| /* |
| * 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. |
| */ |
| package org.apache.directory.api.ldap.model.cursor; |
| |
| |
| import java.io.IOException; |
| import java.util.Collections; |
| import java.util.Comparator; |
| import java.util.Set; |
| |
| import org.apache.directory.api.i18n.I18n; |
| import org.apache.directory.api.ldap.model.constants.Loggers; |
| import org.apache.directory.api.ldap.model.exception.LdapException; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| |
| /** |
| * A simple implementation of a Cursor on a {@link Set}. Optionally, the |
| * Cursor may be limited to a specific range within the list. |
| * |
| * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> |
| * @param <E> The element on which this cursor will iterate |
| */ |
| public class SetCursor<E> extends AbstractCursor<E> |
| { |
| /** A dedicated log for cursors */ |
| private static final Logger LOG_CURSOR = LoggerFactory.getLogger( Loggers.CURSOR_LOG.getName() ); |
| |
| /** The inner Set */ |
| private final E[] set; |
| |
| /** The associated comparator */ |
| private final Comparator<E> comparator; |
| |
| /** The current position in the list */ |
| private int index = -1; |
| |
| /** A limit to what we can print */ |
| private static final int MAX_PRINTED_ELEMENT = 100; |
| |
| |
| /** |
| * Creates a new SetCursor. |
| * |
| * As with all Cursors, this SetCursor requires a successful return from |
| * advance operations (next() or previous()) to properly return values |
| * using the get() operation. |
| * |
| * @param comparator an optional comparator to use for ordering |
| * @param set the Set this StCursor operates on |
| */ |
| @SuppressWarnings("unchecked") |
| public SetCursor( Comparator<E> comparator, Set<E> set ) |
| { |
| if ( set == null ) |
| { |
| set = Collections.EMPTY_SET; |
| } |
| |
| if ( LOG_CURSOR.isDebugEnabled() ) |
| { |
| LOG_CURSOR.debug( I18n.msg( I18n.MSG_13105_CREATING_SET_CURSOR, this ) ); |
| } |
| |
| this.comparator = comparator; |
| this.set = ( E[] ) set.toArray(); |
| } |
| |
| |
| /** |
| * Creates a new SetCursor |
| * |
| * As with all Cursors, this SetCursor requires a successful return from |
| * advance operations (next() or previous()) to properly return values |
| * using the get() operation. |
| * |
| * @param set the Set this SetCursor operates on |
| */ |
| public SetCursor( Set<E> set ) |
| { |
| this( null, set ); |
| } |
| |
| |
| /** |
| * Creates a new SetCursor without any elements. |
| */ |
| @SuppressWarnings("unchecked") |
| public SetCursor() |
| { |
| this( null, Collections.EMPTY_SET ); |
| } |
| |
| |
| /** |
| * Creates a new SetCursor without any elements. We also provide |
| * a comparator. |
| * |
| * @param comparator The comparator to use for the <E> elements |
| */ |
| @SuppressWarnings("unchecked") |
| public SetCursor( Comparator<E> comparator ) |
| { |
| this( comparator, Collections.EMPTY_SET ); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public boolean available() |
| { |
| return ( index >= 0 ) && ( index < set.length ); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public void before( E element ) throws LdapException, CursorException |
| { |
| checkNotClosed(); |
| |
| if ( comparator == null ) |
| { |
| throw new IllegalStateException(); |
| } |
| |
| // handle some special cases |
| if ( set.length == 0 ) |
| { |
| return; |
| } |
| else if ( set.length == 1 ) |
| { |
| if ( comparator.compare( element, set[0] ) <= 0 ) |
| { |
| beforeFirst(); |
| } |
| else |
| { |
| afterLast(); |
| } |
| } |
| |
| throw new UnsupportedOperationException( I18n.err( I18n.ERR_13108_LIST_MAY_BE_SORTED ) ); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public void after( E element ) throws LdapException, CursorException |
| { |
| checkNotClosed(); |
| |
| if ( comparator == null ) |
| { |
| throw new IllegalStateException(); |
| } |
| |
| // handle some special cases |
| if ( set.length == 0 ) |
| { |
| return; |
| } |
| else if ( set.length == 1 ) |
| { |
| if ( comparator.compare( element, set[0] ) >= 0 ) |
| { |
| afterLast(); |
| } |
| else |
| { |
| beforeFirst(); |
| } |
| } |
| |
| throw new UnsupportedOperationException( I18n.err( I18n.ERR_13108_LIST_MAY_BE_SORTED ) ); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public void beforeFirst() throws LdapException, CursorException |
| { |
| checkNotClosed(); |
| this.index = -1; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public void afterLast() throws LdapException, CursorException |
| { |
| checkNotClosed(); |
| this.index = set.length; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public boolean first() throws LdapException, CursorException |
| { |
| checkNotClosed(); |
| |
| if ( set.length > 0 ) |
| { |
| index = 0; |
| |
| return true; |
| } |
| |
| return false; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public boolean last() throws LdapException, CursorException |
| { |
| checkNotClosed(); |
| |
| if ( set.length > 0 ) |
| { |
| index = set.length - 1; |
| |
| return true; |
| } |
| |
| return false; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public boolean isFirst() |
| { |
| return ( set.length > 0 ) && ( index == 0 ); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public boolean isLast() |
| { |
| return ( set.length > 0 ) && ( index == set.length - 1 ); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public boolean isAfterLast() |
| { |
| return index == set.length; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public boolean isBeforeFirst() |
| { |
| return index == -1; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public boolean previous() throws LdapException, CursorException |
| { |
| checkNotClosed(); |
| |
| // if parked at -1 we cannot go backwards |
| if ( index == -1 ) |
| { |
| return false; |
| } |
| |
| // if the index moved back is still greater than or eq to start then OK |
| if ( index - 1 >= 0 ) |
| { |
| index--; |
| |
| return true; |
| } |
| |
| // if the index currently less than or equal to start we need to park it at -1 and return false |
| if ( index <= 0 ) |
| { |
| index = -1; |
| |
| return false; |
| } |
| |
| if ( set.length <= 0 ) |
| { |
| index = -1; |
| } |
| |
| return false; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public boolean next() throws LdapException, CursorException |
| { |
| checkNotClosed(); |
| |
| // if parked at -1 we advance to the start index and return true |
| if ( ( set.length > 0 ) && ( index == -1 ) ) |
| { |
| index = 0; |
| |
| return true; |
| } |
| |
| // if the index plus one is less than the end then increment and return true |
| if ( ( set.length > 0 ) && ( index + 1 < set.length ) ) |
| { |
| index++; |
| |
| return true; |
| } |
| |
| // if the index plus one is equal to the end then increment and return false |
| if ( ( set.length > 0 ) && ( index + 1 == set.length ) ) |
| { |
| index++; |
| |
| return false; |
| } |
| |
| if ( set.length <= 0 ) |
| { |
| index = set.length; |
| } |
| |
| return false; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public E get() throws CursorException |
| { |
| checkNotClosed(); |
| |
| if ( ( index < 0 ) || ( index >= set.length ) ) |
| { |
| throw new CursorException( I18n.err( I18n.ERR_13109_CURSOR_NOT_POSITIONED ) ); |
| } |
| |
| return set[index]; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public void close() throws IOException |
| { |
| if ( LOG_CURSOR.isDebugEnabled() ) |
| { |
| LOG_CURSOR.debug( I18n.msg( I18n.MSG_13102_CLOSING_SET_CURSOR, this ) ); |
| } |
| |
| super.close(); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public void close( Exception cause ) throws IOException |
| { |
| if ( LOG_CURSOR.isDebugEnabled() ) |
| { |
| LOG_CURSOR.debug( I18n.msg( I18n.MSG_13102_CLOSING_SET_CURSOR, this ) ); |
| } |
| |
| super.close( cause ); |
| } |
| |
| |
| /** |
| * @see Object#toString() |
| */ |
| @Override |
| public String toString( String tabs ) |
| { |
| StringBuilder sb = new StringBuilder(); |
| |
| sb.append( tabs ).append( "SetCursor :\n" ); |
| sb.append( tabs ).append( " Index : " ).append( index ).append( "\n" ); |
| |
| if ( ( set != null ) && ( set.length > 0 ) ) |
| { |
| sb.append( tabs ).append( " Size : " ).append( set.length ).append( "\n" ); |
| |
| // Don't print more than 100 elements... |
| int counter = 0; |
| |
| for ( E e : set ) |
| { |
| sb.append( tabs ).append( " " ).append( e ).append( "\n" ); |
| counter++; |
| |
| if ( counter == MAX_PRINTED_ELEMENT ) |
| { |
| break; |
| } |
| } |
| } |
| |
| return sb.toString(); |
| } |
| |
| |
| /** |
| * @see Object#toString() |
| */ |
| @Override |
| public String toString() |
| { |
| return toString( "" ); |
| } |
| } |