    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.beanutils;
    019
    020import java.io.IOException;
    021import java.io.ObjectInputStream;
    022import java.io.ObjectOutputStream;
    023import java.io.Serializable;
    024import java.io.StreamCorruptedException;
    025import java.util.List;
    026import java.util.Map;
    027
    028/**
    029 * <p>The metadata describing an individual property of a DynaBean.</p>
    030 *
    031 * <p>The meta contains an <em>optional</em> content type property ({@link #getContentType})
    032 * for use by mapped and iterated properties.
    033 * A mapped or iterated property may choose to indicate the type it expects.
    034 * The DynaBean implementation may choose to enforce this type on its entries.
    035 * Alternatively, an implementatin may choose to ignore this property.
    036 * All keys for maps must be of type String so no meta data is needed for map keys.</p>
    037 *
    038 */
    039
    040public class DynaProperty implements Serializable {
    041
    042    private static final long serialVersionUID = 1L;
    043    /*
    044     * There are issues with serializing primitive class types on certain JVM versions
    045     * (including java 1.3).
    046     * This class uses a custom serialization implementation that writes an integer
    047     * for these primitive class.
    048     * This list of constants are the ones used in serialization.
    049     * If these values are changed, then older versions will no longer be read correctly
    050     */
    051    private static final int BOOLEAN_TYPE = 1;
    052    private static final int BYTE_TYPE = 2;
    053    private static final int CHAR_TYPE = 3;
    054    private static final int DOUBLE_TYPE = 4;
    055    private static final int FLOAT_TYPE = 5;
    056    private static final int INT_TYPE = 6;
    057    private static final int LONG_TYPE = 7;
    058    private static final int SHORT_TYPE = 8;
    059
    060    /** Property name */
    061    protected String name;
    062
    063    /** Property type */
    064    protected transient Class<?> type;
    065
    066    /** The <em>(optional)</em> type of content elements for indexed <code>DynaProperty</code> */
    067    protected transient Class<?> contentType;
    068
    069    /**
    070     * Construct a property that accepts any data type.
    071     *
    072     * @param name Name of the property being described
    073     */
    074    public DynaProperty(final String name) {
    075
    076        this(name, Object.class);
    077
    078    }
    079    /**
    080     * Construct a property of the specified data type.
    081     *
    082     * @param name Name of the property being described
    083     * @param type Java class representing the property data type
    084     */
    085    public DynaProperty(final String name, final Class<?> type) {
    086
    087        this.name = name;
    088        this.type = type;
    089        if (type != null && type.isArray()) {
    090            this.contentType = type.getComponentType();
    091        }
    092
    093    }
    094
    095    /**
    096     * Construct an indexed or mapped <code>DynaProperty</code> that supports (pseudo)-introspection
    097     * of the content type.
    098     *
    099     * @param name Name of the property being described
    100     * @param type Java class representing the property data type
    101     * @param contentType Class that all indexed or mapped elements are instances of
    102     */
    103    public DynaProperty(final String name, final Class<?> type, final Class<?> contentType) {
    104
    105        this.name = name;
    106        this.type = type;
    107        this.contentType = contentType;
    108
    109    }
    110    /**
    111     * Checks this instance against the specified Object for equality. Overrides the
    112     * default refererence test for equality provided by {@link java.lang.Object#equals(Object)}
    113     * @param obj The object to compare to
    114     * @return <code>true</code> if object is a dyna property with the same name
    115     * type and content type, otherwise <code>false</code>
    116     * @since 1.8.0
    117     */
    118    @Override
    119    public boolean equals(final Object obj) {
    120
    121        boolean result = false;
    122
    123        result = obj == this;
    124
    125        if (!result && obj instanceof DynaProperty) {
    126            final DynaProperty that = (DynaProperty) obj;
    127            result =
    128               (this.name == null ? that.name == null : this.name.equals(that.name)) &&
    129               (this.type == null ? that.type == null : this.type.equals(that.type)) &&
    130               (this.contentType == null ? that.contentType == null : this.contentType.equals(that.contentType));
    131        }
    132
    133        return result;
    134    }
    135
    136    /**
    137     * Gets the <em>(optional)</em> type of the indexed content for <code>DynaProperty</code>'s
    138     * that support this feature.
    139     *
    140     * <p>There are issues with serializing primitive class types on certain JVM versions
    141     * (including java 1.3).
    142     * Therefore, this field <strong>must not be serialized using the standard methods</strong>.</p>
    143     *
    144     * @return the Class for the content type if this is an indexed <code>DynaProperty</code>
    145     * and this feature is supported. Otherwise null.
    146     */
    147    public Class<?> getContentType() {
    148        return contentType;
    149    }
    150    /**
    151     * Get the name of this property.
    152     * @return the name of the property
    153     */
    154    public String getName() {
    155        return this.name;
    156    }
    157
    158    /**
    159     * <p>Gets the Java class representing the data type of the underlying property
    160     * values.</p>
    161     *
    162     * <p>There are issues with serializing primitive class types on certain JVM versions
    163     * (including java 1.3).
    164     * Therefore, this field <strong>must not be serialized using the standard methods</strong>.</p>
    165     *
    166     * <p><strong>Please leave this field as <code>transient</code></strong></p>
    167     *
    168     * @return the property type
    169     */
    170    public Class<?> getType() {
    171        return this.type;
    172    }
    173
    174    /**
    175     * @return the hashcode for this dyna property
    176     * @see java.lang.Object#hashCode
    177     * @since 1.8.0
    178     */
    179    @Override
    180    public int hashCode() {
    181
    182       int result = 1;
    183
    184       result = result * 31 + (name == null ? 0 : name.hashCode());
    185       result = result * 31 + (type == null ? 0 : type.hashCode());
    186       return result * 31 + (contentType == null ? 0 : contentType.hashCode());
    187    }
    188
    189    /**
    190     * Does this property represent an indexed value (ie an array or List)?
    191     *
    192     * @return <code>true</code> if the property is indexed (i.e. is a List or
    193     * array), otherwise <code>false</code>
    194     */
    195    public boolean isIndexed() {
    196
    197        if (type == null) {
    198            return false;
    199        }
    200        if (type.isArray() || List.class.isAssignableFrom(type)) {
    201            return true;
    202        }
    203        return false;
    204
    205    }
    206
    207    /**
    208     * Does this property represent a mapped value (ie a Map)?
    209     *
    210     * @return <code>true</code> if the property is a Map
    211     * otherwise <code>false</code>
    212     */
    213    public boolean isMapped() {
    214
    215        if (type == null) {
    216            return false;
    217        }
    218        return Map.class.isAssignableFrom(type);
    219
    220    }
    221
    222    /**
    223     * Reads a class using safe encoding to workaround java 1.3 serialization bug.
    224     */
    225    private Class<?> readAnyClass(final ObjectInputStream in) throws IOException, ClassNotFoundException {
    226        // read back type class safely
    227        if (!in.readBoolean()) {
    228            // it's another class
    229            return (Class<?>) in.readObject();
    230        }
    231        // it's a type constant
    232        switch (in.readInt()) {
    233
    234            case BOOLEAN_TYPE: return   Boolean.TYPE;
    235            case BYTE_TYPE:    return      Byte.TYPE;
    236            case CHAR_TYPE:    return Character.TYPE;
    237            case DOUBLE_TYPE:  return    Double.TYPE;
    238            case FLOAT_TYPE:   return     Float.TYPE;
    239            case INT_TYPE:     return   Integer.TYPE;
    240            case LONG_TYPE:    return      Long.TYPE;
    241            case SHORT_TYPE:   return     Short.TYPE;
    242            default:
    243                // something's gone wrong
    244                throw new StreamCorruptedException(
    245                    "Invalid primitive type. "
    246                    + "Check version of beanutils used to serialize is compatible.");
    247
    248        }
    249    }
    250
    251    /**
    252     * Reads field values for this object safely. There are issues with serializing primitive class types on certain JVM versions (including java 1.3). This
    253     * method provides a workaround.
    254     *
    255     * @param in the content source.
    256     * @throws IOException            when the stream data values are outside expected range
    257     * @throws ClassNotFoundException Class of a serialized object cannot be found.
    258     */
    259    private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
    260        this.type = readAnyClass(in);
    261        if (isMapped() || isIndexed()) {
    262            this.contentType = readAnyClass(in);
    263        }
    264        // read other values
    265        in.defaultReadObject();
    266    }
    267
    268    /**
    269     * Return a String representation of this Object.
    270     *
    271     * @return a String representation of the dyna property
    272     */
    273    @Override
    274    public String toString() {
    275        final StringBuilder sb = new StringBuilder("DynaProperty[name=");
    276        sb.append(this.name);
    277        sb.append(",type=");
    278        sb.append(this.type);
    279        if (isMapped() || isIndexed()) {
    280            sb.append(" <").append(this.contentType).append(">");
    281        }
    282        sb.append("]");
    283        return sb.toString();
    284
    285    }
    286
    287    /**
    288     * Writes a class using safe encoding to workaround java 1.3 serialization bug.
    289     *
    290     * @throws IOException if I/O errors occur while writing to the underlying stream.
    291     */
    292    private void writeAnyClass(final Class<?> clazz, final ObjectOutputStream out) throws IOException {
    293        // safely write out any class
    294        int primitiveType = 0;
    295        if (Boolean.TYPE.equals(clazz)) {
    296            primitiveType = BOOLEAN_TYPE;
    297        } else if (Byte.TYPE.equals(clazz)) {
    298            primitiveType = BYTE_TYPE;
    299        } else if (Character.TYPE.equals(clazz)) {
    300            primitiveType = CHAR_TYPE;
    301        } else if (Double.TYPE.equals(clazz)) {
    302            primitiveType = DOUBLE_TYPE;
    303        } else if (Float.TYPE.equals(clazz)) {
    304            primitiveType = FLOAT_TYPE;
    305        } else if (Integer.TYPE.equals(clazz)) {
    306            primitiveType = INT_TYPE;
    307        } else if (Long.TYPE.equals(clazz)) {
    308            primitiveType = LONG_TYPE;
    309        } else if (Short.TYPE.equals(clazz)) {
    310            primitiveType = SHORT_TYPE;
    311        }
    312        if (primitiveType == 0) {
    313            // then it's not a primitive type
    314            out.writeBoolean(false);
    315            out.writeObject(clazz);
    316        } else {
    317            // we'll write out a constant instead
    318            out.writeBoolean(true);
    319            out.writeInt(primitiveType);
    320        }
    321    }
    322
    323    /**
    324     * Writes this object safely. There are issues with serializing primitive class types on certain JVM versions (including java 1.3). This method provides a
    325     * workaround.
    326     *
    327     * @param out Where to write.
    328     * @throws IOException if I/O errors occur while writing to the underlying stream.
    329     */
    330    private void writeObject(final ObjectOutputStream out) throws IOException {
    331        writeAnyClass(this.type,out);
    332        if (isMapped() || isIndexed()) {
    333            writeAnyClass(this.contentType,out);
    334        }
    335        // write out other values
    336        out.defaultWriteObject();
    337    }
    338}