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Object-Oriented VPF/DNC Database Modeling

Object-Oriented VPF/DNC Database Modeling. Hong and Rahael. VPF vs DNC. VPF is a vector formatted database storage for GIS data (Vector product format) DNC implements VPF, Digital Nautical Chart They are plain file structure. Introduction to DNC.

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Object-Oriented VPF/DNC Database Modeling

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  1. Object-Oriented VPF/DNC Database Modeling Hong and Rahael

  2. VPF vs DNC • VPF is a vector formatted database storage for GIS data (Vector product format) • DNC implements VPF, Digital Nautical Chart • They are plain file structure

  3. Introduction to DNC • The whole earth could be divided into small parts for mapping • A DNC database only maps to a small portion of the earth map

  4. Introduction to DNC Database DNC LIB Dir 1 Browse Lib Dir 3 coverages 14 Coverages Primitive Dirs Primitives

  5. Intro to DNC • DNC03: 03 represents the disc number geographically. At the database level, only Database Header Table and Library Attribute Table • A library is a collection of coverages sharing the same tiling structure and coordinate system.

  6. Intro to DNC • DNC has 4 Libs: Harbor (H), Approach (A), Coastal (COA), General (GEN). In addition, there is a single BROWSE library. • Each Lib except BROWSE contains up to 14 Coverages. • At Lib level, only Library Header Table (LHT), Geographic reference table and Coverage Attribute table • A coverage is composed of one or more feature class types stored in a coverage directory. Features: area, line, point and text -> face, ring, edge, nodes, text

  7. Intro To DNC • In non-browse Libs, there may have: CUL, ECR, ENV, HYD, IWY, LCR, LIM, NAV, OBS, POR, REL, DQY, TILEREF, and LIBREF coverages • Tables: FCS, .FIT, FCA, NOTES.RAT, *.NJT, *.AJT, *.LJT, CHAR.VDT, INT.VDT, and tables for primitives • The topology level of each coverage is defined by the types of the feature classes present: 0, 1, 2, 3. • We only concern the topology level 3

  8. Intro To DNC • Tileref and Libref are mandatory for tiled libraries. Tileref contains an area feature table and primitive tables which relate the tile names and areas. • Libref contains a line feature table and primitive tables needed to draw a small scale depiction of the coverage • So, these two coverages have to be taken into consideration first before all other coverages for a Lib

  9. Intro to DNC • So, a database is composed of five types of Libraries each of which is composed of upto 14 coverages that layer over each other • Inside each coverage, features are the core part that depict each coverage • Features are grouped into different classes: point, line, area and text. • Each feature is a collection of primitives in geographic order

  10. DNC File Structure Database Library … Coverage ….. ……... [Tile] and Feature Class Feature & Primitives ………...

  11. DNC OOM • DNC file structure is a tree • Perfectly matches to Object-oriented tree navigation model • OOM is a navigation architecture in which each object is identified by an unique ID • Different OOMs may have different architectures

  12. What We Need? interface Database agents access Data retrieved

  13. What We Need? • We need an interface to bridge the agents and the database no matter in what form the database is. The interface is actually a simple DBMS • The interface could either arm the agents with XML format data, or simply assign objects to agents for later usage

  14. What We Need • For database compatibility, we do not want to modify the DNC database structure • For better usage and future enhancements, it is ok to store everything in Object forms -- requires to build our own database structure • Which way to go?

  15. What We Need • Of course the easiest way is to build our DBMS on the existing file structure • The DBMS interface is OOD • The DBMS underline implementation is then Object-Oriented-Relational • Temporarily for easy illustration, let’s give it a name: “OOH”

  16. Architecture of OOH Clients OO Interface OO-Relational Impl DNC File System

  17. OOH Package Architecture org.usm.vpf.dnc exception database .impl internal .impl

  18. DNC File Structure Database Library … Coverage ….. ……... [Tile] and Feature Class Feature & Primitives ………...

  19. Database Library Coverage FeatureManager VirtualTile Primitives Features

  20. Class DatabaseTreeNode • public interface DatabaseTreeNode extends java.io.Serializable • { • public DatabaseTreeNode findNode(NodeID ID); • public NodeID getIDObject(); • public Object getParentObject(); • public MetaData getMetaData(); • public XMLObject toXML(); • public void noParent(boolean noParent); • public NodeConstraint getConstraint(); • public void validate() throws ConstraintViolatedException; • }

  21. DataManager • A database manager manages a group of DatabaseTreeNodes that are of the same level and same type. For example, a group of Features in a coverage is organized as a Feature class, which could be managed by a FeatureManager. • The basic functions of a DataManager are: 1. Find a Node that is managed by it 2. On finding, return a proxy of the Node for RW. However, since RW happens on proxy, no affect on the original FeatureManager, PrimitiveManager, EntityNodeManager, ConnectedNodeManager, EdgeManager, FaceManager, TextManager, NotesManager

  22. Class DataManager • public interface DataManager extends java.io.Serializable • { • public Object findData(NodeID ID); • public void commit() throws InvalidTableUpdateException,ConstraintViolatedException; • }

  23. Class Database • public interface Database extends DatabaseTreeNode • { • public DatabaseMetaData getDatabaseMetaData(); • public Vector getAllLibraries(); • public String getRootDir(); • public void setRootDir(String root); • public void dbStart() throws DatabaseDefectException,DatabaseFailedException; • public void dbStop() throws DatabaseFailedException; • }

  24. Class Library • public interface Library extends DatabaseTreeNode • { • public String getName(); • public LibraryMetaData getLibraryMetaData(); • public Database getDatabaseObject(); • public GeographicExtent getGeographicExtent(); • public boolean isTiled(); • public boolean isBrowseLibrary(); • public GeographicReference getGeographicReference(); • public TileScheme getTileScheme(); • public LibrefScheme getLibrefScheme(); • public Vector getAllCoverages(); • public Coverage find(String coverageName) throws CoverageNotExistException; • public String getFilePath(); • }

  25. Class Coverage • public interface Coverage extends DatabaseTreeNode • { • public String getFilePath(); • public Vector getFeatureManagers(); • public FeatureManager find(String name); • public FeatureManager find(NodeID featureManagerID); • public CoverageMetaData getCoverageMetaData(); • public Library getLibrary(); • public VirtualTile getTile(int tileID); • public VirtualTile getTile(); • public void load() throws CoverageNotExistException, TileSchemeConflictException; • public void unload(); • public boolean isLoaded(); • }

  26. Class VirtualTile • public interface VirtualTile extends DatabaseTreeNode • { • public Coverage getCoverage(); • public EntityNodeManager getEntityNodeManager(); • public ConnectedNodeManager getConnectedNodeManager(); • public EdgeManager getEdgeManager(); • public FaceManager getFaceManager(); • public TextManager getTextManager(); • public String getFilePath(); • }

  27. Class FeatureManager • public abstract class FeatureManager implements DatabaseTreeNode,DataManager • { • public abstract Coverage getCoverage(); • public abstract Feature findFeature(int ID); • public abstract Vector getAllFeatures(); • public abstract byte getFeatureType(); • public abstract String getName(); • public abstract String getDescription(); • }

  28. Class Feature • public abstract class Feature implements DatabaseTreeNode • { • public final static byte POINT_FEATURE = 1; • public final static byte LINE_FEATURE = 2; • public final static byte AREA_FEATURE = 3; • public final static byte TEXT_FEATURE = 0; • public abstract FeatureManager getMyManager(); • public abstract byte getFeatureType(); • public abstract int getCurrentLevelID(); • public abstract String getName(); • public abstract Vector getPrimitives(); • public abstract void updatePrim(Primitive previous, Primitive current); • public abstract Object[][] getAttributeAndValues(); • public abstract Vector getReferencedNotes(); • public abstract ComparableFeature getComparable(boolean noTopology); • public abstract ComparableFeature getComparable(boolean noTopology, • FeatureComparisonAlgorithm myAlgorithm); • }

  29. Class Primitive • public abstract class Primitive • { • public final static byte ENTITYNODE = 0; • public final static byte CONNECTEDNODE = 1; • public final static byte EDGE = 2; • public final static byte FACE = 3; • public final static byte text = 10; • protected byte m_type; • public byte getType(){ • return m_type; • } • protected void setType(byte type){ • this.m_type = type; • } • public abstract DataManager getDataManager(); • public abstract Vector getReferencedFeatures(); • }

  30. Class EntityNode • public abstract class EntityNode extends Primitive implements DatabaseTreeNode • { • public abstract EntityNodeManager getMyManager(); • public abstract Face getContainingFace(); • public abstract void setContainingFace(Face f); • public abstract double[] getCordinates(); • public abstract void setCordinates(double[] cordinates); • }

  31. ConnectedNode • public abstract class ConnectedNode extends Primitive implements DatabaseTreeNode • { • public abstract ConnectedNodeManager getMyManager(); • public abstract Face getFirstEdge(); • public abstract void setFirstEdge(Edge e); • public abstract double[] getCordinates(); • public abstract void setCordinates(double[] cordinates); • }

  32. Edge • public abstract class Edge extends Primitive implements DatabaseTreeNode • { • public abstract EdgeManager getMyManager(); • public abstract ConnectedNode getStartNode(); • public abstract ConnectedNode getEndNode(); • public abstract Face getRightFace(); • public abstract Face getNearbyRightFace(); • public abstract Face getLeftFace(); • public abstract Face getNearbyLeftFace(); • public abstract Edge getRightEdge(); • public abstract Edge getNearbyRightEdge(); • public abstract Edge getLeftEdge(); • public abstract Edge getNearbyLeftEdge(); • public abstract double[][] getCordinates(); • public abstract void setCordinates(double[][] cordinates); • public abstract GeographicExtent getGeographicExtent(); • }

  33. Class Face • public abstract class Face extends Primitive implements DatabaseTreeNode • { • public abstract FaceManager getMyManager(); • public abstract Vector getAllEdges(); • public abstract Vector getInnerFaces(); • public abstract GeographicExtent getGeographicExtent(); • }

  34. Class LineFeature • public abstract class LineFeature extends Feature • { • public byte getType() • { • return Feature.LINE_FEATURE; • } • public abstract Vector getEdges(); • public abstract Vector getConnectedNodes(); • }

  35. Class TopologyManager • public interface TopologyManager extends java.io.Serializable • { • public boolean deleteFeature(Feature f) throws ConstraintViolatedException; • public boolean deletePrimitive(Primitive p)throws ConstraintViolatedException; • public Feature addPrimitive(Primitive p) • throws ConstraintViolatedException, InvalidParameterException; • public Feature addPrimitive(Primitive p, boolean asFeature) • throws ConstraintViolatedException, InvalidParameterException; • public void addPrimitive(Primitive p, Feature f) • throws ConstraintViolatedException, InvalidParameterException; • public boolean updatePrimitive(Primitive p) • throws ConstraintViolatedException, InvalidParameterException; • public void begin(); • public void end(); • public void commit(); • public Coverage getCoverage(); • }

  36. Class Topology • The class TopologyManager is dedicated for Feature & Primitive updates. Since the topology of each coverage has be kept after the updates of a feature or a primitive, and the update of a feature or primitive affect others, we then have to go through a complicated process to keep the topology. • The basic algorithm is from the paper "An Object-Oriented Approach For Handling Topology in VPF Products", though there are something different. • <p>It has to be mentioned that all changes you want to make have to be • through this class. Also, for any changes permanently happen in the • database, you have to call the commit() method. The usage of this class • is similiar to ODMG's Java Binding: • TopologyManager t = myCoverage.getTopologyManager(); • t.begin(); • t.update ... • t.delete ... • t.add ... • t.commit(); • t.end(); • Here, t.begin means that a transaction begins, and t.end() states that • this transaction ends. t.commit() states that the above modifications are requested to be made permanently to the database now.

  37. Class Table • public interface Table extends java.io.Serializable • { • public String getFileName(); • public void bindFile(String fileName); • public void load() throws NoSuchTableFileException; • public RowSet findByPrimaryKey(IDObject id); • public void update() throws NoSuchTableFileException, InvalidTableUpdateException; • Public String getTableName(); • Public Object getRows(); • ------ • }

  38. Class RowSet • public interface RowSet extends java.io.Serializable • { • public int getPrimaryKey() throws NoSuchColumnException; • public Object get(String key) throws NoSuchColumnException; • public byte getDataType(String key); • public Object get(int position) throws NoSuchColumnException; • public byte getDataType(int position); • public void set(String key, Object value) throws NoSuchColumnException; • public void set(int position, Object value) throws NoSuchColumnException; • public int getColumnCount(); • }

  39. LogManager • A good way to control log message systematically. • Static methods • Anytime when there should be debug messages, must use LogManager

  40. What have been done • The implementation of org.usm.vpf.dnc.internal.impl has been finished. Next step is to implement org.usm.vpf.dnc.internal which is a easy task. Later, org.usm.vpf.dnc.impl which is the real part. • Job done by: Hong, Rahael, Johan. Thanks.

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