tigase.xml.db

## Class XMLDB

- java.lang.Object
- - tigase.xml.db.XMLDB

-     public class XMLDB
      extends Object

  `XMLDB` is the main database access class. It allows you to create new database in given file, open database from given file, add, delete and retrieve data and data lists. All data or data lists are stored in database nodes. There are three possible kinds of nodes for each database:
  1. root node - this is top node in each XML hierachy tree. There can be only one root node in database as there can be only one root element in XML file. The element name for root node can be defined by the user when new database is created or defualt element name '`root`' is used.
  2. node1 nodes - these are the first level nodes under root node. There can be any number of nodes on this level. All data added for this database are added to first level node unless subnode path is given. User can define element name of node1 when new database is created. If not given default element name '`node`' is used.
  3. subnodes - node on any deeper level under node1 level. There can be any number of subnodes on any level. Subnodes have always '`node`' element name and this can't be changed.

  All node1 nodes and subnodes can contains any number of data associated with keys. With some keys there ca be more than one value assigned. Such kind of data are called data lists.
  Although element name for subnode can not be defined it is actually not important. Because user database doesn't use subnode element names. He doesn't even use neiher root node element name nor node1 element name. database user uses node name what is quite different from node element name. Let see example below:

       <node name='roster'/>

  In this example node element name is node and node name is roster.
  database users (actually developers) use only node names.
  If you want to access subnode on some level you need to give full path to this subnode. For example, let's assume we have following database:

       <node name='tigase'>
            <node name='server'></node>
            <node name='xmpp'></node>
       </node>

  If you need to access '`server`' subnode you need to call method with '`/tigase/server`' as subnode path and for subnode '`xmpp`' proper subnode path is of course '`/tigase/xmpp`'. If you skip subnode path or give `null` as a parameter you will be accessing data on node1 level. You can not access or save data on root node level.

  Created: Tue Oct 26 15:27:33 2004

  Author:
    Artur Hefczyc

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `XMLDB(String db_file)` Creates XMLDB object with desired filename, if file modes is enabled then appropriate saver thread is created as well.

  - ### Method Summary

    All Methods Static Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `addNode1(String node1_id)` Adds new node
    `static XMLDB` | `createDB(String db_file, String root_name, String node1_name)` Factory method creating and setting up XMLDB
    `DBElement` | `findNode1(String node1_id)` Return Element corresponding to the node name
    `List<String>` | `getAllNode1s()` Retrieve list of nodes
    `long` | `getAllNode1sCount()` Retrieve number of nodes
    `Object` | `getData(String node1_id, String key)` Retrieve value of given node
    `Object` | `getData(String node1_id, String subnode, String key)` Retrieve value of given node under specific path
    `Object` | `getData(String node1_id, String subnode, String key, Object def)` Retrieve value of given node under specific path
    `double` | `getDataDouble(String node1_id, String subnode, String key, double def)` Retrieve value of given node under specific path
    `double[]` | `getDataDoubleList(String node1_id, String subnode, String key)` Retrieve values of given node under specific path
    `int` | `getDataInt(String node1_id, String subnode, String key, int def)` Retrieve value of given node under specific path
    `int[]` | `getDataIntList(String node1_id, String subnode, String key)` Retrieve values of given node under specific path
    `String[]` | `getDataList(String node1_id, String subnode, String key)` Retrieve values of given node under specific path
    `String` | `getDBFileName()` Retrieves filename
    `String[]` | `getKeys(String node1_id)` Retrieve list of keys under root
    `String[]` | `getKeys(String node1_id, String subnode)` Retrieve list of keys under specific path
    `protected DBElement` | `getNode(String node1_id, String subnode, boolean auto_create)` Retrieves the node of the given name at specific path
    `protected DBElement` | `getNode1(String node1_id)`
    `String[]` | `getSubnodes(String node1_id)` Retrieve list of subnodes under root
    `String[]` | `getSubnodes(String node1_id, String subnode)` Retrieve list of subnodes under specific path
    `protected void` | `loadDB()` Loads XML from file
    `void` | `removeData(String node1_id, String key)` Removes data of specific key from node of given name under root element
    `void` | `removeData(String node1_id, String subnode, String key)` Removes data of specific key from node of given name under given path
    `void` | `removeNode1(String node1_id)` Removes the node
    `void` | `removeSubnode(String node1_id, String subnode)` Removes node of given name under given path
    `protected void` | `saveDB()` Saves XML to file
    `void` | `setData(String node1_id, String key, Object value)` Sets data for the given node at root
    `void` | `setData(String node1_id, String subnode, String key, Object value)` Sets data for the given node at given path
    `protected void` | `setupNewDB(String db_file, String root_name, String node1_name)` Creates basic Elements of the XMLDB
    `void` | `sync()` Performs synchronization with the file
    `String` | `toString()`

    - ### Methods inherited from class java.lang.Object

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

- - ### Constructor Detail

    - #### XMLDB

          public XMLDB(String db_file)
                throws IOException,
                       XMLDBException

      Creates XMLDB object with desired filename, if file modes is enabled then appropriate saver thread is created as well. For filenames starting with "memory://" memory mode (i.e. without writing to disk) is enabled
      Parameters:
        `db_file` - indicates path to the file on disk to/from which write/read; if parameter starts with "memory://" then memory mode (without actual file usage) is enabled
      Throws:
        `IOException` - when the file doesn't exist
        `XMLDBException` - when there is a problem with XML DB

  - ### Method Detail

    - #### createDB

          public static XMLDB createDB(String db_file,
                                       String root_name,
                                       String node1_name)

      Factory method creating and setting up XMLDB
      Parameters:
        `db_file` - indicates path to the file on disk to/from which write/read; if parameter starts with "memory://" then memory mode (without actual file usage) is enabled
        `root_name` - name of the root element
        `node1_name` - name of the node
      Returns:
        XMLDB object

    - #### getDBFileName

          public String getDBFileName()

      Retrieves filename
      Returns:
        filename

    - #### toString

          public String toString()

      Overrides:
        `toString` in class `Object`

    - #### getAllNode1sCount

          public final long getAllNode1sCount()

      Retrieve number of nodes
      Returns:
        number of nodes

    - #### getAllNode1s

          public final List<String> getAllNode1s()

      Retrieve list of nodes
      Returns:
        list of nodes

    - #### findNode1

          public final DBElement findNode1(String node1_id)

      Return Element corresponding to the node name
      Parameters:
        `node1_id` - node name
      Returns:
        Element corresponding to the node name

    - #### addNode1

          public void addNode1(String node1_id)
                        throws NodeExistsException

      Adds new node
      Parameters:
        `node1_id` - name of the node to add
      Throws:
        `NodeExistsException` - when the node already exists

    - #### removeNode1

          public void removeNode1(String node1_id)
                           throws NodeNotFoundException

      Removes the node
      Parameters:
        `node1_id` - name of the node to remove
      Throws:
        `NodeNotFoundException` - when node doesn't exist on first level

    - #### setData

          public void setData(String node1_id,
                              String subnode,
                              String key,
                              Object value)
                       throws NodeNotFoundException

      Sets data for the given node at given path
      Parameters:
        `node1_id` - name of the node
        `subnode` - path to the node
        `key` - under which save the data
        `value` - actual value to be saved
      Throws:
        `NodeNotFoundException` - when node doesn't exist on first level

    - #### setData

          public void setData(String node1_id,
                              String key,
                              Object value)
                       throws NodeNotFoundException

      Sets data for the given node at root
      Parameters:
        `node1_id` - name of the node
        `key` - under which save the data
        `value` - actual value to be saved
      Throws:
        `NodeNotFoundException` - when node doesn't exist on first level

    - #### getDataList

          public String[] getDataList(String node1_id,
                                      String subnode,
                                      String key)
                               throws NodeNotFoundException

      Retrieve values of given node under specific path
      Parameters:
        `node1_id` - name of the node
        `subnode` - path to the node
        `key` - under which read the data
      Returns:
        array of Strings
      Throws:
        `NodeNotFoundException` - when node doesn't exist on first level

    - #### getDataIntList

          public int[] getDataIntList(String node1_id,
                                      String subnode,
                                      String key)
                               throws NodeNotFoundException

      Retrieve values of given node under specific path
      Parameters:
        `node1_id` - name of the node
        `subnode` - path to the node
        `key` - under which read the data
      Returns:
        array of Integers
      Throws:
        `NodeNotFoundException` - when node doesn't exist on first level

    - #### getDataDoubleList

          public double[] getDataDoubleList(String node1_id,
                                            String subnode,
                                            String key)
                                     throws NodeNotFoundException

      Retrieve values of given node under specific path
      Parameters:
        `node1_id` - name of the node
        `subnode` - path to the node
        `key` - under which read the data
      Returns:
        array of Doubles
      Throws:
        `NodeNotFoundException` - when node doesn't exist on first level

    - #### getData

          public Object getData(String node1_id,
                                String subnode,
                                String key,
                                Object def)
                         throws NodeNotFoundException

      Retrieve value of given node under specific path
      Parameters:
        `node1_id` - name of the node
        `subnode` - path to the node
        `key` - under which read the data
        `def` - default value if nothing is stored
      Returns:
        Object with value
      Throws:
        `NodeNotFoundException` - when node doesn't exist on first level

    - #### getDataInt

          public int getDataInt(String node1_id,
                                String subnode,
                                String key,
                                int def)
                         throws NodeNotFoundException

      Retrieve value of given node under specific path
      Parameters:
        `node1_id` - name of the node
        `subnode` - path to the node
        `key` - under which read the data
        `def` - default value if nothing is stored
      Returns:
        Integer value
      Throws:
        `NodeNotFoundException` - when node doesn't exist on first level

    - #### getDataDouble

          public double getDataDouble(String node1_id,
                                      String subnode,
                                      String key,
                                      double def)
                               throws NodeNotFoundException

      Retrieve value of given node under specific path
      Parameters:
        `node1_id` - name of the node
        `subnode` - path to the node
        `key` - under which read the data
        `def` - default value if nothing is stored
      Returns:
        Double value
      Throws:
        `NodeNotFoundException` - when node doesn't exist on first level

    - #### getData

          public Object getData(String node1_id,
                                String subnode,
                                String key)
                         throws NodeNotFoundException

      Retrieve value of given node under specific path
      Parameters:
        `node1_id` - name of the node
        `subnode` - path to the node
        `key` - under which read the data
      Returns:
        Object value
      Throws:
        `NodeNotFoundException` - when node doesn't exist on first level

    - #### getData

          public Object getData(String node1_id,
                                String key)
                         throws NodeNotFoundException

      Retrieve value of given node
      Parameters:
        `node1_id` - name of the node
        `key` - under which read the data
      Returns:
        Double value
      Throws:
        `NodeNotFoundException` - when node doesn't exist on first level

    - #### getSubnodes

          public String[] getSubnodes(String node1_id,
                                      String subnode)
                               throws NodeNotFoundException

      Retrieve list of subnodes under specific path
      Parameters:
        `node1_id` - name of the node
        `subnode` - path to the node
      Returns:
        arrays of subnodes names
      Throws:
        `NodeNotFoundException` - when node doesn't exist on first level

    - #### getSubnodes

          public String[] getSubnodes(String node1_id)
                               throws NodeNotFoundException

      Retrieve list of subnodes under root
      Parameters:
        `node1_id` - name of the node
      Returns:
        arrays of subnodes names
      Throws:
        `NodeNotFoundException` - when node doesn't exist on first level

    - #### getKeys

          public String[] getKeys(String node1_id,
                                  String subnode)
                           throws NodeNotFoundException

      Retrieve list of keys under specific path
      Parameters:
        `node1_id` - name of the node
        `subnode` - path to the node
      Returns:
        arrays of keys names
      Throws:
        `NodeNotFoundException` - when node doesn't exist on first level

    - #### getKeys

          public String[] getKeys(String node1_id)
                           throws NodeNotFoundException

      Retrieve list of keys under root
      Parameters:
        `node1_id` - name of the node
      Returns:
        arrays of subnodes names
      Throws:
        `NodeNotFoundException` - when node doesn't exist on first level

    - #### removeData

          public void removeData(String node1_id,
                                 String subnode,
                                 String key)
                          throws NodeNotFoundException

      Removes data of specific key from node of given name under given path
      Parameters:
        `node1_id` - name of the node
        `subnode` - path to the node
        `key` - name of the key
      Throws:
        `NodeNotFoundException` - when node doesn't exist on first level

    - #### removeData

          public void removeData(String node1_id,
                                 String key)
                          throws NodeNotFoundException

      Removes data of specific key from node of given name under root element
      Parameters:
        `node1_id` - name of the node
        `key` - name of the key
      Throws:
        `NodeNotFoundException` - when node doesn't exist on first level

    - #### removeSubnode

          public void removeSubnode(String node1_id,
                                    String subnode)
                             throws NodeNotFoundException

      Removes node of given name under given path
      Parameters:
        `node1_id` - name of the node
        `subnode` - path to the node
      Throws:
        `NodeNotFoundException` - when node doesn't exist on first level

    - #### sync

          public void sync()
                    throws IOException

      Performs synchronization with the file
      Throws:
        `IOException` - when the file doesn't exist

    - #### setupNewDB

          protected void setupNewDB(String db_file,
                                    String root_name,
                                    String node1_name)

      Creates basic Elements of the XMLDB
      Parameters:
        `db_file` - indicates path to the file on disk to/from which write/read; if parameter starts with "memory://" then memory mode (without actual file usage) is enabled
        `root_name` - name of the root element
        `node1_name` - name of the node

    - #### loadDB

          protected void loadDB()
                         throws IOException,
                                XMLDBException

      Loads XML from file
      Throws:
        `IOException` - when the file doesn't exist
        `XMLDBException` - when root node doesn't exist

    - #### saveDB

          protected void saveDB()

      Saves XML to file

    - #### getNode1

          protected final DBElement getNode1(String node1_id)
                                      throws NodeNotFoundException

      Throws:
        `NodeNotFoundException`

    - #### getNode

          protected final DBElement getNode(String node1_id,
                                            String subnode,
                                            boolean auto_create)
                                     throws NodeNotFoundException

      Retrieves the node of the given name at specific path
      Parameters:
        `node1_id` - name of the node
        `subnode` - path to the node
        `auto_create` - whether to create path if it's missing
      Returns:
        retrieved node
      Throws:
        `NodeNotFoundException` - when node doesn't exist on first level

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