Package edu.isi.pegasus.planner.parser

Class Parser

  • All Implemented Interfaces:
    org.xml.sax.ContentHandler, org.xml.sax.DTDHandler, org.xml.sax.EntityResolver, org.xml.sax.ErrorHandler
    Direct Known Subclasses:
    ConfigXmlParser, DAXParser2, PDAXParser, SiteCatalogXMLMetadataParser, StackBasedXMLParser, XML2
    public abstract class Parser
extends org.xml.sax.helpers.DefaultHandler
    This is the base class which all the xml parsing classes extend. It initializes the xml parser namely Xerces, sets it's various features like turning on validation against schema etc, plus the namespace resolution.
    Version:
    $Revision$
    Author:
    Karan Vahi, Gaurang Mehta

    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected java.lang.String DEFAULT_PARSER_NAME
      Default parser name.
      protected boolean mAdjFName
      Boolean flag to ensure that two adjacent filenames are separated by a whitespace.
      protected org.xml.sax.Locator mLocator
      Locator object to determine on which line in the xml has the error occured.
      protected LogManager mLogger
      The LogManager object which logs the Pegasus messages.
      protected java.lang.String mLogMsg
      The String which contains the messages to be logged.
      protected org.xml.sax.XMLReader mParser
      The object which is used to parse the dax.
      protected PegasusProperties mProps
      The object holding all the properties pertaining to Pegasus.
      protected java.lang.StringBuffer mTextContent
      Holds the text in an element (text between start and final tags if any).
      protected java.lang.String mTextString
      A String that holds the contents of data passed as text.

    • Method Summary

      All Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      void characters​(char[] chars, int start, int length)
      This is used to store the character data that is in xml.
      private void createParserInstance()
      Creates an instance of the parser, and sets the various options to it.
      abstract void endDocument()
      This is called automatically when the end of the XML file is reached.
      abstract void endElement​(java.lang.String uri, java.lang.String localName, java.lang.String qName)
      An empty implementation is provided by DefaultHandler class.
      abstract java.lang.String getSchemaLocation()
      Helps the load database to locate the XML schema, if available.
      abstract java.lang.String getSchemaNamespace()
      Returns the XML schema namespace that a document being parsed conforms to.
      java.lang.String ignoreWhitespace​(java.lang.String str)
      Our own implementation for ignorable whitespace.
      java.lang.String ignoreWhitespace​(java.lang.String str, boolean preserveLineBreak)
      Our own implementation for ignorable whitespace.
      void setDocumentLocator​(org.xml.sax.Locator loc)
      Overrides the empty implementation provided by Default Handler and sets the locator variable for the locator.
      boolean setParserFeature​(java.lang.String uri, boolean flag)
      Sets a parser feature, and fails here enabling us to set all the following features.
      void setSchemaLocations​(java.lang.String list)
      Sets the list of external real locations where the XML schema may be found.
      abstract void startElement​(java.lang.String uri, java.lang.String local, java.lang.String raw, org.xml.sax.Attributes attrs)
      An empty implementation is provided by DefaultHandler of ContentHandler.
      abstract void startParser​(java.lang.String file)
      Start the parser.
      void testForFile​(java.lang.String file)
      Tests whether the file exists or not.

      • Methods inherited from class org.xml.sax.helpers.DefaultHandler

        endPrefixMapping, error, fatalError, ignorableWhitespace, notationDecl, processingInstruction, resolveEntity, skippedEntity, startDocument, startPrefixMapping, unparsedEntityDecl, warning

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • DEFAULT_PARSER_NAME

        protected final java.lang.String DEFAULT_PARSER_NAME
        Default parser name. Using Xerces at present.
        See Also:
        Constant Field Values

      • mLocator

        protected org.xml.sax.Locator mLocator
        Locator object to determine on which line in the xml has the error occured.

      • mTextContent

        protected java.lang.StringBuffer mTextContent
        Holds the text in an element (text between start and final tags if any). Used in case of elements of mixed type.

      • mLogger

        protected LogManager mLogger
        The LogManager object which logs the Pegasus messages.

      • mLogMsg

        protected java.lang.String mLogMsg
        The String which contains the messages to be logged.

      • mParser

        protected org.xml.sax.XMLReader mParser
        The object which is used to parse the dax. This reads the XML document and sends it to the event handlers.

      • mProps

        protected PegasusProperties mProps
        The object holding all the properties pertaining to Pegasus.

      • mTextString

        protected java.lang.String mTextString
        A String that holds the contents of data passed as text. The string should only be trimmed when the appropriate end tag of the element is invoked. At this point, a whitespace is added if there are whitespaces in at the ends.

      • mAdjFName

        protected boolean mAdjFName
        Boolean flag to ensure that two adjacent filenames are separated by a whitespace.

    • Constructor Detail

      • Parser

        public Parser​(PegasusBag bag)
        Intialises the parser. Sets the various features. However the parsing is done in the implementing class, by call mParser.parse(filename).
        Parameters:
        bag - the bag of objects that is useful for initialization.

      • Parser

        public Parser​(PegasusProperties properties)
        Intialises the parser. Sets the various features. However the parsing is done in the implementing class, by call mParser.parse(filename).
        Parameters:
        properties - the properties passed at runtime.

    • Method Detail

      • startElement

        public abstract void startElement​(java.lang.String uri,
                                  java.lang.String local,
                                  java.lang.String raw,
                                  org.xml.sax.Attributes attrs)
                           throws org.xml.sax.SAXException
        An empty implementation is provided by DefaultHandler of ContentHandler. This method receives the notification from the sacks parser when start tag of an element comes. Any parser class must implement this method.
        Specified by:
        startElement in interface org.xml.sax.ContentHandler
        Overrides:
        startElement in class org.xml.sax.helpers.DefaultHandler
        Throws:
        org.xml.sax.SAXException

      • endElement

        public abstract void endElement​(java.lang.String uri,
                                java.lang.String localName,
                                java.lang.String qName)
                         throws org.xml.sax.SAXException
        An empty implementation is provided by DefaultHandler class. This method is called automatically by the Sax parser when the end tag of an element comes in the xml file. Any parser class should implement this method
        Specified by:
        endElement in interface org.xml.sax.ContentHandler
        Overrides:
        endElement in class org.xml.sax.helpers.DefaultHandler
        Throws:
        org.xml.sax.SAXException

      • endDocument

        public abstract void endDocument()
        This is called automatically when the end of the XML file is reached.
        Specified by:
        endDocument in interface org.xml.sax.ContentHandler
        Overrides:
        endDocument in class org.xml.sax.helpers.DefaultHandler

      • startParser

        public abstract void startParser​(java.lang.String file)
        Start the parser. This starts the parsing of the file by the parser.
        Parameters:
        file - the path to the XML file you want to parse.

      • getSchemaLocation

        public abstract java.lang.String getSchemaLocation()
        Helps the load database to locate the XML schema, if available. Please note that the schema location URL in the instance document is only a hint, and may be overriden by the findings of this method.
        Returns:
        a location pointing to a definition document of the XML schema that can read VDLx. Result may be null, if such a document is unknown or unspecified.

      • getSchemaNamespace

        public abstract java.lang.String getSchemaNamespace()
        Returns the XML schema namespace that a document being parsed conforms to.
        Returns:
        the schema namespace

      • setSchemaLocations

        public void setSchemaLocations​(java.lang.String list)
        Sets the list of external real locations where the XML schema may be found. Since this list can be determined at run-time through properties etc., we expect this function to be called between instantiating the parser, and using the parser
        Parameters:
        list - is a list of strings representing schema locations. The content exists in pairs, one of the namespace URI, one of the location URL.

      • characters

        public void characters​(char[] chars,
                       int start,
                       int length)
        This is used to store the character data that is in xml. An implementation of the interface for the Sacks parser.
        Specified by:
        characters in interface org.xml.sax.ContentHandler
        Overrides:
        characters in class org.xml.sax.helpers.DefaultHandler

      • ignoreWhitespace

        public java.lang.String ignoreWhitespace​(java.lang.String str)
        Our own implementation for ignorable whitespace. A String that holds the contents of data passed as text by the underlying parser. The whitespaces at the end are replaced by one whitespace.
        Parameters:
        str - The string that contains whitespaces.
        Returns:
        String corresponding to the trimmed version.

      • ignoreWhitespace

        public java.lang.String ignoreWhitespace​(java.lang.String str,
                                         boolean preserveLineBreak)
        Our own implementation for ignorable whitespace. A String that holds the contents of data passed as text by the underlying parser. The whitespaces at the end are replaced by one whitespace.
        Parameters:
        str - The string that contains whitespaces.
        Returns:
        String corresponding to the trimmed version.

      • setDocumentLocator

        public void setDocumentLocator​(org.xml.sax.Locator loc)
        Overrides the empty implementation provided by Default Handler and sets the locator variable for the locator.
        Specified by:
        setDocumentLocator in interface org.xml.sax.ContentHandler
        Overrides:
        setDocumentLocator in class org.xml.sax.helpers.DefaultHandler
        Parameters:
        loc - the Locator object which keeps the track as to the line numbers of the line being parsed.

      • testForFile

        public void testForFile​(java.lang.String file)
                 throws java.io.FileNotFoundException
        Tests whether the file exists or not.
        Throws:
        java.io.FileNotFoundException

      • createParserInstance

        private void createParserInstance()
        Creates an instance of the parser, and sets the various options to it.

      • setParserFeature

        public boolean setParserFeature​(java.lang.String uri,
                                boolean flag)
        Sets a parser feature, and fails here enabling us to set all the following features.
        Parameters:
        uri - is the feature's URI to modify
        flag - is the new value to set.
        Returns:
        true if the feature could be set, else false for an exception.