org.lexgrid.valuesets.helper.compiler.FileSystemCachingValueSetDefinitionCompilerDecorator.java Source code

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Here is the source code for org.lexgrid.valuesets.helper.compiler.FileSystemCachingValueSetDefinitionCompilerDecorator.java

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/*
 * Copyright: (c) 2004-2010 Mayo Foundation for Medical Education and 
 * Research (MFMER). All rights reserved. MAYO, MAYO CLINIC, and the
 * triple-shield Mayo logo are trademarks and service marks of MFMER.
 *
 * Except as contained in the copyright notice above, or as used to identify 
 * MFMER as the author of this software, the trade names, trademarks, service
 * marks, or product names of the copyright holder shall not be used in
 * advertising, promotion or otherwise in connection with this software without
 * prior written authorization of the copyright holder.
 * 
 * Licensed under the Eclipse Public License, Version 1.0 (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.eclipse.org/legal/epl-v10.html
 * 
 */
package org.lexgrid.valuesets.helper.compiler;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInput;
import java.io.ObjectInputStream;
import java.io.ObjectOutput;
import java.io.ObjectOutputStream;
import java.util.Arrays;

import org.LexGrid.LexBIG.Impl.CodedNodeSetImpl;
import org.LexGrid.LexBIG.LexBIGService.CodedNodeSet;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.comparator.LastModifiedFileComparator;
import org.lexevs.locator.LexEvsServiceLocator;
import org.lexevs.logging.LoggerFactory;
import org.lexgrid.valuesets.helper.VSDServiceHelper;

/**
 * The Class FileSystemCachingValueSetDefinitionCompilerDecorator.
 * 
 * @author <a href="mailto:kevin.peterson@mayo.edu">Kevin Peterson</a>
 */
public class FileSystemCachingValueSetDefinitionCompilerDecorator
        extends AbstractCachingValueSetDefinitionCompilerDecorator {

    private static String COMPILED_VS_DIR = "compiledVSDefinitions";

    private static String COMPILED_VS_FILE_EXTENSION = ".cvd";

    public static int MAX_IN_CACHE;

    /**
     * Instantiates a new caching value set definition compiler decorator.
     * 
     * @param delegate the delegate
     */
    public FileSystemCachingValueSetDefinitionCompilerDecorator(ValueSetDefinitionCompiler delegate,
            VSDServiceHelper vsdServiceHelper) {
        super(delegate, vsdServiceHelper);

        File cacheLocation = new File(this.getDiskStorePath());

        if (!cacheLocation.exists()) {
            LoggerFactory.getLogger()
                    .info("Creating Initial Compiled Value Set Definition Store at: " + cacheLocation.getPath());

            if (cacheLocation.mkdir()) {
                LoggerFactory.getLogger().info("Initial Compiled Value Set Definition Store Creation Success.");
            } else {
                LoggerFactory.getLogger().info(
                        "Initial Compiled Value Set Definition Store Creation Failed... caching will not be used.");
            }
        }
        MAX_IN_CACHE = LexEvsServiceLocator.getInstance().getSystemResourceService().getSystemVariables()
                .getMax_value_set_cache();
    }

    /**
     * Persist coded node set.
     * 
     * @param md5 the md5
     * @param cns the cns
     * 
     * @throws Exception the exception
     */
    protected void persistCodedNodeSet(String md5, CodedNodeSet cns) {
        try {
            File cachedCnsFile = new File(this.getDiskStorePath() + File.separator + this.getFileName(md5));

            if (cachedCnsFile.exists()) {
                LoggerFactory.getLogger().info("Compiled Value Set Definition already cached.");

                return;
            }

            this.deleteOldestFile();

            ObjectOutput out = new ObjectOutputStream(
                    new FileOutputStream(this.getDiskStorePath() + File.separator + this.getFileName(md5)));
            out.writeObject(cns);
            out.close();
        } catch (Exception e) {
            LoggerFactory.getLogger().warn("There was an error persisting the Compiled Value Set Definition."
                    + " Caching will not be used for this Value Set Definition.", e);
        }
    }

    private String getFileName(String md5) {

        return md5 + COMPILED_VS_FILE_EXTENSION;
    }

    /**
     * Retrieve coded node set.
     * 
     * @param md5 the md5
     * 
     * @return the coded node set
     * 
     * @throws Exception the exception
     */
    protected CodedNodeSet retrieveCodedNodeSet(String md5) {

        try {

            File cachedCnsFile = new File(this.getDiskStorePath() + File.separator + this.getFileName(md5));
            if (!cachedCnsFile.exists()) {
                LoggerFactory.getLogger().info("Compiled Value Set Definition cache miss.");

                return null;
            } else {
                LoggerFactory.getLogger().info("Compiled Value Set Definition cache hit.");

                FileUtils.touch(cachedCnsFile);
            }

            ObjectInput in = new ObjectInputStream(new FileInputStream(cachedCnsFile));
            CodedNodeSetImpl cns;
            try {
                cns = (CodedNodeSetImpl) in.readObject();
            } catch (Exception e) {
                LoggerFactory.getLogger().warn(
                        "Compiled Value Set Definition was found, but it is invalid or corrupted. Removing...", e);
                if (!FileUtils.deleteQuietly(cachedCnsFile)) {
                    FileUtils.forceDeleteOnExit(cachedCnsFile);
                }

                throw e;
            }

            in.close();

            if (cns == null) {
                return null;
            } else {
                return cns;
            }
        } catch (Exception e) {
            LoggerFactory.getLogger()
                    .warn("There was an error retrieving the Compiled Value Set Definition from the Cache."
                            + " Caching will not be used for this Value Set Definition.", e);

            return null;
        }
    }

    @SuppressWarnings("unchecked")
    private void deleteOldestFile() {
        File[] files = new File(getDiskStorePath()).listFiles();

        if (files != null && files.length > 0 && files.length >= MAX_IN_CACHE) {

            Arrays.sort(files, LastModifiedFileComparator.LASTMODIFIED_COMPARATOR);

            try {
                if (!files[0].delete()) {
                    files[0].deleteOnExit();
                }
            } catch (Exception e) {
                LoggerFactory.getLogger()
                        .warn("There was an error evicting a Compiled Value Set Definition from the Cache.", e);
            }
        }
    }

    /**
     * Gets the disk store path.
     * 
     * @return the disk store path
     */
    private String getDiskStorePath() {
        String configPath = LexEvsServiceLocator.getInstance().getSystemResourceService().getSystemVariables()
                .getAutoLoadIndexLocation();

        return configPath.substring(0, configPath.lastIndexOf(File.separator) + 1) + COMPILED_VS_DIR;
    }
}