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    1   /*
    2    * $Id: NewInstanceMetaMethod.java,v 1.1 2004/03/25 00:35:19 glaforge Exp $
    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 that the
    8    * following conditions are met:
    9    *  1. Redistributions of source code must retain copyright statements and
    10   * notices. Redistributions must also contain a copy of this document.
    11   *  2. Redistributions in binary form must reproduce the above copyright
    12   * notice, this list of conditions and the following disclaimer in the
    13   * documentation and/or other materials provided with the distribution.
    14   *  3. The name "groovy" must not be used to endorse or promote products
    15   * derived from this Software without prior written permission of The Codehaus.
    16   * For written permission, please contact info@codehaus.org.
    17   *  4. Products derived from this Software may not be called "groovy" nor may
    18   * "groovy" appear in their names without prior written permission of The
    19   * Codehaus. "groovy" is a registered trademark of The Codehaus.
    20   *  5. Due credit should be given to The Codehaus - http://groovy.codehaus.org/
    21   *
    22   * THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS ``AS IS'' AND ANY
    23   * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
    24   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    25   * DISCLAIMED. IN NO EVENT SHALL THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR
    26   * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
    27   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
    28   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
    29   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
    30   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
    31   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
    32   * DAMAGE.
    33   *
    34   */
    35  package org.codehaus.groovy.runtime;
    36
    37  import groovy.lang.MetaMethod;
    38
    39  import java.lang.reflect.Modifier;
    40
    41  /***
    42   * A MetaMethod implementation where the underlying method is really a static
    43   * helper method on some class but it appears to be an instance method on a class.
    44   *
    45   * This implementation is used to add new methods to the JDK writing them as normal
    46   * static methods with the first parameter being the class on which the method is added.
    47   *
    48   * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
    49   * @version $Revision: 1.1 $
    50   */
    51  public class NewInstanceMetaMethod extends MetaMethod {
    52
    53      private static final Class[] EMPTY_TYPE_ARRAY = {};
    54
    55      private MetaMethod metaMethod;
    56      private Class[] logicalParameterTypes;
    57
    58      public NewInstanceMetaMethod(MetaMethod metaMethod) {
    59          super(metaMethod);
    60          this.metaMethod = metaMethod;
    61          Class[] realParameterTypes = metaMethod.getParameterTypes();
    62          int size = realParameterTypes.length;
    63          if (size <= 1) {
    64              logicalParameterTypes = EMPTY_TYPE_ARRAY;
    65          }
    66          else {
    67              logicalParameterTypes = new Class[--size];
    68              System.arraycopy(realParameterTypes, 1, logicalParameterTypes, 0, size);
    69          }
    70      }
    71
    72      public Class getDeclaringClass() {
    73          return getBytecodeParameterTypes()[0];
    74      }
    75
    76      public boolean isStatic() {
    77          return false;
    78      }
    79
    80      public int getModifiers() {
    81          // lets clear the static bit
    82          return super.getModifiers() ^ Modifier.STATIC;
    83      }
    84
    85      public Class[] getParameterTypes() {
    86          return logicalParameterTypes;
    87      }
    88
    89      public Class[] getBytecodeParameterTypes() {
    90          return super.getParameterTypes();
    91      }
    92
    93      public Object invoke(Object object, Object[] arguments) throws Exception {
    94          // we need to cheat using the type
    95          int size = arguments.length;
    96          Object[] newArguments = new Object[size + 1];
    97          newArguments[0] = object;
    98          System.arraycopy(arguments, 0, newArguments, 1, size);
    99          return metaMethod.invoke(null, newArguments);
    100     }
    101 }