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 */ 017package org.apache.commons.imaging.internal; 018 019import org.apache.commons.imaging.ImageFormat; 020import org.apache.commons.imaging.ImageFormats; 021import org.apache.commons.imaging.ImageParser; 022import org.apache.commons.imaging.Imaging; 023import org.apache.commons.imaging.common.bytesource.ByteSource; 024 025import java.io.IOException; 026import java.util.function.Predicate; 027import java.util.function.Supplier; 028 029/** 030 * Internal utilities. 031 * 032 * @since 1.0-alpha3 033 */ 034public class Util { 035 036 private Util() {} 037 038 public static ImageParser<?> getImageParser(ImageFormat format) { 039 return getImageParser((parser) -> parser.canAcceptType(format), () -> new IllegalArgumentException("Unknown Format: " + format)); 040 } 041 042 public static ImageParser<?> getImageParser(String fileExtension) { 043 return getImageParser((parser) -> parser.canAcceptExtension(fileExtension), () -> new IllegalArgumentException("Unknown Extension: " + fileExtension)); 044 } 045 046 // This generics suppression is as good as the predicate given. If the predicate violates a generics design, 047 // then there will be an error during runtime. 048 private static ImageParser<?> getImageParser(Predicate<ImageParser<?>> pred, Supplier<? extends RuntimeException> supplier) { 049 return (ImageParser<?>) ImageParser 050 .getAllImageParsers() 051 .stream() 052 .filter(pred) 053 .findFirst() 054 .orElseThrow(supplier); 055 } 056 057 public static ImageParser<?> getImageParser(final ByteSource byteSource) throws IOException { 058 // TODO: circular dependency between Imaging and internal Util class below. 059 final ImageFormat format = Imaging.guessFormat(byteSource); 060 if (!format.equals(ImageFormats.UNKNOWN)) { 061 return Util.getImageParser(format); 062 } 063 064 final String fileName = byteSource.getFileName(); 065 if (fileName != null) { 066 return Util.getImageParser(fileName); 067 } 068 069 throw new IllegalArgumentException("Can't parse this format."); 070 } 071}