/*
* 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.uibinder.elementparsers;
import com.google.gwt.core.ext.UnableToCompleteException;
import com.google.gwt.uibinder.client.LazyDomElement;
import com.google.gwt.uibinder.rebind.FieldManager;
import com.google.gwt.uibinder.rebind.FieldWriter;
import com.google.gwt.uibinder.rebind.UiBinderWriter;
import com.google.gwt.uibinder.rebind.XMLElement;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
/**
* Used by {@link HTMLPanelParser} to interpret elements that call for widget
* instances. Declares the appropriate widget, and replaces them in the markup
* with a <span>.
*/
class WidgetInterpreter implements XMLElement.Interpreter<String> {
private static final Map<String, String> LEGAL_CHILD_ELEMENTS;
private static final String DEFAULT_CHILD_ELEMENT = "span";
static {
// Other cases?
HashMap<String, String> map = new HashMap<String, String>();
map.put("table", "tbody");
map.put("thead", "tr");
map.put("tbody", "tr");
map.put("tfoot", "tr");
map.put("ul", "li");
map.put("ol", "li");
map.put("dl", "dt");
LEGAL_CHILD_ELEMENTS = Collections.unmodifiableMap(map);
}
private static String getLegalPlaceholderTag(XMLElement elem) {
XMLElement parent = elem.getParent();
String tag = null;
if (parent != null) {
tag = LEGAL_CHILD_ELEMENTS.get(parent.getLocalName());
}
if (tag == null) {
tag = DEFAULT_CHILD_ELEMENT;
}
return tag;
}
private final String fieldName;
private final UiBinderWriter uiWriter;
public WidgetInterpreter(String fieldName, UiBinderWriter writer) {
this.fieldName = fieldName;
this.uiWriter = writer;
}
public String interpretElement(XMLElement elem)
throws UnableToCompleteException {
if (!uiWriter.isWidgetElement(elem)) {
return null;
}
FieldManager fieldManager = uiWriter.getFieldManager();
FieldWriter fieldWriter = fieldManager.require(fieldName);
// Allocate a local variable to hold the dom id for this widget. Note
// that idHolder is a local variable reference, not a string id. We
// have to generate the ids at runtime, not compile time, or else
// we'll reuse ids for any template rendered more than once.
String idHolder = uiWriter.declareDomIdHolder(null);
uiWriter.ensureCurrentFieldAttached();
FieldWriter childFieldWriter = uiWriter.parseElementToField(elem);
String elementPointer = idHolder + "Element";
uiWriter.addInitStatement(
"Element %s = com.google.gwt.dom.client.Document.get().getElementById(%s);",
elementPointer, idHolder);
if (uiWriter.useLazyWidgetBuilders()) {
// Register a DOM id field.
String lazyDomElementPath = LazyDomElement.class.getCanonicalName();
FieldWriter elementWriter = fieldManager.registerField(lazyDomElementPath, elementPointer);
elementWriter.setInitializer(String.format("new %s<Element>(%s)",
lazyDomElementPath, fieldManager.convertFieldToGetter(idHolder)));
// Add attach/detach sections for this element.
fieldWriter.addAttachStatement("%s.get();",
fieldManager.convertFieldToGetter(elementPointer));
fieldWriter.addDetachStatement(
"%s.addAndReplaceElement(%s, %s.get());",
fieldName,
fieldManager.convertFieldToGetter(childFieldWriter.getName()),
fieldManager.convertFieldToGetter(elementPointer));
} else {
// Delay replacing the placeholders with the widgets until after
// detachment so as not to end up attaching the widget to the DOM
// unnecessarily
uiWriter.addDetachStatement(
"%1$s.addAndReplaceElement(%2$s, %3$s);",
fieldName,
childFieldWriter.getName(),
elementPointer);
}
// Create an element to hold the widget.
String tag = getLegalPlaceholderTag(elem);
idHolder = fieldManager.convertFieldToGetter(idHolder);
if (uiWriter.useSafeHtmlTemplates()) {
idHolder = uiWriter.tokenForStringExpression(elem, idHolder);
} else {
idHolder = "\" + " + idHolder + " + \"";
}
return "<" + tag + " id='" + idHolder + "'></" + tag + ">";
}
}