tapestry-framework/src/java/org/apache/tapestry/wml/Do.java

// Copyright 2004, 2005 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.wml;

import org.apache.hivemind.HiveMind;
import org.apache.tapestry.AbstractComponent;
import org.apache.tapestry.IMarkupWriter;
import org.apache.tapestry.IRequestCycle;

/**
 * The do element provides a general mechanism for the user to act upon the
 * current card, in other words a card-level user interface element. The
 * representation of the do element is user agent dependent and the author must
 * only assume that the element is mapped to a unique user interface widget that
 * the user can activate. For example, the widget mapping may be to a
 * graphically rendered button, a soft or function key, a voice-activated
 * command sequence, or any other interface that has a simple "activate"
 * operation with no inter-operation persistent state. The do element may appear
 * at both the card and deck-level.
 * 
 * @author David Solis
 * @since 3.0
 */

public abstract class Do extends AbstractComponent
{

    /**
     * @see AbstractComponent#renderComponent(IMarkupWriter, IRequestCycle)
     */

    protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle)
    {
        boolean render = !cycle.isRewinding();

        if (render)
        {
            writer.begin("do");

            writer.attribute("type", getType());

            String label = getLabel();
            if (HiveMind.isNonBlank(label)) writer.attribute("label", label);

            renderInformalParameters(writer, cycle);
        }

        renderBody(writer, cycle);

        if (render) writer.end();
    }

    public abstract String getType();

    public abstract String getLabel();
}