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From jstrac...@apache.org
Subject cvs commit: jakarta-commons/jelly/src/java/org/apache/commons/jelly/tags/core InvokeStaticTag.java
Date Wed, 19 Feb 2003 07:44:35 GMT
jstrachan    2003/02/18 23:44:35

  Added:       jelly/src/java/org/apache/commons/jelly/tags/core
                        InvokeStaticTag.java
  Log:
  applied patch supplied by Robert McIntosh to allow invocations of static methods
  
  Revision  Changes    Path
  1.1                  jakarta-commons/jelly/src/java/org/apache/commons/jelly/tags/core/InvokeStaticTag.java
  
  Index: InvokeStaticTag.java
  ===================================================================
  /*
   * $Header: /home/cvs/jakarta-commons/jelly/src/java/org/apache/commons/jelly/tags/core/InvokeStaticTag.java,v
1.1 2003/02/19 07:44:35 jstrachan Exp $
   * $Revision: 1.1 $
   * $Date: 2003/02/19 07:44:35 $
   *
   * ====================================================================
   *
   * The Apache Software License, Version 1.1
   *
   * Copyright (c) 2002 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", "Commons", 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/>.
   * 
   * $Id: InvokeStaticTag.java,v 1.1 2003/02/19 07:44:35 jstrachan Exp $
   */
  package org.apache.commons.jelly.tags.core;
  
  import java.lang.reflect.InvocationTargetException;
  import java.lang.reflect.Method;
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.commons.jelly.JellyTagException;
  import org.apache.commons.jelly.MissingAttributeException;
  import org.apache.commons.jelly.TagSupport;
  import org.apache.commons.jelly.XMLOutput;
  
  /** 
    * <p>
    * A Tag which can invoke a static method on a class, without an 
    * instance of the class being needed.
    * </p>
    * <p>
    * Like the {@link InvokeTag}, this tag can take a set of
    * arguments using the {@link ArgTag}.
    * </p>
    * <p>
    *  The following attributes are required:<br />
    * <ul>
    *   <li>var - The variable to assign the return of the method call to</li>
    *   <li>method - The name of the static method to invoke</li>
    *   <li>className - The name of the class containing the static method</li>
    * </ul>
    * </p>
    *
    * @author <a href="mailto:robert@bull-enterprises.com>Robert McIntosh</a>
    * @version $Revision: 1.1 $
    */
  public class InvokeStaticTag extends TagSupport implements ArgTagParent {
  
      /** the variable exported */
      private String var;
      
      /** the method to invoke */
      private String methodName;
      
      /** the object to invoke the method on */
      private String className;
      
      private List paramTypes = new ArrayList();
      private List paramValues = new ArrayList();
      
      public InvokeStaticTag() {
      }
  
      /** 
       * Sets the name of the variable exported by this tag
       *
       * @param var The variable name
       */
      public void setVar(String var) {
          this.var = var;
      }
      
      /**
       * Sets the name of the method to invoke
       *
       * @param method The method name
       */
      public void setMethod(String methodName) {
          this.methodName = methodName;
      }
      
      /**
       * Sets the fully qualified class name containing the static method
       *
       * @param className The name of the class
       */
      public void setClassName(String className) {
          this.className = className;
      }
      
      /**
       * Adds an argument to supply to the method
       *
       * @param type The Class type of the argument
       * @param value The value of the argument
       */
      public void addArgument(Class type, Object value) {
          paramTypes.add(type);
          paramValues.add(value);
      }
      
      // Tag interface
      //------------------------------------------------------------------------- 
      public void doTag(XMLOutput output) throws JellyTagException {
          try {        
  	        if ( null == methodName) {
  	            throw new MissingAttributeException( "method" );
  	        }
  	        invokeBody(output);
  	
  	        Object[] values = paramValues.toArray();
  	        Class[] types = (Class[])(paramTypes.toArray(new Class[paramTypes.size()]));
  	        Method method = loadClass().getMethod( methodName, types );
  	        Object result = method.invoke( null, values );
  	        if(null != var) {
  	            context.setVariable(var, result);
  	        }
  	        
  	        ArgTag parentArg = (ArgTag)(findAncestorWithClass(ArgTag.class));
  	        if(null != parentArg) {
  	            parentArg.setValue(result);
  	        }
          }
          catch (ClassNotFoundException e) {
              throw createLoadClassFailedException(e);
          } 
          catch (NoSuchMethodException e) {
              throw createLoadClassFailedException(e);
          } 
          catch (IllegalAccessException e) {
              throw createLoadClassFailedException(e);
          } 
          catch (InvocationTargetException e) {
              throw createLoadClassFailedException(e);
          }
          finally {
              paramTypes.clear();
              paramValues.clear();
          }
      }
      
      // Tag interface
      //-------------------------------------------------------------------------
      
      /**
       * Loads the class using either the class loader which loaded me or the 
       * current threads context class loader
       */ 
      protected Class loadClass() throws ClassNotFoundException {
          Class theClass = getClass().getClassLoader().loadClass( className );
          if (theClass == null ) {
              theClass = Thread.currentThread().getContextClassLoader().loadClass( className
);
          }
          return theClass; 
      }
  
  	/**
  	 * Factory method to create a new JellyTagException instance from a given
  	 * failure exception
  	 * @param e is the exception which occurred attempting to load the class
  	 * @return JellyTagException
  	 */
      protected JellyTagException createLoadClassFailedException(Exception e) {
          return new JellyTagException(
              "Could not load class: " + className + ". Reason: " + e, e
          );
      }
  }
  
  
  
  

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