https://projects.eclipse.org/projects/ee4j.jersey/project/jersey-media-multipart: Jersey Multipart entity providers support module. (Eclipse Foundation) 
/*
 * Copyright (c) 2010, 2018 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package org.glassfish.jersey.media.multipart;

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

import javax.ws.rs.ext.ContextResolver;

import org.glassfish.jersey.internal.util.PropertiesClass;


Injectable JavaBean containing the configuration parameters for jersey-multipart as used in this particular application. 
Author:Craig McClanahan, Paul Sandoz, Michal Gajdos
/**
 * Injectable JavaBean containing the configuration parameters for
 * {@code jersey-multipart} as used in this particular application.
 *
 * @author Craig McClanahan
 * @author Paul Sandoz
 * @author Michal Gajdos
 */
@PropertiesClass
public class MultiPartProperties {

    
Default threshold size for buffer.

/**
     * Default threshold size for buffer.
     */
    public static final int DEFAULT_BUFFER_THRESHOLD = 4096;

    
Name of a properties resource that (if found in the classpath
for this application) will be used to configure the settings returned
by our getter methods.

/**
     * Name of a properties resource that (if found in the classpath
     * for this application) will be used to configure the settings returned
     * by our getter methods.
     */
    public static final String MULTI_PART_CONFIG_RESOURCE = "jersey-multipart-config.properties";

    
Name of the resource property for the threshold size (in bytes) above which a body part entity will be buffered to disk instead of being held in memory. The default value is 4096. 
/**
     * Name of the resource property for the threshold size (in bytes) above which a body part entity will be
     * buffered to disk instead of being held in memory.
     *
     * The default value is {@value #DEFAULT_BUFFER_THRESHOLD}.
     */
    public static final String BUFFER_THRESHOLD = "jersey.config.multipart.bufferThreshold";

    
The BUFFER_THRESHOLD property value to keep a body part entity in memory only. 
/**
     * The {@link #BUFFER_THRESHOLD} property value to keep a body part entity in memory only.
     */
    public static final int BUFFER_THRESHOLD_MEMORY_ONLY = -1;

    
Name of the resource property for the directory to store temporary files containing body parts of multipart message that extends allowed memory threshold.. The default value is not set (will be taken from java.io.tmpdir system property). 
/**
     * Name of the resource property for the directory to store temporary files containing body parts of multipart message that
     * extends allowed memory threshold..
     *
     * The default value is not set (will be taken from {@code java.io.tmpdir} system property).
     */
    public static final String TEMP_DIRECTORY = "jersey.config.multipart.tempDir";

    
The threshold size (in bytes) above which a body part entity will be
buffered to disk instead of being held in memory.

/**
     * The threshold size (in bytes) above which a body part entity will be
     * buffered to disk instead of being held in memory.
     */
    private int bufferThreshold = DEFAULT_BUFFER_THRESHOLD;

    
Directory to store temporary files containing body parts of multipart message that extends allowed memory threshold.

/**
     * Directory to store temporary files containing body parts of multipart message that extends allowed memory threshold.
     */
    private String tempDir = null;

    
Load and customize (if necessary) the configuration values for the jersey-multipart injection binder. 
Throws:
/**
     * Load and customize (if necessary) the configuration values for the
     * {@code jersey-multipart} injection binder.
     *
     * @throws IllegalArgumentException if the configuration resource
     *                                  exists, but there are problems reading it
     */
    public MultiPartProperties() {
        configure();
    }

    
Get the size (in bytes) of the entity of an incoming BodyPart before it will be buffered to disk. If not customized, the default value is 4096. 
Returns:return threshold size for starting to buffer the incoming entity
        to disk.
/**
     * Get the size (in bytes) of the entity of an incoming
     * {@link BodyPart} before it will be buffered to disk.  If not
     * customized, the default value is 4096.
     *
     * @return return threshold size for starting to buffer the incoming entity
     *         to disk.
     */
    public int getBufferThreshold() {
        return bufferThreshold;
    }

    
Get the directory to store temporary files containing body parts of multipart message that extends allowed memory
threshold.

Returns:path to the temporary directory.
Since:2.4.1
/**
     * Get the directory to store temporary files containing body parts of multipart message that extends allowed memory
     * threshold.
     *
     * @return path to the temporary directory.
     * @since 2.4.1
     */
    public String getTempDir() {
        return tempDir;
    }

    
Set the size (in bytes) of the entity of an incoming BodyPart before it will be buffered to disk. 
Params:
  • threshold – size of body part.
Returns:MultiPartProperties instance.
Since:2.4.1
/**
     * Set the size (in bytes) of the entity of an incoming {@link BodyPart} before it will be buffered to disk.
     *
     * @param threshold size of body part.
     * @return {@code MultiPartProperties} instance.
     * @since 2.4.1
     */
    public MultiPartProperties bufferThreshold(final int threshold) {
        this.bufferThreshold = threshold < BUFFER_THRESHOLD_MEMORY_ONLY ? BUFFER_THRESHOLD_MEMORY_ONLY : threshold;
        return this;
    }

    
Set the path to the directory to store temporary files containing body parts of multipart message that extends allowed
memory threshold.

Params:
  • path – path to the temporary directory.
Returns:MultiPartProperties instance.
Since:2.4.1
/**
     * Set the path to the directory to store temporary files containing body parts of multipart message that extends allowed
     * memory threshold.
     *
     * @param path path to the temporary directory.
     * @return {@code MultiPartProperties} instance.
     * @since 2.4.1
     */
    public MultiPartProperties tempDir(final String path) {
        this.tempDir = path;
        return this;
    }

    
Configure the values returned by this instance's getters based on
the contents of a properties resource, if it exists on the classpath
for this application.

Throws:
  • IllegalArgumentException – if the configuration resource
                                 exists, but there are problems reading it
/**
     * Configure the values returned by this instance's getters based on
     * the contents of a properties resource, if it exists on the classpath
     * for this application.
     *
     * @throws IllegalArgumentException if the configuration resource
     *                                  exists, but there are problems reading it
     */
    private void configure() {
        // Identify the class loader we will use
        ClassLoader loader = Thread.currentThread().getContextClassLoader();
        if (loader == null) {
            loader = this.getClass().getClassLoader();
        }

        // Attempt to find our properties resource
        InputStream stream = null;
        try {
            stream = loader.getResourceAsStream(MULTI_PART_CONFIG_RESOURCE);
            if (stream == null) {
                return;
            }
            final Properties props = new Properties();
            props.load(stream);

            if (props.containsKey(BUFFER_THRESHOLD)) {
                this.bufferThreshold = Integer.parseInt(props.getProperty(BUFFER_THRESHOLD));
            }
            if (props.containsKey(TEMP_DIRECTORY)) {
                this.tempDir = props.getProperty(TEMP_DIRECTORY);
            }
        } catch (final IOException e) {
            throw new IllegalArgumentException(e);
        } finally {
            if (stream != null) {
                try {
                    stream.close();
                } catch (final IOException e) {
                    // Pass through
                }
            }
        }
    }

    
Create a context resolver for a current state of this MultiPartProperties. 
Returns:context resolver for this config.
Since:2.4.1
/**
     * Create a {@link ContextResolver context resolver} for a current state of this {@code MultiPartProperties}.
     *
     * @return context resolver for this config.
     * @since 2.4.1
     */
    public ContextResolver<MultiPartProperties> resolver() {
        return new ContextResolver<MultiPartProperties>() {

            @Override
            public MultiPartProperties getContext(final Class<?> type) {
                return MultiPartProperties.this;
            }
        };
    }
}