Module org.hdfgroup.object

Package hdf.object.h5

Class H5MetaDataContainer

Object

hdf.object.HObject

hdf.object.h5.H5MetaDataContainer

All Implemented Interfaces:

MetaDataContainer, Serializable

public class H5MetaDataContainer
extends HObject
implements MetaDataContainer

An class that provides general I/O operations for object metadata attached to an object. For example, reading metadata content from the file into memory or writing metadata content from memory into the file.

Version:

2.0 4/2/2018

Author:

Peter X. Cao, Jordan T. Henderson

See Also:

• HObject
• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected List	attributeList	The list of attributes of this data object.
protected HObject	parentObject	The HObject to which this MetaDataContainer is attached

Fields inherited from class hdf.object.HObject

fileFormat, linkTargetObjName, oid, SEPARATOR

Constructor Summary

Constructors

Constructor	Description
H5MetaDataContainer(FileFormat theFile, String name, String path, HObject parent)	Constructs an HDF5 group with specific name, path, and parent.
H5MetaDataContainer(FileFormat theFile, String name, String path, HObject parent, long[] oid)	Deprecated. Not for public use in the future.

Method Summary

Modifier and Type	Method	Description
void	clear()	Removes all of the elements from metadata list.
void	close(long tid)	Closes access to the object.
List	getAttributeList()	Retrieves the object's attributeList.
List	getMetadata()	Retrieves the object's metadata, such as attributes, from the file.
List	getMetadata(int... attrPropList)	Retrieves the object's metadata, such as attributes, from the file.
int	getObjectAttributeSize()	Retrieves the object's number of attributes.
boolean	hasAttribute()	Check if the object has any attributes attached.
long	open()	Opens an existing object such as a dataset or group for access.
void	removeMetadata(Object metadata)	Deletes an existing piece of metadata from this object.
void	setObjectAttributeSize(int objectAttributes)	Updates the object's number of attributes.
void	updateMetadata(Object metadata)	Updates an existing piece of metadata attached to this object.
void	writeMetadata(Object metadata)	Writes a specific piece of metadata (such as an attribute) into the file.

Methods inherited from class hdf.object.HObject

createFullname, debug, equals, equals, equalsOID, getFID, getFile, getFileFormat, getFullName, getLinkTargetObjName, getName, getOID, getPath, hashCode, setFullname, setLinkTargetObjName, setName, setPath, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Details

parentObject

protected HObject parentObject

The HObject to which this MetaDataContainer is attached

attributeList

protected List attributeList

The list of attributes of this data object. Members of the list are instance of Attribute.

Constructor Details

H5MetaDataContainer

public H5MetaDataContainer(FileFormat theFile,
 String name,
 String path,
 HObject parent)

Constructs an HDF5 group with specific name, path, and parent.

Parameters:

theFile - the file which containing the group.

name - the name of this group, e.g. "grp01".

path - the full path of this group, e.g. "/groups/".

parent - the parent of this group.

H5MetaDataContainer

@Deprecated
public H5MetaDataContainer(FileFormat theFile,
 String name,
 String path,
 HObject parent,
 long[] oid)

Deprecated.

Not for public use in the future.

Parameters:

theFile - the file which containing the group.

name - the name of this group, e.g. "grp01".

path - the full path of this group, e.g. "/groups/".

parent - the parent of this group.

oid - the oid of this group.

Method Details

clear

public void clear()

Removes all of the elements from metadata list. The list should be empty after this call returns.

Specified by:

clear in interface MetaDataContainer

getAttributeList

public List getAttributeList()

Retrieves the object's attributeList.

Returns:

the list.

getObjectAttributeSize

public int getObjectAttributeSize()

Retrieves the object's number of attributes.

Returns:

the list size.

setObjectAttributeSize

public void setObjectAttributeSize(int objectAttributes)

Updates the object's number of attributes.

Parameters:

objectAttributes - the number of attributes for an object.

getMetadata

public List getMetadata()
                 throws Exception

Retrieves the object's metadata, such as attributes, from the file. Metadata, such as attributes, is stored in a List.

Specified by:

getMetadata in interface MetaDataContainer

Returns:

the list of metadata objects.

Throws:

Exception - if the metadata can not be retrieved

getMetadata

public List getMetadata(int... attrPropList)
                 throws Exception

Retrieves the object's metadata, such as attributes, from the file. Metadata, such as attributes, is stored in a List.

Parameters:

attrPropList - the list of properties to get

Returns:

the list of metadata objects.

Throws:

Exception - if the metadata can not be retrieved

writeMetadata

public void writeMetadata(Object metadata)
                   throws Exception

Writes a specific piece of metadata (such as an attribute) into the file. If an HDF5 attribute exists in the file, this method updates its value. If the attribute does not exist in the file, it creates the attribute in the file and attaches it to the object. It will fail to write a new attribute to the object where an attribute with the same name already exists. To update the value of an existing attribute in the file, one needs to get the instance of the attribute by getMetadata(), change its values, then use writeMetadata() to write the value.

Specified by:

writeMetadata in interface MetaDataContainer

Parameters:

metadata - the metadata to write.

Throws:

Exception - if the metadata can not be written

removeMetadata

public void removeMetadata(Object metadata)
                    throws Exception

Deletes an existing piece of metadata from this object.

Specified by:

removeMetadata in interface MetaDataContainer

Parameters:

metadata - the metadata to delete.

Throws:

Exception - if the metadata can not be removed

updateMetadata

public void updateMetadata(Object metadata)
                    throws Exception

Updates an existing piece of metadata attached to this object.

Specified by:

updateMetadata in interface MetaDataContainer

Parameters:

metadata - the metadata to update.

Throws:

Exception - if the metadata can not be updated

hasAttribute

public boolean hasAttribute()

Check if the object has any attributes attached.

Specified by:

hasAttribute in interface MetaDataContainer

Returns:

true if it has any attributes, false otherwise.

open

public long open()

Description copied from class: HObject

Opens an existing object such as a dataset or group for access. The return value is an object identifier obtained by implementing classes such as H5.H5Dopen(). This function is needed to allow other objects to be able to access the object. For instance, H5File class uses the open() function to obtain object identifier for copyAttributes(long src_id, long dst_id) and other purposes. The open() function should be used in pair with close(long) function.

Specified by:

open in class HObject

Returns:

the object identifier if successful; otherwise returns a negative value.

See Also:

• HObject.close(long)

close

public void close(long tid)

Description copied from class: HObject

Closes access to the object. Sub-classes must implement this interface because different data objects have their own ways of how the data resources are closed. For example, H5Group.close() calls the hdf.hdf5lib.H5.H5Gclose() method and closes the group resource specified by the group id.

Specified by:

close in class HObject

Parameters:

tid - The object identifier.