org.cropinformatics.ui.components.impl.AbstractComboViewerEditComponent.java Source code

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Here is the source code for org.cropinformatics.ui.components.impl.AbstractComboViewerEditComponent.java

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/*******************************************************************************
 * Copyright 2011 Guy Davenport
 *
 * Licensed 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.cropinformatics.ui.components.impl;

import java.util.LinkedList;
import java.util.List;

import org.cropinformatics.ui.components.Component;
import org.cropinformatics.ui.configuration.ComponentConfiguration;
import org.cropinformatics.ui.configuration.ContainerConfiguration;
import org.cropinformatics.ui.configuration.ControlConfiguration;
import org.eclipse.jface.viewers.ArrayContentProvider;
import org.eclipse.jface.viewers.ComboViewer;
import org.eclipse.jface.viewers.ILabelProvider;
import org.eclipse.jface.viewers.ISelectionChangedListener;
import org.eclipse.jface.viewers.IStructuredContentProvider;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.jface.viewers.SelectionChangedEvent;
import org.eclipse.jface.viewers.StructuredSelection;
import org.eclipse.jface.viewers.ViewerSorter;
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Composite;

public abstract class AbstractComboViewerEditComponent<T, E> extends LabelledEditComponent<T> {
    private static final String VIEWER_COMPONENT_ID = "comboViewer";

    private ComboViewer comboViewer;

    private List<E> values;

    private E selectedValue;

    private boolean allowingNewValues;

    public AbstractComboViewerEditComponent(Composite parent, ContainerConfiguration containerConfiguration,
            String labelValue, List<E> values, boolean allowingNewValues) {
        this(parent, containerConfiguration, labelValue, null, values, allowingNewValues);
    }

    public AbstractComboViewerEditComponent(Composite parent, ContainerConfiguration containerConfiguration,
            String labelValue, T value, List<E> values, boolean allowingNewValues) {
        super(parent, containerConfiguration, labelValue);

        this.values = new LinkedList<E>();

        this.values.addAll(values);

        createCache();

        setValue(value);
    }

    @Override
    public void setValue(T value) {
        if (isValidValue(value)) {
            super.setValue(value);
        }
    }

    @Override
    protected void updateInternalComponents() {
        if (comboViewer != null) {
            updateSelection();
        }
    }

    protected abstract void createCache();

    protected final boolean isAllowingNewValues() {
        return allowingNewValues;
    }

    protected final List<E> getValidValues() {
        return values;
    }

    @Override
    protected Component<? extends ComponentConfiguration> initialiseChildComponent(Composite parent,
            ComponentConfiguration configuration, String id) {
        Component<? extends ComponentConfiguration> component = super.initialiseChildComponent(parent,
                configuration, id);

        if (component == null) {
            ControlConfiguration controlConfiguration = null;

            if (configuration instanceof ControlConfiguration)
                controlConfiguration = (ControlConfiguration) configuration;

            if (VIEWER_COMPONENT_ID.equals(id)) {
                comboViewer = new ComboViewer(parent, SWT.NONE);

                comboViewer.setContentProvider(createContentProvider());
                comboViewer.setLabelProvider(createLabelProvider());
                comboViewer.setInput(values);
                comboViewer.setSorter(createViewerSorter());

                updateSelection();

                comboViewer.addSelectionChangedListener(new ISelectionChangedListener() {
                    @Override
                    public void selectionChanged(SelectionChangedEvent event) {
                        handleSelectionChanged();
                    }

                });

                component = new SimpleViewerComponent<ComboViewer>(comboViewer, controlConfiguration);
            }
        }

        return component;
    }

    @SuppressWarnings("unchecked")
    protected void handleSelectionChanged() {
        selectedValue = (E) ((StructuredSelection) comboViewer.getSelection()).getFirstElement();

        setValueInternalWithEvent(parseToValue(selectedValue));
    }

    @Override
    protected void registerChildComponentIDs() {
        super.registerChildComponentIDs();

        registerChildComponentID(VIEWER_COMPONENT_ID);
    }

    protected IStructuredContentProvider createContentProvider() {
        return new ArrayContentProvider();
    }

    protected ILabelProvider createLabelProvider() {
        return new LabelProvider();
    }

    protected ViewerSorter createViewerSorter() {
        return null;
    }

    protected boolean isValidValue(T value) {
        return true;
    }

    protected abstract T parseToValue(E value);

    protected abstract E parseFromValue(T value);

    private void updateSelection() {
        E parsedValue = parseFromValue(getValue());

        if (parsedValue != null)
            comboViewer.setSelection(new StructuredSelection(parseFromValue(getValue())));
        else
            comboViewer.setSelection(StructuredSelection.EMPTY);
    }

}