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diff --git a/simple/simple-common/src/main/java/org/simpleframework/common/lease/ContractController.java b/simple/simple-common/src/main/java/org/simpleframework/common/lease/ContractController.java
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+/*
+ * ContractController.java May 2004
+ *
+ * Copyright (C) 2004, Niall Gallagher <niallg@users.sf.net>
+ *
+ * Licensed 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.simpleframework.common.lease;
+
+import org.simpleframework.common.lease.LeaseException;
+
+/**
+ * The <code>ContractController</code> forms the interface to the 
+ * lease management system. There are two actions permitted for 
+ * leased resources, these are lease issue and lease renewal. When 
+ * the lease is first issued it is scheduled for the contract
+ * duration. Once issued the lease can be renewed with another
+ * duration, which can be less than the previous duration used.
+ *
+ * @author Niall Gallagher
+ *
+ * @see org.simpleframework.common.lease.ContractMaintainer
+ */
+interface ContractController<T> {
+   
+   /**
+    * This method will establish a contract for the given duration.
+    * If the contract duration expires before it is renewed then a
+    * notification is sent, typically to a <code>Cleaner</code> to
+    * to signify that the resource should be released. The contract
+    * can also be cancelled by providing a zero length duration.
+    * 
+    * @param contract a contract representing a leased resource
+    *
+    * @exception Exception if the lease could not be done
+    */   
+   void issue(Contract<T> contract) throws LeaseException;
+   
+   /**
+    * This ensures that the contract is renewed for the duration on
+    * the contract, which may have changed since it was issued or
+    * last renewed. If the duration on the contract has changed this
+    * will insure the previous contract duration is revoked and the 
+    * new duration is used to maintain the leased resource.
+    *
+    * @param contract a contract representing a leased resource
+    *
+    * @exception Exception if the lease could not be done
+    */
+   void renew(Contract<T> contract) throws LeaseException;   
+   
+   /**
+    * This will cancel the lease and release the resource. This 
+    * has the same effect as the <code>renew</code> method with
+    * a zero length duration. Once this has been called the
+    * <code>Cleaner</code> used should be notified immediately.
+    * If the lease has already expired this throws an exception.
+    *
+    * @param contract a contract representing a leased resource
+    *
+    * @exception Exception if the expiry has been passed
+    */
+   void cancel(Contract<T> contract) throws LeaseException;
+   
+   /**
+    * This method is used to cancel all outstanding leases and to
+    * close the controller. Closing the controller ensures that it
+    * can no longer be used to issue or renew leases. All resources
+    * occupied by the controller are released, including threads,
+    * memory, and all leased resources occupied by the instance.  
+    */
+   void close();
+}