init

java/org/apache/tomcat/dbcp/pool2/BaseObjectPool.java

@@ -0,0 +1,144 @@
+/*
+ * 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.tomcat.dbcp.pool2;
+
+/**
+ * A simple base implementation of {@link ObjectPool}.
+ * Optional operations are implemented to either do nothing, return a value
+ * indicating it is unsupported or throw {@link UnsupportedOperationException}.
+ * <p>
+ * This class is intended to be thread-safe.
+ * </p>
+ *
+ * @param <T> Type of element pooled in this pool.
+ *
+ * @since 2.0
+ */
+public abstract class BaseObjectPool<T> extends BaseObject implements ObjectPool<T> {
+
+    @Override
+    public abstract T borrowObject() throws Exception;
+
+    @Override
+    public abstract void returnObject(T obj) throws Exception;
+
+    @Override
+    public abstract void invalidateObject(T obj) throws Exception;
+
+    /**
+     * Not supported in this base implementation.
+     *
+     * @return a negative value.
+     */
+    @Override
+    public int getNumIdle() {
+        return -1;
+    }
+
+    /**
+     * Not supported in this base implementation.
+     *
+     * @return a negative value.
+     */
+    @Override
+    public int getNumActive() {
+        return -1;
+    }
+
+    /**
+     * Not supported in this base implementation.
+     *
+     * @throws UnsupportedOperationException if the pool does not implement this
+     *          method
+     */
+    @Override
+    public void clear() throws Exception, UnsupportedOperationException {
+        throw new UnsupportedOperationException();
+    }
+
+    /**
+     * Not supported in this base implementation. Subclasses should override
+     * this behavior.
+     *
+     * @throws UnsupportedOperationException if the pool does not implement this
+     *          method
+     */
+    @Override
+    public void addObject() throws Exception, UnsupportedOperationException {
+        throw new UnsupportedOperationException();
+    }
+
+    /**
+     * Calls {@link ObjectPool#addObject()} <code>count</code>
+     * number of times.
+     *
+     * @param count
+     *            the number of idle objects to add.
+     * @throws Exception
+     *             when {@link ObjectPool#addObject()} fails.
+     * @since 2.8.0
+     */
+    @Override
+    public void addObjects(final int count) throws Exception {
+        for (int i = 0; i < count; i++) {
+            addObject();
+        }
+    }
+
+    /**
+     * {@inheritDoc}
+     * <p>
+     * This affects the behavior of <code>isClosed</code> and
+     * <code>assertOpen</code>.
+     * </p>
+     */
+    @Override
+    public void close() {
+        closed = true;
+    }
+
+    /**
+     * Has this pool instance been closed.
+     *
+     * @return <code>true</code> when this pool has been closed.
+     */
+    public final boolean isClosed() {
+        return closed;
+    }
+
+    /**
+     * Throws an <code>IllegalStateException</code> when this pool has been
+     * closed.
+     *
+     * @throws IllegalStateException when this pool has been closed.
+     *
+     * @see #isClosed()
+     */
+    protected final void assertOpen() throws IllegalStateException {
+        if (isClosed()) {
+            throw new IllegalStateException("Pool not open");
+        }
+    }
+
+    private volatile boolean closed = false;
+
+    @Override
+    protected void toStringAppendFields(final StringBuilder builder) {
+        builder.append("closed=");
+        builder.append(closed);
+    }
+}