org.apache.axiom.attachments.lifecycle.impl.DataHandlerExtImpl.java Source code

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Here is the source code for org.apache.axiom.attachments.lifecycle.impl.DataHandlerExtImpl.java

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/*
 * 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.axiom.attachments.lifecycle.impl;

import java.io.File;
import java.io.IOException;
import java.util.Observable;
import java.util.Observer;

import javax.activation.DataHandler;
import javax.activation.DataSource;

import org.apache.axiom.attachments.CachedFileDataSource;
import org.apache.axiom.attachments.lifecycle.DataHandlerExt;
import org.apache.axiom.attachments.lifecycle.LifecycleManager;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class DataHandlerExtImpl extends DataHandler implements DataHandlerExt, Observer {

    private static final Log log = LogFactory.getLog(DataHandlerExtImpl.class);
    private DataHandler dataHandler = null;
    private LifecycleManager manager = null;
    private static int READ_COUNT = 1;
    private boolean deleteOnreadOnce = false;

    public DataHandlerExtImpl(DataHandler dataHandler, LifecycleManager manager) {
        super(dataHandler.getDataSource());
        this.dataHandler = dataHandler;
        this.manager = manager;
    }

    public void deleteWhenReadOnce() throws IOException {
        deleteOnreadOnce = true;
        FileAccessor fa = manager.getFileAccessor(getName());
        if (fa == null) {
            log.warn("Could not find FileAccessor, delete on readOnce Failed");
            return;
        }
        if (fa.getAccessCount() >= READ_COUNT) {
            purgeDataSource();
        } else {
            fa.addObserver(this);
        }
    }

    public void purgeDataSource() throws IOException {
        if (log.isDebugEnabled()) {
            log.debug("Start purgeDataSource");
        }
        File file = getFile();
        if (file != null) {
            //Invoke delete from LifecycleManager
            manager.delete(file);
            //If file was registered with VMShutdown hook
            //lets remove it from the list to be deleted on VMExit.
            VMShutdownHook hook = VMShutdownHook.hook();
            if (hook.isRegistered()) {
                hook.remove(file);
            }
            if (log.isDebugEnabled()) {
                log.debug("File Purged and removed from Shutdown Hook Collection");
            }
        } else {
            if (log.isDebugEnabled()) {
                log.debug("DataSource is not a CachedFileDataSource, Unable to Purge.");
            }
        }

        if (log.isDebugEnabled()) {
            log.debug("End purgeDataSource");
        }
    }

    public void update(Observable o, Object arg) {
        try {
            if (log.isDebugEnabled()) {
                log.debug("Start update in Observer");
            }
            if (o instanceof FileAccessor) {
                FileAccessor fa = (FileAccessor) o;
                if (deleteOnreadOnce && fa.getAccessCount() >= READ_COUNT) {
                    purgeDataSource();
                }
            }
        } catch (IOException e) {
            if (log.isDebugEnabled()) {
                log.debug("delete on readOnce Failed");
            }
            log.warn("delete on readOnce Failed with IOException in Observer" + e.getMessage());
        }
        if (log.isDebugEnabled()) {
            log.debug("End update in Observer");
        }
    }

    private File getFile() {
        //get DataSource from DataHandler
        DataSource dataSource = dataHandler.getDataSource();
        if (dataSource instanceof CachedFileDataSource) {
            CachedFileDataSource cds = (CachedFileDataSource) dataSource;
            //get the file object from data source.
            return cds.getFile();
        }
        return null;
    }
}