Module org.hdfgroup.object
Package hdf.object

Class Group

Object
hdf.object.HObject
hdf.object.Group
All Implemented Interfaces:
MetaDataContainer, Serializable
Direct Known Subclasses:
FitsGroup, H4Group, H5Group, NC2Group
public abstract class Group
extends HObject
implements MetaDataContainer
Group is an abstract class. Current implementing classes are the H4Group and H5Group. This class includes general information of a group object such as members of a group and common operations on groups.

Members of a group may include other groups, datasets or links.

Version:
1.1 9/4/2007
Author:
Peter X. Cao
See Also:
Serialized Form

  • Field Details

  • Constructor Details

    • Group

      public Group​(FileFormat theFile, String grpName, String grpPath, Group grpParent)
      Constructs an instance of the group with specific name, path and parent group. An HDF data object must have a name. The path is the group path starting from the root. The parent group is the group where this group is located.

      For example, in H5Group(h5file, "grp", "/groups/", pgroup), "grp" is the name of the group, "/groups/" is the group path of the group, and pgroup is the group where "grp" is located.

      Parameters:
      theFile - the file containing the group.
      grpName - the name of this group, e.g. "grp01".
      grpPath - the full path of this group, e.g. "/groups/".
      grpParent - the parent of this group.

    • Group

      @Deprecated public Group​(FileFormat theFile, String grpName, String grpPath, Group grpParent, long[] oid)
      Deprecated.
      Not for public use in the future.
      Using Group(FileFormat, String, String, Group)
      Parameters:
      theFile - the file containing the group.
      grpName - the name of this group, e.g. "grp01".
      grpPath - the full path of this group, e.g. "/groups/".
      grpParent - the parent of this group.
      oid - the oid of this group.

  • Method Details

    • clear

      public void clear()
      Clears up member list and other resources in memory for the group. Since the destructor will clear memory space, the function is usually not needed.

    • addToMemberList

      public void addToMemberList​(HObject object)
      Adds an object to the member list of this group in memory.
      Parameters:
      object - the HObject to be added to the member list.

    • removeFromMemberList

      public void removeFromMemberList​(HObject object)
      Removes an object from the member list of this group in memory.
      Parameters:
      object - the HObject (Group or Dataset) to be removed from the member list.

    • getMemberList

      public List<HObject> getMemberList()
      Returns the list of members of this group. The list is an java.util.List containing HObjects.
      Returns:
      the list of members of this group.

    • breadthFirstMemberList

      public List<HObject> breadthFirstMemberList()
      Returns:
      the members of this Group in breadth-first order.

    • depthFirstMemberList

      public List<HObject> depthFirstMemberList()
      Returns:
      the members of this Group in depth-first order.

    • setName

      public void setName​(String newName) throws Exception
      Sets the name of the group.

      setName (String newName) changes the name of the group in memory and file.

      setName() updates the path in memory for all the objects that are under the group with the new name.

      Overrides:
      setName in class HObject
      Parameters:
      newName - The new name of the group.
      Throws:
      Exception - if the name can not be set

    • getParent

      public final Group getParent()
      Returns:
      the parent group.

    • isRoot

      public final boolean isRoot()
      Checks if it is a root group.
      Returns:
      true if the group is a root group; otherwise, returns false.

    • getNumberOfMembersInFile

      public int getNumberOfMembersInFile()
      Returns the total number of members of this group in file. Current Java applications such as HDFView cannot handle files with large numbers of objects (1,000,000 or more objects) due to JVM memory limitation. The max_members is used so that applications such as HDFView will load up to max_members number of objects. If the number of objects in file is larger than max_members, only max_members are loaded in memory.

      getNumberOfMembersInFile() returns the number of objects in this group. The number of objects in memory is obtained by getMemberList().size().

      Returns:
      Total number of members of this group in the file.

    • getMember

      public HObject getMember​(int idx)
      Get the HObject at the specified index in this Group's member list.
      Parameters:
      idx - The index of the HObject to get.
      Returns:
      The HObject at the specified index.