org.apache.wicket.markup.head.OnEventHeaderItem Maven / Gradle / Ivy

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Wicket is a Java web application framework that takes simplicity, separation of concerns and ease of development to a whole new level. Wicket pages can be mocked up, previewed and later revised using standard WYSIWYG HTML design tools. Dynamic content processing and form handling is all handled in Java code using a first-class component model backed by POJO data beans that can easily be persisted using your favorite technology.

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.wicket.markup.head;

import java.util.Collections;
import java.util.Locale;

import org.apache.wicket.Application;
import org.apache.wicket.request.Response;
import org.apache.wicket.request.resource.ResourceReference;
import org.apache.wicket.settings.IJavaScriptLibrarySettings;
import org.apache.wicket.util.lang.Args;
import org.apache.wicket.core.util.string.JavaScriptUtils;
import org.apache.wicket.util.string.Strings;

/**
 * {@link HeaderItem} for event triggered scripts.
 * 
 * @author papegaaij
 */
public class OnEventHeaderItem extends HeaderItem
{
	/**
	 * Creates a {@link OnEventHeaderItem} for the given parameters.
	 * 
	 * @param target
	 *            The target of the event handler, for example 'window' or 'document'.
	 * @param event
	 *            The event itself, for example 'click'.
	 * @param javaScript
	 *            The script to execute on the event.
	 * 
	 * @return A newly created {@link OnEventHeaderItem}.
	 */
	public static OnEventHeaderItem forScript(String target, String event, CharSequence javaScript)
	{
		return new OnEventHeaderItem(target, event, javaScript);
	}

	private final String target;
	private final String event;
	private final CharSequence javaScript;

	/**
	 * Constructor.
	 *
	 * The JavaScript should be provided by overloaded #getJavaScript
	 *
	 * @param target
	 * @param event
	 */
	public OnEventHeaderItem(String target, String event)
	{
		this(target, event, null);
	}

	/**
	 * Construct.
	 * 
	 * @param target
	 * @param event
	 * @param javaScript
	 */
	public OnEventHeaderItem(String target, String event, CharSequence javaScript)
	{
		this.target = Args.notEmpty(target, "target");

		Args.notEmpty(event, "event");
		event = event.toLowerCase(Locale.ENGLISH);
		if (event.startsWith("on"))
		{
			event = event.substring(2);
		}
		this.event = event;

		this.javaScript = javaScript;
	}

	/**
	 * @return The target of the event handler, for example 'window' or 'document'.
	 */
	public String getTarget()
	{
		return target;
	}

	/**
	 * @return The event itself, for example 'onclick'.
	 */
	public String getEvent()
	{
		return event;
	}

	/**
	 * @return The script to execute on the event.
	 */
	public CharSequence getJavaScript()
	{
		return javaScript;
	}

	@Override
	public void render(Response response)
	{
		if (Strings.isEmpty(getJavaScript()) == false)
		{
			JavaScriptUtils.writeJavaScript(response, getCompleteJavaScript());
		}
	}

	/**
	 * @return The JavaScript that registers the event handler.
	 */
	public CharSequence getCompleteJavaScript()
	{
		StringBuilder result = new StringBuilder();
		result.append("Wicket.Event.add(")
				.append(getTarget())
				.append(", \"")
				.append(getEvent())
				.append("\", function(event) { ")
				.append(getJavaScript())
				.append(";});");
		return result;
	}

	@Override
	public Iterable getRenderTokens()
	{
		return Collections.singletonList("javascript-event-" + getTarget() + "-" + getEvent() +
			"-" + getJavaScript());
	}

	@Override
	public String toString()
	{
		return "OnEventHeaderItem(" + getTarget() + ", '" + getEvent() + "', '" + getJavaScript() + "')";
	}

	@Override
	public int hashCode()
	{
		return getTarget().hashCode() ^ getEvent().hashCode() ^ getJavaScript().hashCode();
	}

	@Override
	public boolean equals(Object obj)
	{
		if (obj instanceof OnEventHeaderItem)
		{
			OnEventHeaderItem other = (OnEventHeaderItem)obj;
			return other.getTarget().equals(getTarget()) && other.getEvent().equals(getEvent()) &&
				other.getJavaScript().equals(getJavaScript());
		}
		return false;
	}

	@Override
	public Iterable getDependencies()
	{
		IJavaScriptLibrarySettings ajaxSettings = Application.get().getJavaScriptLibrarySettings();
		ResourceReference wicketEventReference = ajaxSettings.getWicketEventReference();
		return Collections.singletonList(JavaScriptHeaderItem.forReference(wicketEventReference));
	}
}