Remove references to Iterators.<T>emptyIterator().

Fixes #57.

Author: Capstan

src/main/java/com/github/fge/jsonschema/core/report/AbstractProcessingReport.java

@@ -20,6 +20,7 @@
 package com.github.fge.jsonschema.core.report;
 
 import com.github.fge.jsonschema.core.exceptions.ProcessingException;
+import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Iterators;
 import com.google.common.collect.Lists;
 
@@ -183,7 +184,7 @@ protected final void dispatch(final ProcessingMessage message)
     @Override
     public Iterator<ProcessingMessage> iterator()
     {
-        return Iterators.emptyIterator();
+        return ImmutableSet.<ProcessingMessage>of().iterator();
     }
 
     @Override

src/test/java/com/github/fge/jsonschema/core/keyword/syntax/checkers/SyntaxCheckersTest.java

@@ -40,7 +40,7 @@
 import com.github.fge.jsonschema.core.tree.SchemaTree;
 import com.github.fge.msgsimple.bundle.MessageBundle;
 import com.github.fge.msgsimple.load.MessageBundles;
-import com.google.common.collect.Iterators;
+import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Lists;
 import org.mockito.ArgumentCaptor;
 import org.testng.annotations.BeforeMethod;
@@ -189,7 +189,7 @@ public final void invalidTypesAreReportedAsErrors(final JsonNode node)
     protected final Iterator<Object[]> getValueTests()
     {
         if (valueTests.isMissingNode())
-            return Iterators.emptyIterator();
+            return ImmutableSet.<Object[]>of().iterator();
 
         final List<Object[]> list = Lists.newArrayList();
 
@@ -247,7 +247,7 @@ public final void valueTestsSucceed(final JsonNode schema,
     protected final Iterator<Object[]> getPointerTests()
     {
         if (pointerTests.isMissingNode())
-            return Iterators.emptyIterator();
+            return ImmutableSet.<Object[]>of().iterator();
 
         final List<Object[]> list = Lists.newArrayList();
 

src/test/java/com/github/fge/jsonschema/core/processing/ProcessingResultTest.java

@@ -27,7 +27,7 @@
 import com.github.fge.jsonschema.core.report.ProcessingReport;
 import com.github.fge.msgsimple.bundle.MessageBundle;
 import com.github.fge.msgsimple.load.MessageBundles;
-import com.google.common.collect.Iterators;
+import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Lists;
 import org.testng.annotations.BeforeMethod;
 import org.testng.annotations.Test;
@@ -143,7 +143,7 @@ public void uncheckedReportCorrectlyReportsException()
         when(processor.process(anyReport(), any(In.class)))
             .thenThrow(exception);
         when(report.iterator())
-            .thenReturn(Iterators.<ProcessingMessage>emptyIterator());
+            .thenReturn(ImmutableSet.<ProcessingMessage>of().iterator());
 
         final ProcessingResult<Out> result
             = ProcessingResult.uncheckedResult(processor, report, input);