0.10/catalog/src/main/java/org/apache/oodt/cas/catalog/page/QueryPager.java

/*
 * 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 org.apache.oodt.cas.catalog.page;

//JDK imports
import java.util.Collections;
import java.util.List;
import java.util.Vector;

/**
 * @author bfoster
 * @version $Revision$
 *
 * <p>
 * A pager for paging through query results
 * <p>
 */
public class QueryPager extends IndexPager {

	protected List<TransactionReceipt> receipts;
	
	public QueryPager(List<TransactionReceipt> receipts) {
		super();
		this.receipts = new Vector<TransactionReceipt>(receipts);
		this.totalPages = this.caculateTotalPages();
		this.numOfHits = receipts.size();
	}

	protected int caculateTotalPages() {
		return (int) Math.ceil((double) receipts.size() / (double) this.getPageSize());
	}
	
	public void setPageInfo(PageInfo pageInfo) {
		this.pageSize = Math.max(pageInfo.getPageSize(), 0);
		this.totalPages = this.caculateTotalPages();
		if (this.totalPages == 0)
			this.pageNum = 0;
		else
			this.pageNum = (pageInfo.getPageNum() == PageInfo.LAST_PAGE || pageInfo.getPageNum() >= this.totalPages) ? this.totalPages : pageInfo.getPageNum();
	}
		
	public List<TransactionReceipt> getTransactionReceipts() {
		return Collections.unmodifiableList(this.receipts);
	}
	
	public List<TransactionReceipt> getCurrentPage() {
		List<TransactionReceipt> currentPage = new Vector<TransactionReceipt>();
		if (this.pageNum > 0)
			for (int i = (this.getPageNum() - 1) * this.getPageSize(); i < receipts.size() && i < this.getPageNum() * this.getPageSize(); i++)
				currentPage.add(receipts.get(i));
		return currentPage;
	}
	
}