ncsa.hdf.object
Class CompoundDS

java.lang.Object
  ncsa.hdf.object.HObject
      ncsa.hdf.object.Dataset
          ncsa.hdf.object.CompoundDS

All Implemented Interfaces:

java.io.Serializable, DataFormat

Direct Known Subclasses:

H4Vdata, H5CompoundDS

public abstract class CompoundDS
extends Dataset

A CompoundDS is a dataset with compound datatype.

A compound datatype is an aggregation of one or more datatypes. Each member of a compound type has a name which is unique within that type, and a datatype of that member in a compound datum. Compound datatype can be nested, i.e. members of compound datatype can be some other compound datatype.

For more details on compound datatype, see HDF5 User's Guide

Since Java cannot handle C-structured compound data, data in compound dataset is loaded in to an Java List. Each element of the list is a data array that corresponds to a compound field. The data is read/written by compound field.

For example, if compound dataset "comp" has the following nested structure, and memeber datatypes

 comp --> m01 (int)
 comp --> m02 (float)
 comp --> nest1 --> m11 (char)
 comp --> nest1 --> m12 (String)
 comp --> nest1 --> nest2 --> m21 (long)
 comp --> nest1 --> nest2 --> m22 (double)
 

The data object is an Java list of six arrays: {int[], float[], char[], Stirng[], long[] and double[]}.

Version:

1.1 9/4/2007

Author:

Peter X. Cao

See Also:

Serialized Form

Field Summary

static java.lang.String

separator A single character to separate the names of nested compound fields.

Fields inherited from class ncsa.hdf.object.HObject

serialVersionUID

Constructor Summary

CompoundDS(FileFormat theFile, java.lang.String name, java.lang.String path)
Constructs a CompoundDS object with given file, dataset name and path.

CompoundDS(FileFormat theFile, java.lang.String name, java.lang.String path, long[] oid)
Deprecated. Not for public use in the future.
Using CompoundDS(FileFormat, String, String)

Method Summary

Dataset	copy(Group pgroup, java.lang.String name, long[] dims, java.lang.Object data) Deprecated. Not implemented for compound dataset.
int	getMemberCount() Returns the number of members of the compound dataset.
java.lang.String[]	getMemberNames() Returns the names of the members of the compound dataset.
int[]	getMemberOrders() Returns array containing the total number of elements of the members of compound.
Datatype[]	getMemberTypes() Returns an array of datatype objects of compound members.
int[]	getMemeberDims(int i) Returns the dimension sizes of of the i-th member.
int	getSelectedMemberCount() Returns the number of selected members of the compound dataset.
int[]	getSelectedMemberOrders() Returns array containing the total number of elements of the elected members of compound.
Datatype[]	getSelectedMemberTypes() Returns an array of datatype objects of selected compound members.
boolean	isMemberSelected(int idx) Checks if a member of compound is selected for read/write.
void	selectMember(int idx) Selects the i-th member for read/write.
void	setMemberSelection(boolean isSelected) Selects/deselects all members.

Methods inherited from class ncsa.hdf.object.Dataset

byteToString, clear, clearData, convertFromUnsignedC, convertFromUnsignedC, convertToUnsignedC, convertToUnsignedC, getChunkSize, getCompression, getConvertByteToString, getData, getDatatype, getDimNames, getDims, getHeight, getMaxDims, getRank, getSelectedDims, getSelectedIndex, getSize, getStartDims, getStride, getWidth, init, isEnumConverted, isString, read, readBytes, setConvertByteToString, setData, setEnumConverted, stringToByte, write, write

Methods inherited from class ncsa.hdf.object.HObject

close, equalsOID, getFID, getFile, getFileFormat, getFullName, getLinkTargetObjName, getName, getOID, getPath, open, setLinkTargetObjName, setName, setPath, toString

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface ncsa.hdf.object.DataFormat

getMetadata, hasAttribute, removeMetadata, writeMetadata

Field Detail

separator

public static final java.lang.String separator

A single character to separate the names of nested compound fields. An extended ASCII character, 0x95, is used to avoid common characters in compound names.

See Also:

Constant Field Values

Constructor Detail

CompoundDS

public CompoundDS(FileFormat theFile,
                  java.lang.String name,
                  java.lang.String path)

Constructs a CompoundDS object with given file, dataset name and path.

The dataset object represents an existing dataset in the file. For example, new H5CompoundDS(file, "dset1", "/g0/") constructs a dataset object that corresponds to the dataset,"dset1", at group "/g0/".

This object is usually constructed at FileFormat.open(), which loads the file structure and object informatoin into tree structure (TreeNode). It is rarely used elsewhere.

Parameters:

theFile - the file that contains the dataset.

name - the name of the CompoundDS, e.g. "compDS".

path - the path of the CompoundDS, e.g. "/g1".

CompoundDS

@Deprecated
public CompoundDS(FileFormat theFile,
                             java.lang.String name,
                             java.lang.String path,
                             long[] oid)

Deprecated. Not for public use in the future.
Using CompoundDS(FileFormat, String, String)

Method Detail

getMemberCount

public final int getMemberCount()

Returns the number of members of the compound dataset.

Returns:

the number of members of the compound dataset.

getSelectedMemberCount

public final int getSelectedMemberCount()

Returns the number of selected members of the compound dataset. Selected members are the compound fields which are selected for read/write.

For example, in a compound datatype of {int A, float B, char[] C}, users can choose to retrieve only {A, C} from dataset. In this case, getSelectedMemberCount() returns two.

Returns:

the number of selected members.

getMemberNames

public final java.lang.String[] getMemberNames()

Returns the names of the members of the compound dataset. The names of compound members are stored in an array of Strings.

For example, for a compound datatype of {int A, float B, char[] C} getMemberNames() returns ["A", "B", "C"}.

Returns:

the names of compound members.

isMemberSelected

public final boolean isMemberSelected(int idx)

Checks if a member of compound is selected for read/write.

Parameters:

idx - the index of compound member.

Returns:

true if the i-th memeber is selected; otherwise returns false.

selectMember

public final void selectMember(int idx)

Selects the i-th member for read/write.

Parameters:

idx - the index of compound member.

setMemberSelection

public final void setMemberSelection(boolean isSelected)

Selects/deselects all members.

Parameters:

isSelected - The indicator to select or deselect all members. If true, all members are selected for read/write. If false, no member is selected for read/write.

getMemberOrders

public final int[] getMemberOrders()

Returns array containing the total number of elements of the members of compound.

For example, a compound dataset COMP has members of A, B and C as

     COMP {
         int A;
         float B[5];
         double C[2][3];
     }
 

getMemberOrders() will return an integer array of {1, 5, 6} to indicate that member A has one element, member B has 5 elements, and member C has 6 elements.

Returns:

the array containing the total number of elements of the members of compound.

getSelectedMemberOrders

public final int[] getSelectedMemberOrders()

Returns array containing the total number of elements of the elected members of compound.

For example, a compound dataset COMP has members of A, B and C as

     COMP {
         int A;
         float B[5];
         double C[2][3];
     }
 

If A and B are selected, getSelectedMemberOrders() returns an array of {1, 5}

Returns:

array containing the total number of elements of the selected members of compound.

getMemeberDims

public final int[] getMemeberDims(int i)

Returns the dimension sizes of of the i-th member.

For example, a compound dataset COMP has members of A, B and C as

     COMP {
         int A;
         float B[5];
         double C[2][3];
     }
 

getMemeberDims(2) returns an array of {2, 3}, while getMemeberDims(1) returns an array of {5}, getMemeberDims(0) returns null.

Returns:

the dimension sizes of of the i-th member, null if the compound member is not an array.

getMemberTypes

public final Datatype[] getMemberTypes()

Returns an array of datatype objects of compound members.

Each member of a compound dataset has its own datatype. The datatype of a member can be atomic or other compound datatype (nested compound). Sub-classes set up the datatype objects at init().

Returns:

the array of datatype objects of the compound members.

getSelectedMemberTypes

public final Datatype[] getSelectedMemberTypes()

Returns an array of datatype objects of selected compound members.

Returns:

an array of datatype objects of selected compound members.

copy

@Deprecated
public Dataset copy(Group pgroup,
                               java.lang.String name,
                               long[] dims,
                               java.lang.Object data)
             throws java.lang.Exception

Deprecated. Not implemented for compound dataset.

Description copied from class: Dataset

Creates a new dataset and writes the data buffer to the new dataset.

This function allows applications to create a new dataset for a given data buffer. For example, users can select a specific interesting part from a large image and create a new image with the selection.

The new dataset retains the datatype and dataset creation properties of this dataset.

Specified by:

copy in class Dataset

Parameters:

pgroup - the group which the dataset is copied to.

name - the name of the new dataset.

dims - the dimension sizes of the the new dataset.

data - the data values of the subset to be copied.

Returns:

the new dataset.

Throws:

java.lang.Exception