cvs commit: jakarta-commons/digester/src/examples/api/addressbook Main.java

[sk...@apache.org]

skitching    2004/04/17 03:57:46

  Added:       digester/src/examples/api/addressbook Main.java
  Log:
  Renamed file AddressBookDigester to this file (Main.java)
  
  Revision  Changes    Path
  1.1                  jakarta-commons/digester/src/examples/api/addressbook/Main.java
  
  Index: Main.java
  ===================================================================
  /*
   * Copyright 2003-2004 The Apache Software Foundation.
   * 
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   * 
   *      http://www.apache.org/licenses/LICENSE-2.0
   * 
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */ 
  
  import org.apache.commons.digester.Digester;
  
  /**
   * A simple program to demonstrate the basic functionality of the
   * Commons Digester module.
   * <p>
   * This code will parse the provided "example.xml" file to build a tree
   * of java objects, then cause those objects to print out their values
   * to demonstrate that the input file has been processed correctly.
   * <p>
   * As with all code, there are many ways of achieving the same goal;
   * the solution here is only one possible solution to the problem.
  * <p> 
   * Very verbose comments are included here, as this class is intended
   * as a tutorial; if you look closely at method "addRules", you will
   * see that the amount of code required to use the Digester is actually
   * quite low.
   * <p>
   * Usage: java Main example.xml
   */
  public class Main {
      
      /**
       * Main method : entry point for running this example program.
       * <p>
       * Usage: java Example example.xml
       */
      public static void main(String[] args) {
          if (args.length != 1) {
              usage();
              System.exit(-1);
          }
          
          String filename = args[0];
          
          // Create a Digester instance
          Digester d = new Digester();
          
          // Prime the digester stack with an object for rules to
          // operate on. Note that it is quite common for "this"
          // to be the object pushed.
          AddressBook book = new AddressBook();
          d.push(book);
          
          // Add rules to the digester that will be triggered while
          // parsing occurs.
          addRules(d);
          
          // Process the input file.
          try {
              java.io.File srcfile = new java.io.File(filename);
              d.parse(srcfile);
          }
          catch(java.io.IOException ioe) {
              System.out.println("Error reading input file:" + ioe.getMessage());
              System.exit(-1);
          }
          catch(org.xml.sax.SAXException se) {
              System.out.println("Error parsing input file:" + se.getMessage());
              System.exit(-1);
          }
          
          
          // Print out all the contents of the address book, as loaded from
          // the input file.
          book.print();
      }
      
      private static void addRules(Digester d) {
  
          //--------------------------------------------------        
          // when we encounter a "person" tag, do the following:
  
          // create a new instance of class Person, and push that
          // object onto the digester stack of objects
          d.addObjectCreate("address-book/person", Person.class);
          
          // map *any* attributes on the tag to appropriate
          // setter-methods on the top object on the stack (the Person
          // instance created by the preceeding rule). 
          //
          // For example:
          // if attribute "id" exists on the xml tag, and method setId 
          // with one parameter exists on the object that is on top of
          // the digester object stack, then a call will be made to that
          // method. The value will be type-converted from string to
          // whatever type the target method declares (where possible), 
          // using the commons ConvertUtils functionality.
          //
          // Attributes on the xml tag for which no setter methods exist
          // on the top object on the stack are just ignored.
          d.addSetProperties("address-book/person");
  
          // call the addPerson method on the second-to-top object on
          // the stack (the AddressBook object), passing the top object
          // on the stack (the recently created Person object).
          d.addSetNext("address-book/person", "addPerson");        
          
          //--------------------------------------------------        
          // when we encounter a "name" tag, call setName on the top
          // object on the stack, passing the text contained within the
          // body of that name element [specifying a zero parameter count
          // implies one actual parameter, being the body text]. 
          // The top object on the stack will be a person object, because 
          // the pattern address-book/person always triggers the 
          // ObjectCreateRule we added previously.
          d.addCallMethod("address-book/person/name", "setName", 0);
          
          //--------------------------------------------------        
          // when we encounter an "email" tag, call addEmail on the top
          // object on the stack, passing two parameters: the "type"
          // attribute, and the text within the tag body.
          d.addCallMethod("address-book/person/email", "addEmail", 2);
          d.addCallParam("address-book/person/email", 0, "type");
          d.addCallParam("address-book/person/email", 1);
      }
  
      private static void usage() {
          System.out.println("Usage: java Main example.xml");
      }
  }
  
  

---------------------------------------------------------------------
To unsubscribe, e-mail: commons-dev-unsubscribe@jakarta.apache.org
For additional commands, e-mail: commons-dev-help@jakarta.apache.org