- /*
- * Copyright 1999-2004 The Apache Software Foundation.
- *
- * 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.apache.commons.pool;
-
- /**
- * A pooling interface.
- * <p>
- * <code>ObjectPool</code> defines a trivially simple pooling interface. The only
- * required methods are {@link #borrowObject borrowObject} and {@link #returnObject returnObject}.
- * <p>
- * Example of use:
- * <table border="1" cellspacing="0" cellpadding="3" align="center" bgcolor="#FFFFFF"><tr><td><pre>
- * Object obj = <font color="#0000CC">null</font>
- *
- * <font color="#0000CC">try</font> {
- * obj = pool.borrowObject();
- * <font color="#00CC00">//...use the object...</font>
- * } <font color="#0000CC">catch</font>(Exception e) {
- * <font color="#00CC00">//...handle any exceptions...</font>
- * } <font color="#0000CC">finally</font> {
- * <font color="#00CC00">// make sure the object is returned to the pool</font>
- * <font color="#0000CC">if</font>(<font color="#0000CC">null</font> != obj) {
- * pool.returnObject(obj);
- * }
- * }</pre></td></tr></table>
- * See {@link org.apache.commons.pool.BaseObjectPool BaseObjectPool} for a simple base implementation.
- *
- * @author Rodney Waldhoff
- * @version $Revision: 1.11 $ $Date: 2004/02/28 11:46:33 $
- *
- */
- public interface ObjectPool {
- /**
- * Obtain an instance from my pool.
- * By contract, clients MUST return
- * the borrowed instance using
- * {@link #returnObject(java.lang.Object) returnObject}
- * or a related method as defined in an implementation
- * or sub-interface.
- * <p>
- * The behaviour of this method when the pool has been exhausted
- * is not specified (although it may be specified by implementations).
- *
- * @return an instance from my pool.
- */
- Object borrowObject() throws Exception;
-
- /**
- * Return an instance to my pool.
- * By contract, <i>obj</i> MUST have been obtained
- * using {@link #borrowObject() borrowObject}
- * or a related method as defined in an implementation
- * or sub-interface.
- *
- * @param obj a {@link #borrowObject borrowed} instance to be returned.
- */
- void returnObject(Object obj) throws Exception;
-
- /**
- * Invalidates an object from the pool
- * By contract, <i>obj</i> MUST have been obtained
- * using {@link #borrowObject() borrowObject}
- * or a related method as defined in an implementation
- * or sub-interface.
- * <p>
- * This method should be used when an object that has been borrowed
- * is determined (due to an exception or other problem) to be invalid.
- * If the connection should be validated before or after borrowing,
- * then the {@link PoolableObjectFactory#validateObject} method should be
- * used instead.
- *
- * @param obj a {@link #borrowObject borrowed} instance to be returned.
- */
- void invalidateObject(Object obj) throws Exception;
-
- /**
- * Create an object using my {@link #setFactory factory} or other
- * implementation dependent mechanism, and place it into the pool.
- * addObject() is useful for "pre-loading" a pool with idle objects.
- * (Optional operation).
- */
- void addObject() throws Exception;
-
- /**
- * Return the number of instances
- * currently idle in my pool (optional operation).
- * This may be considered an approximation of the number
- * of objects that can be {@link #borrowObject borrowed}
- * without creating any new instances.
- *
- * @return the number of instances currently idle in my pool
- * @throws UnsupportedOperationException if this implementation does not support the operation
- */
- int getNumIdle() throws UnsupportedOperationException;
-
- /**
- * Return the number of instances
- * currently borrowed from my pool
- * (optional operation).
- *
- * @return the number of instances currently borrowed in my pool
- * @throws UnsupportedOperationException if this implementation does not support the operation
- */
- int getNumActive() throws UnsupportedOperationException;
-
- /**
- * Clears any objects sitting idle in the pool, releasing any
- * associated resources (optional operation).
- *
- * @throws UnsupportedOperationException if this implementation does not support the operation
- */
- void clear() throws Exception, UnsupportedOperationException;
-
- /**
- * Close this pool, and free any resources associated with it.
- */
- void close() throws Exception;
-
- /**
- * Sets the {@link PoolableObjectFactory factory} I use
- * to create new instances (optional operation).
- * @param factory the {@link PoolableObjectFactory} I use to create new instances.
- *
- * @throws IllegalStateException when the factory cannot be set at this time
- * @throws UnsupportedOperationException if this implementation does not support the operation
- */
- void setFactory(PoolableObjectFactory factory) throws IllegalStateException, UnsupportedOperationException;
- }