DescriptorHandler (Apache Ant API)
Date: 2017-02-02

org.apache.tools.ant.taskdefs.optional.ejb

## Class DescriptorHandler

- java.lang.Object
- - org.xml.sax.HandlerBase
  - - org.apache.tools.ant.taskdefs.optional.ejb.DescriptorHandler

- All Implemented Interfaces:
    org.xml.sax.DocumentHandler, org.xml.sax.DTDHandler, org.xml.sax.EntityResolver, org.xml.sax.ErrorHandler

      public class DescriptorHandler
      extends org.xml.sax.HandlerBase

  Inner class used by EjbJar to facilitate the parsing of deployment descriptors and the capture of appropriate information. Extends HandlerBase so it only implements the methods needed. During parsing creates a hashtable consisting of entries mapping the name it should be inserted into an EJB jar as to a File representing the file on disk. This list can then be accessed through the getFiles() method.

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `protected java.lang.String` | `currentElement` Instance variable used to store the name of the current element being processed by the SAX parser.
    `protected java.lang.String` | `currentText` The text of the current element
    `protected java.util.Hashtable` | `ejbFiles` Instance variable that stores the names of the files as they will be put into the jar file, mapped to File objects Accessed by the SAX parser call-back method characters().
    `protected java.lang.String` | `ejbName` Instance variable that stores the value found in the <ejb-name> element

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `DescriptorHandler(Task task, java.io.File srcDir)` Constructor for DescriptorHandler.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `characters(char[] ch, int start, int length)` SAX parser call-back method invoked whenever characters are located within an element.
    `void` | `endElement(java.lang.String name)` SAX parser call-back method that is invoked when an element is exited.
    `java.lang.String` | `getEjbName()` Getter method that returns the value of the <ejb-name> element.
    `java.util.Hashtable` | `getFiles()` Getter method that returns the set of files to include in the EJB jar.
    `java.lang.String` | `getPublicId()` Get the publicId of the DTD
    `protected void` | `processElement()` Called when an endelement is seen.
    `void` | `registerDTD(java.lang.String publicId, java.lang.String location)` Register a dtd with a location.
    `org.xml.sax.InputSource` | `resolveEntity(java.lang.String publicId, java.lang.String systemId)` Resolve the entity.
    `void` | `startDocument()` SAX parser call-back method that is used to initialize the values of some instance variables to ensure safe operation.
    `void` | `startElement(java.lang.String name, org.xml.sax.AttributeList attrs)` SAX parser call-back method that is invoked when a new element is entered into.

    - ### Methods inherited from class org.xml.sax.HandlerBase

      `endDocument, error, fatalError, ignorableWhitespace, notationDecl, processingInstruction, setDocumentLocator, unparsedEntityDecl, warning`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Field Detail

    - #### currentElement

          protected java.lang.String currentElement

      Instance variable used to store the name of the current element being processed by the SAX parser. Accessed by the SAX parser call-back methods startElement() and endElement().

    - #### currentText

          protected java.lang.String currentText

      The text of the current element

    - #### ejbFiles

          protected java.util.Hashtable ejbFiles

      Instance variable that stores the names of the files as they will be put into the jar file, mapped to File objects Accessed by the SAX parser call-back method characters().

    - #### ejbName

          protected java.lang.String ejbName

      Instance variable that stores the value found in the <ejb-name> element

  - ### Constructor Detail

    - #### DescriptorHandler

          public DescriptorHandler(Task task,
                                   java.io.File srcDir)

      Constructor for DescriptorHandler.
      Parameters:
        `task` - the task that owns this descriptor
        `srcDir` - the source directory

  - ### Method Detail

    - #### registerDTD

          public void registerDTD(java.lang.String publicId,
                                  java.lang.String location)

      Register a dtd with a location. The location is one of a filename, a resource name in the classpath, or a URL.
      Parameters:
        `publicId` - the public identity of the dtd
        `location` - the location of the dtd

    - #### resolveEntity

          public org.xml.sax.InputSource resolveEntity(java.lang.String publicId,
                                                       java.lang.String systemId)
                                                throws org.xml.sax.SAXException

      Resolve the entity.
      Specified by:
        `resolveEntity` in interface `org.xml.sax.EntityResolver`
      Overrides:
        `resolveEntity` in class `org.xml.sax.HandlerBase`
      Parameters:
        `publicId` - The public identifier, or `null` if none is available.
        `systemId` - The system identifier provided in the XML document. Will not be `null`.
      Returns:
        an inputsource for this identifier
      Throws:
        `org.xml.sax.SAXException` - if there is a problem.
      See Also:
        `EntityResolver.resolveEntity(String, String).`

    - #### getFiles

          public java.util.Hashtable getFiles()

      Getter method that returns the set of files to include in the EJB jar.
      Returns:
        the map of files

    - #### getPublicId

          public java.lang.String getPublicId()

      Get the publicId of the DTD
      Returns:
        the public id

    - #### getEjbName

          public java.lang.String getEjbName()

      Getter method that returns the value of the <ejb-name> element.
      Returns:
        the ejb name

    - #### startDocument

          public void startDocument()
                             throws org.xml.sax.SAXException

      SAX parser call-back method that is used to initialize the values of some instance variables to ensure safe operation.
      Specified by:
        `startDocument` in interface `org.xml.sax.DocumentHandler`
      Overrides:
        `startDocument` in class `org.xml.sax.HandlerBase`
      Throws:
        `org.xml.sax.SAXException` - on error

    - #### startElement

          public void startElement(java.lang.String name,
                                   org.xml.sax.AttributeList attrs)
                            throws org.xml.sax.SAXException

      SAX parser call-back method that is invoked when a new element is entered into. Used to store the context (attribute name) in the currentAttribute instance variable.
      Specified by:
        `startElement` in interface `org.xml.sax.DocumentHandler`
      Overrides:
        `startElement` in class `org.xml.sax.HandlerBase`
      Parameters:
        `name` - The name of the element being entered.
        `attrs` - Attributes associated to the element.
      Throws:
        `org.xml.sax.SAXException` - on error

    - #### endElement

          public void endElement(java.lang.String name)
                          throws org.xml.sax.SAXException

      SAX parser call-back method that is invoked when an element is exited. Used to blank out (set to the empty string, not nullify) the name of the currentAttribute. A better method would be to use a stack as an instance variable, however since we are only interested in leaf-node data this is a simpler and workable solution.
      Specified by:
        `endElement` in interface `org.xml.sax.DocumentHandler`
      Overrides:
        `endElement` in class `org.xml.sax.HandlerBase`
      Parameters:
        `name` - The name of the attribute being exited. Ignored in this implementation.
      Throws:
        `org.xml.sax.SAXException` - on error

    - #### characters

          public void characters(char[] ch,
                                 int start,
                                 int length)
                          throws org.xml.sax.SAXException

      SAX parser call-back method invoked whenever characters are located within an element. currentAttribute (modified by startElement and endElement) tells us whether we are in an interesting element (one of the up to four classes of an EJB). If so then converts the classname from the format org.apache.tools.ant.Parser to the convention for storing such a class, org/apache/tools/ant/Parser.class. This is then resolved into a file object under the srcdir which is stored in a Hashtable.
      Specified by:
        `characters` in interface `org.xml.sax.DocumentHandler`
      Overrides:
        `characters` in class `org.xml.sax.HandlerBase`
      Parameters:
        `ch` - A character array containing all the characters in the element, and maybe others that should be ignored.
        `start` - An integer marking the position in the char array to start reading from.
        `length` - An integer representing an offset into the char array where the current data terminates.
      Throws:
        `org.xml.sax.SAXException` - on error

    - #### processElement

          protected void processElement()

      Called when an endelement is seen. This may be overridden in derived classes. This updates the ejbfiles if the element is an interface or a bean class. This updates the ejbname if the element is an ejb name.