/*
 * 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.
 */

/* $Id: AbstractImagePreloader.java 750418 2009-03-05 11:03:54Z vhennebert $ */

package org.apache.xmlgraphics.image.loader.impl;

import java.io.IOException;
import java.util.Arrays;

import javax.imageio.stream.ImageInputStream;

import org.apache.xmlgraphics.image.loader.spi.ImagePreloader;

Abstract base class for image preloaders. It provides helper methods for often-used tasks.
/** * Abstract base class for image preloaders. It provides helper methods for often-used tasks. */
public abstract class AbstractImagePreloader implements ImagePreloader {
Allows to read an image header (usually just a magic number). The InputStream is reset to the position before the header was read.
Params:
  • in – the ImageInputStream to read from
  • size – the size of the header
Throws:
  • IOException – if an I/O error occurs while reading the header
Returns:the loaded header
/** * Allows to read an image header (usually just a magic number). The InputStream is reset * to the position before the header was read. * @param in the ImageInputStream to read from * @param size the size of the header * @return the loaded header * @throws IOException if an I/O error occurs while reading the header */
protected byte[] getHeader(ImageInputStream in, int size) throws IOException { byte[] header = new byte[size]; long startPos = in.getStreamPosition(); int read = in.read(header); if (read < size) { Arrays.fill(header, (byte)0); } in.seek(startPos); //Seek back to start position return header; }
{@inheritDoc}
/** {@inheritDoc} */
public int getPriority() { return DEFAULT_PRIORITY; } }