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/*
 * Copyright 2009-2014 PrimeTek.
 *
 * 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.primefaces.model;

import java.io.Serializable;
import java.util.List;
import java.util.Map;

import javax.faces.model.DataModel;
import javax.faces.model.DataModelEvent;
import javax.faces.model.DataModelListener;

/**
 * Custom lazy loading DataModel to deal with huge datasets
 */
public abstract class LazyDataModel extends DataModel implements SelectableDataModel, Serializable {

	private int rowIndex = -1;

	private int rowCount;

	private int pageSize;

	private List data;

	public LazyDataModel() {
		super();
	}
	
	public boolean isRowAvailable() {
		if(data == null) {
            return false;
        }

		return rowIndex >= 0 && rowIndex < data.size();
	}

	public int getRowCount() {
		return rowCount;
	}

	public T getRowData() {
        return data.get(rowIndex);
	}

    public int getRowIndex() {
        return this.rowIndex;
    }
    
    public void setRowIndex(int rowIndex) {
        int oldIndex = this.rowIndex;
        
        if(rowIndex == -1 || pageSize == 0)
            this.rowIndex = -1;
        else
            this.rowIndex = (rowIndex % pageSize);
        
        if(data == null) {
            return;
        }
        
        DataModelListener[] listeners = getDataModelListeners();
        if(listeners != null && oldIndex != this.rowIndex) {
            Object rowData = null;
            if(isRowAvailable()) {
                rowData = getRowData();
            }
            
            DataModelEvent dataModelEvent = new DataModelEvent(this, rowIndex, rowData);
            for (int i = 0; i < listeners.length; i++) {
                listeners[i].rowSelected(dataModelEvent);
            }
        }
    }

	public Object getWrappedData() {
		return data;
	}
	public void setWrappedData(Object list) {
		this.data = (List) list;
	}
	
	public int getPageSize() {
		return pageSize;
	}
	public void setPageSize(int pageSize) {
		this.pageSize = pageSize;
	}

    public void setRowCount(int rowCount) {
        this.rowCount = rowCount;
    }

    public List load(int first, int pageSize, String sortField, SortOrder sortOrder, Map filters) {
        throw new UnsupportedOperationException("Lazy loading is not implemented.");
    }
    
    public List load(int first, int pageSize, List multiSortMeta, Map filters) {
        throw new UnsupportedOperationException("Lazy loading is not implemented.");
    }

    public T getRowData(String rowKey) {
        throw new UnsupportedOperationException("getRowData(String rowKey) must be implemented when basic rowKey algorithm is not used.");
    }

    public Object getRowKey(T object) {
        throw new UnsupportedOperationException("getRowKey(T object) must be implemented when basic rowKey algorithm is not used.");
    }
}