diff --git a/src/java/davmail/exchange/ews/MultipleOperandBooleanExpression.java b/src/java/davmail/exchange/ews/MultipleOperandBooleanExpression.java
new file mode 100644
index 00000000..6a0455cb
--- /dev/null
+++ b/src/java/davmail/exchange/ews/MultipleOperandBooleanExpression.java
@@ -0,0 +1,53 @@
+/*
+ * DavMail POP/IMAP/SMTP/CalDav/LDAP Exchange Gateway
+ * Copyright (C) 2010  Mickael Guessant
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package davmail.exchange.ews;
+
+import java.io.IOException;
+import java.io.Writer;
+
+/**
+ * Boolean search expression
+ */
+public class MultipleOperandBooleanExpression implements SearchExpression {
+    public enum Operator {
+        And, Or, Not
+    }
+
+    private SearchExpression[] searchExpressions;
+    private Operator operator;
+
+    public MultipleOperandBooleanExpression(Operator operator, SearchExpression... searchExpressions) {
+        this.searchExpressions = searchExpressions;
+        this.operator = operator;
+    }
+
+    public void write(Writer writer) throws IOException {
+        writer.write("<t:");
+        writer.write(operator.toString());
+        writer.write(">");
+
+        for (SearchExpression searchExpression : searchExpressions) {
+            searchExpression.write(writer);
+        }
+
+        writer.write("</t:");
+        writer.write(operator.toString());
+        writer.write(">");
+    }
+}
diff --git a/src/java/davmail/exchange/ews/SearchExpression.java b/src/java/davmail/exchange/ews/SearchExpression.java
index cb92531f..4dd8a260 100644
--- a/src/java/davmail/exchange/ews/SearchExpression.java
+++ b/src/java/davmail/exchange/ews/SearchExpression.java
@@ -24,12 +24,12 @@ import java.io.Writer;
 /**
  * EWS Search Expression.
  */
-public abstract class SearchExpression {
+public interface SearchExpression {
     /**
      * Write XML content to writer.
      *
      * @param writer writer
      * @throws IOException on error
      */
-    public abstract void write(Writer writer) throws IOException;
+    public void write(Writer writer) throws IOException;
 }
diff --git a/src/java/davmail/exchange/ews/TwoOperandExpression.java b/src/java/davmail/exchange/ews/TwoOperandExpression.java
index 69d5fd65..6e346a78 100644
--- a/src/java/davmail/exchange/ews/TwoOperandExpression.java
+++ b/src/java/davmail/exchange/ews/TwoOperandExpression.java
@@ -24,7 +24,7 @@ import java.io.Writer;
 /**
  * Two operand expression.
  */
-public class TwoOperandExpression extends SearchExpression {
+public class TwoOperandExpression implements SearchExpression {
     protected enum Operator {
         IsEqualTo, IsNotEqualTo, IsGreaterThan, IsGreaterThanOrEqualTo, IsLessThan, IsLessThanOrEqualTo
     }
@@ -46,7 +46,6 @@ public class TwoOperandExpression extends SearchExpression {
         this.value = value;
     }
 
-    @Override
     public void write(Writer writer) throws IOException {
         writer.write("<t:");
         writer.write(operator.toString());