Use isEmpty().

Add BlockDiskKeyStore.isEmpty().
diff --git a/commons-jcs-core/src/main/java/org/apache/commons/jcs3/auxiliary/disk/block/BlockDiskCache.java b/commons-jcs-core/src/main/java/org/apache/commons/jcs3/auxiliary/disk/block/BlockDiskCache.java
index 35a8c59..05103a2 100644
--- a/commons-jcs-core/src/main/java/org/apache/commons/jcs3/auxiliary/disk/block/BlockDiskCache.java
+++ b/commons-jcs-core/src/main/java/org/apache/commons/jcs3/auxiliary/disk/block/BlockDiskCache.java
@@ -136,7 +136,7 @@
 
             final boolean alright = verifyDisk();
 
-            if ( keyStore.size() == 0 || !alright )
+            if ( keyStore.isEmpty() || !alright )
             {
                 this.reset();
             }
diff --git a/commons-jcs-core/src/main/java/org/apache/commons/jcs3/auxiliary/disk/block/BlockDiskKeyStore.java b/commons-jcs-core/src/main/java/org/apache/commons/jcs3/auxiliary/disk/block/BlockDiskKeyStore.java
index 0b7bcfa..53eb1b7 100644
--- a/commons-jcs-core/src/main/java/org/apache/commons/jcs3/auxiliary/disk/block/BlockDiskKeyStore.java
+++ b/commons-jcs-core/src/main/java/org/apache/commons/jcs3/auxiliary/disk/block/BlockDiskKeyStore.java
@@ -343,6 +343,17 @@
     }
 
     /**
+     * Tests emptiness (size == 0).
+     * 
+     * @return Whether or not this is empty.
+     * @since 3.1
+     */
+    public boolean isEmpty()
+    {
+        return size() == 0;
+    }
+
+    /**
      * Gets the key set.
      * <p>
      *
diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index c9f95dd..4fad36a 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -19,6 +19,11 @@
 		<author email="dev@commons.apache.org">Apache Commons Developers</author>
 	</properties>
 	<body>
+        <release version="3.1" date="20YY-MM-DD">
+            <action dev="ggregory" type="add">
+                Add BlockDiskKeyStore.isEmpty().
+            </action>
+        </release>
         <release version="3.0" date="2020-08-16">
             <action issue="JCS-205" dev="tv" type="fix">
                 Fix packaging