opendap.dap

Class DGrid

java.lang.Object

opendap.dap.DAPNode

opendap.dap.BaseType

opendap.dap.DConstructor

opendap.dap.DGrid

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, ClientIO

public class DGrid
extends DConstructor
implements ClientIO

This class holds a DArray and a set of "Map" vectors. The Map vectors are one-dimensional arrays corresponding to each dimension of the central Array. Using this scheme, a Grid can represent, in a rectilinear array, data which is not in reality rectilinear. An example will help make this clear.

Assume that the following array contains measurements of some real quantity, conducted at nine different points in space:

 A = [ 1  2  3  4 ]
     [ 2  4  6  8 ]
     [ 3  6  9  12]
 

To locate this Array in the real world, we could note the location of one corner of the grid, and the grid spacing. This would allow us to calculate the location of any of the other points of the Array.

This approach will not work, however, unless the grid spacing is precisely regular. If the distance between Row 1 and Row 2 is not the same as the distance between Row 2 and Row 3, the scheme will break down. The solution is to equip the Array with two Map vectors that define the location of each row or column of the array:

       A = [ 1  2  3  4 ] Row = [ 0 ]
           [ 2  4  6  8 ]       [ 3 ]
           [ 3  6  9  12]       [ 8 ]
 

  Column = [ 0  2  8  27]
 

The real location of the point in the first row and column of the array is now exactly fixed at (0,0), and the point in the last row and last column is at (8,27).

See Also:

BaseType, DArray, Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class opendap.dap.DAPNode

DAPNode.CloneMap

Field Summary

Fields

Modifier and Type	Field and Description
static int	ARRAY The Array part of the DGrid
protected DArray	arrayVar The Array component of this DGrid.
static int	MAPS The Map part of the DGrid
protected java.util.Vector	mapVars The Map component of this DGrid.

Fields inherited from class opendap.dap.DAPNode

_nameClear, _nameEncoded, log

Constructor Summary

Constructors

Constructor and Description
DGrid() Constructs a new DGrid.
DGrid(java.lang.String n) Constructs a new DGrid with name n.

Method Summary

Modifier and Type	Method and Description
void	addVariable(BaseType v, int part) Adds a variable to the container.
void	checkSemantics(boolean all) Checks for internal consistency.
DAPNode	cloneDAG(DAPNode.CloneMap map) Returns a clone of this DGrid.
void	deserialize(java.io.DataInputStream source, ServerVersion sv, StatusUI statusUI) Reads data from a DataInputStream.
int	elementCount(boolean leaves) Returns the number of variables contained in this object.
void	externalize(java.io.DataOutputStream sink) Writes data to a DataOutputStream.
DArray	getArray()
java.util.Vector<DArrayDimension>	getArrayDims()
java.lang.String	getTypeName() Returns the OPeNDAP type name of the class instance as a String.
BaseType	getVar(int index) Gets the indexed variable.
int	getVarCount() Get the number of contained variables (for use with getVar()
BaseType	getVariable(java.lang.String name) Returns the named variable.
java.util.Enumeration	getVariables() Return an Enumeration that can be used to iterate over the members of a Structure.
void	printDecl(java.io.PrintWriter os, java.lang.String space, boolean print_semi, boolean constrained) Write the variable's declaration in a C-style syntax.
void	printVal(java.io.PrintWriter os, java.lang.String space, boolean print_decl_p) Prints the value of the variable, with its declaration.
void	printXML(java.io.PrintWriter pw, java.lang.String pad, boolean constrained)
int	projectedComponents(boolean constrained) How many prohected components of this Grid object?
boolean	projectionYieldsGrid(boolean constrained) When projected (using whatever the current constraint provides in the way of a projection) am I still a Grid?

Methods inherited from class opendap.dap.DConstructor

addVariable, someChildHasAttributes

Methods inherited from class opendap.dap.BaseType

addAttributeAlias, addAttributeContainer, appendAttribute, appendAttribute, appendAttributeContainer, checkSemantics, delAttribute, delAttribute, elementCount, getAttribute, getAttribute, getAttributeNames, getAttributeTable, getLongName, hasAttributes, newPrimitiveVector, printAttributes, printAttributes, printAttributes, printAttributes, printConstraint, printDecl, printDecl, printDecl, printDecl, printDecl, printDecl, printDecl, printVal, printVal, printVal, printXML, printXML, printXML, printXML, setClearName

Methods inherited from class opendap.dap.DAPNode

clone, cloneDAG, getClearName, getEncodedName, getParent, isProject, setEncodedName, setParent, setProject, setProject, setProjected

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ARRAY

public static final int ARRAY

The Array part of the DGrid

See Also:

Constant Field Values

MAPS

public static final int MAPS

The Map part of the DGrid

See Also:

Constant Field Values

arrayVar

protected DArray arrayVar

The Array component of this DGrid.

mapVars

protected java.util.Vector mapVars

The Map component of this DGrid.

Constructor Detail

DGrid

public DGrid()

Constructs a new DGrid.

DGrid

public DGrid(java.lang.String n)

Constructs a new DGrid with name n.

Parameters:

n - the name of the variable.

Method Detail

getTypeName

public java.lang.String getTypeName()

Returns the OPeNDAP type name of the class instance as a String.

Specified by:

getTypeName in class BaseType

Returns:

the OPeNDAP type name of the class instance as a String.

elementCount

public int elementCount(boolean leaves)

Returns the number of variables contained in this object. For simple and vector type variables, it always returns 1. To count the number of simple-type variable in the variable tree rooted at this variable, set leaves to true.

Overrides:

elementCount in class BaseType

Parameters:

leaves - If true, count all the simple types in the `tree' of variables rooted at this variable.

Returns:

the number of contained variables.

addVariable

public void addVariable(BaseType v,
                        int part)

Adds a variable to the container.

Specified by:

addVariable in class DConstructor

Parameters:

v - the variable to add.

part - the part of the DGrid to be modified. Allowed values are ARRAY or MAPS.

Throws:

java.lang.IllegalArgumentException - if an invalid part was given.

getVariable

public BaseType getVariable(java.lang.String name)
                     throws NoSuchVariableException

Returns the named variable.

Specified by:

getVariable in class DConstructor

Parameters:

name - the name of the variable.

Returns:

the named variable.

Throws:

NoSuchVariableException - if the named variable does not exist in this container.

getVar

public BaseType getVar(int index)
                throws NoSuchVariableException

Gets the indexed variable. For a DGrid the index 0 returns the DArray and indexes 1 and higher return the associated map Vectors.

Specified by:

getVar in class DConstructor

Parameters:

index - the index of the variable in the Vector Vars.

Returns:

the indexed variable.

Throws:

NoSuchVariableException - if the named variable does not exist in this container.

getVarCount

public int getVarCount()

Get the number of contained variables (for use with getVar()

Specified by:

getVarCount in class DConstructor

Returns:

the number of contained variables

getVariables

public java.util.Enumeration getVariables()

Return an Enumeration that can be used to iterate over the members of a Structure. This implementation provides access to the elements of the Structure. Each Object returned by the Enumeration can be cast to a BaseType.

Specified by:

getVariables in class DConstructor

Returns:

An Enumeration

checkSemantics

public void checkSemantics(boolean all)
                    throws BadSemanticsException

Checks for internal consistency. For DGrid, verify that the map variables have unique names and match the number of dimensions of the array variable.

Overrides:

checkSemantics in class BaseType

Parameters:

all - for complex constructor types, this flag indicates whether to check the semantics of the member variables, too.

Throws:

BadSemanticsException - if semantics are bad, explains why.

See Also:

BaseType.checkSemantics(boolean)

printDecl

public void printDecl(java.io.PrintWriter os,
                      java.lang.String space,
                      boolean print_semi,
                      boolean constrained)

Write the variable's declaration in a C-style syntax. This function is used to create textual representation of the Data Descriptor Structure (DDS). See The OPeNDAP User Manual for information about this structure.

Overrides:

printDecl in class BaseType

Parameters:

os - The PrintWriter on which to print the declaration.

space - Each line of the declaration will begin with the characters in this string. Usually used for leading spaces.

print_semi - a boolean value indicating whether to print a semicolon at the end of the declaration.

constrained - a boolean value indicating whether to print the declartion dependent on the projection information. This is only used by Server side code.

See Also:

BaseType.printDecl(PrintWriter, String, boolean)

printVal

public void printVal(java.io.PrintWriter os,
                     java.lang.String space,
                     boolean print_decl_p)

Prints the value of the variable, with its declaration. This function is primarily intended for debugging OPeNDAP applications and text-based clients such as geturl.

Specified by:

printVal in class BaseType

Parameters:

os - the PrintWriter on which to print the value.

space - this value is passed to the printDecl method, and controls the leading spaces of the output.

print_decl_p - a boolean value controlling whether the variable declaration is printed as well as the value.

See Also:

BaseType.printVal(PrintWriter, String, boolean)

deserialize

public void deserialize(java.io.DataInputStream source,
                        ServerVersion sv,
                        StatusUI statusUI)
                 throws java.io.IOException,
                        DataReadException

Reads data from a DataInputStream. This method is only used on the client side of the OPeNDAP client/server connection.

Specified by:

deserialize in interface ClientIO

Parameters:

source - a DataInputStream to read from.

sv - the ServerVersion returned by the server.

statusUI - the StatusUI object to use for GUI updates and user cancellation notification (may be null).

Throws:

java.io.EOFException - if EOF is found before the variable is completely deserialized.

java.io.IOException - thrown on any other InputStream exception.

DataReadException - if an unexpected value was read.

See Also:

ClientIO.deserialize(DataInputStream, ServerVersion, StatusUI)

externalize

public void externalize(java.io.DataOutputStream sink)
                 throws java.io.IOException

Writes data to a DataOutputStream. This method is used primarily by GUI clients which need to download OPeNDAP data, manipulate it, and then re-save it as a binary file.

Specified by:

externalize in interface ClientIO

Parameters:

sink - a DataOutputStream to write to.

Throws:

java.io.IOException - thrown on any OutputStream exception.

printXML

public void printXML(java.io.PrintWriter pw,
                     java.lang.String pad,
                     boolean constrained)

Overrides:

printXML in class DConstructor

Parameters:

pw - Where to print

pad - Padding for iondentation (makes the output easier for humans to read).

constrained - If true then only projected variables (and their Attributes) will be printed.

getArray

public DArray getArray()

getArrayDims

public java.util.Vector<DArrayDimension> getArrayDims()

projectedComponents

public int projectedComponents(boolean constrained)

How many prohected components of this Grid object?

Returns:

The number of projected components.

projectionYieldsGrid

public boolean projectionYieldsGrid(boolean constrained)

When projected (using whatever the current constraint provides in the way of a projection) am I still a Grid?

Returns:

True if projected grid is still a grid. False otherwise.

cloneDAG

public DAPNode cloneDAG(DAPNode.CloneMap map)
                 throws java.lang.CloneNotSupportedException

Returns a clone of this DGrid. See DAPNode.cloneDag()

Overrides:

cloneDAG in class BaseType

Parameters:

map - track previously cloned nodes

Returns:

a clone of this object.

Throws:

java.lang.CloneNotSupportedException