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Apache Solr (module: core)
/*
* 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.solr.schema;
import java.io.IOException;
import java.lang.invoke.MethodHandles;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import org.apache.lucene.util.ResourceLoader;
import org.apache.solr.common.SolrException;
import org.apache.solr.util.SafeXMLParsing;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
/** Configuration for currency. Provides currency exchange rates. */
public class FileExchangeRateProvider implements ExchangeRateProvider {
private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
protected static final String PARAM_CURRENCY_CONFIG = "currencyConfig";
// Exchange rate map, maps Currency Code -> Currency Code -> Rate
private Map> rates = new HashMap<>();
private String currencyConfigFile;
private ResourceLoader loader;
/**
* Returns the currently known exchange rate between two currencies. If a direct rate has been
* loaded, it is used. Otherwise, if a rate is known to convert the target currency to the source,
* the inverse exchange rate is computed.
*
* @param sourceCurrencyCode The source currency being converted from.
* @param targetCurrencyCode The target currency being converted to.
* @return The exchange rate.
* @throws SolrException if the requested currency pair cannot be found
*/
@Override
public double getExchangeRate(String sourceCurrencyCode, String targetCurrencyCode) {
if (sourceCurrencyCode == null || targetCurrencyCode == null) {
throw new SolrException(
SolrException.ErrorCode.BAD_REQUEST, "Cannot get exchange rate; currency was null.");
}
if (sourceCurrencyCode.equals(targetCurrencyCode)) {
return 1.0;
}
Double directRate = lookupRate(sourceCurrencyCode, targetCurrencyCode);
if (directRate != null) {
return directRate;
}
Double symmetricRate = lookupRate(targetCurrencyCode, sourceCurrencyCode);
if (symmetricRate != null) {
return 1.0 / symmetricRate;
}
throw new SolrException(
SolrException.ErrorCode.BAD_REQUEST,
"No available conversion rate between " + sourceCurrencyCode + " to " + targetCurrencyCode);
}
/**
* Looks up the current known rate, if any, between the source and target currencies.
*
* @param sourceCurrencyCode The source currency being converted from.
* @param targetCurrencyCode The target currency being converted to.
* @return The exchange rate, or null if no rate has been registered.
*/
private Double lookupRate(String sourceCurrencyCode, String targetCurrencyCode) {
Map rhs = rates.get(sourceCurrencyCode);
if (rhs != null) {
return rhs.get(targetCurrencyCode);
}
return null;
}
/**
* Registers the specified exchange rate.
*
* @param ratesMap The map to add rate to
* @param sourceCurrencyCode The source currency.
* @param targetCurrencyCode The target currency.
* @param rate The known exchange rate.
*/
private void addRate(
Map> ratesMap,
String sourceCurrencyCode,
String targetCurrencyCode,
double rate) {
Map rhs = ratesMap.get(sourceCurrencyCode);
if (rhs == null) {
rhs = new HashMap<>();
ratesMap.put(sourceCurrencyCode, rhs);
}
rhs.put(targetCurrencyCode, rate);
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (!(o instanceof FileExchangeRateProvider)) return false;
FileExchangeRateProvider that = (FileExchangeRateProvider) o;
return Objects.equals(rates, that.rates);
}
@Override
public int hashCode() {
return rates != null ? rates.hashCode() : 0;
}
@Override
public String toString() {
return "[" + this.getClass().getName() + " : " + rates.size() + " rates.]";
}
@Override
public Set listAvailableCurrencies() {
Set currencies = new HashSet<>();
for (Map.Entry> entry : rates.entrySet()) {
currencies.add(entry.getKey());
for (String to : entry.getValue().keySet()) {
currencies.add(to);
}
}
return currencies;
}
@Override
public boolean reload() throws SolrException {
Map> tmpRates = new HashMap<>();
log.debug("Reloading exchange rates from file {}", currencyConfigFile);
try {
Document doc = SafeXMLParsing.parseConfigXML(log, loader, currencyConfigFile);
XPathFactory xpathFactory = XPathFactory.newInstance();
XPath xpath = xpathFactory.newXPath();
// Parse exchange rates.
NodeList nodes =
(NodeList) xpath.evaluate("/currencyConfig/rates/rate", doc, XPathConstants.NODESET);
for (int i = 0; i < nodes.getLength(); i++) {
Node rateNode = nodes.item(i);
NamedNodeMap attributes = rateNode.getAttributes();
Node from = attributes.getNamedItem("from");
Node to = attributes.getNamedItem("to");
Node rate = attributes.getNamedItem("rate");
if (from == null || to == null || rate == null) {
throw new SolrException(
SolrException.ErrorCode.SERVER_ERROR,
"Exchange rate missing attributes (required: from, to, rate) " + rateNode);
}
String fromCurrency = from.getNodeValue();
String toCurrency = to.getNodeValue();
Double exchangeRate;
if (null == CurrencyFieldType.getCurrency(fromCurrency)) {
throw new SolrException(
SolrException.ErrorCode.SERVER_ERROR,
"Specified 'from' currency not supported in this JVM: " + fromCurrency);
}
if (null == CurrencyFieldType.getCurrency(toCurrency)) {
throw new SolrException(
SolrException.ErrorCode.SERVER_ERROR,
"Specified 'to' currency not supported in this JVM: " + toCurrency);
}
try {
exchangeRate = Double.parseDouble(rate.getNodeValue());
} catch (NumberFormatException e) {
throw new SolrException(
SolrException.ErrorCode.SERVER_ERROR,
"Could not parse exchange rate: " + rateNode,
e);
}
addRate(tmpRates, fromCurrency, toCurrency, exchangeRate);
}
} catch (SAXException | IOException | XPathExpressionException e) {
throw new SolrException(
SolrException.ErrorCode.SERVER_ERROR,
"Error while parsing currency configuration file " + currencyConfigFile,
e);
}
// Atomically swap in the new rates map, if it loaded successfully
this.rates = tmpRates;
return true;
}
@Override
public void init(Map params) throws SolrException {
this.currencyConfigFile = params.get(PARAM_CURRENCY_CONFIG);
if (currencyConfigFile == null) {
throw new SolrException(
SolrException.ErrorCode.NOT_FOUND,
"Missing required configuration " + PARAM_CURRENCY_CONFIG);
}
// Removing config params custom to us
params.remove(PARAM_CURRENCY_CONFIG);
}
@Override
public void inform(ResourceLoader loader) throws SolrException {
if (loader == null) {
throw new SolrException(
SolrException.ErrorCode.SERVER_ERROR,
"Needs ResourceLoader in order to load config file");
}
this.loader = loader;
reload();
}
}