user/src/com/google/gwt/uibinder/client/impl/AbstractUiRenderer.java - gwt - Git at Google

 /*
  * Copyright 2011 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.uibinder.client.impl;

 import com.google.gwt.core.client.GWT;
 import com.google.gwt.dom.client.Document;
 import com.google.gwt.dom.client.Element;
 import com.google.gwt.dom.client.EventTarget;
 import com.google.gwt.dom.client.NativeEvent;
 import com.google.gwt.event.dom.client.DomEvent;
 import com.google.gwt.event.shared.HasHandlers;
 import com.google.gwt.safehtml.shared.SafeHtml;
 import com.google.gwt.safehtml.shared.SafeHtmlUtils;
 import com.google.gwt.uibinder.client.UiRenderer;

 import java.util.HashMap;

 /**
  * Abstract implementation of a safe HTML binder to make implementation of generated rendering
  * simpler.
  */
 public abstract class AbstractUiRenderer implements UiRenderer {

   /**
    * Helps handle method dispatch to classes that use UiRenderer.
    *
    * @param <T> class that can receive events from a UiRenderer implementation
    */
   protected abstract static class UiRendererDispatcher<T> implements HasHandlers {
     private T eventTarget;

     private int methodIndex;

     private Element root;

     /**
      * Maps strings describing event types and field names to methods
      * contained in type {@code T} (which are indexed by an integer).
      */
     private HashMap<String, Integer> table;

     /**
      * Fire an event to the receiver.
      * @param target object that will handle the events
      * @param event event to dispatch
      * @param parentOrRoot root element of a previously rendered DOM structure (or its parent)
      */
     protected void fireEvent(T target, NativeEvent event, Element parentOrRoot) {
       if (target == null) {
         throw new NullPointerException("Null event handler received");
       }
       if (event == null) {
         throw new NullPointerException("Null event object received");
       }
       if (parentOrRoot == null) {
         throw new NullPointerException("Null parent received");
       }

       if (!isParentOrRenderer(parentOrRoot, RENDERED_ATTRIBUTE)) {
         return;
       }
       eventTarget = target;
       root = findRootElementOrNull(parentOrRoot, RENDERED_ATTRIBUTE);
       methodIndex = computeDispatchEvent(table, root, event);
       DomEvent.fireNativeEvent(event, this);
     }

     /**
      * Object that will receive the event.
      */
     protected T getEventTarget() {
       return eventTarget;
     }

     /**
      * Index of the method that will receive the event.
      */
     protected int getMethodIndex() {
       return methodIndex;
     }

     /**
      * Root Element of a previously rendered DOM structure.
      */
     protected Element getRoot() {
       return root;
     }

     /**
      * Initializes the dispatch table if necessary.
      */
     protected void initDispatchTable(String[] keys, Integer[] values) {
       table = buildDispatchMap(keys, values);
     }
   }

   /**
    * Marker attribute for DOM structures previously generated by UiRenderer.
    */
   public static final String RENDERED_ATTRIBUTE = "gwtuirendered";

   /**
    * Field name used to identify the root element while dispatching events.
    */
   public static final String ROOT_FAKE_NAME = "^";

   public static final String UI_ID_SEPARATOR = ":";

   private static final int NO_HANDLER_FOUND = -1;

   /**
    * Build id strings used to identify DOM elements related to ui:fields.
    *
    * @param fieldName name of the field that identifies the element
    * @param uiId common part of the identifier for all elements in the rendered DOM structure
    */
   protected static String buildInnerId(String fieldName, String uiId) {
     return uiId + UI_ID_SEPARATOR + fieldName;
   }

   /**
    * Retrieves a specific element within a previously rendered element.
    *
    * @param parent parent element containing the element of interest
    * @param fieldName name of the field to retrieve
    * @param attribute that identifies the root element as such
    * @return the element identified by {@code fieldName}
    *
    * @throws IllegalArgumentException if the {@code parent} does not point to or contains
    *         a previously rendered element. In DevMode also when the root element is not
    *         attached to the DOM
    * @throws IllegalStateException parent does not contain an element matching
    *         {@code filedName}
    *
    * @throws RuntimeException if the root element is not attached to the DOM and not running in
    *         DevMode
    *
    * @throws NullPointerException if {@code parent} == null
    */
   protected static Element findInnerField(Element parent, String fieldName, String attribute) {
     Element root = findRootElement(parent, attribute);

     if (parent != root && !isRenderedElementSingleChild(root)) {
       throw new IllegalArgumentException(
           "Parent Element of previously rendered element contains more than one child"
           + " while getting \"" + fieldName + "\"");
     }

     String uiId = root.getAttribute(attribute);
     String renderedId = buildInnerId(fieldName, uiId);

     Element elementById = Document.get().getElementById(renderedId);
     if (elementById == null) {
       if (!isAttachedToDom(root)) {
         throw new RuntimeException("UiRendered element is not attached to DOM while getting \""
             + fieldName + "\"");
       } else if (!GWT.isProdMode()) {
         throw new IllegalStateException("\"" + fieldName
             + "\" not found within rendered element");
       } else {
         // In prod mode we do not distinguish between being unattached or not finding the element
         throw new IllegalArgumentException("UiRendered element is not attached to DOM, or \""
             + fieldName + "\" not found within rendered element");
       }
     }
     return elementById;
   }

   /**
    * Retrieves the root of a previously rendered element contained within the {@code parent}.
    * The {@code parent} must either contain the previously rendered DOM structure as its only child,
    * or point directly to the rendered element root.
    *
    * @param parent element containing, or pointing to, a previously rendered DOM structure
    * @param attribute attribute name that identifies the root of the DOM structure
    * @return the root element of the previously rendered DOM structure
    *
    * @throws NullPointerException if {@code parent} == null
    * @throws IllegalArgumentException if {@code parent} does not contain a previously rendered
    *         element
    */
   protected static Element findRootElement(Element parent, String attribute) {
     Element root = findRootElementOrNull(parent, attribute);
     if (root == null) {
       throw new IllegalArgumentException(
           "Parent element does not contain a previously rendered element");
     }
     return root;
   }

   /**
    * Inserts an attribute into the first tag found in a {@code safeHtml} template.
    * This method assumes that the {@code safeHtml} template begins with an open HTML tag.
    * {@code SafeHtml} templates produced by UiBinder always meet these conditions.
    * <p>
    * This method does not attempt to ensure {@code atributeName} and {@code attributeValue}
    * contain safe values.
    *
    * @returns the {@code safeHtml} template with "{@code attributeName}={@code attributeValue}"
    *          inserted as an attribute of the first tag found
    */
   protected static SafeHtml stampUiRendererAttribute(SafeHtml safeHtml, String attributeName,
       String attributeValue) {
     String html = safeHtml.asString();
     int endOfFirstTag = html.indexOf(">");

     assert endOfFirstTag > 1 : "Safe html template does not start with an HTML open tag";

     if (html.charAt(endOfFirstTag - 1) == '/') {
       endOfFirstTag--;
     }

     html = html.substring(0, endOfFirstTag) + " " + attributeName + "=\"" + attributeValue + "\""
             + html.substring(endOfFirstTag);
     return SafeHtmlUtils.fromTrustedString(html);
   }

   /**
    * Converts an array of keys and values into a map.
    */
   private static HashMap<String, Integer> buildDispatchMap(String[] keys, Integer[] values) {
     HashMap<String, Integer> result = new HashMap<String, Integer>(keys.length);
     for (int i = 0; i < keys.length; i++) {
       result.put(keys[i], values[i]);
     }
     return result;
   }

   /**
    * Obtains the index of the method that will receive an event.
    * @param table event types and field names indexed by the method that
    *              can handle an event.
    * @param root of a previously rendered DOM structure
    * @param event event to handle
    * @return index of the method that will process the event or NO_HANDLER_FOUND.
    */
   private static int computeDispatchEvent(HashMap<String, Integer> table, Element root,
       NativeEvent event) {
     String uiId = root.getAttribute(RENDERED_ATTRIBUTE);

     EventTarget eventTarget = event.getEventTarget();
     if (!Element.is(eventTarget)) {
       return NO_HANDLER_FOUND;
     }

     Element cursor = Element.as(eventTarget);

     while (cursor != null && cursor != root && cursor.getNodeType() != Element.DOCUMENT_NODE) {
       String fieldName = getFieldName(uiId, cursor);
       if (fieldName == null) {
         cursor = cursor.getParentElement();
         continue;
       }
       String key = event.getType() + UI_ID_SEPARATOR + fieldName;
       if (table.containsKey(key)) {
         return table.get(key);
       }
       cursor = cursor.getParentElement();
     }

     if (cursor == root) {
       String key = event.getType() + UI_ID_SEPARATOR + ROOT_FAKE_NAME;
       if (table.containsKey(key)) {
         return table.get(key);
       }
     }

     return NO_HANDLER_FOUND;
   }

   /**
    * Retrieves the root of a previously rendered element contained within the {@code parent}.
    * The {@code parent} must either contain the previously rendered DOM structure as its only child,
    * or point directly to the rendered element root.
    *
    * @param parent element containing, or pointing to, a previously rendered DOM structure
    * @param attribute attribute name that identifies the root of the DOM structure
    * @return the root element of the previously rendered DOM structure or <code>null</code>
    *         if {@code parent} does not contain a previously rendered element
    *
    * @throws NullPointerException if {@code parent} == null
    */
   private static Element findRootElementOrNull(Element parent, String attribute) {
     if (parent == null) {
       throw new NullPointerException("parent argument is null");
     }

     Element rendered;
     if (parent.hasAttribute(attribute)) {
       // The parent is the root
       return parent;
     } else if ((rendered = parent.getFirstChildElement()) != null
         && rendered.hasAttribute(attribute)) {
       // The first child is the root
       return rendered;
     } else {
       return null;
     }
   }

   /**
    * Obtains the field name of a previously rendered DOM Element.
    * @param uiId identifier of the fields contained in a previously rendered DOM structure
    * @param element which may correspond to {@code ui:field}
    * @return the field name or {@code null} if the {@code element} does not have
    *         an id attribute as would be produced by {@link #buildInnerId(String, String)}) with
    *         {@code fieldName} and {@code uiId}
    */
   private static String getFieldName(String uiId, Element element) {
     String id = element.getId();
     if (id == null) {
       return null;
     }
     int split = id.indexOf(UI_ID_SEPARATOR);
     return split != -1 && uiId.length() == split && id.startsWith(uiId)
         ? id.substring(split + 1)
         : null;
   }

   /**
    * In DevMode, walks up the parents of the {@code rendered} element to ascertain that it is
    * attached to the document. Always returns <code>true</code> in ProdMode.
    */
   private static boolean isAttachedToDom(Element rendered) {
     if (GWT.isProdMode()) {
       return true;
     }

     Element body = Document.get().getBody();

     while (rendered != null && rendered.hasParentElement() && !body.equals(rendered)) {
       rendered = rendered.getParentElement();
     }
     return body.equals(rendered);
   }

   /**
    * Implements {@link com.google.gwt.uibinder.client.UiRenderer#isParentOrRenderer(Element)}.
    */
   private static boolean isParentOrRenderer(Element parent, String attribute) {
     if (parent == null) {
       return false;
     }

     Element root = findRootElementOrNull(parent, attribute);
     return root != null && isAttachedToDom(root)
         && isRenderedElementSingleChild(root);
   }

   /**
    * Checks that the parent of {@code rendered} has a single child.
    */
   private static boolean isRenderedElementSingleChild(Element rendered) {
     return GWT.isProdMode() || rendered.getParentElement().getChildCount() == 1;
   }

   /**
    * Holds the part of the id attribute common to all elements being rendered.
    */
   protected String uiId;

   @Override
   public boolean isParentOrRenderer(Element parent) {
     return isParentOrRenderer(parent, RENDERED_ATTRIBUTE);
   }
 }
	/*
	* Copyright 2011 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.uibinder.client.impl;

	import com.google.gwt.core.client.GWT;
	import com.google.gwt.dom.client.Document;
	import com.google.gwt.dom.client.Element;
	import com.google.gwt.dom.client.EventTarget;
	import com.google.gwt.dom.client.NativeEvent;
	import com.google.gwt.event.dom.client.DomEvent;
	import com.google.gwt.event.shared.HasHandlers;
	import com.google.gwt.safehtml.shared.SafeHtml;
	import com.google.gwt.safehtml.shared.SafeHtmlUtils;
	import com.google.gwt.uibinder.client.UiRenderer;

	import java.util.HashMap;

	/**
	* Abstract implementation of a safe HTML binder to make implementation of generated rendering
	* simpler.
	*/
	public abstract class AbstractUiRenderer implements UiRenderer {

	/**
	* Helps handle method dispatch to classes that use UiRenderer.
	*
	* @param <T> class that can receive events from a UiRenderer implementation
	*/
	protected abstract static class UiRendererDispatcher<T> implements HasHandlers {
	private T eventTarget;

	private int methodIndex;

	private Element root;

	/**
	* Maps strings describing event types and field names to methods
	* contained in type {@code T} (which are indexed by an integer).
	*/
	private HashMap<String, Integer> table;

	/**
	* Fire an event to the receiver.
	* @param target object that will handle the events
	* @param event event to dispatch
	* @param parentOrRoot root element of a previously rendered DOM structure (or its parent)
	*/
	protected void fireEvent(T target, NativeEvent event, Element parentOrRoot) {
	if (target == null) {
	throw new NullPointerException("Null event handler received");
	}
	if (event == null) {
	throw new NullPointerException("Null event object received");
	}
	if (parentOrRoot == null) {
	throw new NullPointerException("Null parent received");
	}

	if (!isParentOrRenderer(parentOrRoot, RENDERED_ATTRIBUTE)) {
	return;
	}
	eventTarget = target;
	root = findRootElementOrNull(parentOrRoot, RENDERED_ATTRIBUTE);
	methodIndex = computeDispatchEvent(table, root, event);
	DomEvent.fireNativeEvent(event, this);
	}

	/**
	* Object that will receive the event.
	*/
	protected T getEventTarget() {
	return eventTarget;
	}

	/**
	* Index of the method that will receive the event.
	*/
	protected int getMethodIndex() {
	return methodIndex;
	}

	/**
	* Root Element of a previously rendered DOM structure.
	*/
	protected Element getRoot() {
	return root;
	}

	/**
	* Initializes the dispatch table if necessary.
	*/
	protected void initDispatchTable(String[] keys, Integer[] values) {
	table = buildDispatchMap(keys, values);
	}
	}

	/**
	* Marker attribute for DOM structures previously generated by UiRenderer.
	*/
	public static final String RENDERED_ATTRIBUTE = "gwtuirendered";

	/**
	* Field name used to identify the root element while dispatching events.
	*/
	public static final String ROOT_FAKE_NAME = "^";

	public static final String UI_ID_SEPARATOR = ":";

	private static final int NO_HANDLER_FOUND = -1;

	/**
	* Build id strings used to identify DOM elements related to ui:fields.
	*
	* @param fieldName name of the field that identifies the element
	* @param uiId common part of the identifier for all elements in the rendered DOM structure
	*/
	protected static String buildInnerId(String fieldName, String uiId) {
	return uiId + UI_ID_SEPARATOR + fieldName;
	}

	/**
	* Retrieves a specific element within a previously rendered element.
	*
	* @param parent parent element containing the element of interest
	* @param fieldName name of the field to retrieve
	* @param attribute that identifies the root element as such
	* @return the element identified by {@code fieldName}
	*
	* @throws IllegalArgumentException if the {@code parent} does not point to or contains
	* a previously rendered element. In DevMode also when the root element is not
	* attached to the DOM
	* @throws IllegalStateException parent does not contain an element matching
	* {@code filedName}
	*
	* @throws RuntimeException if the root element is not attached to the DOM and not running in
	* DevMode
	*
	* @throws NullPointerException if {@code parent} == null
	*/
	protected static Element findInnerField(Element parent, String fieldName, String attribute) {
	Element root = findRootElement(parent, attribute);

	if (parent != root && !isRenderedElementSingleChild(root)) {
	throw new IllegalArgumentException(
	"Parent Element of previously rendered element contains more than one child"
	+ " while getting \"" + fieldName + "\"");
	}

	String uiId = root.getAttribute(attribute);
	String renderedId = buildInnerId(fieldName, uiId);

	Element elementById = Document.get().getElementById(renderedId);
	if (elementById == null) {
	if (!isAttachedToDom(root)) {
	throw new RuntimeException("UiRendered element is not attached to DOM while getting \""
	+ fieldName + "\"");
	} else if (!GWT.isProdMode()) {
	throw new IllegalStateException("\"" + fieldName
	+ "\" not found within rendered element");
	} else {
	// In prod mode we do not distinguish between being unattached or not finding the element
	throw new IllegalArgumentException("UiRendered element is not attached to DOM, or \""
	+ fieldName + "\" not found within rendered element");
	}
	}
	return elementById;
	}

	/**
	* Retrieves the root of a previously rendered element contained within the {@code parent}.
	* The {@code parent} must either contain the previously rendered DOM structure as its only child,
	* or point directly to the rendered element root.
	*
	* @param parent element containing, or pointing to, a previously rendered DOM structure
	* @param attribute attribute name that identifies the root of the DOM structure
	* @return the root element of the previously rendered DOM structure
	*
	* @throws NullPointerException if {@code parent} == null
	* @throws IllegalArgumentException if {@code parent} does not contain a previously rendered
	* element
	*/
	protected static Element findRootElement(Element parent, String attribute) {
	Element root = findRootElementOrNull(parent, attribute);
	if (root == null) {
	throw new IllegalArgumentException(
	"Parent element does not contain a previously rendered element");
	}
	return root;
	}

	/**
	* Inserts an attribute into the first tag found in a {@code safeHtml} template.
	* This method assumes that the {@code safeHtml} template begins with an open HTML tag.
	* {@code SafeHtml} templates produced by UiBinder always meet these conditions.
	* <p>
	* This method does not attempt to ensure {@code atributeName} and {@code attributeValue}
	* contain safe values.
	*
	* @returns the {@code safeHtml} template with "{@code attributeName}={@code attributeValue}"
	* inserted as an attribute of the first tag found
	*/
	protected static SafeHtml stampUiRendererAttribute(SafeHtml safeHtml, String attributeName,
	String attributeValue) {
	String html = safeHtml.asString();
	int endOfFirstTag = html.indexOf(">");

	assert endOfFirstTag > 1 : "Safe html template does not start with an HTML open tag";

	if (html.charAt(endOfFirstTag - 1) == '/') {
	endOfFirstTag--;
	}

	html = html.substring(0, endOfFirstTag) + " " + attributeName + "=\"" + attributeValue + "\""
	+ html.substring(endOfFirstTag);
	return SafeHtmlUtils.fromTrustedString(html);
	}

	/**
	* Converts an array of keys and values into a map.
	*/
	private static HashMap<String, Integer> buildDispatchMap(String[] keys, Integer[] values) {
	HashMap<String, Integer> result = new HashMap<String, Integer>(keys.length);
	for (int i = 0; i < keys.length; i++) {
	result.put(keys[i], values[i]);
	}
	return result;
	}

	/**
	* Obtains the index of the method that will receive an event.
	* @param table event types and field names indexed by the method that
	* can handle an event.
	* @param root of a previously rendered DOM structure
	* @param event event to handle
	* @return index of the method that will process the event or NO_HANDLER_FOUND.
	*/
	private static int computeDispatchEvent(HashMap<String, Integer> table, Element root,
	NativeEvent event) {
	String uiId = root.getAttribute(RENDERED_ATTRIBUTE);

	EventTarget eventTarget = event.getEventTarget();
	if (!Element.is(eventTarget)) {
	return NO_HANDLER_FOUND;
	}

	Element cursor = Element.as(eventTarget);

	while (cursor != null && cursor != root && cursor.getNodeType() != Element.DOCUMENT_NODE) {
	String fieldName = getFieldName(uiId, cursor);
	if (fieldName == null) {
	cursor = cursor.getParentElement();
	continue;
	}
	String key = event.getType() + UI_ID_SEPARATOR + fieldName;
	if (table.containsKey(key)) {
	return table.get(key);
	}
	cursor = cursor.getParentElement();
	}

	if (cursor == root) {
	String key = event.getType() + UI_ID_SEPARATOR + ROOT_FAKE_NAME;
	if (table.containsKey(key)) {
	return table.get(key);
	}
	}

	return NO_HANDLER_FOUND;
	}

	/**
	* Retrieves the root of a previously rendered element contained within the {@code parent}.
	* The {@code parent} must either contain the previously rendered DOM structure as its only child,
	* or point directly to the rendered element root.
	*
	* @param parent element containing, or pointing to, a previously rendered DOM structure
	* @param attribute attribute name that identifies the root of the DOM structure
	* @return the root element of the previously rendered DOM structure or <code>null</code>
	* if {@code parent} does not contain a previously rendered element
	*
	* @throws NullPointerException if {@code parent} == null
	*/
	private static Element findRootElementOrNull(Element parent, String attribute) {
	if (parent == null) {
	throw new NullPointerException("parent argument is null");
	}

	Element rendered;
	if (parent.hasAttribute(attribute)) {
	// The parent is the root
	return parent;
	} else if ((rendered = parent.getFirstChildElement()) != null
	&& rendered.hasAttribute(attribute)) {
	// The first child is the root
	return rendered;
	} else {
	return null;
	}
	}

	/**
	* Obtains the field name of a previously rendered DOM Element.
	* @param uiId identifier of the fields contained in a previously rendered DOM structure
	* @param element which may correspond to {@code ui:field}
	* @return the field name or {@code null} if the {@code element} does not have
	* an id attribute as would be produced by {@link #buildInnerId(String, String)}) with
	* {@code fieldName} and {@code uiId}
	*/
	private static String getFieldName(String uiId, Element element) {
	String id = element.getId();
	if (id == null) {
	return null;
	}
	int split = id.indexOf(UI_ID_SEPARATOR);
	return split != -1 && uiId.length() == split && id.startsWith(uiId)
	? id.substring(split + 1)
	: null;
	}

	/**
	* In DevMode, walks up the parents of the {@code rendered} element to ascertain that it is
	* attached to the document. Always returns <code>true</code> in ProdMode.
	*/
	private static boolean isAttachedToDom(Element rendered) {
	if (GWT.isProdMode()) {
	return true;
	}

	Element body = Document.get().getBody();

	while (rendered != null && rendered.hasParentElement() && !body.equals(rendered)) {
	rendered = rendered.getParentElement();
	}
	return body.equals(rendered);
	}

	/**
	* Implements {@link com.google.gwt.uibinder.client.UiRenderer#isParentOrRenderer(Element)}.
	*/
	private static boolean isParentOrRenderer(Element parent, String attribute) {
	if (parent == null) {
	return false;
	}

	Element root = findRootElementOrNull(parent, attribute);
	return root != null && isAttachedToDom(root)
	&& isRenderedElementSingleChild(root);
	}

	/**
	* Checks that the parent of {@code rendered} has a single child.
	*/
	private static boolean isRenderedElementSingleChild(Element rendered) {
	return GWT.isProdMode() \|\| rendered.getParentElement().getChildCount() == 1;
	}

	/**
	* Holds the part of the id attribute common to all elements being rendered.
	*/
	protected String uiId;

	@Override
	public boolean isParentOrRenderer(Element parent) {
	return isParentOrRenderer(parent, RENDERED_ATTRIBUTE);
	}
	}