Java tutorial
/* * Copyright (c) 2011-2019 Contributors to the Eclipse Foundation * * This program and the accompanying materials are made available under the * terms of the Eclipse Public License 2.0 which is available at * http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0 * which is available at https://www.apache.org/licenses/LICENSE-2.0. * * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 */ package io.vertx.core.http; import io.vertx.core.Handler; import io.vertx.core.MultiMap; import java.util.Iterator; import java.util.LinkedList; import java.util.List; import java.util.Map; import java.util.Objects; import java.util.Set; import java.util.TreeSet; import java.util.function.BiConsumer; import java.util.function.Consumer; /** * This multi-map implementation has case insensitive keys, and can be used to hold some HTTP headers * prior to making an HTTP request. * * @author <a href="mailto:nmaurer@redhat.com">Norman Maurer</a> */ public final class CaseInsensitiveHeaders implements MultiMap { private static final int BUCKET_SIZE = 17; private static int hash(String name) { int h = 0; for (int i = name.length() - 1; i >= 0; i--) { char c = name.charAt(i); if (c >= 'A' && c <= 'Z') { c += 32; } h = 31 * h + c; } if (h > 0) { return h; } else if (h == Integer.MIN_VALUE) { return Integer.MAX_VALUE; } else { return -h; } } private MultiMap set0(Iterable<Map.Entry<String, String>> map) { clear(); for (Map.Entry<String, String> entry : map) { add(entry.getKey(), entry.getValue()); } return this; } @Override public MultiMap setAll(MultiMap headers) { return set0(headers); } @Override public MultiMap setAll(Map<String, String> headers) { return set0(headers.entrySet()); } @Override public int size() { return names().size(); } private static boolean eq(String name1, String name2) { int nameLen = name1.length(); if (nameLen != name2.length()) { return false; } for (int i = nameLen - 1; i >= 0; i--) { char c1 = name1.charAt(i); char c2 = name2.charAt(i); if (c1 != c2) { if (c1 >= 'A' && c1 <= 'Z') { c1 += 32; } if (c2 >= 'A' && c2 <= 'Z') { c2 += 32; } if (c1 != c2) { return false; } } } return true; } private static int index(int hash) { return hash % BUCKET_SIZE; } private final MapEntry[] entries = new MapEntry[BUCKET_SIZE]; private final MapEntry head = new MapEntry(-1, null, null); public CaseInsensitiveHeaders() { head.before = head.after = head; } @Override public MultiMap add(final String name, final String strVal) { int h = hash(name); int i = index(h); add0(h, i, name, strVal); return this; } @Override public MultiMap add(String name, Iterable<String> values) { int h = hash(name); int i = index(h); for (String vstr : values) { add0(h, i, name, vstr); } return this; } @Override public MultiMap addAll(MultiMap headers) { for (Map.Entry<String, String> entry : headers.entries()) { add(entry.getKey(), entry.getValue()); } return this; } @Override public MultiMap addAll(Map<String, String> map) { for (Map.Entry<String, String> entry : map.entrySet()) { add(entry.getKey(), entry.getValue()); } return this; } private void add0(int h, int i, final String name, final String value) { // Update the hash table. MapEntry e = entries[i]; MapEntry newEntry; entries[i] = newEntry = new MapEntry(h, name, value); newEntry.next = e; // Update the linked list. newEntry.addBefore(head); } @Override public MultiMap remove(final String name) { Objects.requireNonNull(name, "name"); int h = hash(name); int i = index(h); remove0(h, i, name); return this; } private void remove0(int h, int i, String name) { MapEntry e = entries[i]; if (e == null) { return; } for (;;) { if (e.hash == h && eq(name, e.key)) { e.remove(); MapEntry next = e.next; if (next != null) { entries[i] = next; e = next; } else { entries[i] = null; return; } } else { break; } } for (;;) { MapEntry next = e.next; if (next == null) { break; } if (next.hash == h && eq(name, next.key)) { e.next = next.next; next.remove(); } else { e = next; } } } @Override public MultiMap set(final String name, final String strVal) { int h = hash(name); int i = index(h); remove0(h, i, name); add0(h, i, name, strVal); return this; } @Override public MultiMap set(final String name, final Iterable<String> values) { Objects.requireNonNull(values, "values"); int h = hash(name); int i = index(h); remove0(h, i, name); for (String v : values) { if (v == null) { break; } add0(h, i, name, v); } return this; } @Override public MultiMap clear() { for (int i = 0; i < entries.length; i++) { entries[i] = null; } head.before = head.after = head; return this; } @Override public String get(final String name) { Objects.requireNonNull(name, "name"); int h = hash(name); int i = index(h); MapEntry e = entries[i]; String value = null; while (e != null) { if (e.hash == h && eq(name, e.key)) { value = e.getValue(); } e = e.next; } return value; } @Override public List<String> getAll(final String name) { Objects.requireNonNull(name, "name"); LinkedList<String> values = new LinkedList<>(); int h = hash(name); int i = index(h); MapEntry e = entries[i]; while (e != null) { if (e.hash == h && eq(name, e.key)) { values.addFirst(e.getValue()); } e = e.next; } return values; } @Override public void forEach(Consumer<? super Map.Entry<String, String>> action) { MapEntry e = head.after; while (e != head) { action.accept(e); e = e.after; } } @Override public List<Map.Entry<String, String>> entries() { List<Map.Entry<String, String>> all = new LinkedList<>(); MapEntry e = head.after; while (e != head) { all.add(e); e = e.after; } return all; } @Override public Iterator<Map.Entry<String, String>> iterator() { return entries().iterator(); } @Override public boolean contains(String name) { return get(name) != null; } @Override public boolean isEmpty() { return head == head.after; } @Override public Set<String> names() { Set<String> names = new TreeSet<>(String.CASE_INSENSITIVE_ORDER); MapEntry e = head.after; while (e != head) { names.add(e.getKey()); e = e.after; } return names; } @Override public String get(CharSequence name) { return get(name.toString()); } @Override public List<String> getAll(CharSequence name) { return getAll(name.toString()); } @Override public boolean contains(CharSequence name) { return contains(name.toString()); } @Override public MultiMap add(CharSequence name, CharSequence value) { return add(name.toString(), value.toString()); } @Override public MultiMap add(CharSequence name, Iterable<CharSequence> values) { String n = name.toString(); for (CharSequence seq : values) { add(n, seq.toString()); } return this; } @Override public MultiMap set(CharSequence name, CharSequence value) { return set(name.toString(), value.toString()); } @Override public MultiMap set(CharSequence name, Iterable<CharSequence> values) { remove(name); String n = name.toString(); for (CharSequence seq : values) { add(n, seq.toString()); } return this; } @Override public MultiMap remove(CharSequence name) { return remove(name.toString()); } public String toString() { StringBuilder sb = new StringBuilder(); for (Map.Entry<String, String> entry : this) { sb.append(entry).append('\n'); } return sb.toString(); } private static final class MapEntry implements Map.Entry<String, String> { final int hash; final String key; String value; MapEntry next; MapEntry before, after; MapEntry(int hash, String key, String value) { this.hash = hash; this.key = key; this.value = value; } void remove() { before.after = after; after.before = before; } void addBefore(MapEntry e) { after = e; before = e.before; before.after = this; after.before = this; } @Override public String getKey() { return key; } @Override public String getValue() { return value; } @Override public String setValue(String value) { Objects.requireNonNull(value, "value"); String oldValue = this.value; this.value = value; return oldValue; } @Override public String toString() { return getKey() + ": " + getValue(); } } }