com.google.gwt.gwtpages.client.page.loader.PageLoader.java Source code

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Here is the source code for com.google.gwt.gwtpages.client.page.loader.PageLoader.java

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package com.google.gwt.gwtpages.client.page.loader;

import java.util.Iterator;

import com.google.gwt.gwtpages.client.Pages;
import com.google.gwt.gwtpages.client.message.exceptions.PageNotFoundException;
import com.google.gwt.gwtpages.client.page.PageAttributes;
import com.google.gwt.gwtpages.client.page.parameters.Tokenizer;

/**
 * Interface class used to load pages based on their "token". The token
 * represents the full history token or partial history token (if accompanied by
 * additional parameters). The page token is identified by the
 * {@link Tokenizer}. The page loaded returns pages using a callback
 * mechanism so they can optionally be implemented in an async fashion.
 * 
 * Known implementations are {@link StandardPageLoader}, {@link AsyncPageLoader}, {@link CompositePageLoader}
 * 
 * @author Joe Hudson
 */
public interface PageLoader {

    public static final String PAGE_DEFAULT = "";
    public static final String PAGE_ERROR = "__error";
    public static final String PAGE_NOT_FOUND = "__notFound";
    public static final String PAGE_ILLEGAL_ACCESS = "__illegalAccess";

    /**
     * Initialize the loader. This is where all pages would be registered.
     */
    public void init(Pages settings);

    /**
     * Return all known page tokens
     */
    public Iterator<String> getValidPageTokens();

    /**
     * Return true if the page token is mapped to a known page and false if not
     * 
     * @param pageToken
     *            the page token
     */
    public boolean isValidPageToken(String pageToken);

    /**
     * Return the optional {@link PageAttributes} associated with this page token
     * 
     * @param pageToken
     *            the page token
     * @return the {@link PageAttributes} or null
     * @throws PageNotFoundException
     *             if no page was mapped to the provided page token
     */
    public PageAttributes getPageAttributes(String pageToken) throws PageNotFoundException;

    /**
     * Method to execute when requesting a page. One of the
     * {@link PageLoadCallback} handler methods *must* be called depending on
     * the state of the page request.
     * 
     * @param pageToken
     *            the page token
     * @param pageHandler
     *            the {@link PageLoadCallback}
     */
    public void getPage(String pageToken, PageLoadCallback pageHandler);
}