/*******************************************************************************
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* Copyright 2011-2013 Sergey Tarasevich
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*******************************************************************************/
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package com.nostra13.universalimageloader.core.download;
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import com.nostra13.universalimageloader.core.DisplayImageOptions;
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import java.io.IOException;
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import java.io.InputStream;
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import java.util.Locale;
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/**
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* Provides retrieving of {@link InputStream} of image by URI.<br />
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* Implementations have to be thread-safe.
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*
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* @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
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* @since 1.4.0
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*/
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public interface ImageDownloader {
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/**
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* Retrieves {@link InputStream} of image by URI.
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*
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* @param imageUri Image URI
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* @param extra Auxiliary object which was passed to {@link DisplayImageOptions.Builder#extraForDownloader(Object)
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* DisplayImageOptions.extraForDownloader(Object)}; can be null
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* @return {@link InputStream} of image
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* @throws IOException if some I/O error occurs during getting image stream
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* @throws UnsupportedOperationException if image URI has unsupported scheme(protocol)
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*/
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InputStream getStream(String imageUri, Object extra) throws IOException;
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/** Represents supported schemes(protocols) of URI. Provides convenient methods for work with schemes and URIs. */
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public enum Scheme {
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HTTP("http"), HTTPS("https"), FILE("file"), CONTENT("content"), ASSETS("assets"), DRAWABLE("drawable"), UNKNOWN("");
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private String scheme;
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private String uriPrefix;
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Scheme(String scheme) {
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this.scheme = scheme;
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uriPrefix = scheme + "://";
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}
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/**
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* Defines scheme of incoming URI
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*
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* @param uri URI for scheme detection
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* @return Scheme of incoming URI
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*/
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public static Scheme ofUri(String uri) {
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if (uri != null) {
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for (Scheme s : values()) {
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if (s.belongsTo(uri)) {
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return s;
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}
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}
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}
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return UNKNOWN;
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}
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private boolean belongsTo(String uri) {
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return uri.toLowerCase(Locale.US).startsWith(uriPrefix);
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}
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/** Appends scheme to incoming path */
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public String wrap(String path) {
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return uriPrefix + path;
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}
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/** Removed scheme part ("scheme://") from incoming URI */
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public String crop(String uri) {
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if (!belongsTo(uri)) {
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throw new IllegalArgumentException(String.format("URI [%1$s] doesn't have expected scheme [%2$s]", uri, scheme));
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}
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return uri.substring(uriPrefix.length());
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}
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}
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}
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