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Groovy example source code file (DOMBuilder.java)

This example Groovy source code file (DOMBuilder.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Groovy tags/keywords

document, document, dom, dombuilder, element, illegalargumentexception, io, map, map, node, object, object, parser, parserconfigurationexception, qname, sax, string, string, util, xml

The Groovy DOMBuilder.java source code

/*
 * Copyright 2003-2007 the original author or authors.
 *
 * 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.
 */

package groovy.xml;

import groovy.util.BuilderSupport;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.util.Iterator;
import java.util.Map;

/**
 * A helper class for creating a W3C DOM tree
 *
 * @author <a href="mailto:james@coredevelopers.net">James Strachan
 * @version $Revision: 14076 $
 */
public class DOMBuilder extends BuilderSupport {

    Document document;
    DocumentBuilder documentBuilder;

    public static DOMBuilder newInstance() throws ParserConfigurationException {
        return newInstance(false, true);
    }

    public static DOMBuilder newInstance(boolean validating, boolean namespaceAware) throws ParserConfigurationException {
        DocumentBuilderFactory factory = FactorySupport.createDocumentBuilderFactory();
        factory.setNamespaceAware(namespaceAware);
        factory.setValidating(validating);
        return new DOMBuilder(factory.newDocumentBuilder());
    }

    /**
     * Creates a DocumentBuilder and uses it to parse the XML text read from the given reader.
     * A non-validating, namespace aware parser is used.
     *
     * @param reader the reader to read the XML text from
     * @return the root node of the parsed tree of Nodes
     * @throws SAXException                 Any SAX exception, possibly wrapping another exception.
     * @throws IOException                  An IO exception from the parser, possibly from a byte
     *                                      stream or character stream supplied by the application.
     * @throws ParserConfigurationException if a DocumentBuilder cannot be created which satisfies
     *                                      the configuration requested.
     * @see #parse(Reader, boolean, boolean)
     */
    public static Document parse(Reader reader) throws SAXException, IOException, ParserConfigurationException {
        return parse(reader, false, true);
    }

    /**
     * Creates a DocumentBuilder and uses it to parse the XML text read from the given reader, allowing
     * parser validation and namespace awareness to be controlled.
     *
     * @param reader         the reader to read the XML text from
     * @param validating     whether to validate the XML
     * @param namespaceAware whether the parser should be namespace aware
     * @return the root node of the parsed tree of Nodes
     * @throws SAXException                 Any SAX exception, possibly wrapping another exception.
     * @throws IOException                  An IO exception from the parser, possibly from a byte
     *                                      stream or character stream supplied by the application.
     * @throws ParserConfigurationException if a DocumentBuilder cannot be created which satisfies
     *                                      the configuration requested.
     */
    public static Document parse(Reader reader, boolean validating, boolean namespaceAware)
            throws SAXException, IOException, ParserConfigurationException {
        DocumentBuilderFactory factory = FactorySupport.createDocumentBuilderFactory();
        factory.setNamespaceAware(namespaceAware);
        factory.setValidating(validating);
        DocumentBuilder documentBuilder = factory.newDocumentBuilder();
        return documentBuilder.parse(new InputSource(reader));
    }

    /**
     * A helper method to parse the given text as XML.
     *
     * @param text the XML text to parse
     * @return the root node of the parsed tree of Nodes
     * @throws SAXException                 Any SAX exception, possibly wrapping another exception.
     * @throws IOException                  An IO exception from the parser, possibly from a byte
     *                                      stream or character stream supplied by the application.
     * @throws ParserConfigurationException if a DocumentBuilder cannot be created which satisfies
     *                                      the configuration requested.
     * @see #parse(Reader)
     */
    public Document parseText(String text) throws SAXException, IOException, ParserConfigurationException {
        return parse(new StringReader(text));
    }

    public DOMBuilder(Document document) {
        this.document = document;
    }

    public DOMBuilder(DocumentBuilder documentBuilder) {
        this.documentBuilder = documentBuilder;
    }

    protected void setParent(Object parent, Object child) {
        Node current = (Node) parent;
        Node node = (Node) child;

        current.appendChild(node);
    }

    protected Object createNode(Object name) {
        if (document == null) {
            document = createDocument();
        }
        if (name instanceof QName) {
            QName qname = (QName) name;
            return document.createElementNS(qname.getNamespaceURI(), qname.getQualifiedName());
        } else {
            return document.createElement(name.toString());
        }
    }

    protected Document createDocument() {
        if (documentBuilder == null) {
            throw new IllegalArgumentException("No Document or DOMImplementation available so cannot create Document");
        } else {
            return documentBuilder.newDocument();
        }
    }

    protected Object createNode(Object name, Object value) {
        Element element = (Element) createNode(name);
        element.appendChild(document.createTextNode(value.toString()));
        return element;
    }

    protected Object createNode(Object name, Map attributes, Object value) {
        Element element = (Element) createNode(name, attributes);
        element.appendChild(document.createTextNode(value.toString()));
        return element;
    }

    protected Object createNode(Object name, Map attributes) {
        Element element = (Element) createNode(name);
        for (Iterator iter = attributes.entrySet().iterator(); iter.hasNext();) {
            Map.Entry entry = (Map.Entry) iter.next();
            String attrName = entry.getKey().toString();
            Object value = entry.getValue();
            if ("xmlns".equals(attrName)) {
                if (value instanceof Map) {
                    appendNamespaceAttributes(element, (Map) value);
                } else if (value instanceof String) {
                    setStringNS(element, "", value);
                } else {
                    throw new IllegalArgumentException("The value of the xmlns attribute must be a Map of QNames to String URIs");
                }
            } else if (attrName.startsWith("xmlns:") && value instanceof String) {
                setStringNS(element, attrName.substring(6), value);
            } else {
                String valueText = (value != null) ? value.toString() : "";
                element.setAttribute(attrName, valueText);
            }
        }
        return element;
    }

    protected void appendNamespaceAttributes(Element element, Map<Object, Object> attributes) {
        for (Map.Entry entry : attributes.entrySet()) {
            Object key = entry.getKey();
            Object value = entry.getValue();
            if (value == null) {
                throw new IllegalArgumentException("The value of key: " + key + " cannot be null");
            }
            if (key instanceof String) {
                setStringNS(element, key, value);
            } else if (key instanceof QName) {
                QName qname = (QName) key;
                element.setAttributeNS(qname.getNamespaceURI(), qname.getQualifiedName(), value.toString());
            } else {
                throw new IllegalArgumentException("The key: " + key + " should be an instanceof of " + QName.class);
            }
        }
    }

    private void setStringNS(Element element, Object key, Object value) {
        String prefix = (String) key;
        element.setAttributeNS("http://www.w3.org/2000/xmlns/", "".equals(prefix) ? "xmlns" : "xmlns:" + prefix, value.toString());
    }
}

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