reportclassloader.java

iReport-0.4.1-src是iReport的源代码,iReport是一个开源的报表项目,可以生成PDF等格式报表

/*
 * ReportClassLoader.java
 *
 * Created on 24 maggio 2004, 12.56
 */

package it.businesslogic.ireport;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.StringTokenizer;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

/**
 * This special class loader is used when running a report.
 * The main feature is that this classloader reload Scriptlet class every
 * time the class is needed.
 * This class is based on JUnit test case class loader.
 * @author  Administrator
 */
public class ReportClassLoader extends java.lang.ClassLoader {
        
    /** scanned class path */
    private ArrayList fPathItems;
    
    /** scanned class path */
    private ArrayList fPathChachedItems;
    private HashMap cachedClasses;
    
    /** default excluded paths */

    /**
     * Constructs a ReloadableTestClassLoader. It tokenizes the value of 
     * <code>reportPath</code> and adds it and any sub-paths to a list.  
     * Paths are searched for tests.  All other classes are loaded
     * by parent loaders, to which this classloader always delegates.
     * 
     * This ClassLoader never looks into or knows about the system classpath.  
     * It should always refer to a path of repositories (jars or dirs) 
     * <em>not</em> on the system classpath (as retrieved via  
     * <code>reportPath</code>).
     * 
     * @param classPath to scan and use for finding and reloading classes
     */
    public ReportClassLoader() {

        fPathItems = new ArrayList();
        fPathChachedItems = new ArrayList();
        cachedClasses = new HashMap();
        rescanLibDirectory();

    }
    
    /**
     *  Add to search paths list as no relodable jar/zip all new .jar,.zip not already in classpath
     */
    public void rescanLibDirectory()
    {
        
        if (it.businesslogic.ireport.gui.MainFrame.getMainInstance() == null) return;
        // Looking for jars or zip in lib directory not in classpath...
        File lib_dir = new File(it.businesslogic.ireport.gui.MainFrame.getMainInstance().IREPORT_HOME_DIR,"lib");     
        String classpath = it.businesslogic.ireport.util.Misc.nvl(System.getProperty("java.class.path"),"");
        if (!lib_dir.exists())
        {
            System.out.println("Cannot find lib in iReport home  directory ("+it.businesslogic.ireport.gui.MainFrame.getMainInstance().IREPORT_HOME_DIR+")");
            return;
        }

        //System.out.println("Rescan lib...");
        File[] new_libs = lib_dir.listFiles();

        for (int i=0; i< new_libs.length; ++i)
        {
            if (!new_libs[i].getName().toLowerCase().endsWith("jar") &&
                !new_libs[i].getName().toLowerCase().endsWith("zip")) continue;
            
            if (classpath.indexOf( new_libs[i].getName()) < 0)
            {
                if (!fPathChachedItems.contains(new_libs[i].getAbsolutePath()))
                {
                    //if ( new File(new_libs[i].getAbsolutePath()).exists())
                    //{
                        //System.out.println("Added dynamically " + new_libs[i].getAbsolutePath() + " to ireport class path");
                        fPathChachedItems.add(new_libs[i].getAbsolutePath());
                    //}
                }
            }
        }
    }
    
    /**
     *  Add a dir or a file (i.e. a jar or a zip) to the search path
     */
    public void addNoRelodablePath(String path)
    {
        if (!fPathChachedItems.contains(path))
        {
          fPathChachedItems.add(path);
        }
    }
    
    public void setRelodablePaths(String classPath)
    {
       scanPath(classPath);
    }

    private void scanPath(String classPath) {
        String separator = System.getProperty("path.separator");
        fPathItems = new ArrayList(31);
        StringTokenizer st = new StringTokenizer(classPath, separator);
        while (st.hasMoreTokens()) {
            String pp = st.nextToken();
            //System.out.println("add " + pp);
            fPathItems.add(pp);
        }
    }

    public URL getResource(String name) {
        return ClassLoader.getSystemResource(name);
    }

    public InputStream getResourceAsStream(String name) {
        return ClassLoader.getSystemResourceAsStream(name);
    }

    public synchronized Class findClass(String name) throws ClassNotFoundException {
        //System.out.println("Requested class: " + name);

        if (cachedClasses.containsKey( name ))
        {
            return (Class)cachedClasses.get(name);
        }
        
        byte[] b = loadClassData(name);
        
        if (cachedClasses.containsKey( name ))
        {
            return (Class)cachedClasses.get(name);
        }
        
        return defineClass(name, b, 0, b.length);

    }
    
    // From here down is all code copied and pasted from JUnit's 
    // TestCaseClassLoader
    private byte[] loadClassData(String className)
        throws ClassNotFoundException {
        
        // 1. Look for cached class...
        
        // if we can't find the cached class, looking first in no relodable paths...    
        
        byte[] data = null;
        
        for (int i = 0; i < fPathChachedItems.size(); i++) {
            String path = (String) fPathChachedItems.get(i);
            String fileName = className.replace('.', File.separatorChar) + ".class";
            
            if (isJar(path)) {
                //System.out.println("looking for " + fileName.replace(File.separatorChar,'/') + " in jar " +path);
                data = loadJarData(path, fileName.replace(File.separatorChar,'/'));
            } else {
                //System.out.println("looking for " + fileName + " in dir " +path);
                data = loadFileData(path, fileName);
            }
            if (data != null)
            {
                if (!cachedClasses.containsKey(className))
                {
                    cachedClasses.put(className,defineClass(className, data, 0, data.length));
                }
                return data;
            }
        }
        
        // Else try to load from reloadable paths...
        for (int i = 0; i < fPathItems.size(); i++) {
            String path = (String) fPathItems.get(i);
            String fileName = className.replace('.', File.separatorChar) + ".class";
            
            if (isJar(path)) {
                data = loadJarData(path, fileName);
            } else {
                data = loadFileData(path, fileName);
            }
            if (data != null)
                return data;
        }
        throw new ClassNotFoundException(className);
    }

    boolean isJar(String pathEntry) {
        return pathEntry.endsWith(".jar") || pathEntry.endsWith(".zip");
    }

    private byte[] loadFileData(String path, String fileName) {
        File file = new File(path, fileName);
        //System.out.println("Final class name: " + file.getPath());
        if (file.exists()) {
            return getClassData(file);
        }
        return null;
    }

    private byte[] getClassData(File f) {
        try {
            FileInputStream stream = new FileInputStream(f);
            ByteArrayOutputStream out = new ByteArrayOutputStream(1000);
            byte[] b = new byte[1000];
            int n;
            while ((n = stream.read(b)) != -1)
                out.write(b, 0, n);
            stream.close();
            out.close();
            return out.toByteArray();

        } catch (IOException e) {
        }
        return null;
    }

    private byte[] loadJarData(String path, String fileName) {
        ZipFile zipFile = null;
        InputStream stream = null;
        File archive = new File(path);
        if (!archive.exists())
        {
            //System.out.println("Il jar non esiste!");
            return null;
        }
        try {
            zipFile = new ZipFile(archive);
        } catch (IOException io) {
            //io.printStackTrace();
            return null;
        }
        
        //System.out.println("Ricerca entry" + fileName );
        ZipEntry entry = zipFile.getEntry(fileName);
        if (entry == null)
        {
            //System.out.println("Entry null!");
            return null;
        }
        int size = (int) entry.getSize();
        try {
            stream = zipFile.getInputStream(entry);
            byte[] data = new byte[size];
            int pos = 0;
            while (pos < size) {
                int n = stream.read(data, pos, data.length - pos);
                pos += n;
            }
            zipFile.close();
            return data;
        } catch (IOException e) {
        } finally {
            try {
                if (stream != null)
                    stream.close();
            } catch (IOException e) {
                //e.printStackTrace();
            }
        }
        //System.out.println("Class not found really!");
        return null;
    }
}