| // Copyright 2004 The Apache Software Foundation |
| // |
| // 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 org.apache.tapestry.contrib.form; |
| |
| import java.io.IOException; |
| |
| import org.apache.tapestry.ApplicationRuntimeException; |
| import org.apache.tapestry.IActionListener; |
| import org.apache.tapestry.IBinding; |
| import org.apache.tapestry.IForm; |
| import org.apache.tapestry.IMarkupWriter; |
| import org.apache.tapestry.IRequestCycle; |
| import org.apache.tapestry.Tapestry; |
| import org.apache.tapestry.form.AbstractFormComponent; |
| import org.apache.tapestry.request.RequestContext; |
| import org.apache.tapestry.util.io.DataSqueezer; |
| |
| /** |
| * A conditional element on a page which will render its wrapped elements |
| * zero or one times. |
| * |
| * This component is a variant of {@link org.apache.tapestry.components.Conditional}, |
| * but is designed for operation in a form. The component parameters are stored in |
| * hidden fields during rendering and are taken from those fields during the rewind, |
| * thus no StaleLink exceptions occur. |
| * |
| * [<a href="../../../../../ComponentReference/contrib.FormConditional.html">Component Reference</a>] |
| * |
| * @author Mindbridge |
| * @version $Id$ |
| * @since 3.0 |
| * |
| **/ |
| |
| public abstract class FormConditional extends AbstractFormComponent |
| { |
| |
| protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle) |
| { |
| IForm form = getForm(cycle); |
| |
| boolean cycleRewinding = cycle.isRewinding(); |
| |
| // If the cycle is rewinding, but not this particular form, |
| // then do nothing (don't even render the body). |
| |
| if (cycleRewinding && !form.isRewinding()) |
| return; |
| |
| String name = form.getElementId(this); |
| |
| boolean condition = getCondition(cycle, form, name); |
| |
| // call listener |
| IActionListener listener = getListener(); |
| if (listener != null) |
| listener.actionTriggered(this, cycle); |
| |
| // render the component body only if the condition is true |
| if (condition) { |
| String element = getElement(); |
| |
| boolean render = !cycleRewinding && Tapestry.isNonBlank(element); |
| |
| if (render) |
| { |
| writer.begin(element); |
| renderInformalParameters(writer, cycle); |
| } |
| |
| renderBody(writer, cycle); |
| |
| if (render) |
| writer.end(element); |
| } |
| } |
| |
| private boolean getCondition(IRequestCycle cycle, IForm form, String name) |
| { |
| boolean condition; |
| |
| if (!cycle.isRewinding()) |
| { |
| condition = getCondition(); |
| writeValue(form, name, condition); |
| } |
| else |
| { |
| RequestContext context = cycle.getRequestContext(); |
| String submittedConditions[] = context.getParameters(name); |
| condition = convertValue(submittedConditions[0]); |
| } |
| |
| IBinding conditionValueBinding = getConditionValueBinding(); |
| if (conditionValueBinding != null) |
| conditionValueBinding.setBoolean(condition); |
| |
| return condition; |
| } |
| |
| private void writeValue(IForm form, String name, boolean value) |
| { |
| String externalValue; |
| |
| Object booleanValue = new Boolean(value); |
| try |
| { |
| externalValue = getDataSqueezer().squeeze(booleanValue); |
| } |
| catch (IOException ex) |
| { |
| throw new ApplicationRuntimeException( |
| Tapestry.format("FormConditional.unable-to-convert-value", booleanValue), |
| this, |
| null, |
| ex); |
| } |
| |
| form.addHiddenValue(name, externalValue); |
| } |
| |
| private boolean convertValue(String value) |
| { |
| try |
| { |
| Object booleanValue = getDataSqueezer().unsqueeze(value); |
| return Tapestry.evaluateBoolean(booleanValue); |
| } |
| catch (IOException ex) |
| { |
| throw new ApplicationRuntimeException( |
| Tapestry.format("FormConditional.unable-to-convert-string", value), |
| this, |
| null, |
| ex); |
| } |
| } |
| |
| private DataSqueezer getDataSqueezer() |
| { |
| return getPage().getEngine().getDataSqueezer(); |
| } |
| |
| public boolean isDisabled() |
| { |
| return false; |
| } |
| |
| public abstract boolean getCondition(); |
| public abstract String getElement(); |
| |
| public abstract IBinding getConditionValueBinding(); |
| |
| public abstract IActionListener getListener(); |
| |
| } |