/**
* 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.app.util;
import org.apache.log4j.Logger;
import org.dspace.app.util.service.MetadataExposureService;
import org.dspace.authorize.service.AuthorizeService;
import org.dspace.core.ConfigurationManager;
import org.dspace.core.Context;
import org.springframework.beans.factory.annotation.Autowired;
import java.sql.SQLException;
import java.util.*;
/**
* Static utility class to manage configuration for exposure (hiding) of
* certain Item metadata fields.
*
* This class answers the question, "is the user allowed to see this
* metadata field?" Any external interface (UI, OAI-PMH, etc) that
* disseminates metadata should consult it before disseminating the value
* of a metadata field.
*
* Since the MetadataExposure.isHidden() method gets called in a lot of inner
* loops, it is important to implement it efficiently, in both time and
* memory utilization. It computes an answer without consuming ANY memory
* (e.g. it does not build any temporary Strings) and in close to constant
* time by use of hash tables. Although most sites will only hide a few
* fields, we can't predict what the usage will be so it's better to make it
* scalable.
*
* Algorithm is as follows:
* 1. If a Context is provided and it has a user who is Administrator,
* always grant access (return false).
* 2. Return true if field is on the hidden list, false otherwise.
*
* The internal maps are populated from DSpace Configuration at the first
* call, in case the properties are not available in the static context.
*
* Configuration Properties:
* ## hide a single metadata field
* #metadata.hide.SCHEMA.ELEMENT[.QUALIFIER] = true
* # example: dc.type
* metadata.hide.dc.type = true
* # example: dc.description.provenance
* metadata.hide.dc.description.provenance = true
*
* @author Larry Stone
* @version $Revision: 3734 $
*/
public class MetadataExposureServiceImpl implements MetadataExposureService
{
protected Logger log = Logger.getLogger(MetadataExposureServiceImpl.class);
protected Map<String,Set<String>> hiddenElementSets = null;
protected Map<String,Map<String,Set<String>>> hiddenElementMaps = null;
protected final String CONFIG_PREFIX = "metadata.hide.";
@Autowired(required = true)
protected AuthorizeService authorizeService;
protected MetadataExposureServiceImpl()
{
}
@Override
public boolean isHidden(Context context, String schema, String element, String qualifier)
throws SQLException
{
boolean hidden = false;
// for schema.element, just check schema->elementSet
if (!isInitialized())
{
init();
}
if (qualifier == null)
{
Set<String> elts = hiddenElementSets.get(schema);
hidden = elts != null && elts.contains(element);
}
// for schema.element.qualifier, just schema->eltMap->qualSet
else
{
Map<String,Set<String>> elts = hiddenElementMaps.get(schema);
if (elts == null)
{
return false;
}
Set<String> quals = elts.get(element);
hidden = quals != null && quals.contains(qualifier);
}
if(hidden && context != null) {
// the administrator's override
hidden = !authorizeService.isAdmin(context);
}
return hidden;
}
/**
* Returns whether the maps from configuration have already been loaded
* into the hiddenElementSets property.
*
* @return true (initialized) or false (not initialized)
*/
protected boolean isInitialized()
{
return hiddenElementSets != null;
}
/**
* Loads maps from configuration unless it's already done.
* The configuration properties are a map starting with the
* "metadata.hide." prefix followed by schema, element and
* qualifier separated by dots and the value is true (hidden)
* or false (exposed).
*/
protected synchronized void init()
{
if (!isInitialized())
{
hiddenElementSets = new HashMap<>();
hiddenElementMaps = new HashMap<>();
Enumeration pne = ConfigurationManager.propertyNames();
while (pne.hasMoreElements())
{
String key = (String)pne.nextElement();
if (key.startsWith(CONFIG_PREFIX))
{
String mdField = key.substring(CONFIG_PREFIX.length());
String segment[] = mdField.split("\\.", 3);
// got schema.element.qualifier
if (segment.length == 3)
{
Map<String,Set<String>> eltMap = hiddenElementMaps.get(segment[0]);
if (eltMap == null)
{
eltMap = new HashMap<String,Set<String>>();
hiddenElementMaps.put(segment[0], eltMap);
}
if (!eltMap.containsKey(segment[1]))
{
eltMap.put(segment[1], new HashSet<String>());
}
eltMap.get(segment[1]).add(segment[2]);
}
// got schema.element
else if (segment.length == 2)
{
if (!hiddenElementSets.containsKey(segment[0]))
{
hiddenElementSets.put(segment[0], new HashSet<String>());
}
hiddenElementSets.get(segment[0]).add(segment[1]);
}
// oops..
else
{
log.warn("Bad format in hidden metadata directive, field=\""+mdField+"\", config property="+key);
}
}
}
}
}
}