com.jawspeak.gwt.verysimpletemplate.client.template.VerySimpleGwtTemplate.java Source code

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Here is the source code for com.jawspeak.gwt.verysimpletemplate.client.template.VerySimpleGwtTemplate.java

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/*
 * Copyright 2008 Jonathan Andrew Wolter
 *
 * 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.jawspeak.gwt.verysimpletemplate.client.template;

import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;

import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.ui.HTML;
import com.google.gwt.user.client.ui.HTMLPanel;
import com.google.gwt.user.client.ui.Widget;

public class VerySimpleGwtTemplate {

    private String htmlTemplate;
    private Map<String, Widget> widgets = new HashMap<String, Widget>();

    public VerySimpleGwtTemplate(String htmlTemplate) {
        this.htmlTemplate = htmlTemplate;
    }

    /** 
     * @param templateKey, what to replace. i.e. <tt>${foo.token}</tt>.
     * @param value to replace the template key with.
     */
    public void set(String templateKey, String value) {
        verifyTemplateKeyExistsInTemplate(templateKey);
        if (value == null) {
            value = "";
        }
        htmlTemplate = htmlTemplate.replace(templateKey, value);
    }

    public void set(String templateKey, Widget widget) {
        verifyTemplateKeyExistsInTemplate(templateKey);
        if (widget == null) {
            set(templateKey, "");
            return;
        }
        widgets.put(templateKey, widget);
    }

    public HTML toHTML() {
        verifyNoWidgetsSetWhenCallingToHTMLMethod();
        verifyTemplateCompletelyFilledOut();
        return new HTML(htmlTemplate);
    }

    public HTMLPanel toHTMLPanel() {
        Map<String, Widget> idToWidget = new HashMap<String, Widget>();
        for (Entry<String, Widget> entryByToken : widgets.entrySet()) {
            String id = DOM.createUniqueId();
            htmlTemplate = htmlTemplate.replace(entryByToken.getKey(), "<span id='" + id + "'></span>");
            idToWidget.put(id, entryByToken.getValue());
        }
        widgets = null; // finally all done using it
        HTMLPanel panel = new HTMLPanel(htmlTemplate);
        for (Entry<String, Widget> entryById : idToWidget.entrySet()) {
            panel.addAndReplaceElement(entryById.getValue(), entryById.getKey());
        }
        verifyTemplateCompletelyFilledOut();
        return panel;
    }

    private void verifyTemplateKeyExistsInTemplate(String templateKey) {
        if (!htmlTemplate.contains(templateKey)) {
            throw new IllegalArgumentException(
                    "The templateKey: " + templateKey + ", you provided was not found in the template.");
        }
    }

    private void verifyNoWidgetsSetWhenCallingToHTMLMethod() {
        if (widgets.size() > 0) {
            throw new IllegalStateException("Can not call toHTML when you have widgets, use toHTMLPanel instead");
        }
    }

    private void verifyTemplateCompletelyFilledOut() {
        if (htmlTemplate.indexOf("${") >= 0) {
            throw new IllegalStateException("Lefover template variables \"${\" in htmlTemplate!\n" + htmlTemplate);
        }
    }

}