    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017
    018package org.apache.commons.imaging.internal;
    019
    020import java.io.IOException;
    021import java.util.function.Predicate;
    022import java.util.function.Supplier;
    023
    024import org.apache.commons.imaging.AbstractImageParser;
    025import org.apache.commons.imaging.ImageFormat;
    026import org.apache.commons.imaging.ImageFormats;
    027import org.apache.commons.imaging.Imaging;
    028import org.apache.commons.imaging.ImagingParameters;
    029import org.apache.commons.imaging.bytesource.ByteSource;
    030
    031/**
    032 * Internal utilities.
    033 *
    034 * @since 1.0-alpha3
    035 */
    036public final class ImageParserFactory {
    037
    038    public static <T extends ImagingParameters<T>> AbstractImageParser<T> getImageParser(final ByteSource byteSource) throws IOException {
    039        // TODO: circular dependency between Imaging and internal Util class below.
    040        final ImageFormat format = Imaging.guessFormat(byteSource);
    041        if (!format.equals(ImageFormats.UNKNOWN)) {
    042            return getImageParser(format);
    043        }
    044        final String fileName = byteSource.getFileName();
    045        if (fileName != null) {
    046            return getImageParser(fileName);
    047        }
    048        throw new IllegalArgumentException("Can't parse this format.");
    049    }
    050
    051    public static <T extends ImagingParameters<T>> AbstractImageParser<T> getImageParser(final ImageFormat format) {
    052        return getImageParser(parser -> parser.canAcceptType(format), () -> new IllegalArgumentException("Unknown ImageFormat: " + format));
    053    }
    054
    055    // This generics suppression is as good as the predicate given. If the predicate violates a generics design,
    056    // then there will be an error during runtime.
    057    @SuppressWarnings("unchecked")
    058    private static <T extends ImagingParameters<T>> AbstractImageParser<T> getImageParser(final Predicate<AbstractImageParser<?>> pred,
    059            final Supplier<? extends RuntimeException> supplier) {
    060        return (AbstractImageParser<T>) AbstractImageParser.getAllImageParsers().stream().filter(pred).findFirst().orElseThrow(supplier);
    061    }
    062
    063    public static <T extends ImagingParameters<T>> AbstractImageParser<T> getImageParser(final String fileExtension) {
    064        return getImageParser(parser -> parser.canAcceptExtension(fileExtension), () -> new IllegalArgumentException("Unknown extension: " + fileExtension));
    065    }
    066
    067    private ImageParserFactory() {
    068    }
    069}