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From sh...@apache.org
Subject cvs commit: jakarta-taglibs/standard/src/org/apache/taglibs/standard/lang/jstl FunctionInvocation.java
Date Mon, 15 Jul 2002 05:55:13 GMT
shawn       2002/07/14 22:55:13

  Added:       standard/src/org/apache/taglibs/standard/lang/jstl
                        FunctionInvocation.java
  Log:
  Oops, forgot the most important piece.  (For EL function support.)
  
  Revision  Changes    Path
  1.1                  jakarta-taglibs/standard/src/org/apache/taglibs/standard/lang/jstl/FunctionInvocation.java
  
  Index: FunctionInvocation.java
  ===================================================================
  /*
   * The Apache Software License, Version 1.1
   *
   * Copyright (c) 1999 The Apache Software Foundation.  All rights 
   * reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer. 
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. The end-user documentation included with the redistribution, if
   *    any, must include the following acknowlegement:  
   *       "This product includes software developed by the 
   *        Apache Software Foundation (http://www.apache.org/)."
   *    Alternately, this acknowlegement may appear in the software itself,
   *    if and wherever such third-party acknowlegements normally appear.
   *
   * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
   *    Foundation" must not be used to endorse or promote products derived
   *    from this software without prior written permission. For written 
   *    permission, please contact apache@apache.org.
   *
   * 5. Products derived from this software may not be called "Apache"
   *    nor may "Apache" appear in their names without prior written
   *    permission of the Apache Group.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */ 
  
  package org.apache.taglibs.standard.lang.jstl;
  
  import java.util.List;
  import java.util.Map;
  import java.util.Iterator;
  import java.lang.reflect.*;
  
  /**
   *
   * <p>Represents a function call.</p>
   * 
   * @author Shawn Bayern (in the style of Nathan's other classes)
   **/
  
  public class FunctionInvocation
    extends Expression
  {
    //-------------------------------------
    // Properties
    //-------------------------------------
    // property index
  
    private String functionName;
    private List argumentList;
    public String getFunctionName() { return functionName; }
    public void setFunctionName(String f) { functionName = f; }
    public List getArgumentList() { return argumentList; }
    public void setArgumentList(List l) { argumentList = l; }
  
    //-------------------------------------
    /**
     * Constructor
     **/
    public FunctionInvocation (String functionName, List argumentList)
    {
      this.functionName = functionName;
      this.argumentList = argumentList;
    }
  
    //-------------------------------------
    // Expression methods
    //-------------------------------------
    /**
     * Returns the expression in the expression language syntax
     **/
    public String getExpressionString ()
    {
      StringBuffer b = new StringBuffer();
      b.append(functionName);
      b.append("(");
      Iterator i = argumentList.iterator();
      while (i.hasNext()) {
        b.append(((Expression) i.next()).getExpressionString());
        if (i.hasNext())
          b.append(", ");
      }
      b.append(")");
      return b.toString();
    }
  
  
    //-------------------------------------
    /**
     *
     * Evaluates by looking up the name in the VariableResolver
     **/
    public Object evaluate (Object pContext,
                            VariableResolver pResolver,
  			  Map functions,
  			  String defaultPrefix,
                            Logger pLogger)
      throws ELException
    {
  
      // if the Map is null, then the function is invalid
      if (functions == null)
        pLogger.logError(Constants.UNKNOWN_FUNCTION, functionName);
  
      // normalize function name against default prefix
      String functionName = this.functionName;
      if (functionName.indexOf(":") == -1) {
        if (defaultPrefix == null)
          pLogger.logError(Constants.UNKNOWN_FUNCTION, functionName);
        functionName = defaultPrefix + ":" + functionName;
      }
  
      // ensure that the number of arguments matches the number of parameters
      Method target = (Method) functions.get(functionName);
      Class[] params = target.getParameterTypes();
      if (params.length != argumentList.size())
        pLogger.logError(Constants.INAPPROPRIATE_FUNCTION_ARG_COUNT,
  		       new Integer(params.length),
  		       new Integer(argumentList.size()));
  
      // now, walk through each parameter, evaluating and casting its argument
      Object[] arguments = new Object[argumentList.size()];
      for (int i = 0; i < params.length; i++) {
        // evaluate
        arguments[i] = ((Expression) argumentList.get(i)).evaluate(pContext,
  								 pResolver,
  								 functions,
  								 defaultPrefix,
  								 pLogger);
        // coerce
        arguments[i] = Coercions.coerce(arguments[i], params[i], pLogger);
      }
  
      // finally, invoke the target method, which we know to be static
      try {
        return (target.invoke(null, arguments));
      } catch (InvocationTargetException ex) {
        pLogger.logError(Constants.FUNCTION_INVOCATION_ERROR,
  			ex.getTargetException(),
  			functionName);
        return null;
      } catch (Exception ex) {
        pLogger.logError(Constants.FUNCTION_INVOCATION_ERROR, ex, functionName);
        return null;
      }
    }
  
    //-------------------------------------
  }
  
  
  

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