org.vishia.util

Class ObjectId

java.lang.Object

org.vishia.util.ObjectId

Direct Known Subclasses:

DataShow, TreeNodeHtmlOutput

public class ObjectId
extends java.lang.Object

This class manages identifications of Objects (instances). An object which is created in the heap has not a identification but it has its unique storage address for this session. The storage address is used as Object.hashCode() usual to identify an object. But this identifier is not the same if the same application runs twice on the same or another execution environment because the memory situation is not the same on the running environment (PC, Operation system). Therefore produced data are different because the hash code is different. It is not proper if textual data are evaluated by a text difference tool.

This class helps to get a unique object identification independent of the memory address and independent of the hash code.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	ObjectId.InstancesOfType

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.Map<java.lang.String,ObjectId.InstancesOfType>	allInstances
private java.util.Map<java.lang.Integer,java.lang.String>	allInstancesHash2Id
private java.util.List<java.lang.Object>	allInstancesInOrder
private java.util.Map<java.lang.Integer,java.lang.Object>	allInstancesPerHash
private java.util.Map<java.lang.String,java.lang.Object>	allInstancesPerId
private int	nextTypeId
static java.lang.String	sVersion Version, history and license.

Constructor Summary

Constructors

Constructor and Description
ObjectId()

Method Summary

Modifier and Type	Method and Description
java.util.List<java.lang.Object>	allInstances() Returns a list which contains all instances in order of registration with #instanceId(Object).
java.lang.String	getIdFromHash(int hash) Returns the identification by a given hash for all instances which are already registered with #instanceId(Object).
java.lang.Object	getPerHash(int hash) Returns the object by a given hash for all instances which are already registered with #instanceId(Object).
java.lang.Object	getPerId(java.lang.String id) Returns the Object by a given identification for all instances which are already registered with #instanceId(Object).
java.lang.String	instanceId(java.lang.Object data, java.util.Queue<java.lang.Object> newInstances) Returns a unique identification String for this instance.
java.lang.String	toStringNoHash(java.lang.Object data) This method executes the toString() method for data.

Methods inherited from class java.lang.Object

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

Field Detail

sVersion

public static final java.lang.String sVersion

Version, history and license.

• 2015-08-01 created. Necessary for DataShow.

Copyright/Copyleft: For this source the LGPL Lesser General Public License, published by the Free Software Foundation is valid. It means:

1. You can use this source without any restriction for any desired purpose.
2. You can redistribute copies of this source to everybody.
3. Every user of this source, also the user of redistribute copies with or without payment, must accept this license for further using.
4. But the LPGL is not appropriate for a whole software product, if this source is only a part of them. It means, the user must publish this part of source, but don't need to publish the whole source of the own product.
5. You can study and modify (improve) this source for own using or for redistribution, but you have to license the modified sources likewise under this LGPL Lesser General Public License. You mustn't delete this Copyright/Copyleft inscription in this source file.

If you are intent to use this sources without publishing its usage, you can get a second license subscribing a special contract with the author.

See Also:

Constant Field Values

nextTypeId

private int nextTypeId

allInstances

private java.util.Map<java.lang.String,ObjectId.InstancesOfType> allInstances

allInstancesHash2Id

private java.util.Map<java.lang.Integer,java.lang.String> allInstancesHash2Id

allInstancesPerId

private final java.util.Map<java.lang.String,java.lang.Object> allInstancesPerId

allInstancesPerHash

private final java.util.Map<java.lang.Integer,java.lang.Object> allInstancesPerHash

allInstancesInOrder

private final java.util.List<java.lang.Object> allInstancesInOrder

Constructor Detail

ObjectId

public ObjectId()

Method Detail

instanceId

public java.lang.String instanceId(java.lang.Object data,
                                   java.util.Queue<java.lang.Object> newInstances)

Returns a unique identification String for this instance. The identification string is unique for a run session which uses this instance and method to get it. The identification string is the same if this method was invoked in different sessions but with the same order of instances, especially if an application with the same data runs twice. This is important for compare-ability.

Parameters:

data - The instance

Returns:

identification String for this instance.

getPerId

public java.lang.Object getPerId(java.lang.String id)

Returns the Object by a given identification for all instances which are already registered with #instanceId(Object). It returns null if the identification is unknown here.

Parameters:

id - given identification

Returns:

the object if #instanceId(Object) was called for this object before, elsewhere null.

getPerHash

public java.lang.Object getPerHash(int hash)

Returns the object by a given hash for all instances which are already registered with #instanceId(Object). It returns null if the hash is unknown here.

Parameters:

hash - given hashCode from an Object

Returns:

the object if #instanceId(Object) was called for this object before, elsewhere null.

getIdFromHash

public java.lang.String getIdFromHash(int hash)

Returns the identification by a given hash for all instances which are already registered with #instanceId(Object). It returns null if the hash is unknown here.

Parameters:

hash - given hashCode from an Object

Returns:

the object identification if #instanceId(Object) was called for this object before, elsewhere null.

allInstances

public java.util.List<java.lang.Object> allInstances()

Returns a list which contains all instances in order of registration with #instanceId(Object). The list should not be modified for further usage.

Returns:

List of all instances.

toStringNoHash

public java.lang.String toStringNoHash(java.lang.Object data)

This method executes the toString() method for data. The Object.toString() produces an output which ends with "@hash". If this pattern was found and the hash code is found for a registered instance with #instanceId(Object) then the hash code is replaced by the instanceId. Elsewhere the toString() output is not replaced.

Parameters:

data -

Returns: