InputStreamFactory.java

/*
 * Copyright 2005 Joe Walker
 *
 * Licensed 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.directwebremoting.io;

import java.io.IOException;
import java.io.InputStream;

import org.directwebremoting.extend.SimpleInputStreamFactory;

/**
 * This class gives some lifecycle to an InputStream.
 * There may be times (particularly with downloading files to browsers) when it
 * is not clear if the data will ever be read.
 * A call to {@link #getInputStream()} is a signal that we really to want data
 * <strong>now</strong> and that if any processing is needed, if should be done.
 * A call to {@link #close()} is a signal that whether or not getInputStream was
 * called, the data is no longer required.
 * {@link SimpleInputStreamFactory}.
 * @see SimpleInputStreamFactory
 * @author Lance Semmens [uklance at gmail dot com]
 */
public interface InputStreamFactory
{
    /**
     * Gets an input stream. This function should be called only once.
     */
    public InputStream getInputStream() throws IOException;

    /**
     * Whether or not this resource has been read from, this should be called
     * to indicate that the resources are no longer required.
     */
    public void close() throws IOException;
}