org.chiba.xml.xforms.ui.Common.java Source code

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/*
 *
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package org.chiba.xml.xforms.ui;

import org.apache.commons.jxpath.JXPathContext;
import org.apache.log4j.Category;
import org.chiba.xml.util.DOMUtil;
import org.chiba.xml.xforms.Model;
import org.chiba.xml.xforms.NamespaceCtx;
import org.chiba.xml.xforms.exception.XFormsException;
import org.chiba.xml.xforms.exception.XFormsLinkException;
import org.w3c.dom.Element;

/**
 * Implementation of <b>8.3.3 The label Element</b>, <b>8.3.4 The help
 * Element</b>, <b>8.3.5 The hint Element</b>, and <b>8.3.6 The alert
 * Element</b>.
 *
 * @author Ulrich Nicolas Liss&eacute;
 * @version $Id: Common.java,v 1.20 2004/12/13 00:11:49 unl Exp $
 */
public class Common extends BoundElement {
    private static final Category LOGGER = Category.getInstance(Common.class);

    /**
     * Creates a new Common object.
     *
     * @param element the DOM Element
     * @param model the Model this Common Element belongs to
     */
    public Common(Element element, Model model) {
        super(element, model);
    }

    // lifecycle methods

    /**
     * Performs element init.
     *
     * @throws XFormsException if any error occurred during init.
     */
    public void init() throws XFormsException {
        if (getLogger().isDebugEnabled()) {
            getLogger().debug(this + " init");
        }

        String value = null;
        if (isBound()) {
            // get instance value
            value = getInstanceValue();
        }

        if (isLinked()) {
            // get linked value
            String src = this.element.getAttributeNS(NamespaceCtx.XFORMS_NS, SRC_ATTRIBUTE);
            Object result;

            try {
                result = this.container.getConnectorFactory().createURIResolver(src, this.element).resolve();
            } catch (Exception e) {
                throw new XFormsLinkException("uri resolution failed", e, this.model.getTarget(), src);
            }

            try {
                value = JXPathContext.newContext(result).getValue("/").toString();
            } catch (Exception e) {
                throw new XFormsLinkException("object model not supported", e, this.model.getTarget(), src);
            }
        }

        if (value != null) {
            // initialize bound or linked value
            DOMUtil.removeAllChildren(this.element);
            this.element.appendChild(this.element.getOwnerDocument().createTextNode(value));
        } else {
            // initialize children
            initializeChildren();
        }
    }

    /**
     * Performs element update.
     *
     * @throws XFormsException if any error occurred during update.
     */
    public void update() throws XFormsException {
        if (getLogger().isDebugEnabled()) {
            getLogger().debug(this + " update");
        }

        if (isBound()) {
            // update text node
            String value = getInstanceValue();
            this.element.getFirstChild().setNodeValue(value);
            return;
        }

        if (isLinked()) {
            // todo: configurable reload ???
            return;
        }

        updateChildren();
    }

    /**
     * Performs element disposal.
     *
     * @throws XFormsException if any error occurred during disposal.
     */
    public void dispose() throws XFormsException {
        if (getLogger().isDebugEnabled()) {
            getLogger().debug(this + " dispose");
        }

        if (!isBound() && !isLinked()) {
            disposeChildren();
        }

        disposeSelf();
    }

    // common specific methods

    /**
     * Checks wether this element is linked to an external resource.
     * <p/>
     * This element is considered linked if it has a <code>src</code>
     * attribute.
     *
     * @return <code>true</code> if this element is linked to an external
     * resource, otherwise <code>false</code>.
     */
    public boolean isLinked() {
        return this.element.hasAttributeNS(NamespaceCtx.XFORMS_NS, SRC_ATTRIBUTE);
    }

    /**
     * Returns the logger object.
     *
     * @return the logger object.
     */
    protected Category getLogger() {
        return LOGGER;
    }

}

// end of class