package datomic.samples;

import datomic.Connection;

import datomic.Database;

import datomic.Datom;

import javax.sql.rowset.Predicate;

import java.io.IOException;

import java.io.InputStreamReader;

import java.net.URL;

import java.util.Collection;

import java.util.concurrent.ExecutionException;

import static datomic.Peer.q;

import static datomic.Peer.tempid;

import static datomic.Util.list;

import static datomic.Util.map;

import static datomic.samples.Fns.printQueryResult;

import static datomic.samples.Fns.scratchConnection;

import static datomic.samples.IO.resource;

import static datomic.samples.IO.transactAll;

public class Trust {

public static void main(String[] args) throws IOException, ExecutionException, InterruptedException {

Connection conn = scratchConnection();

URL url = resource("datomic-java-examples/social-news.edn");

transactAll(conn, new InputStreamReader(url.openStream()));

conn.transact(list(map(":db/id", tempid(":db.part/user"),

":story/title", "ElastiCache in 6 minutes",

":story/url", "http://blog.datomic.com/2012/09/elasticache-in-5-minutes.html"),

map(":db/id", tempid(":db.part/tx"),

"source/confidence", 95L))).get();

conn.transact(list(map(":db/id", tempid(":db.part/user"),

":story/title", "Request for Urgent Business Relationship",

":story/url", "http://example.com/bogus-url"),

map(":db/id", tempid(":db.part/tx"),

"source/confidence", 40L))).get();

Database db = conn.db();

System.out.println("\nAll stories...");

printQueryResult(allStories(db));

System.out.println("\nStories with 90% confidence, by query...");

printQueryResult(storiesWithHighConfidenceByQuery(db));

System.out.println("\nStories with 90% confidence, by filter...");

printQueryResult(storiesWithHighConfidenceByFilter(db));

}

public static Collection allStories(Database db) {

return q("[:find ?title" +

" :where [_ :story/title ?title]]", db);

}

public static Collection storiesWithHighConfidenceByQuery(Database db) {

return q("[:find ?title" +

" :where [_ :story/title ?title ?tx]" +

" [?tx :source/confidence ?conf]" +

" [(<= 90 ?conf)]]", db);

}

/**

* Returns database filtered to only facts whose transactions have

* :source/confidence level of 90% or higher

*/

public static Database filterByConfidence(Database db, final long conf) {

return db.filter(new Database.Predicate<datomic.Datom>() {

public boolean apply(Database db, Datom datom) {

Long confidence = (Long) db.entity(datom.tx()).get(":source/confidence");

return (confidence != null) && (confidence > conf);

}

});

}

public static Collection storiesWithHighConfidenceByFilter(Database db) {

return q("[:find ?title" +

" :where [_ :story/title ?title]]", filterByConfidence(db, 90L));

}

}