ncsa.hdf.object.CompoundDS Maven / Gradle / Ivy
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package ncsa.hdf.object;
/**
* 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 {@link 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
*/
public abstract class CompoundDS extends Dataset {
/**
*
*/
private static final long serialVersionUID = -4880399929644095662L;
/**
* 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.
*/
public static final String separator = "\u0095";
/**
* The number of members of the compound dataset.
*/
protected int numberOfMembers;
/**
* The names of members of the compound dataset.
*/
protected String[] memberNames;
/**
* 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];
* }
*
*
* 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.
*/
protected int[] memberOrders;
/**
* 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.
*/
protected Object[] memberDims;
/**
* The datatypes of compound members.
*/
protected Datatype[] memberTypes;
/**
* The array to store flags to indicate if a member of 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.
*
*/
protected boolean[] isMemberSelected;
/**
* 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.
*
*
* @param theFile
* the file that contains the dataset.
* @param name
* the name of the CompoundDS, e.g. "compDS".
* @param path
* the path of the CompoundDS, e.g. "/g1".
*/
public CompoundDS(FileFormat theFile, String name, String path) {
this(theFile, name, path, null);
}
/**
* @deprecated Not for public use in the future.
* Using {@link #CompoundDS(FileFormat, String, String)}
*/
@Deprecated
public CompoundDS(FileFormat theFile, String name, String path, long[] oid) {
super(theFile, name, path, oid);
numberOfMembers = 0;
memberNames = null;
isMemberSelected = null;
memberTypes = null;
}
/**
* Returns the number of members of the compound dataset.
*
* @return the number of members of the compound dataset.
*/
public final int getMemberCount() {
return numberOfMembers;
}
/**
* 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.
*
* @return the number of selected members.
*/
public final int getSelectedMemberCount() {
int count = 0;
if (isMemberSelected != null) {
for (int i = 0; i < isMemberSelected.length; i++) {
if (isMemberSelected[i]) {
count++;
}
}
}
return count;
}
/**
* 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"}.
*
* @return the names of compound members.
*/
public final String[] getMemberNames() {
return memberNames;
}
/**
* Checks if a member of compound is selected for read/write.
*
* @param idx
* the index of compound member.
*
* @return true if the i-th memeber is selected; otherwise returns false.
*/
public final boolean isMemberSelected(int idx) {
if ((isMemberSelected != null) && (isMemberSelected.length > idx)) {
return isMemberSelected[idx];
}
else {
return false;
}
}
/**
* Selects the i-th member for read/write.
*
* @param idx
* the index of compound member.
*/
public final void selectMember(int idx) {
if ((isMemberSelected != null) && (isMemberSelected.length > idx)) {
isMemberSelected[idx] = true;
}
}
/**
* Selects/deselects all members.
*
* @param 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.
*/
public final void setMemberSelection(boolean isSelected) {
if (isMemberSelected == null) {
return;
}
for (int i = 0; i < isMemberSelected.length; i++) {
isMemberSelected[i] = isSelected;
}
}
/**
* 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.
*
* @return the array containing the total number of elements of the members
* of compound.
*/
public final int[] getMemberOrders() {
return memberOrders;
}
/**
* 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}
*
* @return array containing the total number of elements of the selected
* members of compound.
*/
public final int[] getSelectedMemberOrders() {
if (isMemberSelected == null) {
return memberOrders;
}
int idx = 0;
int[] orders = new int[getSelectedMemberCount()];
for (int i = 0; i < isMemberSelected.length; i++) {
if (isMemberSelected[i]) {
orders[idx++] = memberOrders[i];
}
}
return orders;
}
/**
* 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.
*
* @return the dimension sizes of of the i-th member, null if the compound
* member is not an array.
*/
public final int[] getMemeberDims(int i) {
if (memberDims == null) {
return null;
}
return (int[]) memberDims[i];
}
/**
* 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().
*
*
* @return the array of datatype objects of the compound members.
*/
public final Datatype[] getMemberTypes() {
return memberTypes;
}
/**
* Returns an array of datatype objects of selected compound members.
*
* @return an array of datatype objects of selected compound members.
*/
public final Datatype[] getSelectedMemberTypes() {
if (isMemberSelected == null) {
return memberTypes;
}
int idx = 0;
Datatype[] types = new Datatype[getSelectedMemberCount()];
for (int i = 0; i < isMemberSelected.length; i++) {
if (isMemberSelected[i]) {
types[idx++] = memberTypes[i];
}
}
return types;
}
/**
* @deprecated Not implemented for compound dataset.
*/
@Deprecated
@Override
public Dataset copy(Group pgroup, String name, long[] dims, Object data)
throws Exception {
throw new UnsupportedOperationException(
"Writing a subset of a compound dataset to a new dataset is not implemented.");
}
}