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## edu.uci.ics.jung.utils
Class UserData

    java.lang.Object
      edu.uci.ics.jung.utils.UserData

All Implemented Interfaces:
  Cloneable, UserDataContainer

Direct Known Subclasses:
  DefaultUserData, UnifiedUserData

public abstract class UserData
extends Object
implements UserDataContainer

Represents custom user- and system-level information to extend the definition of a node. This is the easiest way to extend the class without subclassing. This works as a dictionary in order to help ensure that there are possibilities for extending user information to a variety of different sorts of data. (Each provider of information can register their own enhanced information without interfering with other providers.) Some suggested uses of UserData include

Underlying data references, such as pointers to data sources
Raw data which can be analyzed or used by the constraint and filter systems
Temporary enhanced information which can be used for visualization

Consider a series of nodes that has, among other things, enhanced information about 3D coordinates. This might be stored in the 3DData data structure, which generates itself with an input from a node. Thus the relevant call might be `n.setUserInfo ("3DData", new 3DData ( ))`. Later, to access this information, the call might be `3DData dd = (3DData) n.getUserInfo("3DData").`

### Shared and Individual Data

Note that the there are no required semantics for the key or the information. However, it is necessary to specify information that is used for SHARED and for INDIVIDUAL data elements. When a new View of a graph is generated, the Node elements inside it are all shallow-copied. The UserInfo that they use, however, is not copied, by default. This is the correct and logical behavior if the UserInfo contains source information. But what when the UserInfo contains transient information, specific to the view, such as graph metrics or coordinates? In that case, the UserInfo would be quite inappropriate to share that information between copies. The solution to this is to add a third flag, "shared", which tells whether the currect data is shared or not. This flag is assigned when the data is added.

Nested Class Summary

Nested classes inherited from class edu.uci.ics.jung.utils.UserDataContainer
`UserDataContainer.CopyAction`

Field Summary
`static UserDataContainer.CopyAction` | `CLONE` A CopyAction that clones UserData--that is, it uses the Java `clone()`call to clone the object.
`static UserDataContainer.CopyAction` | `REMOVE` Causes the userdata not to be copied over, and instead returns null.
`static UserDataContainer.CopyAction` | `SHARED` A CopyAction that links UserData--that is, points to the original data.

Constructor Summary
`UserData()`

Method Summary
`Object` | `clone()`
`String` | `toString()`

Methods inherited from class java.lang.Object
`equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

Methods inherited from interface edu.uci.ics.jung.utils.UserDataContainer
`addUserDatum, containsUserDatumKey, getUserDatum, getUserDatumCopyAction, getUserDatumKeyIterator, importUserData, removeUserDatum, setUserDatum`

Field Detail

### CLONE

    public static final UserDataContainer.CopyAction CLONE

  A CopyAction that clones UserData--that is, it uses the Java `clone()`call to clone the object. Throws a `CloneNotSupportedException` if clone isn't allowed.

### SHARED

    public static final UserDataContainer.CopyAction SHARED

  A CopyAction that links UserData--that is, points to the original data. At that point, both UserDataContainers will contain references to the same UserData, and, if that data is mutable, will both see changes to it. (In the case of immutable user data, such as Strings, they will disconnect if one or the other attempts to change its value: this is the normal behavior with `String s = "X"; String t = s; s = "Y"; System.out.pritnln( t ); // will still contain X.`

### REMOVE

    public static final UserDataContainer.CopyAction REMOVE

  Causes the userdata not to be copied over, and instead returns null. Useful for temporary userdata that isn't meant to be used.

Constructor Detail

### UserData

    public UserData()

Method Detail

### toString

    public String toString()

  See Also:
    `Object.toString()`

### clone

    public Object clone()
                 throws CloneNotSupportedException

  Specified by:
    `clone` in interface `UserDataContainer`
  Throws:
    `CloneNotSupportedException`

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