Package hdf.object

Class CompoundDS

  • All Implemented Interfaces:
    CompoundDataFormat, DataFormat, MetaDataContainer, Serializable
    public abstract class CompoundDS
extends Dataset
implements CompoundDataFormat
    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 datatypes can be nested, i.e. members of a compound datatype can be some other compound datatype.

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

    Since Java cannot handle C-structured compound data, data in a 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 member 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 a 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 Detail

      • SEPARATOR

        public static final 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

      • numberOfMembers

        protected int numberOfMembers
        The number of members of the compound dataset.

      • memberNames

        protected String[] memberNames
        The names of members of the compound dataset.

      • memberOrders

        protected int[] memberOrders
        Returns array containing the total number of elements of the members of this compound dataset.

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

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

      • memberDims

        protected transient Object[] memberDims
        The dimension sizes of each member.

        The i-th element of the Object[] is an integer array (int[]) that contains the dimension sizes of the i-th member.

      • isMemberSelected

        protected boolean[] isMemberSelected
        The array to store flags to indicate if a member of this compound dataset is selected for read/write.

        If a member is selected, the read/write will perform on the member. Applications such as HDFView will only display the selected members of the compound dataset. 

         For example, if a compound dataset has four members
     String[] memberNames = {"X", "Y", "Z", "TIME"};
 and
     boolean[] isMemberSelected = {true, false, false, true};
 members "X" and "TIME" are selected for read and write.

    • Constructor Detail

      • CompoundDS

        public CompoundDS​(FileFormat theFile,
                  String dsName,
                  String dsPath)
        Constructs a CompoundDS object with the 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 information into memory. It is rarely used elsewhere.

        Parameters:
        theFile - the file that contains the dataset.
        dsName - the name of the CompoundDS, e.g. "compDS".
        dsPath - the full path of the CompoundDS, e.g. "/g1".

      • CompoundDS

        @Deprecated
public CompoundDS​(FileFormat theFile,
                  String dsName,
                  String dsPath,
                  long[] oid)
        Deprecated.
        Not for public use in the future.
        Using CompoundDS(FileFormat, String, String)
        Parameters:
        theFile - the file that contains the dataset.
        dsName - the name of the CompoundDS, e.g. "compDS".
        dsPath - the full path of the CompoundDS, e.g. "/g1".
        oid - the oid of the CompoundDS.

    • Method Detail

      • 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 the dataset. In this case, getSelectedMemberCount() returns two.

        Specified by:
        getSelectedMemberCount in interface CompoundDataFormat
        Returns:
        the number of selected members.

      • getMemberNames

        public final 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"}.

        Specified by:
        getMemberNames in interface CompoundDataFormat
        Returns:
        the names of compound members.

      • isMemberSelected

        public final boolean isMemberSelected​(int idx)
        Checks if a member of the compound dataset is selected for read/write.
        Specified by:
        isMemberSelected in interface CompoundDataFormat
        Parameters:
        idx - the index of compound member.
        Returns:
        true if the i-th memeber is selected; otherwise returns false.

      • setAllMemberSelection

        public final void setAllMemberSelection​(boolean selectAll)
        Selects/deselects all members.
        Specified by:
        setAllMemberSelection in interface CompoundDataFormat
        Parameters:
        selectAll - 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 the compound dataset.

        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.
        Specified by:
        getMemberOrders in interface CompoundDataFormat
        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 selected members of the compound dataset.

        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}
        Specified by:
        getSelectedMemberOrders in interface CompoundDataFormat
        Returns:
        array containing the total number of elements of the selected members of compound.

      • getMemberDims

        public final int[] getMemberDims​(int i)
        Returns the dimension sizes 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];
     }
        getMemberDims(2) returns an array of {2, 3}, while getMemberDims(1) returns an array of {5}, and getMemberDims(0) returns null.
        Specified by:
        getMemberDims in interface CompoundDataFormat
        Parameters:
        i - the i-th member
        Returns:
        the dimension sizes 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().

        Specified by:
        getMemberTypes in interface CompoundDataFormat
        Returns:
        the array of datatype objects of the compound members.

      • copy

        @Deprecated
public Dataset copy​(Group pgroup,
                    String name,
                    long[] dims,
                    Object data)
             throws 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:
        Exception - if dataset can not be copied