--- /dev/null
+package org.apache.lucene.document;
+
+/**
+ * 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 java.io.Reader;
+
+import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.NumericTokenStream;
+import org.apache.lucene.index.FieldInfo.IndexOptions;
+import org.apache.lucene.util.NumericUtils;
+import org.apache.lucene.search.NumericRangeQuery; // javadocs
+import org.apache.lucene.search.NumericRangeFilter; // javadocs
+import org.apache.lucene.search.SortField; // javadocs
+import org.apache.lucene.search.FieldCache; // javadocs
+
+/**
+ * <p>This class provides a {@link Field} that enables indexing
+ * of numeric values for efficient range filtering and
+ * sorting. Here's an example usage, adding an int value:
+ * <pre>
+ * document.add(new NumericField(name).setIntValue(value));
+ * </pre>
+ *
+ * For optimal performance, re-use the
+ * <code>NumericField</code> and {@link Document} instance for more than
+ * one document:
+ *
+ * <pre>
+ * NumericField field = new NumericField(name);
+ * Document document = new Document();
+ * document.add(field);
+ *
+ * for(all documents) {
+ * ...
+ * field.setIntValue(value)
+ * writer.addDocument(document);
+ * ...
+ * }
+ * </pre>
+ *
+ * <p>The java native types <code>int</code>, <code>long</code>,
+ * <code>float</code> and <code>double</code> are
+ * directly supported. However, any value that can be
+ * converted into these native types can also be indexed.
+ * For example, date/time values represented by a
+ * {@link java.util.Date} can be translated into a long
+ * value using the {@link java.util.Date#getTime} method. If you
+ * don't need millisecond precision, you can quantize the
+ * value, either by dividing the result of
+ * {@link java.util.Date#getTime} or using the separate getters
+ * (for year, month, etc.) to construct an <code>int</code> or
+ * <code>long</code> value.</p>
+ *
+ * <p>To perform range querying or filtering against a
+ * <code>NumericField</code>, use {@link NumericRangeQuery} or {@link
+ * NumericRangeFilter}. To sort according to a
+ * <code>NumericField</code>, use the normal numeric sort types, eg
+ * {@link SortField#INT}. <code>NumericField</code> values
+ * can also be loaded directly from {@link FieldCache}.</p>
+ *
+ * <p>By default, a <code>NumericField</code>'s value is not stored but
+ * is indexed for range filtering and sorting. You can use
+ * the {@link #NumericField(String,Field.Store,boolean)}
+ * constructor if you need to change these defaults.</p>
+ *
+ * <p>You may add the same field name as a <code>NumericField</code> to
+ * the same document more than once. Range querying and
+ * filtering will be the logical OR of all values; so a range query
+ * will hit all documents that have at least one value in
+ * the range. However sort behavior is not defined. If you need to sort,
+ * you should separately index a single-valued <code>NumericField</code>.</p>
+ *
+ * <p>A <code>NumericField</code> will consume somewhat more disk space
+ * in the index than an ordinary single-valued field.
+ * However, for a typical index that includes substantial
+ * textual content per document, this increase will likely
+ * be in the noise. </p>
+ *
+ * <p>Within Lucene, each numeric value is indexed as a
+ * <em>trie</em> structure, where each term is logically
+ * assigned to larger and larger pre-defined brackets (which
+ * are simply lower-precision representations of the value).
+ * The step size between each successive bracket is called the
+ * <code>precisionStep</code>, measured in bits. Smaller
+ * <code>precisionStep</code> values result in larger number
+ * of brackets, which consumes more disk space in the index
+ * but may result in faster range search performance. The
+ * default value, 4, was selected for a reasonable tradeoff
+ * of disk space consumption versus performance. You can
+ * use the expert constructor {@link
+ * #NumericField(String,int,Field.Store,boolean)} if you'd
+ * like to change the value. Note that you must also
+ * specify a congruent value when creating {@link
+ * NumericRangeQuery} or {@link NumericRangeFilter}.
+ * For low cardinality fields larger precision steps are good.
+ * If the cardinality is < 100, it is fair
+ * to use {@link Integer#MAX_VALUE}, which produces one
+ * term per value.
+ *
+ * <p>For more information on the internals of numeric trie
+ * indexing, including the <a
+ * href="../search/NumericRangeQuery.html#precisionStepDesc"><code>precisionStep</code></a>
+ * configuration, see {@link NumericRangeQuery}. The format of
+ * indexed values is described in {@link NumericUtils}.
+ *
+ * <p>If you only need to sort by numeric value, and never
+ * run range querying/filtering, you can index using a
+ * <code>precisionStep</code> of {@link Integer#MAX_VALUE}.
+ * This will minimize disk space consumed. </p>
+ *
+ * <p>More advanced users can instead use {@link
+ * NumericTokenStream} directly, when indexing numbers. This
+ * class is a wrapper around this token stream type for
+ * easier, more intuitive usage.</p>
+ *
+ * @since 2.9
+ */
+public final class NumericField extends AbstractField {
+
+ /** Data type of the value in {@link NumericField}.
+ * @since 3.2
+ */
+ public static enum DataType { INT, LONG, FLOAT, DOUBLE }
+
+ private transient NumericTokenStream numericTS;
+ private DataType type;
+ private final int precisionStep;
+
+ /**
+ * Creates a field for numeric values using the default <code>precisionStep</code>
+ * {@link NumericUtils#PRECISION_STEP_DEFAULT} (4). The instance is not yet initialized with
+ * a numeric value, before indexing a document containing this field,
+ * set a value using the various set<em>???</em>Value() methods.
+ * This constructor creates an indexed, but not stored field.
+ * @param name the field name
+ */
+ public NumericField(String name) {
+ this(name, NumericUtils.PRECISION_STEP_DEFAULT, Field.Store.NO, true);
+ }
+
+ /**
+ * Creates a field for numeric values using the default <code>precisionStep</code>
+ * {@link NumericUtils#PRECISION_STEP_DEFAULT} (4). The instance is not yet initialized with
+ * a numeric value, before indexing a document containing this field,
+ * set a value using the various set<em>???</em>Value() methods.
+ * @param name the field name
+ * @param store if the field should be stored, {@link Document#getFieldable}
+ * then returns {@code NumericField} instances on search results.
+ * @param index if the field should be indexed using {@link NumericTokenStream}
+ */
+ public NumericField(String name, Field.Store store, boolean index) {
+ this(name, NumericUtils.PRECISION_STEP_DEFAULT, store, index);
+ }
+
+ /**
+ * Creates a field for numeric values with the specified
+ * <code>precisionStep</code>. The instance is not yet initialized with
+ * a numeric value, before indexing a document containing this field,
+ * set a value using the various set<em>???</em>Value() methods.
+ * This constructor creates an indexed, but not stored field.
+ * @param name the field name
+ * @param precisionStep the used <a href="../search/NumericRangeQuery.html#precisionStepDesc">precision step</a>
+ */
+ public NumericField(String name, int precisionStep) {
+ this(name, precisionStep, Field.Store.NO, true);
+ }
+
+ /**
+ * Creates a field for numeric values with the specified
+ * <code>precisionStep</code>. The instance is not yet initialized with
+ * a numeric value, before indexing a document containing this field,
+ * set a value using the various set<em>???</em>Value() methods.
+ * @param name the field name
+ * @param precisionStep the used <a href="../search/NumericRangeQuery.html#precisionStepDesc">precision step</a>
+ * @param store if the field should be stored, {@link Document#getFieldable}
+ * then returns {@code NumericField} instances on search results.
+ * @param index if the field should be indexed using {@link NumericTokenStream}
+ */
+ public NumericField(String name, int precisionStep, Field.Store store, boolean index) {
+ super(name, store, index ? Field.Index.ANALYZED_NO_NORMS : Field.Index.NO, Field.TermVector.NO);
+ this.precisionStep = precisionStep;
+ setIndexOptions(IndexOptions.DOCS_ONLY);
+ }
+
+ /** Returns a {@link NumericTokenStream} for indexing the numeric value. */
+ public TokenStream tokenStreamValue() {
+ if (!isIndexed())
+ return null;
+ if (numericTS == null) {
+ // lazy init the TokenStream as it is heavy to instantiate (attributes,...),
+ // if not needed (stored field loading)
+ numericTS = new NumericTokenStream(precisionStep);
+ // initialize value in TokenStream
+ if (fieldsData != null) {
+ assert type != null;
+ final Number val = (Number) fieldsData;
+ switch (type) {
+ case INT:
+ numericTS.setIntValue(val.intValue()); break;
+ case LONG:
+ numericTS.setLongValue(val.longValue()); break;
+ case FLOAT:
+ numericTS.setFloatValue(val.floatValue()); break;
+ case DOUBLE:
+ numericTS.setDoubleValue(val.doubleValue()); break;
+ default:
+ assert false : "Should never get here";
+ }
+ }
+ }
+ return numericTS;
+ }
+
+ /** Returns always <code>null</code> for numeric fields */
+ @Override
+ public byte[] getBinaryValue(byte[] result){
+ return null;
+ }
+
+ /** Returns always <code>null</code> for numeric fields */
+ public Reader readerValue() {
+ return null;
+ }
+
+ /** Returns the numeric value as a string. This format is also returned if you call {@link Document#get(String)}
+ * on search results. It is recommended to use {@link Document#getFieldable} instead
+ * that returns {@code NumericField} instances. You can then use {@link #getNumericValue}
+ * to return the stored value. */
+ public String stringValue() {
+ return (fieldsData == null) ? null : fieldsData.toString();
+ }
+
+ /** Returns the current numeric value as a subclass of {@link Number}, <code>null</code> if not yet initialized. */
+ public Number getNumericValue() {
+ return (Number) fieldsData;
+ }
+
+ /** Returns the precision step. */
+ public int getPrecisionStep() {
+ return precisionStep;
+ }
+
+ /** Returns the data type of the current value, {@code null} if not yet set.
+ * @since 3.2
+ */
+ public DataType getDataType() {
+ return type;
+ }
+
+ /**
+ * Initializes the field with the supplied <code>long</code> value.
+ * @param value the numeric value
+ * @return this instance, because of this you can use it the following way:
+ * <code>document.add(new NumericField(name, precisionStep).setLongValue(value))</code>
+ */
+ public NumericField setLongValue(final long value) {
+ if (numericTS != null) numericTS.setLongValue(value);
+ fieldsData = Long.valueOf(value);
+ type = DataType.LONG;
+ return this;
+ }
+
+ /**
+ * Initializes the field with the supplied <code>int</code> value.
+ * @param value the numeric value
+ * @return this instance, because of this you can use it the following way:
+ * <code>document.add(new NumericField(name, precisionStep).setIntValue(value))</code>
+ */
+ public NumericField setIntValue(final int value) {
+ if (numericTS != null) numericTS.setIntValue(value);
+ fieldsData = Integer.valueOf(value);
+ type = DataType.INT;
+ return this;
+ }
+
+ /**
+ * Initializes the field with the supplied <code>double</code> value.
+ * @param value the numeric value
+ * @return this instance, because of this you can use it the following way:
+ * <code>document.add(new NumericField(name, precisionStep).setDoubleValue(value))</code>
+ */
+ public NumericField setDoubleValue(final double value) {
+ if (numericTS != null) numericTS.setDoubleValue(value);
+ fieldsData = Double.valueOf(value);
+ type = DataType.DOUBLE;
+ return this;
+ }
+
+ /**
+ * Initializes the field with the supplied <code>float</code> value.
+ * @param value the numeric value
+ * @return this instance, because of this you can use it the following way:
+ * <code>document.add(new NumericField(name, precisionStep).setFloatValue(value))</code>
+ */
+ public NumericField setFloatValue(final float value) {
+ if (numericTS != null) numericTS.setFloatValue(value);
+ fieldsData = Float.valueOf(value);
+ type = DataType.FLOAT;
+ return this;
+ }
+
+}
fnp / pylucene.git / blobdiff