MedicationTableViewerContentProvider.java

package ch.elexis.core.ui.medication.views;

import java.util.Collections;
import java.util.List;

import org.eclipse.jface.action.Action;
import org.eclipse.jface.action.IContributionItem;
import org.eclipse.jface.action.ToolBarManager;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.viewers.IStructuredContentProvider;
import org.eclipse.jface.viewers.StructuredViewer;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.RowLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Label;

import ch.elexis.core.ui.icons.Images;
import ch.elexis.data.Prescription;

public class MedicationTableViewerContentProvider implements IStructuredContentProvider {
	
	private List<Prescription> input;
	
	private List<MedicationTableViewerItem> currentItems;
	
	private StructuredViewer viewer;
	
	private int pageSize;
	private int currentPageOffset;
	
	public MedicationTableViewerContentProvider(StructuredViewer viewer){
		this.viewer = viewer;
		this.pageSize = 500;
		this.currentPageOffset = 0;
	}
	
	@Override
	public void dispose(){
		viewer = null;
		currentItems = null;
		input = null;
	}
	
	@SuppressWarnings("unchecked")
	@Override
	public void inputChanged(Viewer viewer, Object oldInput, Object newInput){
		if (newInput instanceof List<?>) {
			currentPageOffset = 0;
			input = (List<Prescription>) newInput;
			createCurrentItems();
		} else {
			currentPageOffset = 0;
			input = Collections.emptyList();
			currentItems = Collections.emptyList();
		}
	}
	
	private void createCurrentItems(){
		if (input.size() < pageSize) {
			currentItems = MedicationTableViewerItem.createFromPrescriptionList(input, viewer);
		} else {
			if (currentPageOffset + pageSize < input.size()) {
				currentItems = MedicationTableViewerItem.createFromPrescriptionList(
					input.subList(currentPageOffset, currentPageOffset + pageSize), viewer);
			} else {
				currentItems = MedicationTableViewerItem.createFromPrescriptionList(
					input.subList(currentPageOffset, input.size()), viewer);
			}
		}
	}
	
	public void nextPage(){
		if ((currentPageOffset + pageSize) < input.size()) {
			currentPageOffset += pageSize;
			createCurrentItems();
		}
	}
	
	public boolean hasNext(){
		return input != null && (currentPageOffset + pageSize) < input.size();
	}
	
	public void previousPage(){
		if (currentPageOffset >= pageSize) {
			currentPageOffset -= pageSize;
			createCurrentItems();
		}
	}
	
	public boolean hasPrevious(){
		return input != null && currentPageOffset >= pageSize;
	}
	
	@Override
	public Object[] getElements(Object inputElement){
		return currentItems.toArray();
	}
	
	public static class MedicationContentProviderComposite extends Composite {
		
		private Label currentState;
		private MedicationTableViewerContentProvider contentProvider;
		private ToolBarManager toolbarmgr;
		
		public MedicationContentProviderComposite(Composite parent, int style){
			super(parent, style);
			setLayout(new RowLayout(SWT.HORIZONTAL));
			createContent();
		}
		
		private void createContent(){
			currentState = new Label(this, SWT.NONE);
			
			toolbarmgr = new ToolBarManager();
			toolbarmgr.add(new PreviousPage());
			toolbarmgr.add(new NextPage());
			toolbarmgr.createControl(this);
		}
		
		public void setContentProvider(MedicationTableViewerContentProvider contentProvider){
			this.contentProvider = contentProvider;
			refresh();
		}
		
		public void refresh(){
			if (contentProvider != null && contentProvider.input != null) {
				currentState.setText(contentProvider.currentPageOffset + " - "
					+ (contentProvider.currentPageOffset + contentProvider.pageSize) + " / "
					+ contentProvider.input.size());
			} else {
				currentState.setText(" / ");
			}
			layout();
			for (IContributionItem item : toolbarmgr.getItems()) {
				item.update();
			}
		}
		
		private class NextPage extends Action {
			@Override
			public ImageDescriptor getImageDescriptor(){
				return Images.IMG_NEXT.getImageDescriptor();
			}
			
			@Override
			public void run(){
				contentProvider.nextPage();
				contentProvider.viewer.refresh();
				refresh();
			}
			
			@Override
			public boolean isEnabled(){
				return contentProvider != null && contentProvider.hasNext();
			}
		}
		
		private class PreviousPage extends Action {
			@Override
			public ImageDescriptor getImageDescriptor(){
				return Images.IMG_PREVIOUS.getImageDescriptor();
			}
			
			@Override
			public void run(){
				contentProvider.previousPage();
				contentProvider.viewer.refresh();
				refresh();
			}
			
			@Override
			public boolean isEnabled(){
				return contentProvider != null && contentProvider.hasPrevious();
			}
		}
	}
}