/*
 * 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", "Ant", 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.ant.antcore.antlib;
import org.apache.ant.common.util.ConfigException;
import org.apache.ant.antcore.xml.ElementHandler;
import org.xml.sax.Attributes;
import org.xml.sax.SAXParseException;

/**
 * XML Element Handler for Ant library definitions
 *
 * @author Conor MacNeill
 * @created 13 January 2002
 */
public class AntLibHandler extends ElementHandler {
    /** The library identifier attribute name */
    public static final String LIBID_ATTR = "libid";
    /** The home attribute name */
    public static final String HOME_ATTR = "home";
    /**
     * The name of the attribute which indicates if Ant's XML parser is to
     * be made available
     */
    public static final String REQXML_ATTR = "reqxml";
    /** The extends attribute name */
    public static final String EXTENDS_ATTR = "extends";
    /** The name of the attribute which indicates tools jar is required */
    public static final String REQTOOLS_ATTR = "reqtools";
    /** The extends attribute name */
    public static final String ISOLATED_ATTR = "isolated";

    
    /** The list of allowed Attributes */
    public static final String[] ALLOWED_ATTRIBUTES
         = {LIBID_ATTR, HOME_ATTR, REQXML_ATTR, REQTOOLS_ATTR,
        EXTENDS_ATTR, ISOLATED_ATTR};

    /** The Ant Library definition being parsed. */
    private AntLibrarySpec antLibrarySpec;

    /**
     * Gets the parsed antLibrary specification
     *
     * @return the parsed antLibrary
     */
    public AntLibrarySpec getAntLibrarySpec() {
        return antLibrarySpec;
    }

    /**
     * Process the antlib element
     *
     * @param elementName the name of the element
     * @exception SAXParseException if there is a problem parsing the
     *      element
     */
    public void processElement(String elementName)
         throws SAXParseException {
        antLibrarySpec = new AntLibrarySpec();

        if (getAttribute(LIBID_ATTR) == null) {
            throw new SAXParseException("antlib must have an libid sttribute",
                getLocator());
        }
        antLibrarySpec.setLibraryId(getAttribute(LIBID_ATTR));
        antLibrarySpec.setHome(getAttribute(HOME_ATTR));
        antLibrarySpec.setExtendsLibraryId(getAttribute(EXTENDS_ATTR));
        antLibrarySpec.setIsolated(getBooleanAttribute(ISOLATED_ATTR));
        antLibrarySpec.setAntXML(getBooleanAttribute(REQXML_ATTR));
        antLibrarySpec.setToolsJarRequired(getBooleanAttribute(REQTOOLS_ATTR));
    }

    /**
     * Start a new element in the antlibrary.
     *
     * @param uri The Namespace URI.
     * @param localName The local name (without prefix).
     * @param qualifiedName The qualified name (with prefix)
     * @param attributes The attributes attached to the element.
     * @throws SAXParseException if there is a parsing problem.
     */
    public void startElement(String uri, String localName, String qualifiedName,
                             Attributes attributes)
         throws SAXParseException {
        try {
            if (qualifiedName.equals("taskdef")
                 || qualifiedName.equals("typedef")) {
                DefinitionHandler defnHandler
                     = new DefinitionHandler(qualifiedName);
                defnHandler.start(getParseContext(), getXMLReader(),
                    this, getLocator(), attributes, getElementSource(),
                    qualifiedName);
                antLibrarySpec.addDefinition(defnHandler.getDefinitionType(),
                    defnHandler.getName(), defnHandler.getClassName());
            } else if (qualifiedName.equals("converter")) {
                ClassNameHandler converterHandler
                    = new ClassNameHandler();
                converterHandler.start(getParseContext(), getXMLReader(),
                    this, getLocator(), attributes, getElementSource(),
                    qualifiedName);
                antLibrarySpec.addConverter(converterHandler.getClassName());
            } else if (qualifiedName.equals("factory")) {
                ClassNameHandler factoryHandler
                    = new ClassNameHandler();
                factoryHandler.start(getParseContext(), getXMLReader(),
                    this, getLocator(), attributes, getElementSource(),
                    qualifiedName);
                String factoryClass = factoryHandler.getClassName();
                antLibrarySpec.setFactory(factoryClass);
            } else {
                super.startElement(uri, localName, qualifiedName, attributes);
            }
        } catch (ConfigException e) {
            throw new SAXParseException(e.getMessage(), getLocator());
        }
    }

    /**
     * Validate that the given attribute and value are valid.
     *
     * @param attributeName The name of the attributes
     * @param attributeValue The value of the attributes
     * @exception SAXParseException if the attribute is not allowed on the
     *      element.
     */
    protected void validateAttribute(String attributeName,
                                     String attributeValue)
         throws SAXParseException {
        for (int i = 0; i < ALLOWED_ATTRIBUTES.length; ++i) {
            if (attributeName.equals(ALLOWED_ATTRIBUTES[i])) {
                return;
            }
        }
        throwInvalidAttribute(attributeName);
    }


}


