com.google.gwt.libideas.client.StyleInjector.java Source code

Introduction

Here is the source code for com.google.gwt.libideas.client.StyleInjector.java

Source

/*
 * 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.libideas.client;

import com.google.gwt.core.client.GWT;
import com.google.gwt.dom.client.Document;
import com.google.gwt.dom.client.StyleElement;
import com.google.gwt.resources.client.ClientBundle;
import com.google.gwt.resources.client.CssResource;
import com.google.gwt.resources.client.DataResource;
import com.google.gwt.resources.client.ResourcePrototype;

/**
 * Used to add stylesheets to the document.
 */
public class StyleInjector {

    /**
     * The DOM-compatible way of adding stylesheets.
     */
    public static class StyleInjectorImpl {
        private static final StyleInjectorImpl IMPL = GWT.create(StyleInjectorImpl.class);

        public StyleElement injectStyleSheet(String contents) {
            StyleElement style = Document.get().createStyleElement();
            style.setPropertyString("language", "text/css");
            setContents(style, contents);
            Document.get().getElementsByTagName("head").getItem(0).appendChild(style);
            return style;
        }

        public void setContents(StyleElement style, String contents) {
            style.setInnerText(contents);
        }
    }

    /**
     * IE doesn't allow manipulation of a style element through DOM methods.
     */
    public static class StyleInjectorImplIE extends StyleInjectorImpl {
        @Override
        public StyleElement injectStyleSheet(String contents) {
            StyleElement style = createElement();
            setContents(style, contents);
            return style;
        }

        @Override
        public native void setContents(StyleElement style, String contents) /*-{
                                                                            style.cssText = contents;
                                                                            }-*/;

        private native StyleElement createElement() /*-{
                                                    return $doc.createStyleSheet();
                                                    }-*/;
    }

    /**
     * Inject all CSSResources in an ImmutableResourceBundle. This method is
     * deprecated to isolate StyleInjector from the bundle API.
     * 
     * @param resources the ImmutableResourceBundle to inject
     * @deprecated Use {@link #injectStyleSheet(String)} and
     *             {@link CssResource#getText()}.
     */
    //  @Deprecated
    //  public static StyleElement injectStylesheet(ClientBundle resources) {
    //    StringBuilder sb = new StringBuilder();
    //    for (ResourcePrototype p : resources.getResources()) {
    //      if (p instanceof CssResource) {
    //        sb.append(((CssResource) p).getText()).append("\n");
    //      }
    //    }
    //    return injectStylesheet(sb.toString());
    //  }

    /**
     * Add a stylesheet to the document.
     * 
     * @param contents the CSS contents of the stylesheet
     */
    public static StyleElement injectStylesheet(String contents) {
        return StyleInjectorImpl.IMPL.injectStyleSheet(contents);
    }

    /**
     * Add a stylesheet to the document. Any occurrence of
     * <code>%resourceName%</code> in the stylesheet's contents will be replaced
     * by the URL of the named {@link DataResource} contained in
     * <code>references</code>.
     * 
     * @param contents the CSS contents of the stylesheet
     * @param references the resources to substitute into the stylesheet.
     * @deprecated Use {@link CssResource} with {@code @url} rules instead.
     */
    //  @Deprecated
    //  public static StyleElement injectStylesheet(String contents,
    //      ClientBundle references) {
    //    if (references != null) {
    //      for (ResourcePrototype p : references.getResources()) {
    //        if (p instanceof DataResource) {
    //          contents = contents.replaceAll("%" + p.getName() + "%",
    //              ((DataResource) p).getUrl());
    //        }
    //      }
    //    }
    //
    //    return injectStylesheet(contents);
    //  }

    /**
     * Replace the contents of a previously-injected stylesheet. Updating the
     * stylesheet in-place is typically more efficient than removing a
     * previously-created element and adding a new one.
     * 
     * @param style a StyleElement previously-returned from
     *          {@link #injectStylesheet(String)}.
     * @param contents the new contents of the stylesheet.
     */
    public static void setContents(StyleElement style, String contents) {
        StyleInjectorImpl.IMPL.setContents(style, contents);
    }

    /**
     * Utility class.
     */
    private StyleInjector() {
    }
}