net.cnri.apps.doserver

Class HashDirectoryStorage

java.lang.Object

net.cnri.apps.doserver.AbstractStorage

net.cnri.apps.doserver.HashDirectoryStorage

All Implemented Interfaces:

Storage

public class HashDirectoryStorage
extends AbstractStorage

HashDirectoryStorage stores digital objects and associated data elements using the file system. In order to support ridiculously large numbers of digital objects on systems that have limited directory sizes, the digital object IDs are hashed into a hexadecimal form, of which every 4 digits represents a part of the path to the directory containing the digital object's data elements.

Constructor Summary

Constructors

Constructor and Description
HashDirectoryStorage()

Method Summary

Methods

Modifier and Type	Method and Description
void	close()
static java.lang.String	convertFromFileName(java.lang.String fileName) Performs a conversion from the given encoded file name to the string that was encoded to get the file name.
static java.lang.String	convertToFileName(java.lang.String str) Performs a conversion from the given string to an encoded version that can be used as a file/URL name.
java.lang.String	createObject(java.lang.String id, java.lang.String objectName, boolean logTxn) Creates a new digital object with the given ID, if one does not already exist.
java.lang.String	createObject(java.lang.String id, java.lang.String objectName, boolean logTxn, long timestamp) Creates a new digital object with the given ID, if one does not already exist.
static byte	decodeHex(char b1, char b2) Decode the given two hexadecimal characters into the byte that they represent.
void	deleteAttributes(java.lang.String objectID, java.lang.String elementID, java.lang.String[] attributeKeys, boolean logTxn, long timestamp) Remove the attributes with the given keys from the object or data element.
boolean	deleteDataElement(java.lang.String objectID, java.lang.String elementID, boolean logTxn) Deletes the specified data element from the given object.
boolean	deleteDataElement(java.lang.String objectID, java.lang.String elementID, boolean logTxn, long timestamp) Deletes the specified data element from the given object.
void	deleteObject(java.lang.String objectID, boolean logTxn) Deletes the given object.
void	deleteObject(java.lang.String objectID, boolean logTxn, long timestamp) Deletes the given object.
void	deserializeObject(java.lang.String objectID, java.lang.String format, java.io.InputStream in) Reset the object's state and re-initialize the object with the data in the given InputStream in the given format.
boolean	doesDataElementExist(java.lang.String objectID, java.lang.String elementID) Returns true if the given data element exists
boolean	doesObjectExist(java.lang.String objectID) Returns true if the given digital object exists.
static void	encodeHex(byte[] buf, int offset, int length, java.lang.StringBuffer strBuf) Encode the given byte array into a hexadecimal string.
HeaderSet	getAttributes(java.lang.String objectID, java.lang.String elementID, HeaderSet container) Get the value that has been associated with the given key.
java.io.InputStream	getDataElement(java.lang.String objectID, java.lang.String elementID) Returns the identified data element for the given object.
java.io.File	getFileForDataElement(java.lang.String objectID, java.lang.String elementID) Returns the File in which the given data element is stored, if any.
DOMetadata	getObjectInfo(java.lang.String objectID, DOMetadata metadata) Returns any known metadata for the digital object with the given identifier.
void	initWithDirectory(Main server, java.io.File baseDirectory) Initializes the storage for use with server based in the given storage directory.
java.util.Enumeration	listDataElements(java.lang.String objectID) Returns an Enumeration (so that not all elements have to be loaded at once)
java.util.Enumeration	listObjects() Returns an Enumeration of all of the objects in the repository.
static void	main(java.lang.String[] argv)
void	serializeObject(java.lang.String objectID, java.lang.String format, java.io.OutputStream out) Write the entire object into the given OutputStream in the given format
void	setAttributes(java.lang.String objectID, java.lang.String elementID, HeaderSet attributes, boolean logTxn, long timestamp) Add the given key-value attribute to the object, replacing any existing attribute that has the same key.
void	setObjectInfo(DOMetadata metadata) Sets the metadata for the given digital object.
void	storeDataElement(java.lang.String objectID, java.lang.String elementID, java.io.InputStream input, boolean logTxn, boolean append) Stores the data read from the given InputStream into the given data element for the object identified by objectID.
void	storeDataElement(java.lang.String objectID, java.lang.String elementID, java.io.InputStream input, boolean logTxn, boolean append, long timestamp) Stores the data read from the given InputStream into the given data element for the object identified by objectID.
java.lang.String	toString()

Methods inherited from class net.cnri.apps.doserver.AbstractStorage

createObject, deleteAttributes, deleteDataElement, deleteObject, getTransactionQueue, initTransactionQueue, isConcatenatedQueueNeeded, setAttributes, setTransactionQueue, storeDataElement

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

HashDirectoryStorage

public HashDirectoryStorage()

Method Detail

initWithDirectory

public void initWithDirectory(Main server,
                     java.io.File baseDirectory)
                       throws DOException

Initializes the storage for use with server based in the given storage directory.

Throws:

DOException

close

public void close()

createObject

public java.lang.String createObject(java.lang.String id,
                            java.lang.String objectName,
                            boolean logTxn)
                              throws DOException

Creates a new digital object with the given ID, if one does not already exist. Returns the object identifier.

Throws:

DOException

createObject

public java.lang.String createObject(java.lang.String id,
                            java.lang.String objectName,
                            boolean logTxn,
                            long timestamp)
                              throws DOException

Creates a new digital object with the given ID, if one does not already exist. Returns the object identifier.

Throws:

DOException

deleteObject

public void deleteObject(java.lang.String objectID,
                boolean logTxn)
                  throws DOException

Deletes the given object.

Throws:

DOException

deleteObject

public void deleteObject(java.lang.String objectID,
                boolean logTxn,
                long timestamp)
                  throws DOException

Deletes the given object.

Throws:

DOException

getObjectInfo

public DOMetadata getObjectInfo(java.lang.String objectID,
                       DOMetadata metadata)
                         throws DOException

Returns any known metadata for the digital object with the given identifier. If the given DOMetadata object is non-null then the metadata is stored in that object which is also returned. Otherwise, a new DOMetadata instance is constructed and returned. Note that this method returns a non-null value whether or not the object exists.

Throws:

DOException

setObjectInfo

public void setObjectInfo(DOMetadata metadata)
                   throws DOException

Sets the metadata for the given digital object.

Throws:

DOException

deleteAttributes

public void deleteAttributes(java.lang.String objectID,
                    java.lang.String elementID,
                    java.lang.String[] attributeKeys,
                    boolean logTxn,
                    long timestamp)
                      throws DOException

Remove the attributes with the given keys from the object or data element. If the elementID is null then the attributes are removed from the object, otherwise they are removed from the element.

Throws:

DOException

setAttributes

public void setAttributes(java.lang.String objectID,
                 java.lang.String elementID,
                 HeaderSet attributes,
                 boolean logTxn,
                 long timestamp)
                   throws DOException

Add the given key-value attribute to the object, replacing any existing attribute that has the same key. If the elementID is non-null then the attribute is associated with the identified element within the object.

Throws:

DOException

getAttributes

public HeaderSet getAttributes(java.lang.String objectID,
                      java.lang.String elementID,
                      HeaderSet container)
                        throws DOException

Get the value that has been associated with the given key. If no value has been associated with the key then this will return null. If the given elementID is null then this will return object-level attributes. Otherwise it will return attributes for the given element.

Throws:

DOException

doesObjectExist

public boolean doesObjectExist(java.lang.String objectID)
                        throws DOException

Returns true if the given digital object exists.

Throws:

DOException

doesDataElementExist

public boolean doesDataElementExist(java.lang.String objectID,
                           java.lang.String elementID)
                             throws DOException

Returns true if the given data element exists

Throws:

DOException

getFileForDataElement

public java.io.File getFileForDataElement(java.lang.String objectID,
                                 java.lang.String elementID)
                                   throws DOException

Returns the File in which the given data element is stored, if any. This can return null on servers where data elements are not stored in files. This is used where operators need to do more with a data element than simple read and write operations. Examples inlude indexes, databases, etc.

Throws:

DOException

listObjects

public java.util.Enumeration listObjects()
                                  throws DOException

Returns an Enumeration of all of the objects in the repository.

Throws:

DOException

listDataElements

public java.util.Enumeration listDataElements(java.lang.String objectID)
                                       throws DOException

Returns an Enumeration (so that not all elements have to be loaded at once)

Throws:

DOException

getDataElement

public java.io.InputStream getDataElement(java.lang.String objectID,
                                 java.lang.String elementID)
                                   throws DOException

Returns the identified data element for the given object.

Throws:

DOException

storeDataElement

public void storeDataElement(java.lang.String objectID,
                    java.lang.String elementID,
                    java.io.InputStream input,
                    boolean logTxn,
                    boolean append)
                      throws DOException

Stores the data read from the given InputStream into the given data element for the object identified by objectID. This reads from the InputStream until the end of the stream has been reached.

Throws:

DOException

storeDataElement

public void storeDataElement(java.lang.String objectID,
                    java.lang.String elementID,
                    java.io.InputStream input,
                    boolean logTxn,
                    boolean append,
                    long timestamp)
                      throws DOException

Stores the data read from the given InputStream into the given data element for the object identified by objectID. This reads from the InputStream until the end of the stream has been reached.

Throws:

DOException

deleteDataElement

public boolean deleteDataElement(java.lang.String objectID,
                        java.lang.String elementID,
                        boolean logTxn)
                          throws DOException

Deletes the specified data element from the given object. Returns true if the specified data element ever existed in the first place.

Throws:

DOException

deleteDataElement

public boolean deleteDataElement(java.lang.String objectID,
                        java.lang.String elementID,
                        boolean logTxn,
                        long timestamp)
                          throws DOException

Deletes the specified data element from the given object. Returns true if the specified data element ever existed in the first place.

Throws:

DOException

serializeObject

public void serializeObject(java.lang.String objectID,
                   java.lang.String format,
                   java.io.OutputStream out)
                     throws DOException

Write the entire object into the given OutputStream in the given format

Throws:

DOException

deserializeObject

public void deserializeObject(java.lang.String objectID,
                     java.lang.String format,
                     java.io.InputStream in)
                       throws DOException

Reset the object's state and re-initialize the object with the data in the given InputStream in the given format.

Throws:

DOException

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

main

public static void main(java.lang.String[] argv)
                 throws java.lang.Exception

Throws:

java.lang.Exception

encodeHex

public static final void encodeHex(byte[] buf,
             int offset,
             int length,
             java.lang.StringBuffer strBuf)

Encode the given byte array into a hexadecimal string.

decodeHex

public static final byte decodeHex(char b1,
             char b2)

Decode the given two hexadecimal characters into the byte that they represent.

convertFromFileName

public static final java.lang.String convertFromFileName(java.lang.String fileName)

Performs a conversion from the given encoded file name to the string that was encoded to get the file name.

convertToFileName

public static final java.lang.String convertToFileName(java.lang.String str)

Performs a conversion from the given string to an encoded version that can be used as a file/URL name.