001/*
002 * Copyright 2002-2018 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.core.io;
018
019import java.io.FileNotFoundException;
020import java.io.IOException;
021import java.io.InputStream;
022
023import org.springframework.lang.Nullable;
024
025/**
026 * Simple {@link Resource} implementation that holds a resource description
027 * but does not point to an actually readable resource.
028 *
029 * <p>To be used as placeholder if a {@code Resource} argument is
030 * expected by an API but not necessarily used for actual reading.
031 *
032 * @author Juergen Hoeller
033 * @since 1.2.6
034 */
035public class DescriptiveResource extends AbstractResource {
036
037        private final String description;
038
039
040        /**
041         * Create a new DescriptiveResource.
042         * @param description the resource description
043         */
044        public DescriptiveResource(@Nullable String description) {
045                this.description = (description != null ? description : "");
046        }
047
048
049        @Override
050        public boolean exists() {
051                return false;
052        }
053
054        @Override
055        public boolean isReadable() {
056                return false;
057        }
058
059        @Override
060        public InputStream getInputStream() throws IOException {
061                throw new FileNotFoundException(
062                                getDescription() + " cannot be opened because it does not point to a readable resource");
063        }
064
065        @Override
066        public String getDescription() {
067                return this.description;
068        }
069
070
071        /**
072         * This implementation compares the underlying description String.
073         */
074        @Override
075        public boolean equals(@Nullable Object other) {
076                return (this == other || (other instanceof DescriptiveResource &&
077                                ((DescriptiveResource) other).description.equals(this.description)));
078        }
079
080        /**
081         * This implementation returns the hash code of the underlying description String.
082         */
083        @Override
084        public int hashCode() {
085                return this.description.hashCode();
086        }
087
088}