com.premiumminds.webapp.wicket.repeaters.AbstractRepeater2.java Source code

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Here is the source code for com.premiumminds.webapp.wicket.repeaters.AbstractRepeater2.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 com.premiumminds.webapp.wicket.repeaters;

import java.util.Iterator;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.wicket.Component;
import org.apache.wicket.markup.IMarkupFragment;
import org.apache.wicket.markup.html.WebMarkupContainer;
import org.apache.wicket.model.IModel;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Base class for repeaters. This container renders each of its children using its own markup.
 * 
 * The children are collected using {@link #renderIterator()} method. This class will take care of
 * properly positioning and rewinding its markup stream so before each child renders it points to
 * the beginning of this component. Each child is rendered by a call to
 * {@link #renderChild(Component)}. A typical implementation simply does
 * <code>child.render();</code>.
 * 
 * @author Igor Vaynberg (ivaynberg)
 */
abstract class AbstractRepeater2 extends WebMarkupContainer {
    private static final long serialVersionUID = 1L;

    private static final Logger log = LoggerFactory.getLogger(AbstractRepeater2.class);

    private static Pattern SAFE_CHILD_ID_PATTERN = Pattern.compile("^\\d+$");

    /**
     * Constructor
     * 
     * @param id
     */
    public AbstractRepeater2(String id) {
        super(id);
    }

    /**
     * Constructor
     * 
     * @param id
     * @param model
     */
    public AbstractRepeater2(String id, IModel<?> model) {
        super(id, model);
    }

    /**
     * Returns an iterator for the collection of child components to be rendered. Users can override
     * this to change order of rendered children.
     * 
     * @return iterator over child components to be rendered
     */
    protected abstract Iterator<? extends Component> renderIterator();

    /**
     * Renders all child items in no specified order
     */
    @Override
    protected final void onRender() {
        Iterator<? extends Component> it = renderIterator();
        while (it.hasNext()) {
            Component child = it.next();
            if (child == null) {
                throw new IllegalStateException("The render iterator returned null for a child. Container: "
                        + this.toString() + "; Iterator=" + it.toString());
            }
            renderChild(child);
        }
    }

    /**
     * Render a single child. This method can be overridden to modify how a single child component
     * is rendered.
     * 
     * @param child
     *            Child component to be rendered
     */
    protected void renderChild(final Component child) {
        child.render();
    }

    /**
     * @see org.apache.wicket.Component#onBeforeRender()
     */
    @Override
    protected void onBeforeRender() {
        onPopulate();

        if (getApplication().usesDevelopmentConfig()) {
            Iterator<? extends Component> i = iterator();
            while (i.hasNext()) {
                Component c = i.next();
                Matcher matcher = SAFE_CHILD_ID_PATTERN.matcher(c.getId());
                if (!matcher.matches()) {
                    log.warn("Child component of repeater " + getClass().getName() + ":" + getId()
                            + " has a non-safe child id of " + c.getId()
                            + ". Safe child ids must be composed of digits only.");
                    // do not flood the log
                    break;
                }

            }
        }
        super.onBeforeRender();
    }

    /**
     * @see org.apache.wicket.MarkupContainer#getMarkup(org.apache.wicket.Component)
     */
    @Override
    public IMarkupFragment getMarkup(final Component child) {
        // each direct child gets the markup of this repeater
        return getMarkup();
    }

    /**
     * Callback to let the repeater know it should populate itself with its items.
     */
    protected abstract void onPopulate();
}