org.apache.wicket.feedback.FeedbackMessagesModel.java Source code

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Here is the source code for org.apache.wicket.feedback.FeedbackMessagesModel.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.feedback;

import java.io.Serializable;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

import org.apache.wicket.Component;
import org.apache.wicket.Page;
import org.apache.wicket.Session;
import org.apache.wicket.model.IModel;
import org.apache.wicket.util.lang.Args;

/**
 * Model for extracting feedback messages.
 * 
 * @author Eelco Hillenius
 */
public class FeedbackMessagesModel implements IModel<List<FeedbackMessage>> {
    private static final long serialVersionUID = 1L;

    /** Message filter */
    private IFeedbackMessageFilter filter;

    /** Lazy loaded, temporary list. */
    private transient List<FeedbackMessage> messages;

    /** Comparator used for sorting the messages. */
    private Comparator<FeedbackMessage> sortingComparator;

    private final Component pageResolvingComponent;

    /** 
     * Controls whether or not feedback from the {@link Session} will be collected.
     * By default is true.
     */
    private boolean includeSession = true;

    /**
     * Constructor. Creates a model for all feedback messages on the page.
     * 
     * @param pageResolvingComponent
     *            The component where the page will be get from for which messages will be displayed
     *            usually the same page as the one feedbackpanel is attached to
     */
    public FeedbackMessagesModel(Component pageResolvingComponent) {
        Args.notNull(pageResolvingComponent, "pageResolvingComponent");
        this.pageResolvingComponent = pageResolvingComponent;
    }

    /**
     * Constructor. Creates a model for all feedback messages accepted by the given filter.
     * 
     * @param filter
     *            The filter to apply
     * @param page
     *            Page for which messages will be displayed - usually the same page as the one
     *            feedbackpanel is attached to
     * 
     */
    public FeedbackMessagesModel(Page page, IFeedbackMessageFilter filter) {
        this(page);
        setFilter(filter);
    }

    /**
     * @return The current message filter
     */
    public final IFeedbackMessageFilter getFilter() {
        return filter;
    }

    /**
     * @return The current sorting comparator
     */
    public final Comparator<FeedbackMessage> getSortingComparator() {
        return sortingComparator;
    }

    @Override
    public final List<FeedbackMessage> getObject() {
        if (messages == null) {
            // Get filtered messages from page where component lives
            messages = collectMessages(pageResolvingComponent, filter);

            // Sort the list before returning it
            if (sortingComparator != null) {
                Collections.sort(messages, sortingComparator);
            }

            // Let subclass do any extra processing it wants to on the messages.
            // It may want to do something special, such as removing a given
            // message under some special condition or perhaps eliminate
            // duplicate messages. It could even add a message under certain
            // conditions.
            messages = processMessages(messages);
        }
        return messages;
    }

    /**
     * Collects feedback messages
     * 
     * @param pageResolvingComponent
     * @param filter
     * @return list of feedback messages
     */
    protected List<FeedbackMessage> collectMessages(Component pageResolvingComponent,
            IFeedbackMessageFilter filter) {
        return new FeedbackCollector(pageResolvingComponent.getPage(), includeSession).collect(filter);
    }

    /**
     * @param filter
     *            Filter to apply to model
     * @return this
     */
    public final FeedbackMessagesModel setFilter(IFeedbackMessageFilter filter) {
        this.filter = filter;
        return this;
    }

    /**
     * Sets the comparator used for sorting the messages.
     * 
     * @param sortingComparator
     *            comparator used for sorting the messages
     * @return this
     */
    public final FeedbackMessagesModel setSortingComparator(Comparator<FeedbackMessage> sortingComparator) {
        if (!(sortingComparator instanceof Serializable)) {
            throw new IllegalArgumentException("sortingComparator must be serializable");
        }
        this.sortingComparator = sortingComparator;
        return this;
    }

    /**
     * Override this method to post process to the FeedbackMessage list.
     * 
     * @param messages
     *            List of sorted and filtered FeedbackMessages for further processing
     * @return The processed FeedbackMessage list
     */
    protected List<FeedbackMessage> processMessages(final List<FeedbackMessage> messages) {
        return messages;
    }

    @Override
    public void setObject(List<FeedbackMessage> object) {
    }

    @Override
    public void detach() {
        messages = null;
    }

    /**
     * Controls whether or not feedback from the {@link Session} will be collected.
     * 
     * See {@link FeedbackCollector#setIncludeSession} and {@link Session#getFeedbackMessages} 
     * 
     * @param value
     * @return 
     * @return {@code this} for chaining
     */
    public FeedbackMessagesModel setIncludeSession(boolean includeSession) {
        this.includeSession = includeSession;
        return this;
    }
}