org.eclipse.ui
Interface IMemento
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All Known Implementing Classes:
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XMLMemento
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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:
- Certain objects need to be saved and restored across platform sessions.
- 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.
- 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. However, the
value of TAG_ID is reserved for internal use.
This interface is not intended to be implemented or extended by clients.
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See Also:
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IPersistableElement,
IElementFactory
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Restriction:
- This interface is not intended to be implemented by clients.
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Field Summary
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static
String
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TAG_ID
Special reserved key used to store the memento id
(value "IMemento.internal.id"). |
TAG_ID
static final
String TAG_ID
- Special reserved key used to store the memento id
(value
"IMemento.internal.id").
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See Also:
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getID(),
Constant Field Values
createChild
IMemento createChild(
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.
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Parameters:
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type - the type
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Returns:
- a new child memento
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See Also:
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getChild(java.lang.String),
getChildren(java.lang.String)
createChild
IMemento createChild(
String type,
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.
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Parameters:
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type - the type -
id - the child id
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Returns:
- a new child memento with the given type and id
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See Also:
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getID()
getChild
IMemento getChild(
String type)
- Returns the first child with the given type id.
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Parameters:
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type - the type id
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Returns:
- the first child with the given type
getChildren
IMemento[] getChildren(
String type)
- Returns all children with the given type id.
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Parameters:
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type - the type id
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Returns:
- an array of children with the given type
getFloat
Float getFloat(
String key)
- Returns the floating point value of the given key.
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Parameters:
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key - the key
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Returns:
- the value, or
null if the key was not found or was found
but was not a floating point number
getType
String getType()
- Returns the type for this memento.
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Returns:
- the memento type
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Since:
- 3.4
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See Also:
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createChild(java.lang.String),
createChild(java.lang.String,java.lang.String)
getID
String getID()
- Returns the id for this memento.
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Returns:
- the memento id, or
null if none -
See Also:
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createChild(java.lang.String,java.lang.String)
getInteger
Integer getInteger(
String key)
- Returns the integer value of the given key.
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Parameters:
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key - the key
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Returns:
- the value, or
null if the key was not found or was found
but was not an integer
getString
String getString(
String key)
- Returns the string value of the given key.
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Parameters:
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key - the key
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Returns:
- the value, or
null if the key was not found
getBoolean
Boolean getBoolean(
String key)
- Returns the boolean value of the given key.
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Parameters:
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key - the key
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Returns:
- the value, or
null if the key was not found -
Since:
- 3.4
getTextData
String getTextData()
- Returns the data of the Text node of the memento. Each memento is allowed
only one Text node.
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Returns:
- the data of the Text node of the memento, or
null
if the memento has no Text node. -
Since:
- 2.0
getAttributeKeys
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.
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Returns:
- an array with all the attribute keys of the memento
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Since:
- 3.4
putFloat
void putFloat(
String key,
float value)
- Sets the value of the given key to the given floating point number.
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Parameters:
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key - the key -
value - the value
putInteger
void putInteger(
String key,
int value)
- Sets the value of the given key to the given integer.
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Parameters:
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key - the key -
value - the value
putMemento
void putMemento(
IMemento memento)
- Copy the attributes and children from
memento
to the receiver.
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Parameters:
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memento - the IMemento to be copied.
putString
void putString(
String key,
String value)
- Sets the value of the given key to the given string.
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Parameters:
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key - the key -
value - the value
putBoolean
void putBoolean(
String key,
boolean value)
- Sets the value of the given key to the given boolean value.
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Parameters:
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key - the key -
value - the value -
Since:
- 3.4
putTextData
void putTextData(
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.
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Parameters:
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data - the data to be placed on the Text node -
Since:
- 2.0
Guidelines for using Eclipse APIs.
Copyright (c) Eclipse contributors and others 2000, 2008. All rights reserved.
