parallel/spmd/MultiDataObject.java

package appl.parallel.spmd;

import java.rmi.RemoteException;

import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;

import schmitzm.data.WritableGrid;
import appl.parallel.client.DataServer;
import appl.parallel.spmd.split.DataPartition;
import edu.bonn.xulu.plugin.data.grid.MultiGrid;

/**
 * A multi data object stores multiple elements of the same type.
 * While the related {@link MultiDataInfo} stores only Information about 
 * multi-data and is used by Xulu / V for transfer of metadata, this class
 * is a actual user object. The user can retrieve a multidata object e.g. via the
 * {@link SPMDServerController} and work with it (e.g. add elements)
 * 
 * @see SPMDServerInterface#getMultiData(String)
 * @see MultiDataInfo
 * 
 * @author Dominik Appl
 **/

public class MultiDataObject {

        private final Logger LOG = LogManager.getLogger(this.getClass().getName());

        private final MultiDataInfo multiDataInfo;

        private final DataServer dataServer;

        private MultiGrid managedGrid = null;

        /**
         * Construct a new Multidata object
         * 
         * @param info a {@link MultiDataInfo} object with the identification of the objects
         * @param dataServer a dataServer which is responsible for the actual loading of the data
         */
        public MultiDataObject(MultiDataInfo info, DataServer dataServer) {
                this.multiDataInfo = info;
                this.dataServer = dataServer;
        }

        /**
         * @param idx the position of the element
         * @return the element at the indicated position
         */
        public Object getElement(int idx) {
                try {
                        checkIndex(idx);
                        return dataServer.getData(multiDataInfo.getMultiID(idx));
                } catch (RemoteException e) {
                        LOG.error("RemoteExeception while retrieving data with ID "
                                        + multiDataInfo.getMultiID(idx)
                                        + " from PartitionDataServer");
                }
                return null;
        }

        /**
         * checks whether the indicated index is valid
         * @throws ArrayIndexOutOfBoundsException if idx is below zero or higher than number of elements 
         */
        private void checkIndex(int idx) {
                if ((idx > multiDataInfo.getCount() - 1) || idx <0 )
                        throw new ArrayIndexOutOfBoundsException("The Element with index "
                                        + idx + " was requested, but the MultiDataObject has only "
                                        + multiDataInfo.getCount() + " elements.");

        }

        /**
         * @return the number of elements in the multidataobject
         */
        public int getCount() {
                return multiDataInfo.getCount();
        }

        /**
         * Adds an element to MultiDataObjects. Method should be thread safe.
         * 
         * @return the index of the new element
         */
        public synchronized int addElement() {
                //the new ID of the MultiDataObject is generated by making
                //the first id negative and than subtracting the index from 
                //the ID
                int idx = multiDataInfo.getCount() - 1;
                try {
                        if (idx == -1)
                                throw new UnsupportedOperationException(
                                                "The MultiDataInfo must have at least one element!");
                        //simply get the first element and create a empty one.
                        int firstElementID = multiDataInfo.getMultiID(0);
                        DataPartition firstElement = dataServer.getData(firstElementID);
                        //generate a new id by making the first ID negative and subtracting the index value
                        int newID = multiDataInfo.getNewIDForIndex(idx + 1);
                        //there is a rare chance of colliding with existing ids:
                        while (dataServer.getData(newID) != null) {
                                newID--;
                        }
                        //create new element 
                        DataPartition newElement = firstElement.getEmpty(newID);
                        multiDataInfo.addElement(newID);
                        //add the element to the dataServer and to the managed MultiGrid (if any)
                        dataServer.addData(newElement);
                        if (managedGrid != null)
                                managedGrid.addGrid((WritableGrid) newElement);
                        return idx + 1;
                } catch (RemoteException e) {
                        LOG
                                        .error("RemoteExeception while trying to add a new element with idx "
                                                        + idx + " to MultiData");
                }
                return 0;
        }

        /**
         * Adds an element with the specified ID.
         * 
         * @param id the id of the element to add
         * @return the index of the new element or 0 if an error occurred
         */
        public int addElement(int id) {
                //actual maxIndex
                int idx = multiDataInfo.getCount() - 1;
                try {
                        if (idx == -1)
                                throw new UnsupportedOperationException(
                                                "The MultiDataInfo must have at least one element!");
                        //simply get the first element and create a empty one.
                        int firstElementID = multiDataInfo.getMultiID(0);
                        DataPartition firstElement = dataServer.getData(firstElementID);

                        //create new element 
                        DataPartition newElement = firstElement.getEmpty(id);
                        multiDataInfo.addElement(id);
                        //add the element to the dataServer and to the managed MultiGrid (if any)
                        dataServer.addData(newElement);
                        if (managedGrid != null)
                                managedGrid.addGrid((WritableGrid) newElement);
                        return idx + 1;
                } catch (RemoteException e) {
                        LOG
                                        .error("RemoteExeception while trying to add a new element with idx "
                                                        + idx + " to MultiData");
                }
                return 0;
        }

        /**
         * Manages a multigrid, which means that when a new element is added 
         * to the multiObject, then the same element is also added to 
         * the managed multiGrid.
         * 
         * @param toManageMultiGrid the grid to be managed. Only one grid will be 
         * managed at a time.
         *  
         */
        public void setManagedGrid(MultiGrid toManageMultiGrid) {
                this.managedGrid = toManageMultiGrid;
        }

        /**
         * @return the encapsulted {@link MultiDataInfo}
         */
        public MultiDataInfo getMultiInfo() {
                return this.multiDataInfo;
        }

        public String getName() {
                return multiDataInfo.getName();
        }

        /**
         * removes the element with the specified index from the dataServer
         * 
         * @param idx the element
         */
        public void deleteElement(int idx) {
                checkIndex(idx);
                try {
                        dataServer.removeData(multiDataInfo.getMultiID(idx));
                } catch (RemoteException e) {
                        LOG.error("Could not reach DataServer" , e);
                        e.printStackTrace();
                }       
        }
}
1	package appl.parallel.spmd;
2
3	import java.rmi.RemoteException;
4
5	import org.apache.log4j.LogManager;
6	import org.apache.log4j.Logger;
7
8	import schmitzm.data.WritableGrid;
9	import appl.parallel.client.DataServer;
10	import appl.parallel.spmd.split.DataPartition;
11	import edu.bonn.xulu.plugin.data.grid.MultiGrid;
12
13	/**
14	* A multi data object stores multiple elements of the same type.
15	* While the related {@link MultiDataInfo} stores only Information about
16	* multi-data and is used by Xulu / V for transfer of metadata, this class
17	* is a actual user object. The user can retrieve a multidata object e.g. via the
18	* {@link SPMDServerController} and work with it (e.g. add elements)
19	*
20	* @see SPMDServerInterface#getMultiData(String)
21	* @see MultiDataInfo
22	*
23	* @author Dominik Appl
24	**/
25
26	public class MultiDataObject {
27
28	private final Logger LOG = LogManager.getLogger(this.getClass().getName());
29
30	private final MultiDataInfo multiDataInfo;
31
32	private final DataServer dataServer;
33
34	private MultiGrid managedGrid = null;
35
36	/**
37	* Construct a new Multidata object
38	*
39	* @param info a {@link MultiDataInfo} object with the identification of the objects
40	* @param dataServer a dataServer which is responsible for the actual loading of the data
41	*/
42	public MultiDataObject(MultiDataInfo info, DataServer dataServer) {
43	this.multiDataInfo = info;
44	this.dataServer = dataServer;
45	}
46
47	/**
48	* @param idx the position of the element
49	* @return the element at the indicated position
50	*/
51	public Object getElement(int idx) {
52	try {
53	checkIndex(idx);
54	return dataServer.getData(multiDataInfo.getMultiID(idx));
55	} catch (RemoteException e) {
56	LOG.error("RemoteExeception while retrieving data with ID "
57	+ multiDataInfo.getMultiID(idx)
58	+ " from PartitionDataServer");
59	}
60	return null;
61	}
62
63	/**
64	* checks whether the indicated index is valid
65	* @throws ArrayIndexOutOfBoundsException if idx is below zero or higher than number of elements
66	*/
67	private void checkIndex(int idx) {
68	if ((idx > multiDataInfo.getCount() - 1) \|\| idx <0 )
69	throw new ArrayIndexOutOfBoundsException("The Element with index "
70	+ idx + " was requested, but the MultiDataObject has only "
71	+ multiDataInfo.getCount() + " elements.");
72
73	}
74
75	/**
76	* @return the number of elements in the multidataobject
77	*/
78	public int getCount() {
79	return multiDataInfo.getCount();
80	}
81
82	/**
83	* Adds an element to MultiDataObjects. Method should be thread safe.
84	*
85	* @return the index of the new element
86	*/
87	public synchronized int addElement() {
88	//the new ID of the MultiDataObject is generated by making
89	//the first id negative and than subtracting the index from
90	//the ID
91	int idx = multiDataInfo.getCount() - 1;
92	try {
93	if (idx == -1)
94	throw new UnsupportedOperationException(
95	"The MultiDataInfo must have at least one element!");
96	//simply get the first element and create a empty one.
97	int firstElementID = multiDataInfo.getMultiID(0);
98	DataPartition firstElement = dataServer.getData(firstElementID);
99	//generate a new id by making the first ID negative and subtracting the index value
100	int newID = multiDataInfo.getNewIDForIndex(idx + 1);
101	//there is a rare chance of colliding with existing ids:
102	while (dataServer.getData(newID) != null) {
103	newID--;
104	}
105	//create new element
106	DataPartition newElement = firstElement.getEmpty(newID);
107	multiDataInfo.addElement(newID);
108	//add the element to the dataServer and to the managed MultiGrid (if any)
109	dataServer.addData(newElement);
110	if (managedGrid != null)
111	managedGrid.addGrid((WritableGrid) newElement);
112	return idx + 1;
113	} catch (RemoteException e) {
114	LOG
115	.error("RemoteExeception while trying to add a new element with idx "
116	+ idx + " to MultiData");
117	}
118	return 0;
119	}
120
121	/**
122	* Adds an element with the specified ID.
123	*
124	* @param id the id of the element to add
125	* @return the index of the new element or 0 if an error occurred
126	*/
127	public int addElement(int id) {
128	//actual maxIndex
129	int idx = multiDataInfo.getCount() - 1;
130	try {
131	if (idx == -1)
132	throw new UnsupportedOperationException(
133	"The MultiDataInfo must have at least one element!");
134	//simply get the first element and create a empty one.
135	int firstElementID = multiDataInfo.getMultiID(0);
136	DataPartition firstElement = dataServer.getData(firstElementID);
137
138	//create new element
139	DataPartition newElement = firstElement.getEmpty(id);
140	multiDataInfo.addElement(id);
141	//add the element to the dataServer and to the managed MultiGrid (if any)
142	dataServer.addData(newElement);
143	if (managedGrid != null)
144	managedGrid.addGrid((WritableGrid) newElement);
145	return idx + 1;
146	} catch (RemoteException e) {
147	LOG
148	.error("RemoteExeception while trying to add a new element with idx "
149	+ idx + " to MultiData");
150	}
151	return 0;
152	}
153
154	/**
155	* Manages a multigrid, which means that when a new element is added
156	* to the multiObject, then the same element is also added to
157	* the managed multiGrid.
158	*
159	* @param toManageMultiGrid the grid to be managed. Only one grid will be
160	* managed at a time.
161	*
162	*/
163	public void setManagedGrid(MultiGrid toManageMultiGrid) {
164	this.managedGrid = toManageMultiGrid;
165	}
166
167	/**
168	* @return the encapsulted {@link MultiDataInfo}
169	*/
170	public MultiDataInfo getMultiInfo() {
171	return this.multiDataInfo;
172	}
173
174	public String getName() {
175	return multiDataInfo.getName();
176	}
177
178	/**
179	* removes the element with the specified index from the dataServer
180	*
181	* @param idx the element
182	*/
183	public void deleteElement(int idx) {
184	checkIndex(idx);
185	try {
186	dataServer.removeData(multiDataInfo.getMultiID(idx));
187	} catch (RemoteException e) {
188	LOG.error("Could not reach DataServer" , e);
189	e.printStackTrace();
190	}
191	}
192	}