    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 */
    017
    018package org.apache.commons.beanutils2;
    019
    020import java.util.List;
    021import java.util.Map;
    022import java.util.Objects;
    023
    024/**
    025 * <p>
    026 * The metadata describing an individual property of a DynaBean.
    027 * </p>
    028 *
    029 * <p>
    030 * The meta contains an <em>optional</em> content type property ({@link #getContentType}) for use by mapped and iterated properties. A mapped or iterated
    031 * property may choose to indicate the type it expects. The DynaBean implementation may choose to enforce this type on its entries. Alternatively, an
    032 * implementation may choose to ignore this property. All keys for maps must be of type String so no meta data is needed for map keys.
    033 * </p>
    034 */
    035public class DynaProperty {
    036
    037    /*
    038     * There are issues with serializing primitive class types on certain JVM versions (including Java 1.3). This class uses a custom serialization
    039     * implementation that writes an integer for these primitive class. This list of constants are the ones used in serialization. If these values are changed,
    040     * then older versions will no longer be read correctly
    041     */
    042    private static final int BOOLEAN_TYPE = 1;
    043    private static final int BYTE_TYPE = 2;
    044    private static final int CHAR_TYPE = 3;
    045    private static final int DOUBLE_TYPE = 4;
    046    private static final int FLOAT_TYPE = 5;
    047    private static final int INT_TYPE = 6;
    048    private static final int LONG_TYPE = 7;
    049    private static final int SHORT_TYPE = 8;
    050
    051    /**
    052     * Empty array.
    053     */
    054    public static final DynaProperty[] EMPTY_ARRAY = {};
    055
    056    /** Property name */
    057    protected String name;
    058
    059    /** Property type */
    060    protected transient Class<?> type;
    061
    062    /** The <em>(optional)</em> type of content elements for indexed {@code DynaProperty} */
    063    protected transient Class<?> contentType;
    064
    065    /**
    066     * Constructs a property that accepts any data type.
    067     *
    068     * @param name Name of the property being described
    069     */
    070    public DynaProperty(final String name) {
    071        this(name, Object.class);
    072    }
    073
    074    /**
    075     * Constructs a property of the specified data type.
    076     *
    077     * @param name Name of the property being described
    078     * @param type Java class representing the property data type
    079     */
    080    public DynaProperty(final String name, final Class<?> type) {
    081        this.name = name;
    082        this.type = type;
    083        if (type != null && type.isArray()) {
    084            this.contentType = type.getComponentType();
    085        }
    086    }
    087
    088    /**
    089     * Constructs an indexed or mapped {@code DynaProperty} that supports (pseudo)-introspection of the content type.
    090     *
    091     * @param name        Name of the property being described
    092     * @param type        Java class representing the property data type
    093     * @param contentType Class that all indexed or mapped elements are instances of
    094     */
    095    public DynaProperty(final String name, final Class<?> type, final Class<?> contentType) {
    096        this.name = name;
    097        this.type = type;
    098        this.contentType = contentType;
    099    }
    100
    101    /**
    102     * Checks this instance against the specified Object for equality. Overrides the default reference test for equality provided by
    103     * {@link Object#equals(Object)}
    104     *
    105     * @param obj The object to compare to
    106     * @return {@code true} if object is a dyna property with the same name type and content type, otherwise {@code false}
    107     * @since 1.8.0
    108     */
    109    @Override
    110    public boolean equals(final Object obj) {
    111        boolean result;
    112
    113        result = obj == this;
    114
    115        if (!result && obj instanceof DynaProperty) {
    116            final DynaProperty that = (DynaProperty) obj;
    117            result = Objects.equals(this.name, that.name) && Objects.equals(this.type, that.type) && Objects.equals(this.contentType, that.contentType);
    118        }
    119
    120        return result;
    121    }
    122
    123    /**
    124     * Gets the <em>(optional)</em> type of the indexed content for {@code DynaProperty}'s that support this feature.
    125     *
    126     * <p>
    127     * There are issues with serializing primitive class types on certain JVM versions (including Java 1.3). Therefore, this field <strong>must not be
    128     * serialized using the standard methods</strong>.
    129     * </p>
    130     *
    131     * @return the Class for the content type if this is an indexed {@code DynaProperty} and this feature is supported. Otherwise null.
    132     */
    133    public Class<?> getContentType() {
    134        return contentType;
    135    }
    136
    137    /**
    138     * Gets the name of this property.
    139     *
    140     * @return the name of the property
    141     */
    142    public String getName() {
    143        return this.name;
    144    }
    145
    146    /**
    147     * <p>
    148     * Gets the Java class representing the data type of the underlying property values.
    149     * </p>
    150     *
    151     * <p>
    152     * There are issues with serializing primitive class types on certain JVM versions (including Java 1.3). Therefore, this field <strong>must not be
    153     * serialized using the standard methods</strong>.
    154     * </p>
    155     *
    156     * <p>
    157     * <strong>Please leave this field as {@code transient}</strong>
    158     * </p>
    159     *
    160     * @return the property type
    161     */
    162    public Class<?> getType() {
    163        return this.type;
    164    }
    165
    166    /**
    167     * @return the hash code for this dyna property
    168     * @see Object#hashCode
    169     * @since 1.8.0
    170     */
    171    @Override
    172    public int hashCode() {
    173        int result = 1;
    174
    175        result = result * 31 + (name == null ? 0 : name.hashCode());
    176        result = result * 31 + (type == null ? 0 : type.hashCode());
    177        result = result * 31 + (contentType == null ? 0 : contentType.hashCode());
    178
    179        return result;
    180    }
    181
    182    /**
    183     * Does this property represent an indexed value (ie an array or List)?
    184     *
    185     * @return {@code true} if the property is indexed (i.e. is a List or array), otherwise {@code false}
    186     */
    187    public boolean isIndexed() {
    188        if (type == null) {
    189            return false;
    190        }
    191        if (type.isArray() || List.class.isAssignableFrom(type)) {
    192            return true;
    193        }
    194        return false;
    195    }
    196
    197    /**
    198     * Does this property represent a mapped value (ie a Map)?
    199     *
    200     * @return {@code true} if the property is a Map otherwise {@code false}
    201     */
    202    public boolean isMapped() {
    203        if (type == null) {
    204            return false;
    205        }
    206        return Map.class.isAssignableFrom(type);
    207
    208    }
    209
    210    /**
    211     * Gets a String representation of this Object.
    212     *
    213     * @return a String representation of the dyna property
    214     */
    215    @Override
    216    public String toString() {
    217        final StringBuilder sb = new StringBuilder("DynaProperty[name=");
    218        sb.append(this.name);
    219        sb.append(",type=");
    220        sb.append(this.type);
    221        if (isMapped() || isIndexed()) {
    222            sb.append(" <").append(this.contentType).append(">");
    223        }
    224        sb.append("]");
    225        return sb.toString();
    226    }
    227
    228}