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    1   /*
    2    $Id: Expando.java 4578 2006-12-22 11:59:52Z blackdrag $
    3
    4    Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved.
    5
    6    Redistribution and use of this software and associated documentation
    7    ("Software"), with or without modification, are permitted provided
    8    that the following conditions are met:
    9
    10   1. Redistributions of source code must retain copyright
    11      statements and notices.  Redistributions must also contain a
    12      copy of this document.
    13
    14   2. Redistributions in binary form must reproduce the
    15      above copyright notice, this list of conditions and the
    16      following disclaimer in the documentation and/or other
    17      materials provided with the distribution.
    18
    19   3. The name "groovy" must not be used to endorse or promote
    20      products derived from this Software without prior written
    21      permission of The Codehaus.  For written permission,
    22      please contact info@codehaus.org.
    23
    24   4. Products derived from this Software may not be called "groovy"
    25      nor may "groovy" appear in their names without prior written
    26      permission of The Codehaus. "groovy" is a registered
    27      trademark of The Codehaus.
    28
    29   5. Due credit should be given to The Codehaus -
    30      http://groovy.codehaus.org/
    31
    32   THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS
    33   ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
    34   NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
    35   FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
    36   THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
    37   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
    38   (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
    39   SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
    40   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
    41   STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
    42   ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
    43   OF THE POSSIBILITY OF SUCH DAMAGE.
    44
    45   */
    46  package groovy.util;
    47
    48  import groovy.lang.Closure;
    49  import groovy.lang.GroovyObjectSupport;
    50  import groovy.lang.GroovyRuntimeException;
    51  import groovy.lang.MetaExpandoProperty;
    52  import groovy.lang.MissingPropertyException;
    53
    54  import java.util.HashMap;
    55  import java.util.Map;
    56  import java.util.Map.Entry;
    57  import java.util.List;
    58  import java.util.ArrayList;
    59  import java.util.Iterator;
    60
    61
    62  /***
    63   * Represents a dynamically expandable bean.
    64   *
    65   * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
    66   * @author Hein Meling
    67   * @author Pilho Kim
    68   * @version $Revision: 4578 $
    69   */
    70  public class Expando extends GroovyObjectSupport {
    71
    72      private Map expandoProperties;
    73
    74      public Expando() {
    75      }
    76
    77      public Expando(Map expandoProperties) {
    78          this.expandoProperties = expandoProperties;
    79      }
    80
    81      /***
    82       * @return the dynamically expanded properties
    83       */
    84      public Map getProperties() {
    85          if (expandoProperties == null) {
    86              expandoProperties = createMap();
    87          }
    88          return expandoProperties;
    89      }
    90
    91      public List getMetaPropertyValues() {
    92          // run through all our current properties and create MetaProperty objects
    93          List ret = new ArrayList();
    94          Iterator itr = getProperties().entrySet().iterator();
    95          while(itr.hasNext()) {
    96              Entry entry = (Entry) itr.next();
    97              ret.add(new MetaExpandoProperty(entry));
    98          }
    99
    100         return ret;
    101     }
    102
    103     public Object getProperty(String property) {
    104         // always use the expando properties first
    105         Object result = getProperties().get(property);
    106         if (result!=null) return result;
    107         try {
    108             return super.getProperty(property);
    109         }
    110         catch (MissingPropertyException e) {}
    111         return null;
    112     }
    113
    114     public void setProperty(String property, Object newValue) {
    115         // always use the expando properties
    116         getProperties().put(property, newValue);
    117     }
    118
    119     public Object invokeMethod(String name, Object args) {
    120         try {
    121             return super.invokeMethod(name, args);
    122         }
    123         catch (GroovyRuntimeException e) {
    124             // br should get a "native" property match first. getProperty includes such fall-back logic
    125             Object value = this.getProperty(name);
    126             if (value instanceof Closure) {
    127                 Closure closure = (Closure) value;
    128                 closure.setDelegate(this);
    129                 return closure.call((Object[]) args);
    130             }
    131             else {
    132                 throw e;
    133             }
    134         }
    135
    136     }
    137
    138     /***
    139      * This allows toString to be overridden by a closure <i>field</i> method attached
    140      * to the expando object.
    141      *
    142      * @see java.lang.Object#toString()
    143      */
    144      public String toString() {
    145         Object method = getProperties().get("toString");
    146         if (method != null && method instanceof Closure) {
    147             // invoke overridden toString closure method
    148             Closure closure = (Closure) method;
    149             closure.setDelegate(this);
    150             return closure.call().toString();
    151         } else {
    152             return expandoProperties.toString();
    153         }
    154      }
    155
    156     /***
    157      * This allows equals to be overridden by a closure <i>field</i> method attached
    158      * to the expando object.
    159      *
    160      * @see java.lang.Object#equals(java.lang.Object)
    161      */
    162     public boolean equals(Object obj) {
    163         Object method = getProperties().get("equals");
    164         if (method != null && method instanceof Closure) {
    165             // invoke overridden equals closure method
    166             Closure closure = (Closure) method;
    167             closure.setDelegate(this);
    168             Boolean ret = (Boolean) closure.call(obj);
    169             return ret.booleanValue();
    170         } else {
    171             return super.equals(obj);
    172         }
    173     }
    174
    175     /***
    176      * This allows hashCode to be overridden by a closure <i>field</i> method attached
    177      * to the expando object.
    178      *
    179      * @see java.lang.Object#hashCode()
    180      */
    181     public int hashCode() {
    182         Object method = getProperties().get("hashCode");
    183         if (method != null && method instanceof Closure) {
    184             // invoke overridden hashCode closure method
    185             Closure closure = (Closure) method;
    186             closure.setDelegate(this);
    187             Integer ret = (Integer) closure.call();
    188             return ret.intValue();
    189         } else {
    190             return super.hashCode();
    191         }
    192     }
    193
    194     /***
    195      * Factory method to create a new Map used to store the expando properties map
    196      * @return a newly created Map implementation
    197      */
    198     protected Map createMap() {
    199         return new HashMap();
    200     }
    201
    202 }