2.4/samples/showcase/src/com/google/gwt/sample/showcase/client/ContentWidget.java - gwt - Git at Google

 /*
  * Copyright 2008 Google Inc.
  *
  * 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 com.google.gwt.sample.showcase.client;

 import com.google.gwt.core.client.GWT;
 import com.google.gwt.event.logical.shared.HasValueChangeHandlers;
 import com.google.gwt.event.logical.shared.ValueChangeEvent;
 import com.google.gwt.event.logical.shared.ValueChangeHandler;
 import com.google.gwt.event.shared.HandlerRegistration;
 import com.google.gwt.http.client.Request;
 import com.google.gwt.http.client.RequestBuilder;
 import com.google.gwt.http.client.RequestCallback;
 import com.google.gwt.http.client.RequestException;
 import com.google.gwt.http.client.Response;
 import com.google.gwt.i18n.client.LocaleInfo;
 import com.google.gwt.safehtml.shared.SafeHtml;
 import com.google.gwt.safehtml.shared.SafeHtmlUtils;
 import com.google.gwt.user.client.Window;
 import com.google.gwt.user.client.rpc.AsyncCallback;
 import com.google.gwt.user.client.ui.SimpleLayoutPanel;
 import com.google.gwt.user.client.ui.Widget;

 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;

 /**
  * <p>
  * A widget used to show GWT examples in the ContentPanel.
  * </p>
  * <p>
  * This {@link Widget} uses a lazy initialization mechanism so that the content
  * is not rendered until the onInitialize method is called, which happens the
  * first time the {@link Widget} is added to the page. The data in the source
  * and css tabs are loaded using an RPC call to the server.
  * </p>
  */
 public abstract class ContentWidget extends SimpleLayoutPanel implements
     HasValueChangeHandlers<String> {

   /**
    * Generic callback used for asynchronously loaded data.
    *
    * @param <T> the data type
    */
   public static interface Callback<T> {
     void onError();

     void onSuccess(T value);
   }

   /**
    * Get the simple filename of a class.
    *
    * @param c the class
    */
   protected static String getSimpleName(Class<?> c) {
     String name = c.getName();
     return name.substring(name.lastIndexOf(".") + 1);
   }

   /**
    * A description of the example.
    */
   private final SafeHtml description;

   /**
    * True if this example has associated styles, false if not.
    */
   private final boolean hasStyle;

   /**
    * The name of the example.
    */
   private final String name;

   /**
    * A mapping of filenames to their raw source code. The map is populated as
    * source is loaded.
    */
   private final Map<String, String> rawSource = new HashMap<String, String>();

   /**
    * A list of filenames of the raw source code included with this example.
    */
   private final List<String> rawSourceFilenames = new ArrayList<String>();

   /**
    * The source code associated with this widget.
    */
   private String sourceCode;

   /**
    * A style definitions used by this widget.
    */
   private String styleDefs;

   /**
    * The view that holds the name, description, and example.
    */
   private ContentWidgetView view;

   /**
    * Whether the demo widget has been initialized.
    */
   private boolean widgetInitialized;

   /**
    * Whether the demo widget is (asynchronously) initializing.
    */
   private boolean widgetInitializing;

   /**
    * Construct a {@link ContentWidget}.
    *
    * @param name the text name of the example
    * @param description a text description of the example
    * @param hasStyle true if the example has associated styles
    * @param rawSourceFiles the list of raw source files to include
    */
   public ContentWidget(String name, String description, boolean hasStyle, String... rawSourceFiles) {
     this(name, SafeHtmlUtils.fromString(description), hasStyle, rawSourceFiles);
   }

   /**
    * Construct a {@link ContentWidget}.
    *
    * @param name the text name of the example
    * @param description a safe html description of the example
    * @param hasStyle true if the example has associated styles
    * @param rawSourceFiles the list of raw source files to include
    */
   public ContentWidget(String name, SafeHtml description, boolean hasStyle,
       String... rawSourceFiles) {
     this.name = name;
     this.description = description;
     this.hasStyle = hasStyle;
     if (rawSourceFiles != null) {
       for (String rawSourceFile : rawSourceFiles) {
         rawSourceFilenames.add(rawSourceFile);
       }
     }
   }

   public HandlerRegistration addValueChangeHandler(ValueChangeHandler<String> handler) {
     return addHandler(handler, ValueChangeEvent.getType());
   }

   /**
    * Get the description of this example.
    *
    * @return a description for this example
    */
   public final SafeHtml getDescription() {
     return description;
   }

   /**
    * Get the name of this example to use as a title.
    *
    * @return a name for this example
    */
   public final String getName() {
     return name;
   }

   /**
    * Get the source code for a raw file.
    *
    * @param filename the filename to load
    * @param callback the callback to call when loaded
    */
   public void getRawSource(final String filename, final Callback<String> callback) {
     if (rawSource.containsKey(filename)) {
       callback.onSuccess(rawSource.get(filename));
     } else {
       RequestCallback rc = new RequestCallback() {
         public void onError(Request request, Throwable exception) {
           callback.onError();
         }

         public void onResponseReceived(Request request, Response response) {
           String text = response.getText();
           rawSource.put(filename, text);
           callback.onSuccess(text);
         }
       };

       String className = this.getClass().getName();
       className = className.substring(className.lastIndexOf(".") + 1);
       sendSourceRequest(rc, ShowcaseConstants.DST_SOURCE_RAW + filename + ".html");
     }
   }

   /**
    * Get the filenames of the raw source files.
    *
    * @return the raw source files.
    */
   public List<String> getRawSourceFilenames() {
     return Collections.unmodifiableList(rawSourceFilenames);
   }

   /**
    * Request the styles associated with the widget.
    *
    * @param callback the callback used when the styles become available
    */
   public void getStyle(final Callback<String> callback) {
     if (styleDefs != null) {
       callback.onSuccess(styleDefs);
     } else {
       RequestCallback rc = new RequestCallback() {
         public void onError(Request request, Throwable exception) {
           callback.onError();
         }

         public void onResponseReceived(Request request, Response response) {
           styleDefs = response.getText();
           callback.onSuccess(styleDefs);
         }
       };

       String srcPath = ShowcaseConstants.DST_SOURCE_STYLE + Showcase.THEME;
       if (LocaleInfo.getCurrentLocale().isRTL()) {
         srcPath += "_rtl";
       }
       String className = this.getClass().getName();
       className = className.substring(className.lastIndexOf(".") + 1);
       sendSourceRequest(rc, srcPath + "/" + className + ".html");
     }
   }

   /**
    * Request the source code associated with the widget.
    *
    * @param callback the callback used when the source become available
    */
   public void getSource(final Callback<String> callback) {
     if (sourceCode != null) {
       callback.onSuccess(sourceCode);
     } else {
       RequestCallback rc = new RequestCallback() {
         public void onError(Request request, Throwable exception) {
           callback.onError();
         }

         public void onResponseReceived(Request request, Response response) {
           sourceCode = response.getText();
           callback.onSuccess(sourceCode);
         }
       };

       String className = this.getClass().getName();
       className = className.substring(className.lastIndexOf(".") + 1);
       sendSourceRequest(rc, ShowcaseConstants.DST_SOURCE_EXAMPLE + className + ".html");
     }
   }

   /**
    * Check if the widget should have margins.
    *
    * @return true to use margins, false to flush against edges
    */
   public boolean hasMargins() {
     return true;
   }

   /**
    * Check if the widget should be wrapped in a scrollable div.
    *
    * @return true to use add scrollbars, false not to
    */
   public boolean hasScrollableContent() {
     return true;
   }

   /**
    * Returns true if this widget has a style section.
    *
    * @return true if style tab available
    */
   public final boolean hasStyle() {
     return hasStyle;
   }

   /**
    * When the widget is first initialized, this method is called. If it returns
    * a Widget, the widget will be added as the first tab. Return null to disable
    * the first tab.
    *
    * @return the widget to add to the first tab
    */
   public abstract Widget onInitialize();

   /**
    * Called when initialization has completed and the widget has been added to
    * the page.
    */
   public void onInitializeComplete() {
   }

   protected abstract void asyncOnInitialize(final AsyncCallback<Widget> callback);

   /**
    * Fire a {@link ValueChangeEvent} indicating that the user wishes to see the
    * specified source file.
    *
    * @param filename the filename that the user wishes to see
    */
   protected void fireRawSourceRequest(String filename) {
     if (!rawSourceFilenames.contains(filename)) {
       throw new IllegalArgumentException("Filename is not registered with this example: "
           + filename);
     }
     ValueChangeEvent.fire(this, filename);
   }

   @Override
   protected void onLoad() {
     if (view == null) {
       view = new ContentWidgetView(hasMargins(), hasScrollableContent());
       view.setName(getName());
       view.setDescription(getDescription());
       setWidget(view);
     }
     ensureWidgetInitialized();
     super.onLoad();
   }

   /**
    * Ensure that the demo widget has been initialized. Note that initialization
    * can fail if there is a network failure.
    */
   private void ensureWidgetInitialized() {
     if (widgetInitializing || widgetInitialized) {
       return;
     }

     widgetInitializing = true;

     asyncOnInitialize(new AsyncCallback<Widget>() {
       public void onFailure(Throwable reason) {
         widgetInitializing = false;
         Window.alert("Failed to download code for this widget (" + reason + ")");
       }

       public void onSuccess(Widget result) {
         widgetInitializing = false;
         widgetInitialized = true;

         Widget widget = result;
         if (widget != null) {
           view.setExample(widget);
         }
         onInitializeComplete();
       }
     });
   }

   /**
    * Send a request for source code.
    *
    * @param callback the {@link RequestCallback} to send
    * @param url the URL to target
    */
   private void sendSourceRequest(RequestCallback callback, String url) {
     RequestBuilder builder = new RequestBuilder(RequestBuilder.GET, GWT.getModuleBaseURL() + url);
     builder.setCallback(callback);
     try {
       builder.send();
     } catch (RequestException e) {
       callback.onError(null, e);
     }
   }
 }
	/*
	* Copyright 2008 Google Inc.
	*
	* 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 com.google.gwt.sample.showcase.client;

	import com.google.gwt.core.client.GWT;
	import com.google.gwt.event.logical.shared.HasValueChangeHandlers;
	import com.google.gwt.event.logical.shared.ValueChangeEvent;
	import com.google.gwt.event.logical.shared.ValueChangeHandler;
	import com.google.gwt.event.shared.HandlerRegistration;
	import com.google.gwt.http.client.Request;
	import com.google.gwt.http.client.RequestBuilder;
	import com.google.gwt.http.client.RequestCallback;
	import com.google.gwt.http.client.RequestException;
	import com.google.gwt.http.client.Response;
	import com.google.gwt.i18n.client.LocaleInfo;
	import com.google.gwt.safehtml.shared.SafeHtml;
	import com.google.gwt.safehtml.shared.SafeHtmlUtils;
	import com.google.gwt.user.client.Window;
	import com.google.gwt.user.client.rpc.AsyncCallback;
	import com.google.gwt.user.client.ui.SimpleLayoutPanel;
	import com.google.gwt.user.client.ui.Widget;

	import java.util.ArrayList;
	import java.util.Collections;
	import java.util.HashMap;
	import java.util.List;
	import java.util.Map;

	/**
	* <p>
	* A widget used to show GWT examples in the ContentPanel.
	* </p>
	* <p>
	* This {@link Widget} uses a lazy initialization mechanism so that the content
	* is not rendered until the onInitialize method is called, which happens the
	* first time the {@link Widget} is added to the page. The data in the source
	* and css tabs are loaded using an RPC call to the server.
	* </p>
	*/
	public abstract class ContentWidget extends SimpleLayoutPanel implements
	HasValueChangeHandlers<String> {

	/**
	* Generic callback used for asynchronously loaded data.
	*
	* @param <T> the data type
	*/
	public static interface Callback<T> {
	void onError();

	void onSuccess(T value);
	}

	/**
	* Get the simple filename of a class.
	*
	* @param c the class
	*/
	protected static String getSimpleName(Class<?> c) {
	String name = c.getName();
	return name.substring(name.lastIndexOf(".") + 1);
	}

	/**
	* A description of the example.
	*/
	private final SafeHtml description;

	/**
	* True if this example has associated styles, false if not.
	*/
	private final boolean hasStyle;

	/**
	* The name of the example.
	*/
	private final String name;

	/**
	* A mapping of filenames to their raw source code. The map is populated as
	* source is loaded.
	*/
	private final Map<String, String> rawSource = new HashMap<String, String>();

	/**
	* A list of filenames of the raw source code included with this example.
	*/
	private final List<String> rawSourceFilenames = new ArrayList<String>();

	/**
	* The source code associated with this widget.
	*/
	private String sourceCode;

	/**
	* A style definitions used by this widget.
	*/
	private String styleDefs;

	/**
	* The view that holds the name, description, and example.
	*/
	private ContentWidgetView view;

	/**
	* Whether the demo widget has been initialized.
	*/
	private boolean widgetInitialized;

	/**
	* Whether the demo widget is (asynchronously) initializing.
	*/
	private boolean widgetInitializing;

	/**
	* Construct a {@link ContentWidget}.
	*
	* @param name the text name of the example
	* @param description a text description of the example
	* @param hasStyle true if the example has associated styles
	* @param rawSourceFiles the list of raw source files to include
	*/
	public ContentWidget(String name, String description, boolean hasStyle, String... rawSourceFiles) {
	this(name, SafeHtmlUtils.fromString(description), hasStyle, rawSourceFiles);
	}

	/**
	* Construct a {@link ContentWidget}.
	*
	* @param name the text name of the example
	* @param description a safe html description of the example
	* @param hasStyle true if the example has associated styles
	* @param rawSourceFiles the list of raw source files to include
	*/
	public ContentWidget(String name, SafeHtml description, boolean hasStyle,
	String... rawSourceFiles) {
	this.name = name;
	this.description = description;
	this.hasStyle = hasStyle;
	if (rawSourceFiles != null) {
	for (String rawSourceFile : rawSourceFiles) {
	rawSourceFilenames.add(rawSourceFile);
	}
	}
	}

	public HandlerRegistration addValueChangeHandler(ValueChangeHandler<String> handler) {
	return addHandler(handler, ValueChangeEvent.getType());
	}

	/**
	* Get the description of this example.
	*
	* @return a description for this example
	*/
	public final SafeHtml getDescription() {
	return description;
	}

	/**
	* Get the name of this example to use as a title.
	*
	* @return a name for this example
	*/
	public final String getName() {
	return name;
	}

	/**
	* Get the source code for a raw file.
	*
	* @param filename the filename to load
	* @param callback the callback to call when loaded
	*/
	public void getRawSource(final String filename, final Callback<String> callback) {
	if (rawSource.containsKey(filename)) {
	callback.onSuccess(rawSource.get(filename));
	} else {
	RequestCallback rc = new RequestCallback() {
	public void onError(Request request, Throwable exception) {
	callback.onError();
	}

	public void onResponseReceived(Request request, Response response) {
	String text = response.getText();
	rawSource.put(filename, text);
	callback.onSuccess(text);
	}
	};

	String className = this.getClass().getName();
	className = className.substring(className.lastIndexOf(".") + 1);
	sendSourceRequest(rc, ShowcaseConstants.DST_SOURCE_RAW + filename + ".html");
	}
	}

	/**
	* Get the filenames of the raw source files.
	*
	* @return the raw source files.
	*/
	public List<String> getRawSourceFilenames() {
	return Collections.unmodifiableList(rawSourceFilenames);
	}

	/**
	* Request the styles associated with the widget.
	*
	* @param callback the callback used when the styles become available
	*/
	public void getStyle(final Callback<String> callback) {
	if (styleDefs != null) {
	callback.onSuccess(styleDefs);
	} else {
	RequestCallback rc = new RequestCallback() {
	public void onError(Request request, Throwable exception) {
	callback.onError();
	}

	public void onResponseReceived(Request request, Response response) {
	styleDefs = response.getText();
	callback.onSuccess(styleDefs);
	}
	};

	String srcPath = ShowcaseConstants.DST_SOURCE_STYLE + Showcase.THEME;
	if (LocaleInfo.getCurrentLocale().isRTL()) {
	srcPath += "_rtl";
	}
	String className = this.getClass().getName();
	className = className.substring(className.lastIndexOf(".") + 1);
	sendSourceRequest(rc, srcPath + "/" + className + ".html");
	}
	}

	/**
	* Request the source code associated with the widget.
	*
	* @param callback the callback used when the source become available
	*/
	public void getSource(final Callback<String> callback) {
	if (sourceCode != null) {
	callback.onSuccess(sourceCode);
	} else {
	RequestCallback rc = new RequestCallback() {
	public void onError(Request request, Throwable exception) {
	callback.onError();
	}

	public void onResponseReceived(Request request, Response response) {
	sourceCode = response.getText();
	callback.onSuccess(sourceCode);
	}
	};

	String className = this.getClass().getName();
	className = className.substring(className.lastIndexOf(".") + 1);
	sendSourceRequest(rc, ShowcaseConstants.DST_SOURCE_EXAMPLE + className + ".html");
	}
	}

	/**
	* Check if the widget should have margins.
	*
	* @return true to use margins, false to flush against edges
	*/
	public boolean hasMargins() {
	return true;
	}

	/**
	* Check if the widget should be wrapped in a scrollable div.
	*
	* @return true to use add scrollbars, false not to
	*/
	public boolean hasScrollableContent() {
	return true;
	}

	/**
	* Returns true if this widget has a style section.
	*
	* @return true if style tab available
	*/
	public final boolean hasStyle() {
	return hasStyle;
	}

	/**
	* When the widget is first initialized, this method is called. If it returns
	* a Widget, the widget will be added as the first tab. Return null to disable
	* the first tab.
	*
	* @return the widget to add to the first tab
	*/
	public abstract Widget onInitialize();

	/**
	* Called when initialization has completed and the widget has been added to
	* the page.
	*/
	public void onInitializeComplete() {
	}

	protected abstract void asyncOnInitialize(final AsyncCallback<Widget> callback);

	/**
	* Fire a {@link ValueChangeEvent} indicating that the user wishes to see the
	* specified source file.
	*
	* @param filename the filename that the user wishes to see
	*/
	protected void fireRawSourceRequest(String filename) {
	if (!rawSourceFilenames.contains(filename)) {
	throw new IllegalArgumentException("Filename is not registered with this example: "
	+ filename);
	}
	ValueChangeEvent.fire(this, filename);
	}

	@Override
	protected void onLoad() {
	if (view == null) {
	view = new ContentWidgetView(hasMargins(), hasScrollableContent());
	view.setName(getName());
	view.setDescription(getDescription());
	setWidget(view);
	}
	ensureWidgetInitialized();
	super.onLoad();
	}

	/**
	* Ensure that the demo widget has been initialized. Note that initialization
	* can fail if there is a network failure.
	*/
	private void ensureWidgetInitialized() {
	if (widgetInitializing \|\| widgetInitialized) {
	return;
	}

	widgetInitializing = true;

	asyncOnInitialize(new AsyncCallback<Widget>() {
	public void onFailure(Throwable reason) {
	widgetInitializing = false;
	Window.alert("Failed to download code for this widget (" + reason + ")");
	}

	public void onSuccess(Widget result) {
	widgetInitializing = false;
	widgetInitialized = true;

	Widget widget = result;
	if (widget != null) {
	view.setExample(widget);
	}
	onInitializeComplete();
	}
	});
	}

	/**
	* Send a request for source code.
	*
	* @param callback the {@link RequestCallback} to send
	* @param url the URL to target
	*/
	private void sendSourceRequest(RequestCallback callback, String url) {
	RequestBuilder builder = new RequestBuilder(RequestBuilder.GET, GWT.getModuleBaseURL() + url);
	builder.setCallback(callback);
	try {
	builder.send();
	} catch (RequestException e) {
	callback.onError(null, e);
	}
	}
	}