Field (MMBase 1.9-SNAPSHOT

All Superinterfaces:

Comparable<Field>, Descriptor

All Known Implementing Classes:

AbstractField, BasicField, CoreField, DataTypeField, FieldDefs, FieldWrapper, MockField, MockNodeManager.SystemField, RemoteField_Proxy, VirtualNodeManager.VirtualNodeManagerField
```
public interface Field
extends Descriptor, Comparable<Field>
```
This interface represents a node's field type information object.

Version:

$Id$

Author:

Pierre van Rooden, Jaco de Groot

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`STATE_PERSISTENT` A field's state is 'persistent' if it is persistent in storage, and editable.
`static int`	`STATE_SYSTEM` A field's state is 'system' if it is persistent in storage, but not editable by users.
`static int`	`STATE_SYSTEM_VIRTUAL` A field's state is 'system virtual' if it is not persistent in storage, nor editable by users.
`static int`	`STATE_UNKNOWN` The field's state when it is not (yet) known.
`static int`	`STATE_VIRTUAL` A field's state is 'virtual' if it is not persistent in storage.
`static int`	`TYPE_BINARY` MMBase base type identifier for the binary (byte[]) data type
`static int`	`TYPE_BOOLEAN` MMBase base type identifier for the Boolean data type
`static int`	`TYPE_BYTE` Deprecated. use `TYPE_BINARY`
`static int`	`TYPE_DATETIME` MMBase base type identifier for the Date data type
`static int`	`TYPE_DECIMAL`
`static int`	`TYPE_DOUBLE` MMBase base type identifier for the Double data type
`static int`	`TYPE_FLOAT` MMBase base type identifier for the Float data type
`static int`	`TYPE_INTEGER` MMBase base type identifier for the Integer data type
`static int`	`TYPE_LIST` MMBase base type identifier for the List data type
`static int`	`TYPE_LONG` MMBase base type identifier for the Long data type
`static int`	`TYPE_NODE` MMBase base type identifier for the Node data type
`static int`	`TYPE_STRING` MMBase base type identifier for the String data type
`static int`	`TYPE_UNKNOWN` MMBase base type identifier for data types whose type is unknown
`static int`	`TYPE_XML` MMBase base type identifier for the DOM Document data type

Method Summary

All Methods Instance Methods Abstract Methods Deprecated Methods
Modifier and Type	Method and Description
`DataType`	`getDataType()` Returns the data type this field contains.
`int`	`getEditPosition()` Retrieve the position of the field when editing.
`String`	`getGUIType()` Deprecated. use `getDataType()` and `Descriptor.getName()`
`int`	`getListItemType()` If the type of this field is TYPE_LIST, this method returns the MMBase base type for the list elements.
`int`	`getListPosition()` Retrieve the position of the field when listing.
`int`	`getMaxLength()` Returns the maximum length of data this field can contain.
`NodeManager`	`getNodeManager()` Returns the node manager this field belongs to.
`int`	`getSearchPosition()` Retrieve the position of the field when searching.
`int`	`getState()` Returns this field's state identifier (virtual, persistent, system, systemvirtual).
`int`	`getStoragePosition()` Retrieve the position of the field in the database table.
`int`	`getType()` Returns the identifier for the MMBase base type for this field.
`boolean`	`hasIndex()` Returns whether this field is a key field, meaning that the storage layer should define an index for it, allowing optimization with search and sort actions.
`boolean`	`isReadOnly()` Returns whether a field is 'read only' - that is, a user cannot edit it.
`boolean`	`isRequired()` Returns whether this field is required (should have content).
`boolean`	`isUnique()` Returns whether this field is part of a unique key (a set of fields whose combined content should occur only once).
`boolean`	`isVirtual()` A field's state is 'virtual' if it is not persistent in storage.
`Collection<String>`	`validate(Object value)` Checks whether a given value is valid for this field.

Methods inherited from interface org.mmbase.bridge.Descriptor
getDescription, getDescription, getGUIName, getGUIName, getLocalizedDescription, getLocalizedGUIName, getName, setDescription, setDescription, setGUIName, setGUIName

Methods inherited from interface java.lang.Comparable
compareTo

- Field Detail
  - TYPE_STRING
```
static final int TYPE_STRING
```
    MMBase base type identifier for the String data type
    
    See Also:
    
    Constant Field Values
  - TYPE_INTEGER
```
static final int TYPE_INTEGER
```
    MMBase base type identifier for the Integer data type
    
    See Also:
    
    Constant Field Values
  - TYPE_BINARY
```
static final int TYPE_BINARY
```
    MMBase base type identifier for the binary (byte[]) data type
    
    See Also:
    
    Constant Field Values
  - TYPE_BYTE
```
@Deprecated
static final int TYPE_BYTE
```
    Deprecated. use TYPE_BINARY
    
    MMBase base type identifier for the binary (byte[]) data type
    
    See Also:
    
    Constant Field Values
  - TYPE_FLOAT
```
static final int TYPE_FLOAT
```
    MMBase base type identifier for the Float data type
    
    See Also:
    
    Constant Field Values
  - TYPE_DOUBLE
```
static final int TYPE_DOUBLE
```
    MMBase base type identifier for the Double data type
    
    See Also:
    
    Constant Field Values
  - TYPE_LONG
```
static final int TYPE_LONG
```
    MMBase base type identifier for the Long data type
    
    See Also:
    
    Constant Field Values
  - TYPE_XML
```
static final int TYPE_XML
```
    MMBase base type identifier for the DOM Document data type
    
    See Also:
    
    Constant Field Values
  - TYPE_NODE
```
static final int TYPE_NODE
```
    MMBase base type identifier for the Node data type
    
    See Also:
    
    Constant Field Values
  - TYPE_DATETIME
```
static final int TYPE_DATETIME
```
    MMBase base type identifier for the Date data type
    
    Since:
    
    MMBase-1.8
    
    See Also:
    
    Constant Field Values
  - TYPE_BOOLEAN
```
static final int TYPE_BOOLEAN
```
    MMBase base type identifier for the Boolean data type
    
    Since:
    
    MMBase-1.8
    
    See Also:
    
    Constant Field Values
  - TYPE_LIST
```
static final int TYPE_LIST
```
    MMBase base type identifier for the List data type
    
    Since:
    
    MMBase-1.8
    
    See Also:
    
    Constant Field Values
  - TYPE_DECIMAL
```
static final int TYPE_DECIMAL
```
    Since:
    
    MMBase-1.9.1
    
    See Also:
    
    Constant Field Values
  - TYPE_UNKNOWN
```
static final int TYPE_UNKNOWN
```
    MMBase base type identifier for data types whose type is unknown
    
    See Also:
    
    Constant Field Values
  - STATE_VIRTUAL
```
static final int STATE_VIRTUAL
```
    A field's state is 'virtual' if it is not persistent in storage.
    
    See Also:
    
    Constant Field Values
  - STATE_PERSISTENT
```
static final int STATE_PERSISTENT
```
    A field's state is 'persistent' if it is persistent in storage, and editable.
    
    See Also:
    
    Constant Field Values
  - STATE_SYSTEM
```
static final int STATE_SYSTEM
```
    A field's state is 'system' if it is persistent in storage, but not editable by users.
    
    See Also:
    
    Constant Field Values
  - STATE_SYSTEM_VIRTUAL
```
static final int STATE_SYSTEM_VIRTUAL
```
    A field's state is 'system virtual' if it is not persistent in storage, nor editable by users.
    
    See Also:
    
    Constant Field Values
    
    To Do:
    
    reserved but not used yet
  - STATE_UNKNOWN
```
static final int STATE_UNKNOWN
```
    The field's state when it is not (yet) known.
    
    See Also:
    
    Constant Field Values
- Method Detail
  - getNodeManager
```
NodeManager getNodeManager()
```
    Returns the node manager this field belongs to.
    
    Returns:
    
    the node manager this field belongs to
  - getState
```
int getState()
```
    Returns this field's state identifier (virtual, persistent, system, systemvirtual).
    
    Returns:
    
    an int which identifies the state of this field
  - getDataType
```
DataType getDataType()
```
    Returns the data type this field contains.
    
    Returns:
    
    a DataType object describing the constraints on this field.
    
    Since:
    
    MMBase-1.8
  - isUnique
```
boolean isUnique()
```
    Returns whether this field is part of a unique key (a set of fields whose combined content should occur only once). Note that MMBase lets the storage layer handle this. If your storage implementation or configuration does not support this the uniqueness may not be enforced.
    
    Returns:
    
    true if the field is part of a unique key
    
    Since:
    
    MMBase-1.6
  - hasIndex
```
boolean hasIndex()
```
    Returns whether this field is a key field, meaning that the storage layer should define an index for it, allowing optimization with search and sort actions. Note that MMBase lets the storage layer decide whether an index is actually defined. Some implementations or configurations may not do this. Note: Currently, this method only returns true if the field is the primary key (number field) or a Node field.
    
    Returns:
    
    true if the field has a key defined
    
    Since:
    
    MMBase-1.7
  - getType
```
int getType()
```
    Returns the identifier for the MMBase base type for this field. This represents one of field type constants. This basic type determines how data is stored in MMBase. Note that it is possible that the datatype for a field (used for validation and in/out put) can be of a different basic type than how it is stored in the database. This shoudl not occur often, but is possible in some cases, such as when you use older clod models (which used INTEGER fields for dates). In general this should not prove a [problem - however you shoudl not assumeto know the classtype iof data of a field based on this method. To acquire the datatype's type, use getDataType.getBaseType() instead.
    
    Returns:
    
    an int which identifies the base type
  - getListItemType
```
int getListItemType()
```
    If the type of this field is TYPE_LIST, this method returns the MMBase base type for the list elements. This represents one of field type constants. This basic type determines how data is stored in MMBase. For any field types other that TYPE_LIST, this method returns TYPE_UNKNOWN.
    
    Returns:
    
    an int which identifies the base type
  - getSearchPosition
```
int getSearchPosition()
```
    Retrieve the position of the field when searching. A value of -1 indicates the field is unavailable during search.
    
    Returns:
    
    position of the field when searching
    
    Since:
    
    MMBase-1.8
  - getListPosition
```
int getListPosition()
```
    Retrieve the position of the field when listing. A value of -1 indicates the field is unavailable in a list.
    
    Returns:
    
    position of the field when listing
    
    Since:
    
    MMBase-1.8
  - getEditPosition
```
int getEditPosition()
```
    Retrieve the position of the field when editing. A value of -1 indicates the field cannot be edited.
    
    Returns:
    
    position of the field when editing
    
    Since:
    
    MMBase-1.8
  - getStoragePosition
```
int getStoragePosition()
```
    Retrieve the position of the field in the database table.
    
    Returns:
    
    position in the database table
    
    Since:
    
    MMBase-1.8
  - getGUIType
```
@Deprecated
String getGUIType()
```
    Deprecated. use getDataType() and Descriptor.getName()
    
    Returns the GUI name for the data type this field contains.
    
    Returns:
    
    the GUI name
    
    See Also:
    
    getDataType()
  - isRequired
```
boolean isRequired()
```
    Returns whether this field is required (should have content). Note that MMBase does not generally enforce required fields to be filled - If not provided, a default value (generally an empty string or the integer value -1) is filled in by the system. As such, isRequired will mostly be used as an indicator for (generic) editors.
    
    Returns:
    
    true if the field is required
    
    Since:
    
    MMBase-1.6
  - getMaxLength
```
int getMaxLength()
```
    Returns the maximum length of data this field can contain. For example if a field contains characters the size indicates the maximum number of characters it can contain. If the field is a numeric field (such as an integer), the result is -1. For a 'decimal' type though, this returns the same as the precision of the associated datatype.
    
    Returns:
    
    the maximum length of data this field can contain
  - validate
```
Collection<String> validate(Object value)
```
    Checks whether a given value is valid for this field.
    
    Parameters:
    
    value - value to validate
    
    Returns:
    
    Collection of error-strings (describing the problem) in the current locale, or an empty collection if the value is ok.
    
    Since:
    
    MMBase-1.8
  - isVirtual
```
boolean isVirtual()
```
    A field's state is 'virtual' if it is not persistent in storage.
    
    Returns:
    
    true when a field is virtual
    
    Since:
    
    MMBase-1.8
  - isReadOnly
```
boolean isReadOnly()
```
    Returns whether a field is 'read only' - that is, a user cannot edit it. In general, fields with state SYSTEM or SYSTEM_VIRTUAL are defined as read only, while others are not. It is possible to override this behaviour per field.
    
    Returns:
    
    true when a field is read only
    
    Since:
    
    MMBase-1.8

Interface Field

Field Summary

Method Summary

Methods inherited from interface org.mmbase.bridge.Descriptor

Methods inherited from interface java.lang.Comparable

Field Detail

TYPE_STRING

TYPE_INTEGER

TYPE_BINARY

TYPE_BYTE

TYPE_FLOAT

TYPE_DOUBLE

TYPE_LONG

TYPE_XML

TYPE_NODE

TYPE_DATETIME

TYPE_BOOLEAN

TYPE_LIST

TYPE_DECIMAL

TYPE_UNKNOWN

STATE_VIRTUAL

STATE_PERSISTENT

STATE_SYSTEM

STATE_SYSTEM_VIRTUAL

STATE_UNKNOWN

Method Detail

getNodeManager

getState

getDataType

isUnique

hasIndex

getType

getListItemType

getSearchPosition

getListPosition

getEditPosition

getStoragePosition

getGUIType

isRequired

getMaxLength

validate

isVirtual

isReadOnly