package org.apache.lucene.search;
/**
* 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.
*/
import org.apache.lucene.index.IndexReader;
import java.io.IOException;
/**
* Expert: Maintains caches of term values.
*
* <p>Created: May 19, 2004 11:13:14 AM
*
* @author Tim Jones (Nacimiento Software)
* @since lucene 1.4
* @version $Id: FieldCache.java 472959 2006-11-09 16:21:50Z yonik $
*/
public interface FieldCache {
/** Indicator for StringIndex values in the cache. */
// NOTE: the value assigned to this constant must not be
// the same as any of those in SortField!!
public static final int STRING_INDEX = -1;
/** Expert: Stores term text values and document ordering data. */
public static class StringIndex {
/** All the term values, in natural order. */
public final String[] lookup;
/** For each document, an index into the lookup array. */
public final int[] order;
/** Creates one of these objects */
public StringIndex (int[] values, String[] lookup) {
this.order = values;
this.lookup = lookup;
}
}
/** Interface to parse ints from document fields.
* @see #getInts(IndexReader, String, IntParser)
*/
public interface IntParser {
/** Return an integer representation of this field's value. */
public int parseInt(String string);
}
/** Interface to parse floats from document fields.
* @see #getFloats(IndexReader, String, FloatParser)
*/
public interface FloatParser {
/** Return an float representation of this field's value. */
public float parseFloat(String string);
}
/** Expert: The cache used internally by sorting and range query classes. */
public static FieldCache DEFAULT = new FieldCacheImpl();
/** Checks the internal cache for an appropriate entry, and if none is
* found, reads the terms in <code>field</code> as integers and returns an array
* of size <code>reader.maxDoc()</code> of the value each document
* has in the given field.
* @param reader Used to get field values.
* @param field Which field contains the integers.
* @return The values in the given field for each document.
* @throws IOException If any error occurs.
*/
public int[] getInts (IndexReader reader, String field)
throws IOException;
/** Checks the internal cache for an appropriate entry, and if none is found,
* reads the terms in <code>field</code> as integers and returns an array of
* size <code>reader.maxDoc()</code> of the value each document has in the
* given field.
* @param reader Used to get field values.
* @param field Which field contains the integers.
* @param parser Computes integer for string values.
* @return The values in the given field for each document.
* @throws IOException If any error occurs.
*/
public int[] getInts (IndexReader reader, String field, IntParser parser)
throws IOException;
/** Checks the internal cache for an appropriate entry, and if
* none is found, reads the terms in <code>field</code> as floats and returns an array
* of size <code>reader.maxDoc()</code> of the value each document
* has in the given field.
* @param reader Used to get field values.
* @param field Which field contains the floats.
* @return The values in the given field for each document.
* @throws IOException If any error occurs.
*/
public float[] getFloats (IndexReader reader, String field)
throws IOException;
/** Checks the internal cache for an appropriate entry, and if
* none is found, reads the terms in <code>field</code> as floats and returns an array
* of size <code>reader.maxDoc()</code> of the value each document
* has in the given field.
* @param reader Used to get field values.
* @param field Which field contains the floats.
* @param parser Computes float for string values.
* @return The values in the given field for each document.
* @throws IOException If any error occurs.
*/
public float[] getFloats (IndexReader reader, String field,
FloatParser parser) throws IOException;
/** Checks the internal cache for an appropriate entry, and if none
* is found, reads the term values in <code>field</code> and returns an array
* of size <code>reader.maxDoc()</code> containing the value each document
* has in the given field.
* @param reader Used to get field values.
* @param field Which field contains the strings.
* @return The values in the given field for each document.
* @throws IOException If any error occurs.
*/
public String[] getStrings (IndexReader reader, String field)
throws IOException;
/** Checks the internal cache for an appropriate entry, and if none
* is found reads the term values in <code>field</code> and returns
* an array of them in natural order, along with an array telling
* which element in the term array each document uses.
* @param reader Used to get field values.
* @param field Which field contains the strings.
* @return Array of terms and index into the array for each document.
* @throws IOException If any error occurs.
*/
public StringIndex getStringIndex (IndexReader reader, String field)
throws IOException;
/** Checks the internal cache for an appropriate entry, and if
* none is found reads <code>field</code> to see if it contains integers, floats
* or strings, and then calls one of the other methods in this class to get the
* values. For string values, a StringIndex is returned. After
* calling this method, there is an entry in the cache for both
* type <code>AUTO</code> and the actual found type.
* @param reader Used to get field values.
* @param field Which field contains the values.
* @return int[], float[] or StringIndex.
* @throws IOException If any error occurs.
*/
public Object getAuto (IndexReader reader, String field)
throws IOException;
/** Checks the internal cache for an appropriate entry, and if none
* is found reads the terms out of <code>field</code> and calls the given SortComparator
* to get the sort values. A hit in the cache will happen if <code>reader</code>,
* <code>field</code>, and <code>comparator</code> are the same (using <code>equals()</code>)
* as a previous call to this method.
* @param reader Used to get field values.
* @param field Which field contains the values.
* @param comparator Used to convert terms into something to sort by.
* @return Array of sort objects, one for each document.
* @throws IOException If any error occurs.
*/
public Comparable[] getCustom (IndexReader reader, String field, SortComparator comparator)
throws IOException;
}
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