net.sf.jasperreports.engine.base.VirtualizableElementList.java Source code

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Here is the source code for net.sf.jasperreports.engine.base.VirtualizableElementList.java

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/*
 * JasperReports - Free Java Reporting Library.
 * Copyright (C) 2001 - 2019 TIBCO Software Inc. All rights reserved.
 * http://www.jaspersoft.com
 *
 * Unless you have purchased a commercial license agreement from Jaspersoft,
 * the following license terms apply:
 *
 * This program is part of JasperReports.
 *
 * JasperReports is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * JasperReports is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with JasperReports. If not, see <http://www.gnu.org/licenses/>.
 */
package net.sf.jasperreports.engine.base;

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

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import net.sf.jasperreports.engine.JRConstants;
import net.sf.jasperreports.engine.JRPrintElement;
import net.sf.jasperreports.engine.fill.JRVirtualizationContext;

/**
 * List implementation that can virtualize blocks of elements.
 * 
 * @author Lucian Chirita (lucianc@users.sourceforge.net)
 */
public class VirtualizableElementList extends AbstractList<JRPrintElement> implements Serializable {
    private static final long serialVersionUID = JRConstants.SERIAL_VERSION_UID;

    private static final Log log = LogFactory.getLog(VirtualizableElementList.class);

    protected final JRVirtualizationContext virtualizationContext;

    protected ElementStore store;

    public VirtualizableElementList(JRVirtualizationContext virtualizationContext, JRVirtualPrintPage page) {
        this.virtualizationContext = virtualizationContext;

        initStore(page);
    }

    protected VirtualizableElementList(JRVirtualizationContext virtualizationContext, ElementStore store) {
        this.virtualizationContext = virtualizationContext;
        this.store = store;
    }

    private void initStore(JRVirtualPrintPage page) {
        // start with a simple block to reduce memory consumption for small pages
        this.store = new ElementsBlock(virtualizationContext, page);

        if (log.isDebugEnabled()) {
            log.debug("created block " + this.store + " for " + this);
        }
    }

    public ElementStore getElementStore() {
        return store;
    }

    public synchronized void set(List<JRPrintElement> elements) {
        clear();
        addAll(elements);
    }

    private void cacheInContext(JRPrintElement element) {
        virtualizationContext.cacheTemplate(element);
    }

    @Override
    public synchronized JRPrintElement get(int index) {
        return store.get(index);
    }

    @Override
    public synchronized int size() {
        return store.size();
    }

    @Override
    public synchronized JRPrintElement set(int index, JRPrintElement element) {
        cacheInContext(element);
        return store.set(index, element);
    }

    private void createBlockList() {
        ElementsBlockList blockList = new ElementsBlockList((ElementsBlock) store);
        blockList.addBlock();

        store = blockList;
    }

    @Override
    public synchronized boolean add(JRPrintElement element) {
        cacheInContext(element);

        if (!store.add(element)) {
            // we had a single block and it overflowed.
            // create a block list.
            createBlockList();

            // add again, block list never overflows.
            store.add(element);
        }
        return true;
    }

    @Override
    public synchronized void add(int index, JRPrintElement element) {
        cacheInContext(element);

        if (!store.add(index, element)) {
            // we had a single block and it overflowed.
            // create a block list.
            createBlockList();

            // add again, block list never overflows.
            store.add(index, element);
        }
    }

    @Override
    public synchronized JRPrintElement remove(int index) {
        return store.remove(index);
    }

    @Override
    public synchronized void clear() {
        // recreating the store
        JRVirtualPrintPage page = store.getPage();
        store.dispose();
        initStore(page);
    }

    public synchronized void dispose() {
        store.dispose();
    }

    public JRVirtualizationContext getVirtualizationContext() {
        return virtualizationContext;
    }

    //FIXME implement faster bulk methods such as addAll
}