bytearrayresource.java

Wicket一个开发Java Web应用程序框架。它使得开发web应用程序变得容易而轻松。 Wicket利用一个POJO data beans组件使得它可以与任何持久层技术相结合。

/*
 * 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.wicket.resource;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Locale;

import org.apache.wicket.markup.html.WebResource;
import org.apache.wicket.protocol.http.WebResponse;
import org.apache.wicket.util.resource.IResourceStream;
import org.apache.wicket.util.resource.ResourceStreamNotFoundException;
import org.apache.wicket.util.time.Time;


/**
 * This class can be used to easy make a Resource from a predefined byte array. If your data comes
 * from a database then a DynamicWebResource is a better choice. Only use this class if you have to
 * have the byte array in memory. Like a pdf that is generated on the fly.
 * 
 * @author Johan Compagner
 */
public class ByteArrayResource extends WebResource
{
	private static final long serialVersionUID = 1L;

	/** the content type. */
	private final String contentType;

	/** binary data. */
	private final byte[] array;

	/** the locale. */
	private final Locale locale;

	/** the time that this resource was last modified; same as construction time. */
	private final Time lastModified = Time.now();

	private final String filename;

	/**
	 * Creates a Resource from the given byte array with its content type
	 * 
	 * @param contentType
	 *            The Content type of the array.
	 * @param array
	 *            The binary content
	 */
	public ByteArrayResource(String contentType, byte[] array)
	{
		this.contentType = contentType;
		this.array = array;
		this.locale = null;
		this.filename = null;
	}

	/**
	 * Creates a Resource from the given byte array with its content type
	 * 
	 * @param contentType
	 *            The Content type of the array.
	 * @param array
	 *            The binary content
	 * @param filename
	 *            The filename that will be set as the Content-Disposition header.
	 */
	public ByteArrayResource(String contentType, byte[] array, String filename)
	{
		this.contentType = contentType;
		this.array = array;
		this.filename = filename;
		this.locale = null;
	}

	/**
	 * Creates a Resource from the given byte array with its content type and the locale for which
	 * it is valid.
	 * 
	 * @param contentType
	 *            The Content type of the array.
	 * @param array
	 *            The binary content.
	 * @param locale
	 *            The locale of this resource
	 */
	public ByteArrayResource(String contentType, byte[] array, Locale locale)
	{
		this.contentType = contentType;
		this.array = array;
		this.locale = locale;
		this.filename = null;
	}

	/**
	 * Creates a Resource from the given byte array with its content type and the locale for which
	 * it is valid.
	 * 
	 * @param contentType
	 *            The Content type of the array.
	 * @param array
	 *            The binary content.
	 * @param locale
	 *            The locale of this resource
	 * @param filename
	 *            The filename that will be set as the Content-Disposition header.
	 */
	public ByteArrayResource(String contentType, byte[] array, Locale locale, String filename)
	{
		this.contentType = contentType;
		this.array = array;
		this.locale = locale;
		this.filename = filename;
	}

	/**
	 * @see org.apache.wicket.markup.html.WebResource#setHeaders(org.apache.wicket.protocol.http.WebResponse)
	 */
	protected void setHeaders(WebResponse response)
	{
		super.setHeaders(response);
		if (filename != null)
		{
			response.setAttachmentHeader(filename);
		}
	}

	/**
	 * @see org.apache.wicket.Resource#getResourceStream()
	 */
	public IResourceStream getResourceStream()
	{
		return new IResourceStream()
		{
			private static final long serialVersionUID = 1L;

			/** Transient input stream to resource */
			private transient InputStream inputStream = null;

			/**
			 * @see org.apache.wicket.util.resource.IResourceStream#close()
			 */
			public void close() throws IOException
			{
				if (inputStream != null)
				{
					inputStream.close();
					inputStream = null;
				}
			}

			/**
			 * @see org.apache.wicket.util.resource.IResourceStream#getContentType()
			 */
			public String getContentType()
			{
				return contentType;
			}

			/**
			 * @see org.apache.wicket.util.resource.IResourceStream#getInputStream()
			 */
			public InputStream getInputStream() throws ResourceStreamNotFoundException
			{
				if (inputStream == null)
				{
					inputStream = new ByteArrayInputStream(array);
				}

				return inputStream;
			}

			/**
			 * @see org.apache.wicket.util.watch.IModifiable#lastModifiedTime()
			 */
			public Time lastModifiedTime()
			{
				return lastModified;
			}

			public long length()
			{
				return array.length;
			}

			public Locale getLocale()
			{
				return locale;
			}

			public void setLocale(Locale locale)
			{
				// ignore
			}
		};
	}
}