    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 *      https://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 */
    017
    018package org.apache.commons.lang3.builder;
    019
    020import java.lang.reflect.AccessibleObject;
    021import java.lang.reflect.Field;
    022import java.lang.reflect.Modifier;
    023import java.util.Arrays;
    024import java.util.Collection;
    025import java.util.Comparator;
    026import java.util.Objects;
    027
    028import org.apache.commons.lang3.ArraySorter;
    029import org.apache.commons.lang3.ArrayUtils;
    030import org.apache.commons.lang3.ClassUtils;
    031import org.apache.commons.lang3.stream.Streams;
    032
    033/**
    034 * Assists in implementing {@link Object#toString()} methods using reflection.
    035 *
    036 * <p>
    037 * This class uses reflection to determine the fields to append. Because these fields are usually private, the class
    038 * uses {@link java.lang.reflect.AccessibleObject#setAccessible(java.lang.reflect.AccessibleObject[], boolean)} to
    039 * change the visibility of the fields. This will fail under a security manager, unless the appropriate permissions are
    040 * set up correctly.
    041 * </p>
    042 * <p>
    043 * Using reflection to access (private) fields circumvents any synchronization protection guarding access to these
    044 * fields. If a toString method cannot safely read a field, you should exclude it from the toString method, or use
    045 * synchronization consistent with the class' lock management around the invocation of the method. Take special care to
    046 * exclude non-thread-safe collection classes, because these classes may throw ConcurrentModificationException if
    047 * modified while the toString method is executing.
    048 * </p>
    049 * <p>
    050 * A typical invocation for this method would look like:
    051 * </p>
    052 * <pre>
    053 * public String toString() {
    054 *     return ReflectionToStringBuilder.toString(this);
    055 * }
    056 * </pre>
    057 * <p>
    058 * You can also use the builder to debug 3rd party objects:
    059 * </p>
    060 * <pre>
    061 * System.out.println(&quot;An object: &quot; + ReflectionToStringBuilder.toString(anObject));
    062 * </pre>
    063 * <p>
    064 * A subclass can control field output by overriding the methods:
    065 * </p>
    066 * <ul>
    067 * <li>{@link #accept(java.lang.reflect.Field)}</li>
    068 * <li>{@link #getValue(java.lang.reflect.Field)}</li>
    069 * </ul>
    070 * <p>
    071 * For example, this method does <em>not</em> include the {@code password} field in the returned {@link String}:
    072 * </p>
    073 * <pre>
    074 * public String toString() {
    075 *     return (new ReflectionToStringBuilder(this) {
    076 *         protected boolean accept(Field f) {
    077 *             return super.accept(f) &amp;&amp; !f.getName().equals(&quot;password&quot;);
    078 *         }
    079 *     }).toString();
    080 * }
    081 * </pre>
    082 * <p>
    083 * Alternatively the {@link ToStringExclude} annotation can be used to exclude fields from being incorporated in the
    084 * result.
    085 * </p>
    086 * <p>
    087 * It is also possible to use the {@link ToStringSummary} annotation to output the summary information instead of the
    088 * detailed information of a field.
    089 * </p>
    090 * <p>
    091 * The exact format of the {@code toString} is determined by the {@link ToStringStyle} passed into the constructor.
    092 * </p>
    093 *
    094 * <p>
    095 * <strong>Note:</strong> the default {@link ToStringStyle} will only do a "shallow" formatting, i.e. composed objects are not
    096 * further traversed. To get "deep" formatting, use an instance of {@link RecursiveToStringStyle}.
    097 * </p>
    098 *
    099 * @since 2.0
    100 */
    101public class ReflectionToStringBuilder extends ToStringBuilder {
    102
    103    /**
    104     * Converts the given Collection into an array of Strings. The returned array does not contain {@code null}
    105     * entries. Note that {@link Arrays#sort(Object[])} will throw an {@link NullPointerException} if an array element
    106     * is {@code null}.
    107     *
    108     * @param collection
    109     *            The collection to convert
    110     * @return A new array of Strings.
    111     */
    112    static String[] toNoNullStringArray(final Collection<String> collection) {
    113        if (collection == null) {
    114            return ArrayUtils.EMPTY_STRING_ARRAY;
    115        }
    116        return toNoNullStringArray(collection.toArray());
    117    }
    118
    119    /**
    120     * Returns a new array of Strings without null elements. Internal method used to normalize exclude lists
    121     * (arrays and collections). Note that {@link Arrays#sort(Object[])} will throw an {@link NullPointerException}
    122     * if an array element is {@code null}.
    123     *
    124     * @param array
    125     *            The array to check
    126     * @return The given array or a new array without null.
    127     */
    128    static String[] toNoNullStringArray(final Object[] array) {
    129        return Streams.nonNull(array).map(Objects::toString).toArray(String[]::new);
    130    }
    131
    132    /**
    133     * Builds a {@code toString} value using the default {@link ToStringStyle} through reflection.
    134     *
    135     * <p>
    136     * It uses {@code AccessibleObject.setAccessible} to gain access to private fields. This means that it will
    137     * throw a security exception if run under a security manager, if the permissions are not set up correctly. It is
    138     * also not as efficient as testing explicitly.
    139     * </p>
    140     *
    141     * <p>
    142     * Transient members will be not be included, as they are likely derived. Static fields will not be included.
    143     * Superclass fields will be appended.
    144     * </p>
    145     *
    146     * @param object
    147     *            the Object to be output
    148     * @return the String result
    149     * @throws IllegalArgumentException
    150     *             if the Object is {@code null}
    151     *
    152     * @see ToStringExclude
    153     * @see ToStringSummary
    154     */
    155    public static String toString(final Object object) {
    156        return toString(object, null, false, false, null);
    157    }
    158
    159    /**
    160     * Builds a {@code toString} value through reflection.
    161     *
    162     * <p>
    163     * It uses {@code AccessibleObject.setAccessible} to gain access to private fields. This means that it will
    164     * throw a security exception if run under a security manager, if the permissions are not set up correctly. It is
    165     * also not as efficient as testing explicitly.
    166     * </p>
    167     *
    168     * <p>
    169     * Transient members will be not be included, as they are likely derived. Static fields will not be included.
    170     * Superclass fields will be appended.
    171     * </p>
    172     *
    173     * <p>
    174     * If the style is {@code null}, the default {@link ToStringStyle} is used.
    175     * </p>
    176     *
    177     * @param object
    178     *            the Object to be output
    179     * @param style
    180     *            the style of the {@code toString} to create, may be {@code null}
    181     * @return the String result
    182     * @throws IllegalArgumentException
    183     *             if the Object or {@link ToStringStyle} is {@code null}
    184     *
    185     * @see ToStringExclude
    186     * @see ToStringSummary
    187     */
    188    public static String toString(final Object object, final ToStringStyle style) {
    189        return toString(object, style, false, false, null);
    190    }
    191
    192    /**
    193     * Builds a {@code toString} value through reflection.
    194     *
    195     * <p>
    196     * It uses {@code AccessibleObject.setAccessible} to gain access to private fields. This means that it will
    197     * throw a security exception if run under a security manager, if the permissions are not set up correctly. It is
    198     * also not as efficient as testing explicitly.
    199     * </p>
    200     *
    201     * <p>
    202     * If the {@code outputTransients} is {@code true}, transient members will be output, otherwise they
    203     * are ignored, as they are likely derived fields, and not part of the value of the Object.
    204     * </p>
    205     *
    206     * <p>
    207     * Static fields will not be included. Superclass fields will be appended.
    208     * </p>
    209     *
    210     * <p>
    211     * If the style is {@code null}, the default {@link ToStringStyle} is used.
    212     * </p>
    213     *
    214     * @param object
    215     *            the Object to be output
    216     * @param style
    217     *            the style of the {@code toString} to create, may be {@code null}
    218     * @param outputTransients
    219     *            whether to include transient fields
    220     * @return the String result
    221     * @throws IllegalArgumentException
    222     *             if the Object is {@code null}
    223     *
    224     * @see ToStringExclude
    225     * @see ToStringSummary
    226     */
    227    public static String toString(final Object object, final ToStringStyle style, final boolean outputTransients) {
    228        return toString(object, style, outputTransients, false, null);
    229    }
    230
    231    /**
    232     * Builds a {@code toString} value through reflection.
    233     *
    234     * <p>
    235     * It uses {@code AccessibleObject.setAccessible} to gain access to private fields. This means that it will
    236     * throw a security exception if run under a security manager, if the permissions are not set up correctly. It is
    237     * also not as efficient as testing explicitly.
    238     * </p>
    239     *
    240     * <p>
    241     * If the {@code outputTransients} is {@code true}, transient fields will be output, otherwise they
    242     * are ignored, as they are likely derived fields, and not part of the value of the Object.
    243     * </p>
    244     *
    245     * <p>
    246     * If the {@code outputStatics} is {@code true}, static fields will be output, otherwise they are
    247     * ignored.
    248     * </p>
    249     *
    250     * <p>
    251     * Static fields will not be included. Superclass fields will be appended.
    252     * </p>
    253     *
    254     * <p>
    255     * If the style is {@code null}, the default {@link ToStringStyle} is used.
    256     * </p>
    257     *
    258     * @param object
    259     *            the Object to be output
    260     * @param style
    261     *            the style of the {@code toString} to create, may be {@code null}
    262     * @param outputTransients
    263     *            whether to include transient fields
    264     * @param outputStatics
    265     *            whether to include static fields
    266     * @return the String result
    267     * @throws IllegalArgumentException
    268     *             if the Object is {@code null}
    269     *
    270     * @see ToStringExclude
    271     * @see ToStringSummary
    272     * @since 2.1
    273     */
    274    public static String toString(final Object object, final ToStringStyle style, final boolean outputTransients, final boolean outputStatics) {
    275        return toString(object, style, outputTransients, outputStatics, null);
    276    }
    277
    278    /**
    279     * Builds a {@code toString} value through reflection.
    280     *
    281     * <p>
    282     * It uses {@code AccessibleObject.setAccessible} to gain access to private fields. This means that it will
    283     * throw a security exception if run under a security manager, if the permissions are not set up correctly. It is
    284     * also not as efficient as testing explicitly.
    285     * </p>
    286     *
    287     * <p>
    288     * If the {@code outputTransients} is {@code true}, transient fields will be output, otherwise they
    289     * are ignored, as they are likely derived fields, and not part of the value of the Object.
    290     * </p>
    291     *
    292     * <p>
    293     * If the {@code outputStatics} is {@code true}, static fields will be output, otherwise they are
    294     * ignored.
    295     * </p>
    296     *
    297     * <p>
    298     * Superclass fields will be appended up to and including the specified superclass. A null superclass is treated as
    299     * {@link Object}.
    300     * </p>
    301     *
    302     * <p>
    303     * If the style is {@code null}, the default {@link ToStringStyle} is used.
    304     * </p>
    305     *
    306     * @param <T>
    307     *            the type of the object
    308     * @param object
    309     *            the Object to be output
    310     * @param style
    311     *            the style of the {@code toString} to create, may be {@code null}
    312     * @param outputTransients
    313     *            whether to include transient fields
    314     * @param outputStatics
    315     *            whether to include static fields
    316     * @param excludeNullValues
    317     *            whether to exclude fields whose values are null
    318     * @param reflectUpToClass
    319     *            the superclass to reflect up to (inclusive), may be {@code null}
    320     * @return the String result
    321     * @throws IllegalArgumentException
    322     *             if the Object is {@code null}
    323     *
    324     * @see ToStringExclude
    325     * @see ToStringSummary
    326     * @since 3.6
    327     */
    328    public static <T> String toString(
    329            final T object, final ToStringStyle style, final boolean outputTransients,
    330            final boolean outputStatics, final boolean excludeNullValues, final Class<? super T> reflectUpToClass) {
    331        return new ReflectionToStringBuilder(object, style, null, reflectUpToClass, outputTransients, outputStatics, excludeNullValues)
    332                .toString();
    333    }
    334
    335    /**
    336     * Builds a {@code toString} value through reflection.
    337     *
    338     * <p>
    339     * It uses {@code AccessibleObject.setAccessible} to gain access to private fields. This means that it will
    340     * throw a security exception if run under a security manager, if the permissions are not set up correctly. It is
    341     * also not as efficient as testing explicitly.
    342     * </p>
    343     *
    344     * <p>
    345     * If the {@code outputTransients} is {@code true}, transient fields will be output, otherwise they
    346     * are ignored, as they are likely derived fields, and not part of the value of the Object.
    347     * </p>
    348     *
    349     * <p>
    350     * If the {@code outputStatics} is {@code true}, static fields will be output, otherwise they are
    351     * ignored.
    352     * </p>
    353     *
    354     * <p>
    355     * Superclass fields will be appended up to and including the specified superclass. A null superclass is treated as
    356     * {@link Object}.
    357     * </p>
    358     *
    359     * <p>
    360     * If the style is {@code null}, the default {@link ToStringStyle} is used.
    361     * </p>
    362     *
    363     * @param <T>
    364     *            the type of the object
    365     * @param object
    366     *            the Object to be output
    367     * @param style
    368     *            the style of the {@code toString} to create, may be {@code null}
    369     * @param outputTransients
    370     *            whether to include transient fields
    371     * @param outputStatics
    372     *            whether to include static fields
    373     * @param reflectUpToClass
    374     *            the superclass to reflect up to (inclusive), may be {@code null}
    375     * @return the String result
    376     * @throws IllegalArgumentException
    377     *             if the Object is {@code null}
    378     *
    379     * @see ToStringExclude
    380     * @see ToStringSummary
    381     * @since 2.1
    382     */
    383    public static <T> String toString(
    384            final T object, final ToStringStyle style, final boolean outputTransients,
    385            final boolean outputStatics, final Class<? super T> reflectUpToClass) {
    386        return new ReflectionToStringBuilder(object, style, null, reflectUpToClass, outputTransients, outputStatics)
    387                .toString();
    388    }
    389
    390    /**
    391     * Builds a String for a toString method excluding the given field names.
    392     *
    393     * @param object
    394     *            The object to "toString".
    395     * @param excludeFieldNames
    396     *            The field names to exclude. Null excludes nothing.
    397     * @return The toString value.
    398     */
    399    public static String toStringExclude(final Object object, final Collection<String> excludeFieldNames) {
    400        return toStringExclude(object, toNoNullStringArray(excludeFieldNames));
    401    }
    402
    403    /**
    404     * Builds a String for a toString method excluding the given field names.
    405     *
    406     * @param object
    407     *            The object to "toString".
    408     * @param excludeFieldNames
    409     *            The field names to exclude
    410     * @return The toString value.
    411     */
    412    public static String toStringExclude(final Object object, final String... excludeFieldNames) {
    413        return new ReflectionToStringBuilder(object).setExcludeFieldNames(excludeFieldNames).toString();
    414    }
    415
    416    /**
    417     * Builds a String for a toString method including the given field names.
    418     *
    419     * @param object
    420     *            The object to "toString".
    421     * @param includeFieldNames
    422     *            {@code null} or empty means all fields are included. All fields are included by default. This method will override the default behavior.
    423     * @return The toString value.
    424     * @since 3.13.0
    425     */
    426    public static String toStringInclude(final Object object, final Collection<String> includeFieldNames) {
    427        return toStringInclude(object, toNoNullStringArray(includeFieldNames));
    428    }
    429
    430    /**
    431     * Builds a String for a toString method including the given field names.
    432     *
    433     * @param object
    434     *            The object to "toString".
    435     * @param includeFieldNames
    436     *            The field names to include. {@code null} or empty means all fields are included. All fields are included by default. This method will override the default
    437     *             behavior.
    438     * @return The toString value.
    439     * @since 3.13.0
    440     */
    441    public static String toStringInclude(final Object object, final String... includeFieldNames) {
    442        return new ReflectionToStringBuilder(object).setIncludeFieldNames(includeFieldNames).toString();
    443    }
    444
    445    /**
    446     * Whether or not to append static fields.
    447     */
    448    private boolean appendStatics;
    449
    450    /**
    451     * Whether or not to append transient fields.
    452     */
    453    private boolean appendTransients;
    454
    455    /**
    456     * Whether or not to append fields that are null.
    457     */
    458    private boolean excludeNullValues;
    459
    460    /**
    461     * Which field names to exclude from output. Intended for fields like {@code "password"}.
    462     *
    463     * @since 3.0 this is protected instead of private
    464     */
    465    protected String[] excludeFieldNames;
    466
    467    /**
    468     * Field names that will be included in the output. All fields are included by default.
    469     *
    470     * @since 3.13.0
    471     */
    472    protected String[] includeFieldNames;
    473
    474    /**
    475     * The last super class to stop appending fields for.
    476     */
    477    private Class<?> upToClass;
    478
    479    /**
    480     * Constructs a new instance.
    481     *
    482     * <p>
    483     * This constructor outputs using the default style set with {@code setDefaultStyle}.
    484     * </p>
    485     *
    486     * @param object
    487     *            the Object to build a {@code toString} for, must not be {@code null}
    488     */
    489    public ReflectionToStringBuilder(final Object object) {
    490        super(object);
    491    }
    492
    493    /**
    494     * Constructs a new instance.
    495     *
    496     * <p>
    497     * If the style is {@code null}, the default style is used.
    498     * </p>
    499     *
    500     * @param object
    501     *            the Object to build a {@code toString} for, must not be {@code null}
    502     * @param style
    503     *            the style of the {@code toString} to create, may be {@code null}
    504     */
    505    public ReflectionToStringBuilder(final Object object, final ToStringStyle style) {
    506        super(object, style);
    507    }
    508
    509    /**
    510     * Constructs a new instance.
    511     *
    512     * <p>
    513     * If the style is {@code null}, the default style is used.
    514     * </p>
    515     *
    516     * <p>
    517     * If the buffer is {@code null}, a new one is created.
    518     * </p>
    519     *
    520     * @param object
    521     *            the Object to build a {@code toString} for
    522     * @param style
    523     *            the style of the {@code toString} to create, may be {@code null}
    524     * @param buffer
    525     *            the {@link StringBuffer} to populate, may be {@code null}
    526     */
    527    public ReflectionToStringBuilder(final Object object, final ToStringStyle style, final StringBuffer buffer) {
    528        super(object, style, buffer);
    529    }
    530
    531    /**
    532     * Constructs a new instance.
    533     *
    534     * @param <T>
    535     *            the type of the object
    536     * @param object
    537     *            the Object to build a {@code toString} for
    538     * @param style
    539     *            the style of the {@code toString} to create, may be {@code null}
    540     * @param buffer
    541     *            the {@link StringBuffer} to populate, may be {@code null}
    542     * @param reflectUpToClass
    543     *            the superclass to reflect up to (inclusive), may be {@code null}
    544     * @param outputTransients
    545     *            whether to include transient fields
    546     * @param outputStatics
    547     *            whether to include static fields
    548     * @since 2.1
    549     */
    550    public <T> ReflectionToStringBuilder(
    551            final T object, final ToStringStyle style, final StringBuffer buffer,
    552            final Class<? super T> reflectUpToClass, final boolean outputTransients, final boolean outputStatics) {
    553        super(object, style, buffer);
    554        setUpToClass(reflectUpToClass);
    555        setAppendTransients(outputTransients);
    556        setAppendStatics(outputStatics);
    557    }
    558
    559    /**
    560     * Constructs a new instance.
    561     *
    562     * @param <T>
    563     *            the type of the object
    564     * @param object
    565     *            the Object to build a {@code toString} for
    566     * @param style
    567     *            the style of the {@code toString} to create, may be {@code null}
    568     * @param buffer
    569     *            the {@link StringBuffer} to populate, may be {@code null}
    570     * @param reflectUpToClass
    571     *            the superclass to reflect up to (inclusive), may be {@code null}
    572     * @param outputTransients
    573     *            whether to include transient fields
    574     * @param outputStatics
    575     *            whether to include static fields
    576     * @param excludeNullValues
    577     *            whether to exclude fields who value is null
    578     * @since 3.6
    579     */
    580    public <T> ReflectionToStringBuilder(
    581            final T object, final ToStringStyle style, final StringBuffer buffer,
    582            final Class<? super T> reflectUpToClass, final boolean outputTransients, final boolean outputStatics,
    583            final boolean excludeNullValues) {
    584        super(object, style, buffer);
    585        setUpToClass(reflectUpToClass);
    586        setAppendTransients(outputTransients);
    587        setAppendStatics(outputStatics);
    588        setExcludeNullValues(excludeNullValues);
    589    }
    590
    591    /**
    592     * Returns whether or not to append the given {@link Field}.
    593     * <ul>
    594     * <li>Transient fields are appended only if {@link #isAppendTransients()} returns {@code true}.
    595     * <li>Static fields are appended only if {@link #isAppendStatics()} returns {@code true}.
    596     * <li>Inner class fields are not appended.</li>
    597     * </ul>
    598     *
    599     * @param field
    600     *            The Field to test.
    601     * @return Whether or not to append the given {@link Field}.
    602     */
    603    protected boolean accept(final Field field) {
    604        if (field.getName().indexOf(ClassUtils.INNER_CLASS_SEPARATOR_CHAR) != -1) {
    605            // Reject field from inner class.
    606            return false;
    607        }
    608        if (Modifier.isTransient(field.getModifiers()) && !isAppendTransients()) {
    609            // Reject transient fields.
    610            return false;
    611        }
    612        if (Modifier.isStatic(field.getModifiers()) && !isAppendStatics()) {
    613            // Reject static fields.
    614            return false;
    615        }
    616
    617        if (this.excludeFieldNames != null
    618            && Arrays.binarySearch(this.excludeFieldNames, field.getName()) >= 0) {
    619            // Reject fields from the getExcludeFieldNames list.
    620            return false;
    621        }
    622
    623        if (ArrayUtils.isNotEmpty(includeFieldNames)) {
    624            // Accept fields from the getIncludeFieldNames list. {@code null} or empty means all fields are included. All fields are included by default.
    625            return Arrays.binarySearch(this.includeFieldNames, field.getName()) >= 0;
    626        }
    627
    628        return !field.isAnnotationPresent(ToStringExclude.class);
    629    }
    630
    631    /**
    632     * Appends the fields and values defined by the given object of the given Class.
    633     *
    634     * <p>
    635     * If a cycle is detected as an object is &quot;toString()'ed&quot;, such an object is rendered as if
    636     * {@code Object.toString()} had been called and not implemented by the object.
    637     * </p>
    638     *
    639     * @param clazz
    640     *            The class of object parameter
    641     */
    642    protected void appendFieldsIn(final Class<?> clazz) {
    643        if (clazz.isArray()) {
    644            reflectionAppendArray(getObject());
    645            return;
    646        }
    647        // The elements in the returned array are not sorted and are not in any particular order.
    648        final Field[] fields = ArraySorter.sort(clazz.getDeclaredFields(), Comparator.comparing(Field::getName));
    649        AccessibleObject.setAccessible(fields, true);
    650        for (final Field field : fields) {
    651            final String fieldName = field.getName();
    652            if (accept(field)) {
    653                try {
    654                    // Warning: Field.get(Object) creates wrappers objects
    655                    // for primitive types.
    656                    final Object fieldValue = getValue(field);
    657                    if (!excludeNullValues || fieldValue != null) {
    658                        this.append(fieldName, fieldValue, !field.isAnnotationPresent(ToStringSummary.class));
    659                    }
    660                } catch (final IllegalAccessException e) {
    661                    // this can't happen. Would get a Security exception instead throw a runtime exception in case the
    662                    // impossible happens.
    663                    throw new IllegalStateException(e);
    664                }
    665            }
    666        }
    667    }
    668
    669    /**
    670     * Gets the excludeFieldNames.
    671     *
    672     * @return the excludeFieldNames.
    673     */
    674    public String[] getExcludeFieldNames() {
    675        return this.excludeFieldNames.clone();
    676    }
    677
    678    /**
    679     * Gets the includeFieldNames
    680     *
    681     * @return the includeFieldNames.
    682     * @since 3.13.0
    683     */
    684    public String[] getIncludeFieldNames() {
    685        return this.includeFieldNames.clone();
    686    }
    687
    688    /**
    689     * Gets the last super class to stop appending fields for.
    690     *
    691     * @return The last super class to stop appending fields for.
    692     */
    693    public Class<?> getUpToClass() {
    694        return this.upToClass;
    695    }
    696
    697    /**
    698     * Calls {@code java.lang.reflect.Field.get(Object)}.
    699     *
    700     * @param field
    701     *            The Field to query.
    702     * @return The Object from the given Field.
    703     * @throws IllegalArgumentException
    704     *             see {@link java.lang.reflect.Field#get(Object)}
    705     * @throws IllegalAccessException
    706     *             see {@link java.lang.reflect.Field#get(Object)}
    707     *
    708     * @see java.lang.reflect.Field#get(Object)
    709     */
    710    protected Object getValue(final Field field) throws IllegalAccessException {
    711        return field.get(getObject());
    712    }
    713
    714    /**
    715     * Gets whether or not to append static fields.
    716     *
    717     * @return Whether or not to append static fields.
    718     * @since 2.1
    719     */
    720    public boolean isAppendStatics() {
    721        return this.appendStatics;
    722    }
    723
    724    /**
    725     * Gets whether or not to append transient fields.
    726     *
    727     * @return Whether or not to append transient fields.
    728     */
    729    public boolean isAppendTransients() {
    730        return this.appendTransients;
    731    }
    732
    733    /**
    734     * Gets whether or not to append fields whose values are null.
    735     *
    736     * @return Whether or not to append fields whose values are null.
    737     * @since 3.6
    738     */
    739    public boolean isExcludeNullValues() {
    740        return this.excludeNullValues;
    741    }
    742
    743    /**
    744     * Appends to the {@code toString} an {@link Object} array.
    745     *
    746     * @param array
    747     *            the array to add to the {@code toString}
    748     * @return {@code this} instance.
    749     */
    750    public ReflectionToStringBuilder reflectionAppendArray(final Object array) {
    751        getStyle().reflectionAppendArrayDetail(getStringBuffer(), null, array);
    752        return this;
    753    }
    754
    755    /**
    756     * Sets whether or not to append static fields.
    757     *
    758     * @param appendStatics
    759     *            Whether or not to append static fields.
    760     * @since 2.1
    761     */
    762    public void setAppendStatics(final boolean appendStatics) {
    763        this.appendStatics = appendStatics;
    764    }
    765
    766    /**
    767     * Sets whether or not to append transient fields.
    768     *
    769     * @param appendTransients
    770     *            Whether or not to append transient fields.
    771     */
    772    public void setAppendTransients(final boolean appendTransients) {
    773        this.appendTransients = appendTransients;
    774    }
    775
    776    /**
    777     * Sets the field names to exclude.
    778     *
    779     * @param excludeFieldNamesParam
    780     *            The excludeFieldNames to excluding from toString or {@code null}.
    781     * @return {@code this}
    782     */
    783    public ReflectionToStringBuilder setExcludeFieldNames(final String... excludeFieldNamesParam) {
    784        if (excludeFieldNamesParam == null) {
    785            this.excludeFieldNames = null;
    786        } else {
    787            // clone and remove nulls
    788            this.excludeFieldNames = ArraySorter.sort(toNoNullStringArray(excludeFieldNamesParam));
    789        }
    790        return this;
    791    }
    792
    793    /**
    794     * Sets whether or not to append fields whose values are null.
    795     *
    796     * @param excludeNullValues
    797     *            Whether or not to append fields whose values are null.
    798     * @since 3.6
    799     */
    800    public void setExcludeNullValues(final boolean excludeNullValues) {
    801        this.excludeNullValues = excludeNullValues;
    802    }
    803
    804    /**
    805     * Sets the field names to include. {@code null} or empty means all fields are included. All fields are included by default. This method will override the default behavior.
    806     *
    807     * @param includeFieldNamesParam
    808     *            The includeFieldNames that must be on toString or {@code null}.
    809     * @return {@code this}
    810     * @since 3.13.0
    811     */
    812    public ReflectionToStringBuilder setIncludeFieldNames(final String... includeFieldNamesParam) {
    813        if (includeFieldNamesParam == null) {
    814            this.includeFieldNames = null;
    815        } else {
    816            // clone and remove nulls
    817            this.includeFieldNames = ArraySorter.sort(toNoNullStringArray(includeFieldNamesParam));
    818        }
    819        return this;
    820    }
    821
    822    /**
    823     * Sets the last super class to stop appending fields for.
    824     *
    825     * @param clazz
    826     *            The last super class to stop appending fields for.
    827     */
    828    public void setUpToClass(final Class<?> clazz) {
    829        if (clazz != null) {
    830            final Object object = getObject();
    831            if (object != null && !clazz.isInstance(object)) {
    832                throw new IllegalArgumentException("Specified class is not a superclass of the object");
    833            }
    834        }
    835        this.upToClass = clazz;
    836    }
    837
    838    /**
    839     * Gets the String built by this builder.
    840     *
    841     * @return the built string
    842     */
    843    @Override
    844    public String toString() {
    845        if (getObject() == null) {
    846            return getStyle().getNullText();
    847        }
    848
    849        validate();
    850
    851        Class<?> clazz = getObject().getClass();
    852        appendFieldsIn(clazz);
    853        while (clazz.getSuperclass() != null && clazz != getUpToClass()) {
    854            clazz = clazz.getSuperclass();
    855            appendFieldsIn(clazz);
    856        }
    857        return super.toString();
    858    }
    859
    860    /**
    861     * Validates that include and exclude names do not intersect.
    862     */
    863    private void validate() {
    864        if (ArrayUtils.containsAny(this.excludeFieldNames, (Object[]) this.includeFieldNames)) {
    865            ToStringStyle.unregister(getObject());
    866            throw new IllegalStateException("includeFieldNames and excludeFieldNames must not intersect");
    867        }
    868    }
    869
    870}