1 files changed, 72 insertions, 0 deletions
diff --git a/qpid/tools/src/java/qpid-qmf2/src/main/java/org/apache/qpid/qmf2/common/BooleanExists.java b/qpid/tools/src/java/qpid-qmf2/src/main/java/org/apache/qpid/qmf2/common/BooleanExists.java
new file mode 100644
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--- /dev/null
+++ b/qpid/tools/src/java/qpid-qmf2/src/main/java/org/apache/qpid/qmf2/common/BooleanExists.java
@@ -0,0 +1,72 @@
+/*
+ *
+ * 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.qpid.qmf2.common;
+
+// Misc Imports
+import java.util.List;
+
+/**
+ * A class to create and evaluate the BooleanExists Expression
+ *
+ * @author Fraser Adams
+ */
+public final class BooleanExists extends BooleanExpression
+{
+    /**
+     * Factory method to create an instance of BooleanExists
+     * @param expr the List of Expressions extracted by parsing the Query predicate
+     * @return an instance of the concrete BooleanExpression
+     */
+    public Expression create(final List expr) throws QmfException
+    {
+        return new BooleanExists(expr);
+    }
+
+    /**
+     * Basic Constructor primarily used by the prototype instance of each concrete BooleanExpression
+     */
+    public BooleanExists()
+    {
+    }
+
+    /**
+     * Main Constructor, uses base class constructor to populate unevaluated operands
+     * @param expr the List of Expressions extracted by parsing the Query predicate
+     */
+    public BooleanExists(final List expr) throws QmfException
+    {
+        super(1, expr);
+    }
+
+    /**
+     * Evaluate "exists" expression against a QmfData instance.
+     * N.B. to avoid complexities with types this class treats operands as Strings performing an appropriate evaluation
+     * of the String that makes sense for a given expression e.g. parsing as a double for >, >=, <, <=
+     *
+     * @param data the object to evaluate the expression against
+     * @return true if query matches the QmfData instance, else false.
+     */    
+    public boolean evaluate(final QmfData data)
+    {
+        return _operands[0] != null;
+    }
+}
+