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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 is an adapted copy of org.apache.lucene.analysis.util.CharArraySet
 * to avoid unnecessary conflicts.
 *
 */

package com.twitter.penguin.korean.util;

import java.util.AbstractSet;
import java.util.Collection;
import java.util.Iterator;
import java.util.Set;


/**
 * A simple class that stores Strings as char[]'s in a
 * hash table.  Note that this is not a general purpose
 * class.  For example, it cannot remove items from the
 * set, nor does it resize its hash table to be smaller,
 * etc.  It is designed to be quick to test if a char[]
 * is in the set without the necessity of converting it
 * to a String first.
 * 

* Please note: This class implements {@link java.util.Set Set} but * does not behave like it should in all cases. The generic type is * {@code Set}, because you can add any object to it, * that has a string representation. The add methods will use * {@link Object#toString} and store the result using a {@code char[]} * buffer. The same behavior have the {@code contains()} methods. * The {@link #iterator()} returns an {@code Iterator}. */ public class CharArraySet extends AbstractSet { public static final CharArraySet EMPTY_SET = new CharArraySet(CharArrayMap.emptyMap()); private static final Object PLACEHOLDER = new Object(); private final CharArrayMap map; /** * Create set with enough capacity to hold startSize terms * * @param startSize the initial capacity * @param ignoreCase false if and only if the set should be case sensitive * otherwise true. */ public CharArraySet(int startSize, boolean ignoreCase) { this(new CharArrayMap<>(startSize, ignoreCase)); } /** * Creates a set from a Collection of objects. * * @param c a collection whose elements to be placed into the set * @param ignoreCase false if and only if the set should be case sensitive * otherwise true. */ public CharArraySet(Collection c, boolean ignoreCase) { this(c.size(), ignoreCase); addAll(c); } /** * Create set from the specified map (internal only), used also by {@link CharArrayMap#keySet()} */ CharArraySet(final CharArrayMap map) { this.map = map; } /** * Clears all entries in this set. This method is supported for reusing, but not {@link Set#remove}. */ @Override public void clear() { map.clear(); } /** * true if the len chars of text starting at off * are in the set */ public boolean contains(char[] text, int off, int len) { return map.containsKey(text, off, len); } /** * true if the CharSequence is in the set */ public boolean contains(CharSequence cs) { return map.containsKey(cs); } @Override public boolean contains(Object o) { return map.containsKey(o); } @Override public boolean add(Object o) { return map.put(o, PLACEHOLDER) == null; } /** * Add this CharSequence into the set */ public boolean add(CharSequence text) { return map.put(text, PLACEHOLDER) == null; } /** * Add this String into the set */ public boolean add(String text) { return map.put(text, PLACEHOLDER) == null; } /** * Add this char[] directly to the set. * If ignoreCase is true for this Set, the text array will be directly modified. * The user should never modify this text array after calling this method. */ public boolean add(char[] text) { return map.put(text, PLACEHOLDER) == null; } @Override public int size() { return map.size(); } /** * Returns an unmodifiable {@link CharArraySet}. This allows to provide * unmodifiable views of internal sets for "read-only" use. * * @param set a set for which the unmodifiable set is returned. * @return an new unmodifiable {@link CharArraySet}. * @throws NullPointerException if the given set is null. */ public static CharArraySet unmodifiableSet(CharArraySet set) { if (set == null) throw new NullPointerException("Given set is null"); if (set == EMPTY_SET) return EMPTY_SET; if (set.map instanceof CharArrayMap.UnmodifiableCharArrayMap) return set; return new CharArraySet(CharArrayMap.unmodifiableMap(set.map)); } /** * Returns a copy of the given set as a {@link CharArraySet}. If the given set * is a {@link CharArraySet} the ignoreCase property will be preserved. * * @param set a set to copy * @return a copy of the given set as a {@link CharArraySet}. If the given set * is a {@link CharArraySet} the ignoreCase property as well as the * matchVersion will be of the given set will be preserved. */ public static CharArraySet copy(final Set set) { if (set == EMPTY_SET) return EMPTY_SET; if (set instanceof CharArraySet) { final CharArraySet source = (CharArraySet) set; return new CharArraySet(CharArrayMap.copy(source.map)); } return new CharArraySet(set, false); } /** * Returns an {@link Iterator} for {@code char[]} instances in this set. */ @Override @SuppressWarnings("unchecked") public Iterator iterator() { // use the AbstractSet#keySet()'s iterator (to not produce endless recursion) return map.originalKeySet().iterator(); } @Override public String toString() { final StringBuilder sb = new StringBuilder("["); for (Object item : this) { if (sb.length() > 1) sb.append(", "); if (item instanceof char[]) { sb.append((char[]) item); } else { sb.append(item); } } return sb.append(']').toString(); } }