IMemento (Eclipse Platform API Specification)

All Known Implementing Classes:

XMLMemento
```
public interface IMemento
```
Interface to a memento used for saving the important state of an object in a form that can be persisted in the file system.
Mementos were designed with the following requirements in mind:
1. Certain objects need to be saved and restored across platform sessions.
2. When an object is restored, an appropriate class for an object might not be available. It must be possible to skip an object in this case.
3. When an object is restored, the appropriate class for the object may be different from the one when the object was originally saved. If so, the new class should still be able to read the old form of the data.
Mementos meet these requirements by providing support for storing a mapping of arbitrary string keys to primitive values, and by allowing mementos to have other mementos as children (arranged into a tree). A robust external storage format based on XML is used.

The key for an attribute may be any alpha numeric value that doesn't start with a number. eg: [A-Za-z][A-Za-z0-9]* Using '.' is unsupported. However, the value of TAG_ID is reserved for internal use.

The default implementation can throw a DOMException for createChild and put operations. See XMLMemento.

This interface is not intended to be implemented or extended by clients.
See Also:

IPersistableElement, IElementFactory, XMLMemento

Restriction:

This interface is not intended to be implemented by clients.

Field Summary

Fields
Modifier and Type Field and Description

static java.lang.String TAG_ID
Special reserved key used to store the memento id (value "IMemento.internal.id").

Fields
Modifier and Type	Field and Description
`static java.lang.String`	`TAG_ID` Special reserved key used to store the memento id (value `"IMemento.internal.id"`).

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`IMemento`	`createChild(java.lang.String type)` Creates a new child of this memento with the given type.
`IMemento`	`createChild(java.lang.String type, java.lang.String id)` Creates a new child of this memento with the given type and id.
`java.lang.String[]`	`getAttributeKeys()` Returns an array of all the attribute keys of the memento.
`java.lang.Boolean`	`getBoolean(java.lang.String key)` Returns the boolean value of the given key.
`IMemento`	`getChild(java.lang.String type)` Returns the first child with the given type id.
`IMemento[]`	`getChildren()` Returns all children of this node.
`IMemento[]`	`getChildren(java.lang.String type)` Returns all children with the given type id.
`java.lang.Float`	`getFloat(java.lang.String key)` Returns the floating point value of the given key.
`java.lang.String`	`getID()` Returns the id for this memento.
`java.lang.Integer`	`getInteger(java.lang.String key)` Returns the integer value of the given key.
`java.lang.String`	`getString(java.lang.String key)` Returns the string value of the given key.
`java.lang.String`	`getTextData()` Returns the data of the Text node of the memento.
`java.lang.String`	`getType()` Returns the type for this memento.
`void`	`putBoolean(java.lang.String key, boolean value)` Sets the value of the given key to the given boolean value.
`void`	`putFloat(java.lang.String key, float value)` Sets the value of the given key to the given floating point number.
`void`	`putInteger(java.lang.String key, int value)` Sets the value of the given key to the given integer.
`void`	`putMemento(IMemento memento)` Copy the attributes and children from `memento` to the receiver.
`void`	`putString(java.lang.String key, java.lang.String value)` Sets the value of the given key to the given string.
`void`	`putTextData(java.lang.String data)` Sets the memento's Text node to contain the given data.

- Field Detail
  - TAG_ID
```
static final java.lang.String TAG_ID
```
    Special reserved key used to store the memento id (value "IMemento.internal.id").
    
    See Also:
    
    getID(), Constant Field Values
- Method Detail
  - createChild
```
IMemento createChild(java.lang.String type)
```
    Creates a new child of this memento with the given type.
    The getChild and getChildren methods are used to retrieve children of a given type.
    
    Parameters:
    
    type - the type
    
    Returns:
    
    a new child memento
    
    See Also:
    
    getChild(java.lang.String), getChildren()
  - createChild
```
IMemento createChild(java.lang.String type,
                     java.lang.String id)
```
    Creates a new child of this memento with the given type and id. The id is stored in the child memento (using a special reserved key, TAG_ID) and can be retrieved using getId.
    The getChild and getChildren methods are used to retrieve children of a given type.
    
    Parameters:
    
    type - the type
    
    id - the child id
    
    Returns:
    
    a new child memento with the given type and id
    
    See Also:
    
    getID()
  - getChild
```
IMemento getChild(java.lang.String type)
```
    Returns the first child with the given type id.
    
    Parameters:
    
    type - the type id
    
    Returns:
    
    the first child with the given type. May return null .
  - getChildren
```
IMemento[] getChildren()
```
    Returns all children of this node.
    
    Returns:
    
    an array of children of this node. This will not be null. If there are no children, an array of length zero will be returned.
    
    Since:
    
    3.8
  - getChildren
```
IMemento[] getChildren(java.lang.String type)
```
    Returns all children with the given type id.
    
    Parameters:
    
    type - the type id
    
    Returns:
    
    an array of children with the given type. This will not be null. If there are no keys, an array of length zero will be returned.
  - getFloat
```
java.lang.Float getFloat(java.lang.String key)
```
    Returns the floating point value of the given key.
    
    Parameters:
    
    key - the key
    
    Returns:
    
    the value, or null if the key was not found or was found but was not a floating point number
  - getType
```
java.lang.String getType()
```
    Returns the type for this memento.
    
    Returns:
    
    the memento type
    
    Since:
    
    3.4
    
    See Also:
    
    createChild(java.lang.String), createChild(java.lang.String,java.lang.String)
  - getID
```
java.lang.String getID()
```
    Returns the id for this memento.
    
    Returns:
    
    the memento id, or null if none
    
    See Also:
    
    createChild(java.lang.String,java.lang.String)
  - getInteger
```
java.lang.Integer getInteger(java.lang.String key)
```
    Returns the integer value of the given key.
    
    Parameters:
    
    key - the key
    
    Returns:
    
    the value, or null if the key was not found or was found but was not an integer
  - getString
```
java.lang.String getString(java.lang.String key)
```
    Returns the string value of the given key.
    
    Parameters:
    
    key - the key
    
    Returns:
    
    the value, or null if the key was not found
  - getBoolean
```
java.lang.Boolean getBoolean(java.lang.String key)
```
    Returns the boolean value of the given key.
    
    Parameters:
    
    key - the key
    
    Returns:
    
    the value, or null if the key was not found
    
    Since:
    
    3.4
  - getTextData
```
java.lang.String getTextData()
```
    Returns the data of the Text node of the memento. Each memento is allowed only one Text node.
    
    Returns:
    
    the data of the Text node of the memento, or null if the memento has no Text node.
    
    Since:
    
    2.0
  - getAttributeKeys
```
java.lang.String[] getAttributeKeys()
```
    Returns an array of all the attribute keys of the memento. This will not be null. If there are no keys, an array of length zero will be returned.
    
    Returns:
    
    an array with all the attribute keys of the memento
    
    Since:
    
    3.4
  - putFloat
```
void putFloat(java.lang.String key,
              float value)
```
    Sets the value of the given key to the given floating point number.
    
    Parameters:
    
    key - the key
    
    value - the value
  - putInteger
```
void putInteger(java.lang.String key,
                int value)
```
    Sets the value of the given key to the given integer.
    
    Parameters:
    
    key - the key
    
    value - the value
  - putMemento
```
void putMemento(IMemento memento)
```
    Copy the attributes and children from memento to the receiver.
    
    Parameters:
    
    memento - the IMemento to be copied.
  - putString
```
void putString(java.lang.String key,
               java.lang.String value)
```
    Sets the value of the given key to the given string.
    
    Parameters:
    
    key - the key
    
    value - the value
  - putBoolean
```
void putBoolean(java.lang.String key,
                boolean value)
```
    Sets the value of the given key to the given boolean value.
    
    Parameters:
    
    key - the key
    
    value - the value
    
    Since:
    
    3.4
  - putTextData
```
void putTextData(java.lang.String data)
```
    Sets the memento's Text node to contain the given data. Creates the Text node if none exists. If a Text node does exist, it's current contents are replaced. Each memento is allowed only one text node.
    
    Parameters:
    
    data - the data to be placed on the Text node
    
    Since:
    
    2.0

Interface IMemento

Field Summary

Method Summary

Field Detail

TAG_ID

Method Detail

createChild

createChild

getChild

getChildren

getChildren

getFloat

getType

getID

getInteger

getString

getBoolean

getTextData

getAttributeKeys

putFloat

putInteger

putMemento

putString

putBoolean

putTextData