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Apache Commons Lang, a package of Java utility classes for the classes that are in java.lang's hierarchy, or are considered to be so standard as to justify existence in java.lang. The code is tested using the latest revision of the JDK for supported LTS releases: 8, 11, 17 and 21 currently. See https://github.com/apache/commons-lang/blob/master/.github/workflows/maven.yml Please ensure your build environment is up-to-date and kindly report any build issues.

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/*
 * 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.commons.lang3.builder;

import java.util.Collection;

import org.apache.commons.lang3.ClassUtils;

/**
 * Works with {@link ToStringBuilder} to create a "deep" {@code toString}.
 *
 * To use this class write code as follows:
 *
 *  * public class Job {
 *   String title;
 *   ...
 * }
 *
 * public class Person {
 *   String name;
 *   int age;
 *   boolean smoker;
 *   Job job;
 *
 *   ...
 *
 *   public String toString() {
 *     return new ReflectionToStringBuilder(this, new RecursiveToStringStyle()).toString();
 *   }
 * }
 * 
 *
 * This will produce a toString of the format:
 * {@code Person@7f54[name=Stephen,age=29,smoker=false,job=Job@43cd2[title=Manager]]}
 *
 * @since 3.2
 */
public class RecursiveToStringStyle extends ToStringStyle {

    /**
     * Required for serialization support.
     *
     * @see java.io.Serializable
     */
    private static final long serialVersionUID = 1L;

    /**
     * Constructor.
     */
    public RecursiveToStringStyle() {
        super();
    }

    @Override
    public void appendDetail(final StringBuffer buffer, final String fieldName, final Object value) {
        if (!ClassUtils.isPrimitiveWrapper(value.getClass()) &&
            !String.class.equals(value.getClass()) &&
            accept(value.getClass())) {
            buffer.append(ReflectionToStringBuilder.toString(value, this));
        } else {
            super.appendDetail(buffer, fieldName, value);
        }
    }

    @Override
    protected void appendDetail(final StringBuffer buffer, final String fieldName, final Collection coll) {
        appendClassName(buffer, coll);
        appendIdentityHashCode(buffer, coll);
        appendDetail(buffer, fieldName, coll.toArray());
    }

    /**
     * Returns whether or not to recursively format the given {@code Class}.
     * By default, this method always returns {@code true}, but may be overwritten by
     * sub-classes to filter specific classes.
     *
     * @param clazz
     *            The class to test.
     * @return Whether or not to recursively format the given {@code Class}.
     */
    protected boolean accept(final Class clazz) {
        return true;
    }
}