001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.pool2;
018
019/**
020 * A base class for common functionality.
021 *
022 * @since 2.4.3
023 */
024public abstract class BaseObject {
025
026    /**
027     * Constructs a new instance.
028     */
029    public BaseObject() {
030        // empty
031    }
032
033    @Override
034    public String toString() {
035        final StringBuilder builder = new StringBuilder();
036        builder.append(getClass().getSimpleName());
037        builder.append(" [");
038        toStringAppendFields(builder);
039        builder.append("]");
040        return builder.toString();
041    }
042
043    /**
044     * Used by sub-classes to include the fields defined by the sub-class in the
045     * {@link #toString()} output.
046     *
047     * @param builder Field names and values are appended to this object
048     */
049    protected void toStringAppendFields(final StringBuilder builder) {
050        // do nothing by default, needed for b/w compatibility.
051    }
052}