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/*
* Copyright (C) 2007-2014 Sebastiano Vigna
*
* 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 PACKAGE;
import java.util.Collection;
/** A simple, brute-force implementation of a set based on a backing array.
*
* <p>The main purpose of this
* implementation is that of wrapping cleanly the brute-force approach to the storage of a very
* small number of items: just put them into an array and scan linearly to find an item.
*/
public class ARRAY_SET KEY_GENERIC extends ABSTRACT_SET KEY_GENERIC implements java.io.Serializable, Cloneable {
private static final long serialVersionUID = 1L;
/** The backing array (valid up to {@link #size}, excluded). */
private transient KEY_TYPE[] a;
/** The number of valid entries in {@link #a}. */
private int size;
/** Creates a new array set using the given backing array. The resulting set will have as many elements as the array.
*
* <p>It is responsibility of the caller that the elements of <code>a</code> are distinct.
*
* @param a the backing array.
*/
public ARRAY_SET( final KEY_TYPE[] a ) {
this.a = a;
size = a.length;
}
/** Creates a new empty array set.
*/
public ARRAY_SET() {
this.a = ARRAYS.EMPTY_ARRAY;
}
/** Creates a new empty array set of given initial capacity.
*
* @param capacity the initial capacity.
*/
public ARRAY_SET( final int capacity ) {
this.a = new KEY_TYPE[ capacity ];
}
/** Creates a new array set copying the contents of a given collection.
* @param c a collection.
*/
public ARRAY_SET( COLLECTION KEY_GENERIC c ) {
this( c.size () );
addAll( c );
}
/** Creates a new array set copying the contents of a given set.
* @param c a collection.
*/
public ARRAY_SET( final Collection<? extends KEY_GENERIC_CLASS> c ) {
this( c.size() );
addAll( c );
}
/** Creates a new array set using the given backing array and the given number of elements of the array.
*
* <p>It is responsibility of the caller that the first <code>size</code> elements of <code>a</code> are distinct.
*
* @param a the backing array.
* @param size the number of valid elements in <code>a</code>.
*/
public ARRAY_SET( final KEY_TYPE[] a, final int size ) {
this.a = a;
this.size = size;
if ( size > a.length ) throw new IllegalArgumentException( "The provided size (" + size + ") is larger than or equal to the array size (" + a.length + ")" );
}
private int findKey( final KEY_TYPE o ) {
for( int i = size; i-- != 0; ) if ( KEY_EQUALS( a[ i ], o ) ) return i;
return -1;
}
@Override
@SuppressWarnings("unchecked")
public KEY_ITERATOR KEY_GENERIC iterator() {
return ITERATORS.wrap( KEY_GENERIC_ARRAY_CAST a, 0, size );
}
@SuppressWarnings("unchecked")
public boolean contains( final KEY_TYPE k ) {
return findKey( k ) != -1;
}
public int size() {
return size;
}
@Override
@SuppressWarnings("unchecked")
public boolean remove( final KEY_TYPE k ) {
final int pos = findKey( k );
if ( pos == -1 ) return false;
final int tail = size - pos - 1;
for( int i = 0; i < tail; i++ ) a[ pos + i ] = a[ pos + i + 1 ];
size--;
#if #keys(reference)
a[ size ] = null;
#endif
return true;
}
@Override
public boolean add( final KEY_GENERIC_TYPE k ) {
final int pos = findKey( k );
if ( pos != -1 ) return false;
if ( size == a.length ) {
final KEY_TYPE[] b = new KEY_TYPE[ size == 0 ? 2 : size * 2 ];
for( int i = size; i-- != 0; ) b[ i ] = a[ i ];
a = b;
}
a[ size++ ] = k;
return true;
}
@Override
public void clear() {
#if #keys(reference)
for( int i = size; i-- != 0; ) a[ i ] = null;
#endif
size = 0;
}
@Override
public boolean isEmpty() {
return size == 0;
}
/** Returns a deep copy of this set.
*
* <P>This method performs a deep copy of this hash set; the data stored in the
* set, however, is not cloned. Note that this makes a difference only for object keys.
*
* @return a deep copy of this set.
*/
@SuppressWarnings("unchecked")
public ARRAY_SET KEY_GENERIC clone() {
ARRAY_SET KEY_GENERIC c;
try {
c = (ARRAY_SET KEY_GENERIC)super.clone();
}
catch(CloneNotSupportedException cantHappen) {
throw new InternalError();
}
c.a = a.clone();
return c;
}
private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException {
s.defaultWriteObject();
for( int i = 0; i < size; i++ ) s.WRITE_KEY( a[ i ] );
}
@SuppressWarnings("unchecked")
private void readObject(java.io.ObjectInputStream s) throws java.io.IOException, ClassNotFoundException {
s.defaultReadObject();
a = new KEY_TYPE[ size ];
for( int i = 0; i < size; i++ ) a[ i ] = s.READ_KEY();
}
}
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