abstractelement.java

Java的面向对象数据库系统的源代码

/*
 * Copyright 2001 (C) MetaStuff, Ltd. All Rights Reserved.
 *
 * This software is open source.
 * See the bottom of this file for the licence.
 *
 * $Id: AbstractElement.java,v 1.4 2003/11/02 18:04:59 per_nyfelt Exp $
 */

package org.dom4j.tree;

import org.dom4j.*;
import org.dom4j.CharacterData;
import org.dom4j.io.XMLWriter;
import org.xml.sax.Attributes;

import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;
import java.util.*;

/** <p><code>AbstractElement</code> is an abstract base class for
  * tree implementors to use for implementation inheritence.</p>
  *
  * @author <a href="mailto:[e-mail]">James Strachan</a>
  * @version $Revision: 1.4 $
  */

public abstract class AbstractElement
    extends AbstractBranch
    implements Element {

    protected static final List EMPTY_LIST = Collections.EMPTY_LIST;

    protected static final Iterator EMPTY_ITERATOR = EMPTY_LIST.iterator();

    protected static final boolean VERBOSE_TOSTRING = false;

    protected static final boolean USE_STRINGVALUE_SEPARATOR = false;

    public AbstractElement() {

    }

    public short getNodeType() {

        return ELEMENT_NODE;

    }

    public boolean isRootElement() {

        Document document = getDocument();

        if (document != null) {

            Element root = document.getRootElement();

            if (root == this) {

                return true;

            }

        }

        return false;

    }

    public void setName(String name) {

        setQName(getNodeFactory().createQName(name));

    }

    public void setNamespace(Namespace namespace) {

        setQName(getNodeFactory().createQName(getName(), namespace));

    }

    /** Returns the XPath expression to match this Elements name
     * which is getQualifiedName() if there is a namespace prefix defined or
     * if no namespace is present then it is getName() or if a namespace is defined
     * with no prefix then the expression is *[name()='X'] where X = getName().
     */

    public String getXPathNameStep() {

        String uri = getNamespaceURI();

        if (uri == null || uri.length() == 0) {

            return getName();

        }

        String prefix = getNamespacePrefix();

        if (prefix == null || prefix.length() == 0) {

            return "*[name()='" + getName() + "']";

        }

        return getQualifiedName();

    }

    public String getPath(Element context) {

        Element parent = getParent();

        if (parent == null) {

            return "/" + getXPathNameStep();

        }

        else if (parent == context) {

            return getXPathNameStep();

        }

        return parent.getPath(context) + "/" + getXPathNameStep();

    }

    public String getUniquePath(Element context) {

        Element parent = getParent();

        if (parent == null) {

            return "/" + getXPathNameStep();

        }

        StringBuffer buffer = new StringBuffer();

        if (parent != context) {

            buffer.append(parent.getUniquePath(context));

            buffer.append("/");

        }

        buffer.append(getXPathNameStep());

        List mySiblings = parent.elements(getQName());

        if (mySiblings.size() > 1) {

            int idx = mySiblings.indexOf(this);

            if (idx >= 0) {

                buffer.append("[");

                buffer.append(Integer.toString(++idx));

                buffer.append("]");

            }

        }

        return buffer.toString();

    }

    public String asXML() {

        try {

            StringWriter out = new StringWriter();

            XMLWriter writer = new XMLWriter(out, outputFormat);

            writer.write(this);

            return out.toString();

        }

        catch (IOException e) {

            throw new RuntimeException(
                "Wierd IOException while generating textual representation: " + e.getMessage());

        }

    }

    public void write(Writer out) throws IOException {

        XMLWriter writer = new XMLWriter(out, outputFormat);

        writer.write(this);

    }

    /** <p><code>accept</code> method is the <code>Visitor Pattern</code> method.
      * </p>
      *
      * @param visitor <code>Visitor</code> is the visitor.
      */

    public void accept(Visitor visitor) {

        visitor.visit(this);

        // visit attributes

        for (int i = 0, size = attributeCount(); i < size; i++) {

            Attribute attribute = attribute(i);

            visitor.visit(attribute);

        }

        // visit content

        for (int i = 0, size = nodeCount(); i < size; i++) {

            Node node = node(i);

            node.accept(visitor);

        }

    }

    public String toString() {

        String uri = getNamespaceURI();

        if (uri != null && uri.length() > 0) {

            if (VERBOSE_TOSTRING) {

                return super.toString()
                    + " [Element: <"
                    + getQualifiedName()
                    + " uri: "
                    + uri
                    + " attributes: "
                    + attributeList()
                    + " content: "
                    + contentList()
                    + " />]";

            }

            else {

                return super.toString()
                    + " [Element: <"
                    + getQualifiedName()
                    + " uri: "
                    + uri
                    + " attributes: "
                    + attributeList()
                    + "/>]";

            }

        }

        else {

            if (VERBOSE_TOSTRING) {

                return super.toString()
                    + " [Element: <"
                    + getQualifiedName()
                    + " attributes: "
                    + attributeList()
                    + " content: "
                    + contentList()
                    + " />]";

            }

            else {

                return super.toString()
                    + " [Element: <"
                    + getQualifiedName()
                    + " attributes: "
                    + attributeList()
                    + "/>]";

            }

        }

    }

    // QName methods

    //-------------------------------------------------------------------------

    public Namespace getNamespace() {
        return getQName().getNamespace();
    }

    public String getName() {
        return getQName().getName();
    }

    public String getNamespacePrefix() {
        return getQName().getNamespacePrefix();
    }

    public String getNamespaceURI() {
        return getQName().getNamespaceURI();
    }

    public String getQualifiedName() {
        return getQName().getQualifiedName();
    }

    public Object getData() {
        return getText();
    }

    public void setData(Object data) {

        // ignore this method

    }

    // Node methods

    //-------------------------------------------------------------------------

    public Node node(int index) {

        if (index >= 0) {

            List list = contentList();

            if (index >= list.size()) {

                return null;

            }

            Object node = list.get(index);

            if (node != null) {

                if (node instanceof Node) {

                    return (Node) node;

                }

                else {

                    return getNodeFactory().createText(node.toString());

                }

            }

        }

        return null;

    }

    public int indexOf(Node node) {

        return contentList().indexOf(node);

    }

    public int nodeCount() {

        return contentList().size();

    }

    public Iterator nodeIterator() {

        return contentList().iterator();

    }

    // Element methods

    //-------------------------------------------------------------------------

    public Element element(String name) {

        List list = contentList();

        int size = list.size();

        for (int i = 0; i < size; i++) {

            Object object = list.get(i);

            if (object instanceof Element) {

                Element element = (Element) object;

                if (name.equals(element.getName())) {

                    return element;

                }

            }

        }

        return null;

    }

    public Element element(QName qName) {

        List list = contentList();

        int size = list.size();

        for (int i = 0; i < size; i++) {

            Object object = list.get(i);

            if (object instanceof Element) {

                Element element = (Element) object;

                if (qName.equals(element.getQName())) {

                    return element;

                }

            }

        }

        return null;

    }

    public Element element(String name, Namespace namespace) {

        return element(getNodeFactory().createQName(name, namespace));

    }

    public List elements() {

        List list = contentList();

        BackedList answer = createResultList();

        int size = list.size();

        for (int i = 0; i < size; i++) {

            Object object = list.get(i);

            if (object instanceof Element) {

                answer.addLocal(object);

            }

        }

        return answer;

    }

    public List elements(String name) {

        List list = contentList();

        BackedList answer = createResultList();

        int size = list.size();

        for (int i = 0; i < size; i++) {

            Object object = list.get(i);

            if (object instanceof Element) {

                Element element = (Element) object;

                if (name.equals(element.getName())) {

                    answer.addLocal(element);

                }

            }

        }

        return answer;

    }

    public List elements(QName qName) {

        List list = contentList();

        BackedList answer = createResultList();

        int size = list.size();

        for (int i = 0; i < size; i++) {

            Object object = list.get(i);

            if (object instanceof Element) {

                Element element = (Element) object;

                if (qName.equals(element.getQName())) {

                    answer.addLocal(element);

                }

            }

        }

        return answer;

    }

    public List elements(String name, Namespace namespace) {

        return elements(getNodeFactory().createQName(name, namespace));

    }

    public Iterator elementIterator() {

        List list = contentList();

        return new ElementIterator(list.iterator());

    }

    public Iterator elementIterator(String name) {

        List list = contentList();

        return new ElementNameIterator(list.iterator(), name);

    }

    public Iterator elementIterator(QName qName) {

        List list = contentList();

        return new ElementQNameIterator(list.iterator(), qName);

    }

    public Iterator elementIterator(String name, Namespace namespace) {

        return elementIterator(getNodeFactory().createQName(name, namespace));

    }

    // Attribute methods

    //-------------------------------------------------------------------------

    public List attributes() {

        return new ContentListFacade(this, attributeList());

    }

    public Iterator attributeIterator() {

        return attributeList().iterator();

    }

    public Attribute attribute(int index) {

        return (Attribute) attributeList().get(index);

    }

    public int attributeCount() {

        return attributeList().size();

    }

    public Attribute attribute(String name) {

        List list = attributeList();

        int size = list.size();

        for (int i = 0; i < size; i++) {

            Attribute attribute = (Attribute) list.get(i);

            if (name.equals(attribute.getName())) {

                return attribute;

            }

        }

        return null;

    }

    public Attribute attribute(QName qName) {

        List list = attributeList();

        int size = list.size();

        for (int i = 0; i < size; i++) {

            Attribute attribute = (Attribute) list.get(i);

            if (qName.equals(attribute.getQName())) {

                return attribute;

            }

        }

        return null;

    }

    public Attribute attribute(String name, Namespace namespace) {

        return attribute(getNodeFactory().createQName(name, namespace));

    }

    /** This method provides a more optimal way of setting all the attributes
     * on an Element particularly for use in {@link org.dom4j.io.SAXReader}.
      */

    public void setAttributes(
        Attributes attributes,
        NamespaceStack namespaceStack,
        boolean noNamespaceAttributes) {

        // now lets add all attribute values

        int size = attributes.getLength();

        if (size > 0) {

            NodeFactory factory = getNodeFactory();

            if (size == 1) {

                // allow lazy construction of the List of Attributes