org.apache.wicket.markup.head.OnEventHeaderItem.java Source code

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Here is the source code for org.apache.wicket.markup.head.OnEventHeaderItem.java

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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.List;
import java.util.Locale;
import java.util.Objects;

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

/**
 * {@link HeaderItem} for event triggered scripts.
 *
 * @author papegaaij
 */
public class OnEventHeaderItem extends HeaderItem {
    private static final long serialVersionUID = 1L;

    /**
     * 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.ROOT);
        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 Objects.hash(target, event, javaScript);
    }

    @Override
    public boolean equals(Object o) {
        if (this == o)
            return true;
        if (o == null || getClass() != o.getClass())
            return false;
        OnEventHeaderItem that = (OnEventHeaderItem) o;
        return Objects.equals(target, that.target) && Objects.equals(event, that.event)
                && Objects.equals(javaScript, that.javaScript);
    }

    @Override
    public List<HeaderItem> getDependencies() {
        JavaScriptLibrarySettings ajaxSettings = Application.get().getJavaScriptLibrarySettings();
        ResourceReference wicketAjaxReference = ajaxSettings.getWicketAjaxReference();
        List<HeaderItem> dependencies = super.getDependencies();
        dependencies.add(JavaScriptHeaderItem.forReference(wicketAjaxReference));
        return dependencies;
    }
}