net.unbewaff.wicketcrudr.providers.editor.Palette.java Source code

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Here is the source code for net.unbewaff.wicketcrudr.providers.editor.Palette.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 net.unbewaff.wicketcrudr.providers.editor;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

import net.unbewaff.wicketcrudr.providers.editorpanel.PalettePanel;

import org.apache.wicket.WicketRuntimeException;
import org.apache.wicket.markup.html.form.HiddenField;
import org.apache.wicket.markup.html.form.IChoiceRenderer;
import org.apache.wicket.model.Model;
import org.apache.wicket.util.string.Strings;

/**
 * Component to keep track of selections on the html side. Also used for
 * encoding and decoding those selections between html and java.
 * 
 * Based on the Recorder Component by Igor Vaynberg ( ivaynberg )
 * 
 * @param <T>
 *            Type of the palette
 * 
 * @author David Hendrix (Nicktarix)
 * @author Igor Vaynberg (ivaynberg)
 */
public class Palette<T> extends HiddenField<T> {
    private static final long serialVersionUID = 1L;

    private static final String[] EMPTY_IDS = new String[0];

    /** conveniently maintained array of selected ids */
    private String[] ids;

    /** parent palettePanel object */
    private final PalettePanel<T> palette;

    private boolean attached = false;

    /**
     * @return parent Palette object
     */
    public PalettePanel<T> getPalettePanel() {
        return palette;
    }

    /**
     * @param id
     *            component id
     * @param palette
     *            parent palette object
     */
    public Palette(final String id, final PalettePanel<T> palette) {
        super(id);
        this.palette = palette;
        setDefaultModel(new Model<Serializable>());
        setOutputMarkupId(true);
    }

    /**
     * 
     * @see org.apache.wicket.markup.html.form.AbstractTextComponent#onBeforeRender()
     */
    @Override
    protected void onBeforeRender() {
        super.onBeforeRender();

        if (!getForm().hasError()) {
            initIds();
        } else if (ids == null) {
            ids = EMPTY_IDS;
        }
        attached = true;
    }

    /**
     * Synchronize ids collection from the palette's model
     */
    private void initIds() {
        // construct the model string based on selection collection
        IChoiceRenderer<T> renderer = getPalettePanel().getChoiceRenderer();
        StringBuilder modelStringBuffer = new StringBuilder();
        Collection<T> modelCollection = getPalettePanel().getModelCollection();
        if (modelCollection == null) {
            throw new WicketRuntimeException(
                    "Expected getPalette().getModelCollection() to return a non-null value."
                            + " Please make sure you have model object assigned to the palette");
        }
        Iterator<T> selection = modelCollection.iterator();

        int i = 0;
        while (selection.hasNext()) {
            modelStringBuffer.append(renderer.getIdValue(selection.next(), i++));
            if (selection.hasNext()) {
                modelStringBuffer.append(",");
            }
        }

        // set model and update ids array
        String modelString = modelStringBuffer.toString();
        setDefaultModel(new Model<String>(modelString));
        updateIds(modelString);
    }

    @Override
    protected void onValid() {
        super.onValid();
        if (attached) {
            updateIds();
        }
    }

    /**
     * @return iterator over selected choices
     */
    @SuppressWarnings("unchecked")
    public Iterator<T> getSelectedChoices() {
        IChoiceRenderer<T> renderer = getPalettePanel().getChoiceRenderer();
        if (ids.length == 0) {
            return Collections.EMPTY_LIST.iterator();
        }

        List<T> selected = new ArrayList<T>(ids.length);
        for (String id : ids) {
            for (T choice : getPalettePanel().getChoices()) {
                if (renderer.getIdValue(choice, 0).equals(id)) {
                    selected.add(choice);
                    break;
                }
            }
        }
        return selected.iterator();
    }

    /**
     * @return iterator over unselected choices
     */
    public Iterator<T> getUnselectedChoices() {
        IChoiceRenderer<T> renderer = getPalettePanel().getChoiceRenderer();
        Collection<? extends T> choices = getPalettePanel().getChoices();

        if (choices.size() - ids.length == 0) {
            return Collections.<T>emptyList().iterator();
        }

        List<T> unselected = new ArrayList<T>(Math.max(1, choices.size() - ids.length));
        for (T choice : choices) {
            final String choiceId = renderer.getIdValue(choice, 0);
            boolean selected = false;
            for (String id : ids) {
                if (id.equals(choiceId)) {
                    selected = true;
                    break;
                }
            }
            if (!selected) {
                unselected.add(choice);
            }
        }
        return unselected.iterator();
    }

    @Override
    protected void onInvalid() {
        super.onInvalid();
        if (attached) {
            updateIds();
        }
    }

    private void updateIds() {
        updateIds(getValue());
    }

    private void updateIds(final String value) {
        if (Strings.isEmpty(value)) {
            ids = EMPTY_IDS;
        } else {
            ids = value.split(",");
        }
    }

}