diff --git a/experimental/uloapi/src/main/java/info/mathhub/uloapi/html/Main.java b/experimental/uloapi/src/main/java/info/mathhub/uloapi/html/Main.java
index f84bdfcd6d28fa221ef14b83ced3e75d2dc0c9b8..82790004902de0b78363874ef480c2dd357cd0c4 100644
--- a/experimental/uloapi/src/main/java/info/mathhub/uloapi/html/Main.java
+++ b/experimental/uloapi/src/main/java/info/mathhub/uloapi/html/Main.java
@@ -13,6 +13,7 @@ public class Main {
public static void main(String[] args) {
get("/", Routes.index, new FreeMarkerEngine());
get("/statistics", Routes.statistics, new FreeMarkerEngine());
+ get("/queries", Routes.queries, new FreeMarkerEngine());
internalServerError(Errors.internalServerError);
notFound(Errors.notFound);
diff --git a/experimental/uloapi/src/main/java/info/mathhub/uloapi/html/Routes.java b/experimental/uloapi/src/main/java/info/mathhub/uloapi/html/Routes.java
index 1776d2b9d2ddcbac7c0564f9cbea0bd9063636d8..626c014f86e50b8fd97c138eb3a0cee3c6512f49 100644
--- a/experimental/uloapi/src/main/java/info/mathhub/uloapi/html/Routes.java
+++ b/experimental/uloapi/src/main/java/info/mathhub/uloapi/html/Routes.java
@@ -2,9 +2,12 @@ package info.mathhub.uloapi.html;
import info.mathhub.uloapi.query.Query;
import info.mathhub.uloapi.query.Statistics;
+import info.mathhub.uloapi.query.Timer;
+import org.eclipse.rdf4j.model.Statement;
import spark.*;
import java.util.HashMap;
+import java.util.List;
import java.util.Map;
/**
@@ -28,4 +31,18 @@ public class Routes {
return new ModelAndView(model, "statistics.flt");
};
+
+ public static final TemplateViewRoute queries = (Request request, Response response) -> {
+ final Query query = Query.getSingleton();
+
+ final Timer inductiveStatementsTimer = new Timer();
+ final List<Statement> inductiveStatements = query.getInductiveStatements();
+ final long inductiveStatementsDuration = inductiveStatementsTimer.elapsedMs();
+
+ final Map<String, Object> model = new HashMap<>();
+ model.put("inductive_statements", inductiveStatements);
+ model.put("inductive_statements_duration", inductiveStatementsDuration);
+
+ return new ModelAndView(model, "queries.flt");
+ };
}
diff --git a/experimental/uloapi/src/main/java/info/mathhub/uloapi/query/Query.java b/experimental/uloapi/src/main/java/info/mathhub/uloapi/query/Query.java
index 8369c91dfa3b5d90f6a430dce769895c9db8d121..7467424c5afcfcbd0edff05dd9fc88fb27a2b01e 100644
--- a/experimental/uloapi/src/main/java/info/mathhub/uloapi/query/Query.java
+++ b/experimental/uloapi/src/main/java/info/mathhub/uloapi/query/Query.java
@@ -1,20 +1,39 @@
package info.mathhub.uloapi.query;
import info.mathhub.uloapi.config.Config;
+import org.eclipse.rdf4j.model.Statement;
+import org.eclipse.rdf4j.repository.RepositoryResult;
import java.io.File;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+/**
+ * Class {@link Query} wraps various common queries to an RDF4j endpoint. Objects of type {@link Query}
+ * are safe for concurrent used by multiple threads.
+ */
public class Query {
private final String serverUrl;
private final String repository;
private static Query singleton;
+ /**
+ * Create a new object for the given endpoint.
+ *
+ * @param serverUrl URL of the RDF4J endpoint. Usually some kind of HTTP(S) URI.
+ * @param repository Name of the repository to connect to.
+ */
public Query(String serverUrl, String repository) {
this.serverUrl = serverUrl;
this.repository = repository;
}
+ /**
+ * Get {@link Query} instance that is configured to connect to the endpoint defined
+ * in {@code uloapi.properties}.
+ */
public static synchronized Query getSingleton() {
if (Query.singleton == null) {
Query.singleton = new Query(Config.serverUrl(), Config.repository());
@@ -23,6 +42,9 @@ public class Query {
return Query.singleton;
}
+ /**
+ * Return {@link Statistics} that contain some meta data about the connected repository.
+ */
public Statistics getStatistics() {
final GraphDB.Operation<Statistics> operation = (manager, repository, connection) -> {
final Statistics statistics = new Statistics();
@@ -43,4 +65,28 @@ public class Query {
return GraphDB.execute(this.serverUrl, this.repository, operation);
}
+
+ /**
+ * Return a list of triplets that define some kind of {@link ULO#INDUCTIVE_ON} relationship.
+ *
+ * @return The triplets. Limited to a small number, the actual number of matching triplets in the
+ * underlying RDF4j repository might be way bigger.
+ */
+ public List<Statement> getInductiveStatements() {
+ final GraphDB.Operation<List<Statement>> operation = (manager, repository, connection) -> {
+ final RepositoryResult<Statement> result = connection.getStatements(null, ULO.INDUCTIVE_ON, null);
+ final Iterator<Statement> iterator = result.iterator();
+
+ final List<Statement> statements = new ArrayList<>();
+
+ for (int i = 0; i < 16 && iterator.hasNext(); i++) {
+ final Statement statement = iterator.next();
+ statements.add(statement);
+ }
+
+ return statements;
+ };
+
+ return GraphDB.execute(this.serverUrl, this.repository, operation);
+ }
}
diff --git a/experimental/uloapi/src/main/java/info/mathhub/uloapi/query/Timer.java b/experimental/uloapi/src/main/java/info/mathhub/uloapi/query/Timer.java
new file mode 100644
index 0000000000000000000000000000000000000000..11bd881eafc858808bd0e1410b50ac0b29b905e5
--- /dev/null
+++ b/experimental/uloapi/src/main/java/info/mathhub/uloapi/query/Timer.java
@@ -0,0 +1,23 @@
+package info.mathhub.uloapi.query;
+
+/**
+ * Class for timing execution of methods. Create a new {@link Timer} object,
+ * run some operation and then get the elapsed time with {@link Timer#elapsedMs}.
+ */
+public class Timer {
+ private final long startMs;
+
+ public Timer() {
+ this.startMs = System.currentTimeMillis();
+ }
+
+ /**
+ * Return elapsed time since this object has been created.
+ *
+ * @return Elapsed time since object creation in milliseconds.
+ */
+ public long elapsedMs() {
+ final long stopMs = System.currentTimeMillis();
+ return stopMs - this.startMs;
+ }
+}
diff --git a/experimental/uloapi/src/main/java/info/mathhub/uloapi/query/ULO.java b/experimental/uloapi/src/main/java/info/mathhub/uloapi/query/ULO.java
index 75884ec67a4c2fde35507a0636bcd0f5d61c1e54..fc1b050404cae20ad6b7c11bb234a5a3971be08b 100644
--- a/experimental/uloapi/src/main/java/info/mathhub/uloapi/query/ULO.java
+++ b/experimental/uloapi/src/main/java/info/mathhub/uloapi/query/ULO.java
@@ -5,7 +5,6 @@ import org.eclipse.rdf4j.model.Namespace;
import org.eclipse.rdf4j.model.ValueFactory;
import org.eclipse.rdf4j.model.impl.SimpleNamespace;
import org.eclipse.rdf4j.model.impl.SimpleValueFactory;
-import org.eclipse.rdf4j.model.vocabulary.FOAF;
/**
* Constants for use with ULO, the Upper Library Ontology [1].
diff --git a/experimental/uloapi/src/main/java/info/mathhub/uloapi/rest/Errors.java b/experimental/uloapi/src/main/java/info/mathhub/uloapi/rest/Errors.java
index b5142d5b0429c287ef4d997b51ab03a362deb785..07dd798c555ad6691b21d3663529f34915c40b2c 100644
--- a/experimental/uloapi/src/main/java/info/mathhub/uloapi/rest/Errors.java
+++ b/experimental/uloapi/src/main/java/info/mathhub/uloapi/rest/Errors.java
@@ -4,7 +4,6 @@ import com.google.gson.Gson;
import org.eclipse.jetty.http.HttpStatus;
import spark.Request;
import spark.Response;
-import spark.ResponseTransformer;
import spark.Route;
public class Errors {
diff --git a/experimental/uloapi/src/main/java/info/mathhub/uloapi/rest/Routes.java b/experimental/uloapi/src/main/java/info/mathhub/uloapi/rest/Routes.java
index d563690a489f55464333dc31d1237627a0fd142b..c59693189e313061c64f83d6533dc5d3a4932d3d 100644
--- a/experimental/uloapi/src/main/java/info/mathhub/uloapi/rest/Routes.java
+++ b/experimental/uloapi/src/main/java/info/mathhub/uloapi/rest/Routes.java
@@ -1,7 +1,6 @@
package info.mathhub.uloapi.rest;
import info.mathhub.uloapi.query.Query;
-import org.eclipse.jetty.http.HttpStatus;
import spark.*;
import java.util.HashMap;
diff --git a/experimental/uloapi/src/main/resources/spark/template/freemarker/base.flt b/experimental/uloapi/src/main/resources/spark/template/freemarker/base.flt
index a0d1317491b573468964f577969c6b2fe067f9aa..19d8bea991f0235fdac3662046c92da83d6317dd 100644
--- a/experimental/uloapi/src/main/resources/spark/template/freemarker/base.flt
+++ b/experimental/uloapi/src/main/resources/spark/template/freemarker/base.flt
@@ -14,6 +14,7 @@
<title><@page_title/></title>
<style>
* {
+ background-color: white;
font-family: "Open Sans", Helvetica, Arial;
font-size: 12pt;
}
@@ -36,6 +37,14 @@
display: inline-block;
font-weight: bold;
}
+
+ h2 {
+ font-size: 14pt;
+ }
+
+ table {
+ text-align: left;
+ }
</style>
</head>
<body>
diff --git a/experimental/uloapi/src/main/resources/spark/template/freemarker/queries.flt b/experimental/uloapi/src/main/resources/spark/template/freemarker/queries.flt
new file mode 100644
index 0000000000000000000000000000000000000000..82c6db0819190591fe0956ff4affbff80bfe05c1
--- /dev/null
+++ b/experimental/uloapi/src/main/resources/spark/template/freemarker/queries.flt
@@ -0,0 +1,36 @@
+<#include "base.flt">
+
+<#macro page_title>
+ Statistics
+</#macro>
+
+<#macro page_main>
+ <h2>Queries</h2>
+
+ <p>
+ This page contains various example queries. They were executed using RDF4j which you
+ can think of as SPARQL for JVM languages.
+ </p>
+
+ <h3>Inductive Queries</h3>
+
+ <p>
+ Show some tuples where <em>x</em> is inductive on <em>y</em>.
+ Query took ${inductive_statements_duration} ms.
+ </p>
+
+ <table>
+ <tr>
+ <th>Subject <em>x</em></th>
+ <th>Object <em>y</em></th>
+ </tr>
+ <#list inductive_statements as statement>
+ <tr>
+ <td>${statement.subject}</td>
+ <td>${statement.object}</td>
+ </tr>
+ </#list>
+ </table>
+</#macro>
+
+<@display_page/>