org.apache.stanbol.entityhub.core.site.CacheUtils Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.stanbol.entityhub.core.site;
import org.apache.stanbol.commons.namespaceprefix.NamespacePrefixService;
import org.apache.stanbol.entityhub.core.mapping.DefaultFieldMapperImpl;
import org.apache.stanbol.entityhub.core.mapping.FieldMappingUtils;
import org.apache.stanbol.entityhub.core.mapping.ValueConverterFactory;
import org.apache.stanbol.entityhub.servicesapi.mapping.FieldMapper;
import org.apache.stanbol.entityhub.servicesapi.mapping.FieldMapping;
import org.apache.stanbol.entityhub.servicesapi.model.Representation;
import org.apache.stanbol.entityhub.servicesapi.util.ModelUtils;
import org.apache.stanbol.entityhub.servicesapi.yard.Cache;
import org.apache.stanbol.entityhub.servicesapi.yard.CacheInitialisationException;
import org.apache.stanbol.entityhub.servicesapi.yard.CacheStrategy;
import org.apache.stanbol.entityhub.servicesapi.yard.Yard;
import org.apache.stanbol.entityhub.servicesapi.yard.YardException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public final class CacheUtils {
private CacheUtils(){}
private static Logger log = LoggerFactory.getLogger(CacheUtils.class);
/**
* Loads the base mappings form the parsed Yard
* @param yard The yard
* @param nsPrefixService if present '{prefix}:{localname}' configurations are
* @return The baseMappings
* @throws YardException on any Error while getting the Representation holding
* the Configuration from the Yard.
* @throws CacheInitialisationException if the configuration is found but not
* valid.
* @throws IllegalArgumentException if null is parsed as {@link Yard}
*/
public static FieldMapper loadBaseMappings(Yard yard, NamespacePrefixService nsPrefixService) throws YardException,CacheInitialisationException{
if(yard == null){
throw new IllegalArgumentException("The parsed Yard MUST NOT be NULL!");
}
Representation baseConfig = yard.getRepresentation(Cache.BASE_CONFIGURATION_URI);
if(baseConfig != null){
FieldMapper mapper = readFieldConfig(yard,baseConfig, nsPrefixService);
if(mapper == null){
String msg = "Invalid Base Configuration: Unable to parse FieldMappings from Field "+Cache.FIELD_MAPPING_CONFIG_FIELD;
log.error(msg);
if(log.isErrorEnabled()){
log.error(ModelUtils.getRepresentationInfo(baseConfig));
}
throw new CacheInitialisationException(msg);
} else {
return mapper;
}
} else {
return null;
//throw new CacheInitialisationException("Base Configuration not present");
}
}
/**
* Loads the additional field mappings used by this cache from the yard.
* This method sets the {@link #baseMapper} field during initialisation.
* @param yard The yard
* @param nsPrefixService if present '{prefix}:{localname}' configurations are
* @return The parsed mappings or null if no found
* @throws YardException on any Error while reading the {@link Representation}
* holding the configuration from the {@link Yard}.
* @throws IllegalArgumentException if null is parsed as {@link Yard}.
*/
protected static FieldMapper loadAdditionalMappings(Yard yard, NamespacePrefixService nsPrefixService) throws YardException {
if(yard == null){
throw new IllegalArgumentException("The parsed Yard MUST NOT be NULL!");
}
Representation addConfig = yard.getRepresentation(Cache.ADDITIONAL_CONFIGURATION_URI);
if(addConfig != null){
FieldMapper mapper = readFieldConfig(yard,addConfig, nsPrefixService);
if(mapper == null){
log.warn("Invalid Additinal Configuration: Unable to parse FieldMappings from Field "+Cache.FIELD_MAPPING_CONFIG_FIELD+"-> return NULL (no additional Configuration)");
if(log.isWarnEnabled()){
log.warn(ModelUtils.getRepresentationInfo(addConfig));
}
}
return mapper;
} else {
return null;
}
}
/**
* Reads the field mapping config from an document
* @param yard the yard of the parsed Representation
* @param config the configuration MUST NOT be null
* @param nsPrefixService if present '{prefix}:{localname}' configurations are
* supported for the fieldmappings used by the cache.
* @return A field mapper configured based on the configuration in the parsed {@link Representation}
* @throws if the parsed {@link Representation} does not contain a value for {@value CacheConstants.FIELD_MAPPING_CONFIG_FIELD}.
*/
private static FieldMapper readFieldConfig(Yard yard,Representation config, NamespacePrefixService nsPrefixService) {
Object mappingValue = config.getFirst(Cache.FIELD_MAPPING_CONFIG_FIELD);
if(mappingValue != null){
DefaultFieldMapperImpl fieldMapper = new DefaultFieldMapperImpl(ValueConverterFactory.getDefaultInstance());
for(String mappingStirng : mappingValue.toString().split("\n")){
FieldMapping mapping = FieldMappingUtils.parseFieldMapping(mappingStirng, nsPrefixService);
if(mapping != null){
log.info(" > add Mapping: "+mappingStirng);
fieldMapper.addMapping(mapping);
}
}
return fieldMapper;
} else {
return null;
}
}
/**
* Stores the baseMappings to the {@link Yard}. This may cause unexpected
* behaviour for subsequest calls of the stored configuration does not
* correspond with the actual data stored within the cache.
* Typically this is only used at the start or end of the creation of a
* full Cache ({@link CacheStrategy#all}) of an referenced site (entity source).
* Note also that if the {@link #baseMapper} is null this
* method removes any existing configuration from the yard.
* @throws YardException an any error while storing the config to the yard.
* @throws IllegalArgumentException if null is parsed as {@link Yard}.
*/
public static void storeBaseMappingsConfiguration(Yard yard,FieldMapper baseMapper) throws YardException,IllegalArgumentException {
if(yard == null){
throw new IllegalArgumentException("The parsed Yard MUST NOT be NULL!");
}
if(baseMapper == null){
yard.remove(Cache.BASE_CONFIGURATION_URI);
} else {
Representation config = yard.getValueFactory().createRepresentation(Cache.BASE_CONFIGURATION_URI);
writeFieldConfig(config,baseMapper);
yard.store(config);
}
}
/**
* Stores the current configuration used for caching documents back to the
* {@link Yard}. This configuration is present in the {@link #additionalMapper}).
* If this field is null than any existing configuration is
* removed form the index.
* @throws YardException on any error while changing the configuration in the
* yard.
* @throws IllegalArgumentException if null is parsed as {@link Yard}.
*/
protected static void storeAdditionalMappingsConfiguration(Yard yard,FieldMapper additionalMapper) throws YardException,IllegalArgumentException {
if(yard == null){
throw new IllegalArgumentException("The parsed Yard MUST NOT be NULL!");
}
if(additionalMapper == null){
yard.remove(Cache.ADDITIONAL_CONFIGURATION_URI);
} else {
Representation config = yard.getValueFactory().createRepresentation(Cache.ADDITIONAL_CONFIGURATION_URI);
writeFieldConfig(config,additionalMapper);
yard.store(config);
}
}
/**
* Serialises all {@link FieldMapping}s of the parsed {@link FieldMapper}
* and stores them in the {@value Cache#FIELD_MAPPING_CONFIG_FIELD} of the
* parsed {@link Representation}
* @param config the representation to store the field mapping configuration
* @param mapper the field mapper with the configuration to store
*/
private static void writeFieldConfig(Representation config, FieldMapper mapper){
StringBuilder builder = new StringBuilder();
for(FieldMapping mapping : mapper.getMappings()){
builder.append(FieldMappingUtils.serialiseFieldMapping(mapping));
builder.append('\n');
}
config.set(Cache.FIELD_MAPPING_CONFIG_FIELD, builder.toString());
}
}