org.griphyn.common.catalog
Class ReplicaCatalogEntry

java.lang.Object
  org.griphyn.common.catalog.ReplicaCatalogEntry

All Implemented Interfaces:

CatalogEntry

public class ReplicaCatalogEntry
extends Object
implements CatalogEntry

The entry is a high-level logical structure representing the physical filename, the site handle, and optional attributes related to the PFN as one entity.

The resource handle is the most frequently used attribute. In reality, the resource handle may be a relational attribute of the mapping relation between an LFN and a PFN - there is disagreement among the developers on this issue. For simplicity purposes, it appears to be sufficient to make the resource handle a regular PFN attribute.

Version:

$Revision: 50 $

Author:

Jens-S. V??ckler, Karan Vahi

Field Summary

private Map	m_attributeMap Any optional attributes associated with the PFN.
private String	m_pfn The physical filename.
static String	RESOURCE_HANDLE The (reserved) attribute name used for the resource handle.

Constructor Summary

ReplicaCatalogEntry()
Default constructor for arrays.

ReplicaCatalogEntry(String pfn)
Convenience constructor initializes the PFN.

ReplicaCatalogEntry(String pfn, Map attributes)
Standard constructor initializes the PFN and arbitrary attributes.

ReplicaCatalogEntry(String pfn, String handle)
Convenience constructor initializes the PFN and the resource handle.

Method Summary

void	addAttribute(Map attributes) Adds attributes to the existing attributes.
void	addAttribute(String key, Object value) Adds an attribute to the set of attributes.
boolean	equals(Object obj) Matches two ReplicaCatalogEntry objects.
Object	getAttribute(String key) Obtains the attribute value for a given key.
int	getAttributeCount() Counts the number of attributes known for the PFN.
Iterator	getAttributeIterator() Provides an iterator to traverse the attributes by their keys.
String	getPFN() Accessor: Obtains the PFN portion from this entry.
String	getResourceHandle() Obtains the resource handle from the attributes map.
boolean	hasAttribute(String key) Checks for the existence of an attribute key.
boolean	merge(ReplicaCatalogEntry rce, boolean overwrite) Merges the attribute maps in a controlled fashion.
static ReplicaCatalogEntry	merge(ReplicaCatalogEntry a, ReplicaCatalogEntry b, boolean overwrite) Merges the attribute maps of two entries in a controlled fashion.
void	removeAllAttribute() Removes all attributes associated with a PFN.
Object	removeAttribute(String name) Removes a specific attribute.
void	setAttribute(Map attributes) Replaces all existing attributes with new attributes.
void	setAttribute(String key, Object value) Adds a new or overwrites an existing attribute.
void	setPFN(String pfn) Accessor: Sets a new PFN to remember.
void	setResourceHandle(String handle) Sets a new resource handle to remember as PFN attribute.
String	toString() Converts the contents into a string.

Methods inherited from class java.lang.Object

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

Field Detail

RESOURCE_HANDLE

public static final String RESOURCE_HANDLE

The (reserved) attribute name used for the resource handle.

See Also:

Constant Field Values

m_pfn

private String m_pfn

The physical filename.

m_attributeMap

private Map m_attributeMap

Any optional attributes associated with the PFN.

Constructor Detail

ReplicaCatalogEntry

public ReplicaCatalogEntry()

Default constructor for arrays. The PFN is initialized to null, and thus must be explicitly set later. The map of attributes associated with the PFN is initialized to be empty. Thus, no resource handle is available.

ReplicaCatalogEntry

public ReplicaCatalogEntry(String pfn)

Convenience constructor initializes the PFN. The map of attributes is initialized to be empty. Thus, no resource handle is avaiable.

Parameters:

pfn - is the PFN to remember.

ReplicaCatalogEntry

public ReplicaCatalogEntry(String pfn,
                           String handle)

Convenience constructor initializes the PFN and the resource handle. The resource handle is stored as regular PFN attribute.

Parameters:

pfn - is the PFN to remember.

handle - is the resource handle to remember.

ReplicaCatalogEntry

public ReplicaCatalogEntry(String pfn,
                           Map attributes)

Standard constructor initializes the PFN and arbitrary attributes.

Parameters:

pfn - is the PFN to remember.

attributes - is a map of arbitrary attributes related to the PFN.

Method Detail

addAttribute

public void addAttribute(String key,
                         Object value)

Adds an attribute to the set of attributes. Note, this is identical to the setAttribute( String, Object ) method of the same signature.

Parameters:

key - is the key denoting an attribute.

value - is a value object to store.

addAttribute

public void addAttribute(Map attributes)

Adds attributes to the existing attributes.

Parameters:

attributes - is a map of attributes to add.

See Also:

setAttribute(Map), Map.putAll( Map )

getAttribute

public Object getAttribute(String key)

Obtains the attribute value for a given key.

Parameters:

key - is the key to look up

Returns:

the object stored as value, may be null.

See Also:

Map.get( Object )

hasAttribute

public boolean hasAttribute(String key)

Checks for the existence of an attribute key.

Parameters:

key - is the key to look up

Returns:

true if the key is known, false otherwise.

getAttributeCount

public int getAttributeCount()

Counts the number of attributes known for the PFN.

Returns:

number of attributes, may be zero.

See Also:

Map.size()

getAttributeIterator

public Iterator getAttributeIterator()

Provides an iterator to traverse the attributes by their keys.

Returns:

an iterator over the keys to walk the attribute list.

merge

public static ReplicaCatalogEntry merge(ReplicaCatalogEntry a,
                                        ReplicaCatalogEntry b,
                                        boolean overwrite)

Merges the attribute maps of two entries in a controlled fashion. Entries are only merged with another entry, if the physical filenames match.

Parameters:

a - is one replica catalog entry to merge.

b - is the other replica catalog entry to merge.

overwrite - resolves intersections. If true, uses rce's attribute to remain, if false, the original attribute remains.

Returns:

the merged entry, if the PFNs matched, or null if the PFN mismatched.

merge

public boolean merge(ReplicaCatalogEntry rce,
                     boolean overwrite)

Merges the attribute maps in a controlled fashion. An entry is only merged with another entry, if the physical filenames match.

Parameters:

rce - is another replica catalog entry to merge with.

overwrite - resolves intersections. If true, uses rce's attribute to remain, if false, the original attribute remains.

Returns:

true if a merge was attempted, false if the PFNs did not match.

removeAllAttribute

public void removeAllAttribute()

Removes all attributes associated with a PFN.

See Also:

removeAttribute( String )

removeAttribute

public Object removeAttribute(String name)

Removes a specific attribute.

Parameters:

name - is the name of the attribute to remove.

Returns:

the value object that was removed, or null, if the key was not in the map.

See Also:

removeAllAttribute()

setAttribute

public void setAttribute(String key,
                         Object value)

Adds a new or overwrites an existing attribute. Note, this is identical to the addAttribute( String, Object) method of the same signature.

Parameters:

key - is the name of the attribute

value - is the value object associated with the attribute.

setAttribute

public void setAttribute(Map attributes)

Replaces all existing attributes with new attributes. Existing attributes are removed before attempting a shallow copy of the new attributes.

Parameters:

attributes - is the map of new attributes to remember.

See Also:

addAttribute(Map)

getResourceHandle

public String getResourceHandle()

Obtains the resource handle from the attributes map. This is a convenience method. Internally, the PFN attribute map is queried for the value of the resource handle.

Returns:

the resource handle, or null if unset.

See Also:

setResourceHandle( String )

setResourceHandle

public void setResourceHandle(String handle)

Sets a new resource handle to remember as PFN attribute. This is a convenience method. Internally, the PFN attribute map is changed to remember the new resource handle.

Parameters:

handle - is the new resource handle.

See Also:

getResourceHandle()

getPFN

public String getPFN()

Accessor: Obtains the PFN portion from this entry.

Returns:

the physical filename, or null if unset.

See Also:

setPFN( String )

setPFN

public void setPFN(String pfn)

Accessor: Sets a new PFN to remember.

Parameters:

pfn - is a new physical filename.

See Also:

getPFN()

toString

public String toString()

Converts the contents into a string.

Overrides:

toString in class Object

Returns:

a textual representation of the item content.

equals

public boolean equals(Object obj)

Matches two ReplicaCatalogEntry objects. The primary key in this case is the pfn and all the attributes.

Overrides:

equals in class Object

Returns:

true if the pfn and all the attributes match, false otherwise.