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    1   /*
    2    $Id: Script.java,v 1.22 2006/02/11 21:28:28 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
    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.lang;
    47
    48  import org.codehaus.groovy.ast.expr.ArgumentListExpression;
    49  import org.codehaus.groovy.control.CompilationFailedException;
    50  import org.codehaus.groovy.runtime.InvokerHelper;
    51
    52  import java.io.File;
    53  import java.io.IOException;
    54
    55  /***
    56   * This object represents a Groovy script
    57   *
    58   * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
    59   * @author Guillaume Laforge
    60   * @version $Revision: 1.22 $
    61   */
    62  public abstract class Script extends GroovyObjectSupport {
    63      private Binding binding = new Binding();
    64
    65      protected Script() {
    66      }
    67
    68      protected Script(Binding binding) {
    69          this.binding = binding;
    70      }
    71
    72      public Binding getBinding() {
    73          return binding;
    74      }
    75
    76      public void setBinding(Binding binding) {
    77          this.binding = binding;
    78      }
    79
    80      public Object getProperty(String property) {
    81          try {
    82              return binding.getVariable(property);
    83          } catch (MissingPropertyException e) {
    84              return super.getProperty(property);
    85          }
    86      }
    87
    88      public void setProperty(String property, Object newValue) {
    89          if ("binding".equals(property))
    90              setBinding((Binding) newValue);
    91          else
    92              binding.setVariable(property, newValue);
    93      }
    94
    95      /***
    96       * Invoke a method (or closure in the binding) defined.
    97       *
    98       * @param name method to call
    99       * @param args arguments to pass to the method
    100      * @return value
    101      */
    102     public Object invokeMethod(String name, Object args) {
    103         try {
    104             return super.invokeMethod(name, args);
    105         }
    106                 // if the method was not found in the current scope (the script's methods)
    107                 // let's try to see if there's a method closure with the same name in the binding
    108         catch (MissingMethodException mme) {
    109             try {
    110                 if (name.equals(mme.getMethod())) {
    111                     Object boundClosure = binding.getVariable(name);
    112                     if (boundClosure != null && boundClosure instanceof Closure) {
    113                         return ((Closure) boundClosure).call((Object[])args);
    114                     } else {
    115                         throw mme;
    116                     }
    117                 } else {
    118                     throw mme;
    119                 }
    120             } catch (MissingPropertyException mpe) {
    121                 throw mme;
    122             }
    123         }
    124     }
    125
    126     /***
    127      * The main instance method of a script which has variables in scope
    128      * as defined by the current {@link Binding} instance.
    129      *
    130      * @return
    131      */
    132     public abstract Object run();
    133
    134     // println helper methods
    135
    136     /***
    137      * Prints a newline to the current 'out' variable which should be a PrintWriter
    138      * or at least have a println() method defined on it.
    139      * If there is no 'out' property then print to standard out.
    140      */
    141     public void println() {
    142         Object object;
    143
    144         try {
    145             object = getProperty("out");
    146         } catch (MissingPropertyException e) {
    147             System.out.println();
    148             return;
    149         }
    150
    151         InvokerHelper.invokeMethod(object, "println", ArgumentListExpression.EMPTY_ARRAY);
    152     }
    153
    154     /***
    155      * Prints the value to the current 'out' variable which should be a PrintWriter
    156      * or at least have a print() method defined on it.
    157      * If there is no 'out' property then print to standard out.
    158      */
    159     public void print(Object value) {
    160         Object object;
    161
    162         try {
    163             object = getProperty("out");
    164         } catch (MissingPropertyException e) {
    165             System.out.print(value);
    166             return;
    167         }
    168
    169         InvokerHelper.invokeMethod(object, "print", new Object[]{value});
    170     }
    171
    172     /***
    173      * Prints the value and a newline to the current 'out' variable which should be a PrintWriter
    174      * or at least have a println() method defined on it.
    175      * If there is no 'out' property then print to standard out.
    176      */
    177     public void println(Object value) {
    178         Object object;
    179
    180         try {
    181             object = getProperty("out");
    182         } catch (MissingPropertyException e) {
    183             System.out.println(value);
    184             return;
    185         }
    186
    187         InvokerHelper.invokeMethod(object, "println", new Object[]{value});
    188     }
    189
    190     /***
    191      * A helper method to allow the dynamic evaluation of groovy expressions using this
    192      * scripts binding as the variable scope
    193      *
    194      * @param expression is the Groovy script expression to evaluate
    195      */
    196     public Object evaluate(String expression) throws CompilationFailedException, IOException {
    197         GroovyShell shell = new GroovyShell(binding);
    198         return shell.evaluate(expression);
    199     }
    200
    201     /***
    202      * A helper method to allow the dynamic evaluation of groovy expressions using this
    203      * scripts binding as the variable scope
    204      *
    205      * @param file is the Groovy script to evaluate
    206      */
    207     public Object evaluate(File file) throws CompilationFailedException, IOException {
    208         GroovyShell shell = new GroovyShell(binding);
    209         return shell.evaluate(file);
    210     }
    211
    212     /***
    213      * A helper method to allow scripts to be run taking command line arguments
    214      */
    215     public void run(File file, String[] arguments) throws CompilationFailedException, IOException {
    216         GroovyShell shell = new GroovyShell(binding);
    217         shell.run(file, arguments);
    218     }
    219 }