Java tutorial
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THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF * MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. * */ package org.chiba.xml.xforms.ui; import org.apache.commons.jxpath.JXPathContext; import org.apache.commons.jxpath.JXPathException; import org.apache.commons.jxpath.Pointer; import org.apache.log4j.Category; import org.chiba.xml.xforms.BindingResolver; import org.chiba.xml.xforms.Instance; import org.chiba.xml.xforms.Model; import org.chiba.xml.xforms.NamespaceCtx; import org.chiba.xml.xforms.exception.XFormsComputeException; import org.chiba.xml.xforms.exception.XFormsException; import org.chiba.xml.xforms.xpath.PathUtil; import org.w3c.dom.Element; /** * Implementation of <b>8.1.5 The output Element</b>. * <p/> * Note: In case this control is not bound but has a <code>value</code> * attribute, re-evaluation of this attribute occurs during * <code>xforms-refresh</code>. * * @author Ulrich Nicolas Lissé * @version $Id: Output.java,v 1.29 2004/11/18 15:57:58 unl Exp $ */ public class Output extends AbstractFormControl { private static final Category LOGGER = Category.getInstance(Output.class); private String valueAttribute; /** * Creates a new Output object. * * @param element the DOM Element * @param model the Model to which this output is bound */ public Output(Element element, Model model) { super(element, model); } /** * Returns the current value of this form control. * * @return the current value of this form control. */ public String getValue() { if (isBound()) { return super.getValue(); } if (this.valueAttribute != null) { return this.dataElement.getElementValue(); } return null; } /** * Sets the value of this form control. * <p/> * If this method is called a warning is issued since the value of an * <code>output</code> control cannot be set. * * @param value the value to be set. */ public void setValue(String value) { getLogger().warn(this + " set value: the value of an output control cannot be set"); } // 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"); } initializeInstanceNode(); initializeOutputData(); initializeChildren(); } /** * Performs element update. * * @throws XFormsException if any error occurred during update. */ public void update() throws XFormsException { if (getLogger().isDebugEnabled()) { getLogger().debug(this + " update"); } updateOutputData(); updateChildren(); } /** * Performs element disposal. * * @throws XFormsException if any error occurred during disposal. */ public void dispose() throws XFormsException { if (getLogger().isDebugEnabled()) { getLogger().debug(this + " dispose"); } disposeChildren(); disposeOutputData(); disposeSelf(); } /** * Returns the logger object. * * @return the logger object. */ protected Category getLogger() { return LOGGER; } // lifecycle template methods /** * Initializes output data. */ protected final void initializeOutputData() throws XFormsException { if (isBound()) { initializeDataElement(); } if (this.element.hasAttributeNS(NamespaceCtx.XFORMS_NS, "value")) { this.valueAttribute = this.element.getAttributeNS(NamespaceCtx.XFORMS_NS, "value"); String value = evaluate(this.valueAttribute); this.dataElement = new DataElement(this); this.dataElement.setHandleProperties(false); this.dataElement.setHandlePath(false); this.dataElement.setHandleTypes(false); this.dataElement.setHandleValue(false); this.dataElement.init(); this.dataElement.setAttributeValue("xpath", this.valueAttribute); this.dataElement.setElementValue(value); } } /** * Updates output data. */ protected final void updateOutputData() throws XFormsException { if (isBound()) { updateDataElement(); } if (this.valueAttribute != null) { String value = evaluate(this.valueAttribute); this.dataElement.setElementValue(value); } } /** * Disposes output data. */ protected final void disposeOutputData() { if (isBound()) { disposeDataElement(); } if (this.valueAttribute != null) { this.dataElement.dispose(); this.dataElement = null; this.valueAttribute = null; } } // private helper private String evaluate(String xpath) throws XFormsException { // get enclosing location path and instance id String locationPath = BindingResolver.getExpressionPath(this, this.repeatItemId); String instanceId = PathUtil.getInstanceId(this.model, locationPath); Instance instance = getModel().getInstance(instanceId); if (instance.existsNode(locationPath)) { try { Pointer pointer = instance.getPointer(locationPath); JXPathContext context = instance.getInstanceContext().getRelativeContext(pointer); return String.valueOf(context.getValue(xpath)); } catch (JXPathException e) { throw new XFormsComputeException("could not evaluate output", e, this.model.getTarget(), xpath); } } return null; } } // end of class