/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed 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.
 */

package org.springframework.http.server.reactive;

import java.util.AbstractSet;
import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;

import org.apache.tomcat.util.buf.MessageBytes;
import org.apache.tomcat.util.http.MimeHeaders;

import org.springframework.http.HttpHeaders;
import org.springframework.lang.Nullable;
import org.springframework.util.MultiValueMap;

MultiValueMap implementation for wrapping Tomcat HTTP headers.
Author:Brian Clozel
Since:5.1.1
/** * {@code MultiValueMap} implementation for wrapping Tomcat HTTP headers. * * @author Brian Clozel * @since 5.1.1 */
class TomcatHeadersAdapter implements MultiValueMap<String, String> { private final MimeHeaders headers; TomcatHeadersAdapter(MimeHeaders headers) { this.headers = headers; } @Override public String getFirst(String key) { return this.headers.getHeader(key); } @Override public void add(String key, @Nullable String value) { this.headers.addValue(key).setString(value); } @Override public void addAll(String key, List<? extends String> values) { values.forEach(value -> add(key, value)); } @Override public void addAll(MultiValueMap<String, String> values) { values.forEach(this::addAll); } @Override public void set(String key, @Nullable String value) { this.headers.setValue(key).setString(value); } @Override public void setAll(Map<String, String> values) { values.forEach(this::set); } @Override public Map<String, String> toSingleValueMap() { Map<String, String> singleValueMap = new LinkedHashMap<>(this.headers.size()); this.keySet().forEach(key -> singleValueMap.put(key, getFirst(key))); return singleValueMap; } @Override public int size() { Enumeration<String> names = this.headers.names(); int size = 0; while (names.hasMoreElements()) { size++; names.nextElement(); } return size; } @Override public boolean isEmpty() { return (this.headers.size() == 0); } @Override public boolean containsKey(Object key) { if (key instanceof String) { return (this.headers.findHeader((String) key, 0) != -1); } return false; } @Override public boolean containsValue(Object value) { if (value instanceof String) { MessageBytes needle = MessageBytes.newInstance(); needle.setString((String) value); for (int i = 0; i < this.headers.size(); i++) { if (this.headers.getValue(i).equals(needle)) { return true; } } } return false; } @Override @Nullable public List<String> get(Object key) { if (containsKey(key)) { return Collections.list(this.headers.values((String) key)); } return null; } @Override @Nullable public List<String> put(String key, List<String> value) { List<String> previousValues = get(key); this.headers.removeHeader(key); value.forEach(v -> this.headers.addValue(key).setString(v)); return previousValues; } @Override @Nullable public List<String> remove(Object key) { if (key instanceof String) { List<String> previousValues = get(key); this.headers.removeHeader((String) key); return previousValues; } return null; } @Override public void putAll(Map<? extends String, ? extends List<String>> map) { map.forEach(this::put); } @Override public void clear() { this.headers.clear(); } @Override public Set<String> keySet() { Set<String> result = new HashSet<>(8); Enumeration<String> names = this.headers.names(); while (names.hasMoreElements()) { result.add(names.nextElement()); } return result; } @Override public Collection<List<String>> values() { return keySet().stream().map(this::get).collect(Collectors.toList()); } @Override public Set<Entry<String, List<String>>> entrySet() { return new AbstractSet<Entry<String, List<String>>>() { @Override public Iterator<Entry<String, List<String>>> iterator() { return new EntryIterator(); } @Override public int size() { return headers.size(); } }; } @Override public String toString() { return HttpHeaders.formatHeaders(this); } private class EntryIterator implements Iterator<Entry<String, List<String>>> { private Enumeration<String> names = headers.names(); @Override public boolean hasNext() { return this.names.hasMoreElements(); } @Override public Entry<String, List<String>> next() { return new HeaderEntry(this.names.nextElement()); } } private final class HeaderEntry implements Entry<String, List<String>> { private final String key; HeaderEntry(String key) { this.key = key; } @Override public String getKey() { return this.key; } @Nullable @Override public List<String> getValue() { return get(this.key); } @Nullable @Override public List<String> setValue(List<String> value) { List<String> previous = getValue(); headers.removeHeader(this.key); addAll(this.key, value); return previous; } } }