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/*
* Copyright (C) 2002-2014 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;
/** An abstract class facilitating the creation of type-specific {@linkplain it.unimi.dsi.fastutil.BidirectionalIterator bidirectional iterators}.
*
* <P>To create a type-specific bidirectional iterator, besides what is needed
* for an iterator you need both a method returning the previous element as
* primitive type and a method returning the previous element as an
* object. However, if you inherit from this class you need just one (anyone).
*
* <P>This class implements also a trivial version of {@link #back(int)} that
* uses type-specific methods.
*/
public abstract class KEY_ABSTRACT_BIDI_ITERATOR KEY_GENERIC extends KEY_ABSTRACT_ITERATOR KEY_GENERIC implements KEY_BIDI_ITERATOR KEY_GENERIC {
protected KEY_ABSTRACT_BIDI_ITERATOR() {}
#if #keys(primitive)
/** Delegates to the corresponding generic method. */
public KEY_TYPE PREV_KEY() { return previous().KEY_VALUE(); }
/** Delegates to the corresponding type-specific method. */
public KEY_GENERIC_CLASS previous() { return KEY_CLASS.valueOf( PREV_KEY() ); }
#endif
/** This method just iterates the type-specific version of {@link #previous()} for
* at most <code>n</code> times, stopping if {@link
* #hasPrevious()} becomes false. */
public int back( final int n ) {
int i = n;
while( i-- != 0 && hasPrevious() ) PREV_KEY();
return n - i - 1;
}
}
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