/**
* The contents of this file are subject to the license and copyright
* detailed in the LICENSE and NOTICE files at the root of the source
* tree and available online at
*
* http://www.dspace.org/license/
*/
package org.dspace.identifier;
import org.apache.log4j.Logger;
import org.dspace.authorize.AuthorizeException;
import org.dspace.content.*;
import org.dspace.core.ConfigurationManager;
import org.dspace.core.Constants;
import org.dspace.core.Context;
import org.dspace.core.LogManager;
import org.dspace.storage.rdbms.DatabaseManager;
import org.dspace.storage.rdbms.TableRow;
import org.springframework.stereotype.Component;
import java.io.IOException;
import java.sql.SQLException;
/**
* The old DSpace handle identifier service, used to create handles or retrieve objects based on their handle
*
* @author Fabio Bolognesi (fabio at atmire dot com)
* @author Mark Diggory (markd at atmire dot com)
* @author Ben Bosman (ben at atmire dot com)
*/
@Component
public class HandleIdentifierProvider extends IdentifierProvider {
/** log4j category */
private static Logger log = Logger.getLogger(HandleIdentifierProvider.class);
/** Prefix registered to no one */
protected static final String EXAMPLE_PREFIX = "123456789";
protected String[] supportedPrefixes = new String[]{"info:hdl", "hdl", "http://"};
@Override
public boolean supports(Class<? extends Identifier> identifier) {
return Handle.class.isAssignableFrom(identifier);
}
public boolean supports(String identifier)
{
for(String prefix : supportedPrefixes){
if(identifier.startsWith(prefix))
{
return true;
}
}
try {
String outOfUrl = retrieveHandleOutOfUrl(identifier);
if(outOfUrl != null)
{
return true;
}
} catch (SQLException e) {
log.error(e.getMessage(), e);
}
return false;
}
public String register(Context context, DSpaceObject dso) {
try{
String id = mint(context, dso);
// move canonical to point the latest version
if(dso instanceof Item)
{
Item item = (Item)dso;
populateHandleMetadata(item, id);
}
return id;
}catch (Exception e){
log.error(LogManager.getHeader(context, "Error while attempting to create handle", "Item id: " + dso.getID()), e);
throw new RuntimeException("Error while attempting to create identifier for Item id: " + dso.getID(), e);
}
}
public void register(Context context, DSpaceObject dso, String identifier) {
try{
createNewIdentifier(context, dso, identifier);
if(dso instanceof Item)
{
Item item = (Item)dso;
populateHandleMetadata(item, identifier);
}
}catch (Exception e){
log.error(LogManager.getHeader(context, "Error while attempting to create handle", "Item id: " + dso.getID()), e);
throw new RuntimeException("Error while attempting to create identifier for Item id: " + dso.getID(), e);
}
}
public void reserve(Context context, DSpaceObject dso, String identifier) {
try{
TableRow handle = DatabaseManager.create(context, "Handle");
modifyHandleRecord(context, dso, handle, identifier);
}catch(Exception e){
log.error(LogManager.getHeader(context, "Error while attempting to create handle", "Item id: " + dso.getID()), e);
throw new RuntimeException("Error while attempting to create identifier for Item id: " + dso.getID());
}
}
/**
* Creates a new handle in the database.
*
* @param context DSpace context
* @param dso The DSpaceObject to create a handle for
* @return The newly created handle
* @exception java.sql.SQLException If a database error occurs
*/
public String mint(Context context, DSpaceObject dso) {
if(dso.getHandle() != null)
{
return dso.getHandle();
}
try{
return createNewIdentifier(context, dso, null);
}catch (Exception e){
log.error(LogManager.getHeader(context, "Error while attempting to create handle", "Item id: " + dso.getID()), e);
throw new RuntimeException("Error while attempting to create identifier for Item id: " + dso.getID());
}
}
public DSpaceObject resolve(Context context, String identifier, String... attributes) {
// We can do nothing with this, return null
try
{
TableRow dbhandle = findHandleInternal(context, identifier);
if (dbhandle == null)
{
//Check for an url
identifier = retrieveHandleOutOfUrl(identifier);
if(identifier != null)
{
dbhandle = findHandleInternal(context, identifier);
}
if(dbhandle == null)
{
return null;
}
}
if ((dbhandle.isColumnNull("resource_type_id")) || (dbhandle.isColumnNull("resource_id")))
{
throw new IllegalStateException("No associated resource type");
}
// What are we looking at here?
int handletypeid = dbhandle.getIntColumn("resource_type_id");
int resourceID = dbhandle.getIntColumn("resource_id");
if (handletypeid == Constants.ITEM)
{
Item item = Item.find(context, resourceID);
if (log.isDebugEnabled()) {
log.debug("Resolved handle " + identifier + " to item "
+ ((item == null) ? (-1) : item.getID()));
}
return item;
}
else if (handletypeid == Constants.COLLECTION)
{
Collection collection = Collection.find(context, resourceID);
if (log.isDebugEnabled()) {
log.debug("Resolved handle " + identifier + " to collection "
+ ((collection == null) ? (-1) : collection.getID()));
}
return collection;
}
else if (handletypeid == Constants.COMMUNITY)
{
Community community = Community.find(context, resourceID);
if (log.isDebugEnabled())
{
log.debug("Resolved handle " + identifier + " to community "
+ ((community == null) ? (-1) : community.getID()));
}
return community;
}
}catch (Exception e){
log.error(LogManager.getHeader(context, "Error while resolving handle to item", "handle: " + identifier), e);
}
// throw new IllegalStateException("Unsupported Handle Type "
// + Constants.typeText[handletypeid]);
return null;
}
@Override
public String lookup(Context context, DSpaceObject dso) throws IdentifierNotFoundException, IdentifierNotResolvableException {
try
{
TableRow row = getHandleInternal(context, dso.getType(), dso.getID());
if (row == null)
{
if (dso.getType() == Constants.SITE)
{
return Site.getSiteHandle();
}
else
{
return null;
}
}
else
{
return row.getStringColumn("handle");
}
}catch(SQLException sqe){
throw new IdentifierNotResolvableException(sqe.getMessage(),sqe);
}
}
@Override
public void delete(Context context, DSpaceObject dso, String identifier) throws IdentifierException {
delete(context, dso);
}
public void delete(Context context, DSpaceObject dso) throws IdentifierException {
try{
TableRow row = getHandleInternal(context, dso.getType(), dso.getID());
if (row != null)
{
//Only set the "resouce_id" column to null when unbinding a handle.
// We want to keep around the "resource_type_id" value, so that we
// can verify during a restore whether the same *type* of resource
// is reusing this handle!
row.setColumnNull("resource_id");
DatabaseManager.update(context, row);
if(log.isDebugEnabled())
{
log.debug("Unbound Handle " + row.getStringColumn("handle") + " from object " + Constants.typeText[dso.getType()] + " id=" + dso.getID());
}
}
else
{
log.warn("Cannot find Handle entry to unbind for object " + Constants.typeText[dso.getType()] + " id=" + dso.getID());
}
}catch(SQLException sqe)
{
throw new IdentifierException(sqe.getMessage(),sqe);
}
}
public static String retrieveHandleOutOfUrl(String url)
throws SQLException {
// We can do nothing with this, return null
if (!url.contains("/"))
{
return null;
}
String[] splitUrl = url.split("/");
return splitUrl[splitUrl.length - 2] + "/" + splitUrl[splitUrl.length - 1];
}
/**
* Get the configured Handle prefix string, or a default
* @return configured prefix or "123456789"
*/
public static String getPrefix()
{
String prefix = ConfigurationManager.getProperty("handle.prefix");
if (null == prefix)
{
prefix = EXAMPLE_PREFIX; // XXX no good way to exit cleanly
log.error("handle.prefix is not configured; using " + prefix);
}
return prefix;
}
protected static String getCanonicalForm(String handle)
{
// Let the admin define a new prefix, if not then we'll use the
// CNRI default. This allows the admin to use "hdl:" if they want to or
// use a locally branded prefix handle.myuni.edu.
String handlePrefix = ConfigurationManager.getProperty("handle.canonical.prefix");
if (handlePrefix == null || handlePrefix.length() == 0)
{
handlePrefix = "http://hdl.handle.net/";
}
return handlePrefix + handle;
}
protected String createNewIdentifier(Context context, DSpaceObject dso, String handleId) throws SQLException {
TableRow handle=null;
if(handleId != null)
{
handle = findHandleInternal(context, handleId);
if(handle!=null && !handle.isColumnNull("resource_id"))
{
//Check if this handle is already linked up to this specified DSpace Object
if(handle.getIntColumn("resource_id")==dso.getID() &&
handle.getIntColumn("resource_type_id")==dso.getType())
{
//This handle already links to this DSpace Object -- so, there's nothing else we need to do
return handleId;
}
else
{
//handle found in DB table & already in use by another existing resource
throw new IllegalStateException("Attempted to create a handle which is already in use: " + handleId);
}
}
}
else if(handle!=null && !handle.isColumnNull("resource_type_id"))
{
//If there is a 'resource_type_id' (but 'resource_id' is empty), then the object using
// this handle was previously unbound (see unbindHandle() method) -- likely because object was deleted
int previousType = handle.getIntColumn("resource_type_id");
//Since we are restoring an object to a pre-existing handle, double check we are restoring the same *type* of object
// (e.g. we will not allow an Item to be restored to a handle previously used by a Collection)
if(previousType != dso.getType())
{
throw new IllegalStateException("Attempted to reuse a handle previously used by a " +
Constants.typeText[previousType] + " for a new " +
Constants.typeText[dso.getType()]);
}
}
if(handle==null){
handle = DatabaseManager.create(context, "Handle");
handleId = createId(handle.getIntColumn("handle_id"));
}
modifyHandleRecord(context, dso, handle, handleId);
return handleId;
}
protected String modifyHandleRecord(Context context, DSpaceObject dso, TableRow handle, String handleId) throws SQLException {
handle.setColumn("handle", handleId);
handle.setColumn("resource_type_id", dso.getType());
handle.setColumn("resource_id", dso.getID());
DatabaseManager.update(context, handle);
if (log.isDebugEnabled())
{
log.debug("Created new handle for "
+ Constants.typeText[dso.getType()] + " " + handleId);
}
return handleId;
}
/**
* Return the handle for an Object, or null if the Object has no handle.
*
* @param context
* DSpace context
* @param type
* The type of object
* @param id
* The id of object
* @return The handle for object, or null if the object has no handle.
* @exception java.sql.SQLException
* If a database error occurs
*/
protected static TableRow getHandleInternal(Context context, int type, int id)
throws SQLException
{
String sql = "SELECT * FROM Handle WHERE resource_type_id = ? " +
"AND resource_id = ?";
return DatabaseManager.querySingleTable(context, "Handle", sql, type, id);
}
/**
* Find the database row corresponding to handle.
*
* @param context DSpace context
* @param handle The handle to resolve
* @return The database row corresponding to the handle
* @exception java.sql.SQLException If a database error occurs
*/
protected static TableRow findHandleInternal(Context context, String handle)
throws SQLException {
if (handle == null)
{
throw new IllegalArgumentException("Handle is null");
}
return DatabaseManager.findByUnique(context, "Handle", "handle", handle);
}
/**
* Create a new handle id. The implementation uses the PK of the RDBMS
* Handle table.
*
* @return A new handle id
* @exception java.sql.SQLException
* If a database error occurs
*/
protected static String createId(int id) throws SQLException
{
String handlePrefix = getPrefix();
return handlePrefix + (handlePrefix.endsWith("/") ? "" : "/") + id;
}
protected void populateHandleMetadata(Item item, String handle)
throws SQLException, IOException, AuthorizeException
{
String handleref = getCanonicalForm(handle);
// Add handle as identifier.uri DC value.
// First check that identifier doesn't already exist.
boolean identifierExists = false;
Metadatum[] identifiers = item.getDC("identifier", "uri", Item.ANY);
for (Metadatum identifier : identifiers)
{
if (handleref.equals(identifier.value))
{
identifierExists = true;
}
}
if (!identifierExists)
{
item.addDC("identifier", "uri", null, handleref);
}
}
}