CNeryDataModel.java

package com.daveoxley.cnery.factories;

import java.util.List;
import java.util.HashMap;
import java.util.Map;
import javax.faces.context.FacesContext;
import org.ajax4jsf.model.DataVisitor;
import org.ajax4jsf.model.ExtendedDataModel;
import org.ajax4jsf.model.Range;
import org.ajax4jsf.model.SequenceRange;

/**
 *
 * @author dave
 */
public abstract class CNeryDataModel<K,V> extends ExtendedDataModel<V> {

    private K current_key = null;
    private List<V> wrappedData;
    private Map<K,V> cache = new HashMap<K, V>();

    CNeryDataModel(List<V> wrappedData) {
        setWrappedData(wrappedData);
    }

    abstract K getKey(V value);

    @Override
    public void setRowKey(Object o) {
        this.current_key = (K)o;
    }

    @Override
    public Object getRowKey() {
        return current_key;
    }

    @Override
    public void walk(FacesContext fc, DataVisitor dv, Range range, Object argument) {
        int firstRow = ((SequenceRange)range).getFirstRow();
        int numberOfRows = ((SequenceRange)range).getRows();
        int lastRow = numberOfRows > 0 ? firstRow + numberOfRows : wrappedData.size();
        if (lastRow > wrappedData.size())
            lastRow = wrappedData.size();
        for (V v : wrappedData.subList(firstRow, lastRow)) {
            K key = getKey(v);
            cache.put(key, v);
            dv.process(fc, key, argument);
        }
    }

    @Override
    public boolean isRowAvailable() {
        return current_key != null;
    }

    @Override
    public int getRowCount() {
        return wrappedData.size();
    }

    @Override
    public V getRowData() {
        if (current_key == null)
            return null;
        V cachedValue = cache.get(current_key);
        if (cachedValue != null)
            return cachedValue;

        for (V value : wrappedData) {
            K key = getKey(value);
            if (key.equals(current_key)) {
                cache.put(key, value);
                return value;
            }
        }
        return null;
    }

    @Override
    public int getRowIndex() {
        V value = getRowData();
        if (value == null)
            return -1;
        return wrappedData.indexOf(value);
    }

    @Override
    public void setRowIndex(int rowIndex) {
        V value = wrappedData.get(rowIndex);
        if (value != null)
            this.current_key = getKey(value);
    }

    @Override
    public Object getWrappedData() {
        return wrappedData;
    }

    @Override
    public void setWrappedData(Object data) {
        wrappedData = (List<V>)data;
    }
    
}