com.facebook.presto.jdbc.internal.apache.http.protocol.ChainBuilder Maven / Gradle / Ivy
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* ====================================================================
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* .
*
*/
package com.facebook.presto.jdbc.internal.apache.http.protocol;
import java.util.Collection;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map;
/**
* Builder class to build a linked list (chain) of unique class instances. Each class can have
* only one instance in the list. Useful for building lists of protocol interceptors.
*
* @see ImmutableHttpProcessor
*
* @since 4.3
*/
final class ChainBuilder {
private final LinkedList list;
private final Map, E> uniqueClasses;
public ChainBuilder() {
this.list = new LinkedList();
this.uniqueClasses = new HashMap, E>();
}
private void ensureUnique(final E e) {
final E previous = this.uniqueClasses.remove(e.getClass());
if (previous != null) {
this.list.remove(previous);
}
this.uniqueClasses.put(e.getClass(), e);
}
public ChainBuilder addFirst(final E e) {
if (e == null) {
return this;
}
ensureUnique(e);
this.list.addFirst(e);
return this;
}
public ChainBuilder addLast(final E e) {
if (e == null) {
return this;
}
ensureUnique(e);
this.list.addLast(e);
return this;
}
public ChainBuilder addAllFirst(final Collection c) {
if (c == null) {
return this;
}
for (final E e: c) {
addFirst(e);
}
return this;
}
public ChainBuilder addAllFirst(final E... c) {
if (c == null) {
return this;
}
for (final E e: c) {
addFirst(e);
}
return this;
}
public ChainBuilder addAllLast(final Collection c) {
if (c == null) {
return this;
}
for (final E e: c) {
addLast(e);
}
return this;
}
public ChainBuilder addAllLast(final E... c) {
if (c == null) {
return this;
}
for (final E e: c) {
addLast(e);
}
return this;
}
public LinkedList build() {
return new LinkedList(this.list);
}
}
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