structure

Structure.ByReference, Structure.ByValue, Structure.FFIType, Structure.FieldOrder, Structure.StructField, Structure.StructureSet

Feldübersicht

Von Klasse geerbte Felder com.sun.jna.Structure

ALIGN_DEFAULT, ALIGN_GNUC, ALIGN_MSVC, ALIGN_NONE, CALCULATE_SIZE, fieldList, fieldListLock, fieldOrder, fieldOrderLock, layoutInfo, layoutInfoLock, validationLock, validationMap

Konstruktorübersicht

Konstruktoren

Modifizierer	Konstruktor	Beschreibung
protected	Union()	Create a Union whose size and alignment will be calculated automatically.
protected	Union(Pointer p)	Create a Union of the given size, using default alignment.
protected	Union(Pointer p, int alignType)	Create a Union of the given size and alignment type.
protected	Union(Pointer p, int alignType, TypeMapper mapper)	Create a Union of the given size and alignment type.
protected	Union(TypeMapper mapper)	Create a Union of the given size and alignment type.

Methodenübersicht

Modifizierer und Typ	Methode	Beschreibung
protected List<String>	getFieldOrder()	Unions do not need a field order, so automatically provide a value to satisfy checking in the Structure superclass.
protected int	getNativeAlignment(Class<?> type, Object value, boolean isFirstElement)	All fields are considered the "first" element.
Object	getTypedValue(Class<?> type)	Reads the Structure field of the given type from memory, sets it as the active type and returns it.
protected Object	readField(Structure.StructField field)	Avoid reading pointer-based fields and structures unless explicitly selected.
Object	readField(String fieldName)	Force a read of the given field from native memory.
void	setType(Class<?> type)	Indicates by type which field will be used to write to native memory.
void	setType(String fieldName)	Indicates which field will be used to write to native memory.
Object	setTypedValue(Object object)	Set the active type and its value.
protected void	writeField(Structure.StructField field)	Only the currently selected field will be written.
void	writeField(String fieldName)	Write the given field value to native memory.
void	writeField(String fieldName, Object value)	Write the given field value to the field and native memory.

Von Klasse geerbte Methoden com.sun.jna.Structure

allocateMemory, allocateMemory, autoAllocate, autoRead, autoRead, autoWrite, autoWrite, busy, cacheTypeInfo, calculateSize, calculateSize, clear, conditionalAutoRead, createFieldsOrder, createFieldsOrder, createFieldsOrder, createFieldsOrder, dataEquals, dataEquals, ensureAllocated, equals, fieldOffset, fields, getAutoRead, getAutoWrite, getFieldList, getFields, getFieldTypeInfo, getFieldValue, getNativeSize, getNativeSize, getPointer, getStringEncoding, getStructAlignment, getTypeInfo, getTypeInfo, getTypeMapper, hashCode, newInstance, newInstance, read, reading, setAlignType, setAutoRead, setAutoSynch, setAutoWrite, setFieldValue, setStringEncoding, size, size, size, sortFields, toArray, toArray, toString, toString, updateStructureByReference, useMemory, useMemory, useMemory, validate, write

Von Klasse geerbte Methoden java.lang.Object

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

Konstruktordetails

Union

protected Union()

Create a Union whose size and alignment will be calculated automatically.

Union

protected Union(Pointer p)

Create a Union of the given size, using default alignment.

Union

protected Union(Pointer p,
 int alignType)

Create a Union of the given size and alignment type.

Union

protected Union(TypeMapper mapper)

Create a Union of the given size and alignment type.

Union

protected Union(Pointer p,
 int alignType,
 TypeMapper mapper)

Create a Union of the given size and alignment type.

Methodendetails

getFieldOrder

protected List<String> getFieldOrder()

Unions do not need a field order, so automatically provide a value to satisfy checking in the Structure superclass.

Setzt außer Kraft:

getFieldOrder in Klasse Structure

Gibt zurück:

ordered list of field names

setType

public void setType(Class<?> type)

Indicates by type which field will be used to write to native memory. If there are multiple fields of the same type, use setType(String) instead with the field name.

Parameter:

type - desired active type for the union

Löst aus:

IllegalArgumentException - if the type does not correspond to any declared union field.

setType

public void setType(String fieldName)

Indicates which field will be used to write to native memory.

Parameter:

fieldName - desired field to use for the active union type

Löst aus:

IllegalArgumentException - if the name does not correspond to any declared union field.

readField

public Object readField(String fieldName)

Force a read of the given field from native memory.

Setzt außer Kraft:

readField in Klasse Structure

Parameter:

fieldName - field to be read

Gibt zurück:

the new field value, after updating

Löst aus:

IllegalArgumentException - if no field exists with the given name

writeField

public void writeField(String fieldName)

Write the given field value to native memory. The given field will become the active one.

Setzt außer Kraft:

writeField in Klasse Structure

Parameter:

fieldName - which field to synch

Löst aus:

IllegalArgumentException - if no field exists with the given name

writeField

public void writeField(String fieldName,
 Object value)

Write the given field value to the field and native memory. The given field will become the active one.

Setzt außer Kraft:

writeField in Klasse Structure

Parameter:

fieldName - field to write

value - value to write

Löst aus:

IllegalArgumentException - if no field exists with the given name

getTypedValue

public Object getTypedValue(Class<?> type)

Reads the Structure field of the given type from memory, sets it as the active type and returns it. Convenience method for

 Union u;
 Class type;
 u.setType(type);
 u.read();
 value = u.field;
 

Parameter:

type - class type of the Structure field to read

Gibt zurück:

the Structure field with the given type

setTypedValue

public Object setTypedValue(Object object)

Set the active type and its value. Convenience method for

 Union u;
 Class type;
 u.setType(type);
 u.field = value;
 

Parameter:

object - instance of a class which is part of the union

Gibt zurück:

this Union object

writeField

protected void writeField(Structure.StructField field)

Only the currently selected field will be written.

Setzt außer Kraft:

writeField in Klasse Structure

Parameter:

field - internal field representation to synch to native memory

readField

protected Object readField(Structure.StructField field)

Avoid reading pointer-based fields and structures unless explicitly selected. Structures may contain pointer-based fields which can crash the VM if not properly initialized.

Setzt außer Kraft:

readField in Klasse Structure

Parameter:

field - field to be read

Gibt zurück:

value of the requested field

getNativeAlignment

protected int getNativeAlignment(Class<?> type,
 Object value,
 boolean isFirstElement)

All fields are considered the "first" element.

Setzt außer Kraft:

getNativeAlignment in Klasse Structure

Parameter:

type - field type

value - field value, if available

isFirstElement - is this field the first element in the struct?

Gibt zurück:

the native byte alignment