I think Olingo doesn't support the current Expression defined in http://docs.oasis-open.org/odata/odata/v4.01/odata-v4.01-part2-url-conventions.html#sec_AddressingtheCountofaCollection

The $filter=Products/$count  expression is supported, but when I try to define $filter=Products/$count($filter=Price eq 5.0) the following error is retrieved:

Illegal value of '$filter' option!

	at org.apache.olingo.server.core.uri.parser.Parser.checkOptionEOF(Parser.java:504)
	at org.apache.olingo.server.core.uri.parser.Parser.parseFilterOption(Parser.java:415)
	at org.apache.olingo.server.core.uri.parser.Parser.parseUri(Parser.java:281)
	at org.apache.olingo.server.core.uri.parser.FilterParserTest.basic(FilterParserTest.java:58)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
	at org.junit.runners.BlockJUnit4ClassRunner$1.evaluate(BlockJUnit4ClassRunner.java:100)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:366)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:103)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:63)
	at org.junit.runners.ParentRunner$4.run(ParentRunner.java:331)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329)
	at org.junit.runners.ParentRunner.access$100(ParentRunner.java:66)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293)
	at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:413)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater$1.execute(IdeaTestRunner.java:38)
	at com.intellij.rt.execution.junit.TestsRepeater.repeat(TestsRepeater.java:11)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:35)
	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:235)
	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)

lib/server-test/src/test/java/org/apache/olingo/server/core/uri/parser/FilterParserTest.java

@@ -0,0 +1,69 @@
+/*
+ * 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.olingo.server.core.uri.parser;
+
+import org.apache.olingo.commons.api.edm.Edm;
+import org.apache.olingo.commons.api.edm.FullQualifiedName;
+import org.apache.olingo.commons.api.edmx.EdmxReference;
+import org.apache.olingo.server.api.OData;
+import org.apache.olingo.server.api.uri.UriInfo;
+import org.apache.olingo.server.api.uri.UriInfoKind;
+import org.apache.olingo.server.api.uri.UriResource;
+import org.apache.olingo.server.api.uri.queryoption.ApplyItem;
+import org.apache.olingo.server.api.uri.queryoption.ApplyOption;
+import org.apache.olingo.server.api.uri.queryoption.FilterOption;
+import org.apache.olingo.server.api.uri.queryoption.OrderByItem;
+import org.apache.olingo.server.api.uri.queryoption.apply.*;
+import org.apache.olingo.server.api.uri.queryoption.apply.AggregateExpression.StandardMethod;
+import org.apache.olingo.server.api.uri.queryoption.apply.BottomTop.Method;
+import org.apache.olingo.server.api.uri.queryoption.expression.MethodKind;
+import org.apache.olingo.server.core.uri.UriInfoImpl;
+import org.apache.olingo.server.core.uri.testutil.*;
+import org.apache.olingo.server.core.uri.validator.UriValidationException;
+import org.apache.olingo.server.tecsvc.provider.*;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import static org.junit.Assert.*;
+
+/** Tests of the $apply parser inspired by the ABNF test cases. */
+public class FilterParserTest {
+
+  private static final OData odata = OData.newInstance();
+  private static final Edm edm = odata.createServiceMetadata(
+      new EdmTechProvider(), Collections.<EdmxReference> emptyList()).getEdm();
+
+  @Test
+  public void testFilterCountWithFilter() throws Exception {
+    final UriInfo uriInfo = new Parser(edm, odata).parseUri(
+            "ESTwoKeyNav", "$filter=NavPropertyETKeyNavMany/$count($filter=PropertyString eq 'hola') gt 1" , null, null);
+
+    Assert.assertNotNull(uriInfo.getFilterOption());
+  }
+
+
+
+
+
+
+}