| // 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.form; |
| |
| import org.apache.tapestry.ApplicationRuntimeException; |
| 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; |
| |
| /** |
| * A special type of form component that is used to contain {@link Radio} |
| * components. The Radio and {@link Radio} group components work together to |
| * update a property of some other object, much like a more flexible |
| * version of a {@link PropertySelection}. |
| * |
| * [<a href="../../../../../ComponentReference/RadioGroup.html">Component Reference</a>] |
| * |
| * @author Howard Lewis Ship |
| * @version $Id$ |
| * |
| **/ |
| |
| public abstract class RadioGroup extends AbstractFormComponent |
| { |
| // Cached copy of the value from the selectedBinding |
| private Object _selection; |
| |
| // The value from the HTTP request indicating which |
| // Radio was selected by the user. |
| private int _selectedOption; |
| |
| private boolean _rewinding; |
| private boolean _rendering; |
| private int _nextOptionId; |
| |
| /** |
| * A <code>RadioGroup</code> places itself into the {@link IRequestCycle} as |
| * an attribute, so that its wrapped {@link Radio} components can identify thier |
| * state. |
| * |
| **/ |
| |
| private static final String ATTRIBUTE_NAME = "org.apache.tapestry.active.RadioGroup"; |
| |
| public static RadioGroup get(IRequestCycle cycle) |
| { |
| return (RadioGroup) cycle.getAttribute(ATTRIBUTE_NAME); |
| } |
| |
| public abstract IBinding getSelectedBinding(); |
| |
| public int getNextOptionId() |
| { |
| if (!_rendering) |
| throw Tapestry.createRenderOnlyPropertyException(this, "nextOptionId"); |
| |
| return _nextOptionId++; |
| } |
| |
| /** |
| * Used by {@link Radio} components wrapped by this <code>RadioGroup</code> to see |
| * if the group as a whole is disabled. |
| * |
| **/ |
| |
| public abstract boolean isDisabled(); |
| |
| public boolean isRewinding() |
| { |
| if (!_rendering) |
| throw Tapestry.createRenderOnlyPropertyException(this, "rewinding"); |
| |
| return _rewinding; |
| } |
| |
| /** |
| * Returns true if the value is equal to the current selection for the |
| * group. This is invoked by a {@link Radio} during rendering |
| * to determine if it should be marked 'checked'. |
| * |
| **/ |
| |
| public boolean isSelection(Object value) |
| { |
| if (!_rendering) |
| throw Tapestry.createRenderOnlyPropertyException(this, "selection"); |
| |
| if (_selection == value) |
| return true; |
| |
| if (_selection == null || value == null) |
| return false; |
| |
| return _selection.equals(value); |
| } |
| |
| /** |
| * Invoked by the {@link Radio} which is selected to update the |
| * property bound to the selected parameter. |
| * |
| **/ |
| |
| public void updateSelection(Object value) |
| { |
| getSelectedBinding().setObject(value); |
| } |
| |
| /** |
| * Used by {@link Radio} components when rewinding to see if their value was submitted. |
| * |
| **/ |
| |
| public boolean isSelected(int option) |
| { |
| return _selectedOption == option; |
| } |
| |
| /** |
| * Doesn't actual render an HTML element as there is no direct equivalent for |
| * an HTML element. A <code>RadioGroup</code> component exists to organize the |
| * {@link Radio} components it wraps (directly or indirectly). |
| * |
| * A {@link Radio} can finds its {@link RadioGroup} as a {@link IRequestCycle} attribute. |
| * |
| **/ |
| |
| protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle) |
| { |
| IForm form = getForm(cycle); |
| |
| if (cycle.getAttribute(ATTRIBUTE_NAME) != null) |
| throw new ApplicationRuntimeException( |
| Tapestry.getMessage("RadioGroup.may-not-nest"), |
| this, |
| null, |
| null); |
| |
| // It isn't enough to know whether the cycle in general is rewinding, need to know |
| // specifically if the form which contains this component is rewinding. |
| |
| _rewinding = form.isRewinding(); |
| |
| // Used whether rewinding or not. |
| |
| String name = form.getElementId(this); |
| |
| cycle.setAttribute(ATTRIBUTE_NAME, this); |
| |
| // When rewinding, find out which (if any) radio was selected by |
| // the user. |
| |
| if (_rewinding) |
| { |
| String value = cycle.getRequestContext().getParameter(name); |
| if (value == null) |
| _selectedOption = -1; |
| else |
| _selectedOption = Integer.parseInt(value); |
| } |
| |
| try |
| { |
| _rendering = true; |
| _nextOptionId = 0; |
| |
| // For rendering, the Radio components need to know what the current |
| // selection is, so that the correct one can mark itself 'checked'. |
| |
| if (!_rewinding) |
| _selection = getSelectedBinding().getObject(); |
| |
| renderBody(writer, cycle); |
| } |
| finally |
| { |
| _rendering = false; |
| _selection = null; |
| } |
| |
| cycle.removeAttribute(ATTRIBUTE_NAME); |
| } |
| } |