TerminatingXsdHeaderContentHandler.java

/*
 * JBoss, Home of Professional Open Source.
 *
 * See the LEGAL.txt file distributed with this work for information regarding copyright ownership and licensing.
 *
 * See the AUTHORS.txt file distributed with this work for a full listing of individual contributors.
 */

package org.teiid.designer.common.xsd;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

/**
 * @since 8.0
 */
public class TerminatingXsdHeaderContentHandler extends DefaultHandler {

    public static final String SCHEMA_NOT_FOUND_EXCEPTION_MESSAGE = "SchemaNotFoundException"; //$NON-NLS-1$
    public static final String SCHEMA_FOUND_EXCEPTION_MESSAGE = "SchemaFoundException"; //$NON-NLS-1$

    private static final String SCHEMA_TAG_NAME = "schema"; //$NON-NLS-1$
    private static final String IMPORT_TAG_NAME = "import"; //$NON-NLS-1$
    private static final String INCLUDE_TAG_NAME = "include"; //$NON-NLS-1$

    private static final String TARGET_NAMESPACE_ATTRIBUTE_NAME = "targetNamespace"; //$NON-NLS-1$
    private static final String NAMESPACE_ATTRIBUTE_NAME = "namespace"; //$NON-NLS-1$
    private static final String SCHEMA_LOCATION_ATTRIBUTE_NAME = "schemaLocation"; //$NON-NLS-1$

    private static final String ELEMENT_TAG_NAME = "element"; //$NON-NLS-1$
    private static final String SIMPLE_TYPE_TAG_NAME = "simpleType"; //$NON-NLS-1$
    private static final String COMPLEX_TYPE_TAG_NAME = "complexType"; //$NON-NLS-1$
    private static final String GROUP_TAG_NAME = "group"; //$NON-NLS-1$
    private static final String ATTRIBUTE_GROUP_TAG_NAME = "attributeGroup"; //$NON-NLS-1$
    private static final String ATTRIBUTE_TAG_NAME = "attribute"; //$NON-NLS-1$
    private static final String NOTATION_TAG_NAME = "notation"; //$NON-NLS-1$

    private boolean foundSchemaStartElement;
    private boolean foundTerminatingTag;
    private XsdHeader header;

    public TerminatingXsdHeaderContentHandler() {
        super();
        this.foundSchemaStartElement = false;
        this.foundTerminatingTag = false;
    }

    // ==================================================================================
    // I N T E R F A C E M E T H O D S
    // ==================================================================================

    /**
     * @see org.xml.sax.ContentHandler#startPrefixMapping(java.lang.String, java.lang.String)
     */
    @Override
    public void startPrefixMapping( String prefix,
                                    String uri ) throws SAXException {
        this.getXsdHeader().addNamespaceURI(uri);
        super.startPrefixMapping(prefix, uri);
    }

    /**
     * @see org.xml.sax.ContentHandler#startElement(java.lang.String, java.lang.String, java.lang.String, org.xml.sax.Attributes)
     */
    @Override
    public void startElement( String uri,
                              String localName,
                              String qName,
                              Attributes atts ) throws SAXException {
        // Found the schema tag
        if (SCHEMA_TAG_NAME.equals(localName)) {
            this.processAttributes(atts);
            this.foundSchemaStartElement = true;
        }
        // Found the schema import tag
        else if (IMPORT_TAG_NAME.equals(localName)) {
            this.processImportAttributes(atts);
        }
        // Found the schema include tag
        else if (INCLUDE_TAG_NAME.equals(localName)) {
            this.processIncludeAttributes(atts);
        }

        else {
            // we can stop processing if encountering any of the folowing tags
            if (ELEMENT_TAG_NAME.equals(localName) || SIMPLE_TYPE_TAG_NAME.equals(localName)
                || COMPLEX_TYPE_TAG_NAME.equals(localName) || GROUP_TAG_NAME.equals(localName)
                || ATTRIBUTE_GROUP_TAG_NAME.equals(localName) || ATTRIBUTE_TAG_NAME.equals(localName)
                || NOTATION_TAG_NAME.equals(localName)) {

                this.foundTerminatingTag = true;
            }
        }

        this.checkForCompletion();
        super.startElement(uri, localName, qName, atts);
    }

    /**
     * @see org.xml.sax.ContentHandler#endElement(java.lang.String, java.lang.String, java.lang.String)
     */
    @Override
    public void endElement( String namespaceURI,
                            String localName,
                            String qName ) throws SAXException {
        this.checkForCompletion();
        super.endElement(namespaceURI, localName, qName);
    }

    // ==================================================================================
    // P U B L I C M E T H O D S
    // ==================================================================================

    public XsdHeader getXsdHeader() {
        if (this.header == null) {
            this.header = new XsdHeader();
        }
        return this.header;
    }

    // ==================================================================================
    // P R I V A T E M E T H O D S
    // ==================================================================================

    private void checkForCompletion() throws SAXException {
        if (!this.foundSchemaStartElement) {
            throw new SAXException(SCHEMA_NOT_FOUND_EXCEPTION_MESSAGE);
        }
        if (this.foundTerminatingTag) {
            throw new SAXException(SCHEMA_FOUND_EXCEPTION_MESSAGE);
        }
    }

    private void processAttributes( final Attributes atts ) {
        for (int i = 0; i < atts.getLength(); i++) {
            String name = atts.getLocalName(i);
            String value = atts.getValue(i);
            if (TARGET_NAMESPACE_ATTRIBUTE_NAME.equals(name)) {
                this.getXsdHeader().setTargetNamespaceURI(value);
            }
        }
    }

    private void processImportAttributes( final Attributes atts ) {
        for (int i = 0; i < atts.getLength(); i++) {
            String name = atts.getLocalName(i);
            String value = atts.getValue(i);
            if (NAMESPACE_ATTRIBUTE_NAME.equals(name)) {
                this.getXsdHeader().addImportNamespaceURI(value);
            } else if (SCHEMA_LOCATION_ATTRIBUTE_NAME.equals(name)) {
                this.getXsdHeader().addImportSchemaLocation(value);
            }
        }
    }

    private void processIncludeAttributes( final Attributes atts ) {
        for (int i = 0; i < atts.getLength(); i++) {
            String name = atts.getLocalName(i);
            String value = atts.getValue(i);
            if (SCHEMA_LOCATION_ATTRIBUTE_NAME.equals(name)) {
                this.getXsdHeader().addIncludeSchemaLocation(value);
            }
        }
    }

}