net.sf.jasperreports.engine.util.SwapFileVirtualizerStore.java Source code

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Here is the source code for net.sf.jasperreports.engine.util.SwapFileVirtualizerStore.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.util;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import net.sf.jasperreports.engine.JRRuntimeException;
import net.sf.jasperreports.engine.JRVirtualizable;
import net.sf.jasperreports.engine.fill.VirtualizerStore;

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

/**
 * @author Lucian Chirita (lucianc@users.sourceforge.net)
 */
public class SwapFileVirtualizerStore implements VirtualizerStore {
    private static final Log log = LogFactory.getLog(SwapFileVirtualizerStore.class);
    public static final String EXCEPTION_MESSAGE_KEY_DEVIRTUALIZING_ERROR = "util.swap.file.virtualizer.devirtualizing.error";
    public static final String EXCEPTION_MESSAGE_KEY_UNABLE_TO_READ_DATA = "util.swap.file.virtualizer.unable.to.read.data";
    public static final String EXCEPTION_MESSAGE_KEY_VIRTUALIZING_ERROR = "util.swap.file.virtualizer.virtualizing.error";

    private final JRSwapFile swap;
    private final boolean swapOwner;
    private final Map<String, JRSwapFile.SwapHandle> handles;
    private final StreamCompression compression;

    public SwapFileVirtualizerStore(JRSwapFile swap, boolean swapOwner) {
        this(swap, swapOwner, null);
    }

    public SwapFileVirtualizerStore(JRSwapFile swap, boolean swapOwner, StreamCompression compression) {
        this.swap = swap;
        this.swapOwner = swapOwner;
        this.handles = Collections.synchronizedMap(new HashMap<String, JRSwapFile.SwapHandle>());
        this.compression = compression;
    }

    @Override
    public String toString() {
        return "SwapFileVirtualizerStore " + swap.toString();
    }

    protected boolean isStored(JRVirtualizable<?> o) {
        return handles.containsKey(o.getUID());
    }

    @Override
    public boolean store(JRVirtualizable<?> o, VirtualizationSerializer serializer) {
        if (isStored(o)) {
            if (log.isTraceEnabled()) {
                log.trace("object " + o.getUID() + " already stored");
            }
            return false;
        }

        try {
            ByteArrayOutputStream bout = new ByteArrayOutputStream(3000);
            OutputStream out = compression == null ? bout : compression.compressedOutput(bout);
            serializer.writeData(o, out);
            out.close();

            byte[] data = bout.toByteArray();
            if (log.isTraceEnabled()) {
                log.trace("writing " + data.length + " for object " + o.getUID() + " to " + swap);
            }

            JRSwapFile.SwapHandle handle = swap.write(data);
            handles.put(o.getUID(), handle);
            return true;
        } catch (IOException e) {
            log.error("Error virtualizing object " + o.getUID() + " to " + swap, e);
            throw new JRRuntimeException(EXCEPTION_MESSAGE_KEY_VIRTUALIZING_ERROR, (Object[]) null, e);
        }
    }

    @Override
    public void retrieve(JRVirtualizable<?> o, boolean remove, VirtualizationSerializer serializer) {
        JRSwapFile.SwapHandle handle = handles.get(o.getUID());
        if (handle == null) {
            // should not happen
            //FIXME lucianc happened once, look into it
            log.error("No swap handle found for " + o.getUID() + " in " + this);
            throw new JRRuntimeException(EXCEPTION_MESSAGE_KEY_UNABLE_TO_READ_DATA, (Object[]) null);
        }

        try {
            byte[] data = swap.read(handle, remove);
            if (log.isTraceEnabled()) {
                log.trace("read " + data.length + " for object " + o.getUID() + " from " + swap);
            }

            ByteArrayInputStream rawInput = new ByteArrayInputStream(data);
            InputStream input = compression == null ? rawInput : compression.uncompressedInput(rawInput);
            serializer.readData(o, input);
            input.close();
        } catch (IOException e) {
            log.error("Error reading object data " + o.getUID() + " from " + swap, e);
            throw new JRRuntimeException(EXCEPTION_MESSAGE_KEY_DEVIRTUALIZING_ERROR, (Object[]) null, e);
        }

        if (remove) {
            handles.remove(o.getUID());
        }
    }

    @Override
    public void remove(String objectId) {
        JRSwapFile.SwapHandle handle = handles.remove(objectId);
        if (handle == null) {
            if (log.isTraceEnabled()) {
                log.trace("object " + objectId + " not found for removal");
            }
        } else {
            if (log.isTraceEnabled()) {
                log.trace("removing object " + objectId + " from " + swap);
            }

            swap.free(handle);
        }
    }

    /**
     * Disposes the swap file used if this virtualizer owns it.
     * @see #SwapFileVirtualizerStore(JRSwapFile, boolean)
     */
    @Override
    public void dispose() {
        handles.clear();
        if (swapOwner) {
            if (log.isDebugEnabled()) {
                log.debug("disposing " + swap);
            }

            swap.dispose();
        }
    }
}