Package org.gnome.glib

Class Relation

java.lang.Object

io.github.jwharm.javagi.base.ProxyInstance

org.gnome.glib.Relation

All Implemented Interfaces:

Proxy

@Generated("io.github.jwharm.JavaGI")
@Deprecated
public class Relation
extends ProxyInstance

Deprecated.

A GRelation is a table of data which can be indexed on any number of fields, rather like simple database tables. A GRelation contains a number of records, called tuples. Each record contains a number of fields. Records are not ordered, so it is not possible to find the record at a particular index.

Note that GRelation tables are currently limited to 2 fields.

To create a GRelation, use new_(int).

To specify which fields should be indexed, use index(int, org.gnome.glib.HashFunc, org.gnome.glib.EqualFunc). Note that this must be called before any tuples are added to the GRelation.

To add records to a GRelation use insert(java.lang.Object...).

To determine if a given record appears in a GRelation, use exists(java.lang.Object...). Note that fields are compared directly, so pointers must point to the exact same position (i.e. different copies of the same string will not match.)

To count the number of records which have a particular value in a given field, use count(java.lang.foreign.MemorySegment, int).

To get all the records which have a particular value in a given field, use select(java.lang.foreign.MemorySegment, int). To access fields of the resulting records, use Tuples.index(int, int). To free the resulting records use Tuples.destroy().

To delete all records which have a particular value in a given field, use delete(java.lang.foreign.MemorySegment, int).

To destroy the GRelation, use destroy().

To help debug GRelation objects, use print().

GRelation has been marked as deprecated, since this API has never been fully implemented, is not very actively maintained and rarely used.

Constructor Summary

Constructors

Constructor	Description
Relation(MemorySegment address)	Deprecated. Create a Relation proxy instance for the provided memory address.

Method Summary

Modifier and Type	Method	Description
int	count(@Nullable MemorySegment key, int field)	Deprecated. Rarely used API
int	delete(@Nullable MemorySegment key, int field)	Deprecated. Rarely used API
void	destroy()	Deprecated. Rarely used API
boolean	exists(Object... varargs)	Deprecated. Rarely used API
void	index(int field, HashFunc hashFunc, EqualFunc keyEqualFunc)	Deprecated. Rarely used API
void	insert(Object... varargs)	Deprecated. Rarely used API
static Relation	new_(int fields)	Deprecated. Rarely used API
void	print()	Deprecated. Rarely used API
Tuples	select(@Nullable MemorySegment key, int field)	Deprecated. Rarely used API

Methods inherited from class io.github.jwharm.javagi.base.ProxyInstance

equals, handle, hashCode

Methods inherited from class java.lang.Object

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

Constructor Details

Relation

public Relation(MemorySegment address)

Deprecated.

Create a Relation proxy instance for the provided memory address.

Parameters:

address - the memory address of the native object

Method Details

new_

@Deprecated
public static Relation new_(int fields)

Deprecated.

Rarely used API

Creates a new GRelation with the given number of fields. Note that currently the number of fields must be 2.

Parameters:

fields - the number of fields.

Returns:

a new GRelation.

count

@Deprecated
public int count(@Nullable
 @Nullable MemorySegment key,
 int field)

Deprecated.

Rarely used API

Returns the number of tuples in a GRelation that have the given value in the given field.

Parameters:

key - the value to compare with.

field - the field of each record to match.

Returns:

the number of matches.

delete

@Deprecated
public int delete(@Nullable
 @Nullable MemorySegment key,
 int field)

Deprecated.

Rarely used API

Deletes any records from a GRelation that have the given key value in the given field.

Parameters:

key - the value to compare with.

field - the field of each record to match.

Returns:

the number of records deleted.

destroy

@Deprecated
public void destroy()

Deprecated.

Rarely used API

Destroys the GRelation, freeing all memory allocated. However, it does not free memory allocated for the tuple data, so you should free that first if appropriate.

exists

@Deprecated
public boolean exists(Object... varargs)

Deprecated.

Rarely used API

Returns true if a record with the given values exists in a GRelation. Note that the values are compared directly, so that, for example, two copies of the same string will not match.

Parameters:

varargs - the fields of the record to compare. The number must match the number of fields in the GRelation.

Returns:

true if a record matches.

index

@Deprecated
public void index(int field,
 HashFunc hashFunc,
 EqualFunc keyEqualFunc)

Deprecated.

Rarely used API

Creates an index on the given field. Note that this must be called before any records are added to the GRelation.

Parameters:

field - the field to index, counting from 0.

hashFunc - a function to produce a hash value from the field data.

keyEqualFunc - a function to compare two values of the given field.

insert

@Deprecated
public void insert(Object... varargs)

Deprecated.

Rarely used API

Inserts a record into a GRelation.

Parameters:

varargs - the fields of the record to add. These must match the number of fields in the GRelation, and of type gpointer or gconstpointer.

print

@Deprecated
public void print()

Deprecated.

Rarely used API

Outputs information about all records in a GRelation, as well as the indexes. It is for debugging.

select

@Deprecated
public Tuples select(@Nullable
 @Nullable MemorySegment key,
 int field)

Deprecated.

Rarely used API

Returns all of the tuples which have the given key in the given field. Use g_tuples_index() to access the returned records. The returned records should be freed with g_tuples_destroy().

Parameters:

key - the value to compare with.

field - the field of each record to match.

Returns:

the records (tuples) that matched.