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    1   /*
    2    $Id: MethodCallExpression.java 4287 2006-12-01 13:00:13Z 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 org.codehaus.groovy.ast.expr;
    47
    48  import groovy.lang.MetaMethod;
    49
    50  import org.codehaus.groovy.ast.ClassHelper;
    51  import org.codehaus.groovy.ast.GroovyCodeVisitor;
    52
    53  /***
    54   * A method call on an object or class
    55   *
    56   * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
    57   * @version $Revision: 4287 $
    58   */
    59  public class MethodCallExpression extends Expression {
    60
    61      private Expression objectExpression;
    62      private Expression method;
    63      private Expression arguments;
    64      private boolean spreadSafe = false;
    65      private boolean safe = false;
    66      private boolean implicitThis;
    67
    68      public static Expression NO_ARGUMENTS = new TupleExpression();
    69
    70      public MetaMethod getMetaMethod() {
    71          return metaMethod;
    72      }
    73
    74      private MetaMethod metaMethod = null;
    75
    76      public MethodCallExpression(Expression objectExpression, String method, Expression arguments) {
    77          this(objectExpression,new ConstantExpression(method),arguments);
    78      }
    79
    80      public MethodCallExpression(Expression objectExpression, Expression method, Expression arguments) {
    81          this.objectExpression = objectExpression;
    82          this.method = method;
    83          this.arguments = arguments;
    84          //TODO: set correct type here
    85          // if setting type and a methodcall is the last expresssion in a method,
    86          // then the method will return null if the method itself is not void too!
    87          // (in bytecode after call: aconst_null, areturn)
    88          this.setType(ClassHelper.DYNAMIC_TYPE);
    89          this.setImplicitThis(true);
    90      }
    91
    92      public void visit(GroovyCodeVisitor visitor) {
    93          visitor.visitMethodCallExpression(this);
    94      }
    95
    96      public Expression transformExpression(ExpressionTransformer transformer) {
    97          MethodCallExpression answer =
    98              new MethodCallExpression(transformer.transform(objectExpression), transformer.transform(method), transformer.transform(arguments));
    99          answer.setSafe(safe);
    100         answer.setSourcePosition(this);
    101         return answer;
    102     }
    103
    104     public Expression getArguments() {
    105         return arguments;
    106     }
    107
    108     public Expression getMethod() {
    109         return method;
    110     }
    111
    112     /***
    113      * This method returns the method name as String if it is no dynamic
    114      * calculated method name, but an constant.
    115      */
    116     public String getMethodAsString() {
    117         if (! (method instanceof ConstantExpression)) return null;
    118         ConstantExpression constant = (ConstantExpression) method;
    119         return constant.getText();
    120     }
    121
    122     public Expression getObjectExpression() {
    123         return objectExpression;
    124     }
    125
    126     public String getText() {
    127         return objectExpression.getText() + "." + method.getText() + arguments.getText();
    128     }
    129
    130     /***
    131      * @return is this a safe method call, i.e. if true then if the source object is null
    132      * then this method call will return null rather than throwing a null pointer exception
    133      */
    134     public boolean isSafe() {
    135         return safe;
    136     }
    137
    138     public void setSafe(boolean safe) {
    139         this.safe = safe;
    140     }
    141
    142     public boolean isSpreadSafe() {
    143         return spreadSafe;
    144     }
    145
    146     public void setSpreadSafe(boolean value) {
    147         spreadSafe = value;
    148     }
    149
    150     /***
    151      * @return true if no object expression was specified otherwise if
    152      * some expression was specified for the object on which to evaluate
    153      * the method then return false
    154      */
    155     public boolean isImplicitThis() {
    156         return implicitThis;
    157     }
    158
    159     public void setImplicitThis(boolean implicitThis) {
    160         this.implicitThis = implicitThis;
    161     }
    162
    163     public String toString() {
    164         return super.toString()
    165             + "[object: "
    166             + objectExpression
    167             + " method: "
    168             + method
    169             + " arguments: "
    170             + arguments
    171             + "]";
    172     }
    173
    174     public void setMethod(MetaMethod mmeth) {
    175         this.metaMethod = mmeth;
    176         super.setType(ClassHelper.make(mmeth.getReturnType()));
    177     }
    178 }