maprenderer.java

JavaeeTutorial5的源代码。

/*
 * Copyright 2007 Sun Microsystems, Inc.
 * All rights reserved.  You may not modify, use,
 * reproduce, or distribute this software except in
 * compliance with  the terms of the License at:
 * http://developer.sun.com/berkeley_license.html
 */


package com.sun.bookstore6.renderers;

import com.sun.bookstore6.components.MapComponent;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.context.ResponseWriter;
import javax.faces.render.Renderer;
import java.io.IOException;


/**
 * <p>Renderer for {@link MapComponent} in an HTML environment.</p>
 */
public class MapRenderer extends Renderer {
    // -------------------------------------------------------- Renderer Methods

    /**
     * <p>Decode the incoming request parameters to determine which
     * hotspot (if any) has been selected.</p>
     *
     * @param context   <code>FacesContext</code>for the current request
     * @param component <code>UIComponent</code> to be decoded
     */
    public void decode(
        FacesContext context,
        UIComponent component) {
        if ((context == null) || (component == null)) {
            throw new NullPointerException();
        }

        MapComponent map = (MapComponent) component;

        String key = getName(context, map);
        String value = (String) context.getExternalContext()
                                       .getRequestParameterMap()
                                       .get(key);

        if (value != null) {
            map.setCurrent(value);
        }
    }

    /**
     * <p>Encode the beginning of this component.</p>
     *
     * @param context   <code>FacesContext</code>for the current request
     * @param component <code>UIComponent</code> to be decoded
     */
    public void encodeBegin(
        FacesContext context,
        UIComponent component) throws IOException {
        if ((context == null) || (component == null)) {
            throw new NullPointerException();
        }

        MapComponent map = (MapComponent) component;
        ResponseWriter writer = context.getResponseWriter();

        writer.startElement("map", map);
        writer.writeAttribute(
            "name",
            map.getId(),
            "id");
    }

    /**
     * <p>Encode the children of this component.</p>
     *
     * @param context   <code>FacesContext</code>for the current request
     * @param component <code>UIComponent</code> to be decoded
     */
    public void encodeChildren(
        FacesContext context,
        UIComponent component) throws IOException {
        if ((context == null) || (component == null)) {
            throw new NullPointerException();
        }
    }

    /**
     * <p>Encode the ending of this component.</p>
     *
     * @param context   <code>FacesContext</code>for the current request
     * @param component <code>UIComponent</code> to be decoded
     */
    public void encodeEnd(
        FacesContext context,
        UIComponent component) throws IOException {
        if ((context == null) || (component == null)) {
            throw new NullPointerException();
        }

        MapComponent map = (MapComponent) component;
        ResponseWriter writer = context.getResponseWriter();

        writer.startElement("input", map);
        writer.writeAttribute("type", "hidden", null);
        writer.writeAttribute(
            "name",
            getName(context, map),
            "clientId");
        writer.endElement("input");
        writer.endElement("map");
    }

    // --------------------------------------------------------- Private Methods

    /**
     * <p>Return the calculated name for the hidden input field.</p>
     *
     * @param context   Context for the current request
     * @param component Component we are rendering
     */
    private String getName(
        FacesContext context,
        UIComponent component) {
        return (component.getId() + "_current");
    }

    /**
     * <p>Return the context-relative path for the current page.</p>
     *
     * @param context Context for the current request
     */
    private String getURI(FacesContext context) {
        StringBuffer sb = new StringBuffer();
        sb.append(context.getExternalContext().getRequestContextPath());
        // PENDING(craigmcc) - will need to change if this is generalized
        sb.append("/faces");
        sb.append(context.getViewRoot().getViewId());

        return (sb.toString());
    }
}