package org.apache.lucene.document;
/**
* Copyright 2004 The Apache Software Foundation
*
* 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.
*/
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
import java.util.ArrayList;
import java.util.Vector;
import org.apache.lucene.index.IndexReader; // for javadoc
import org.apache.lucene.search.Searcher; // for javadoc
import org.apache.lucene.search.Hits; // for javadoc
/** Documents are the unit of indexing and search.
*
* A Document is a set of fields. Each field has a name and a textual value.
* A field may be {@link Field#isStored() stored} with the document, in which
* case it is returned with search hits on the document. Thus each document
* should typically contain one or more stored fields which uniquely identify
* it.
*
* <p>Note that fields which are <i>not</i> {@link Field#isStored() stored} are
* <i>not</i> available in documents retrieved from the index, e.g. with {@link
* Hits#doc(int)}, {@link Searcher#doc(int)} or {@link
* IndexReader#document(int)}.
*/
public final class Document implements java.io.Serializable {
List fields = new Vector();
private float boost = 1.0f;
/** Constructs a new document with no fields. */
public Document() {}
/** Sets a boost factor for hits on any field of this document. This value
* will be multiplied into the score of all hits on this document.
*
* <p>Values are multiplied into the value of {@link Field#getBoost()} of
* each field in this document. Thus, this method in effect sets a default
* boost for the fields of this document.
*
* @see Field#setBoost(float)
*/
public void setBoost(float boost) {
this.boost = boost;
}
/** Returns the boost factor for hits on any field of this document.
*
* <p>The default value is 1.0.
*
* <p>Note: This value is not stored directly with the document in the index.
* Documents returned from {@link IndexReader#document(int)} and
* {@link Hits#doc(int)} may thus not have the same value present as when
* this document was indexed.
*
* @see #setBoost(float)
*/
public float getBoost() {
return boost;
}
/**
* <p>Adds a field to a document. Several fields may be added with
* the same name. In this case, if the fields are indexed, their text is
* treated as though appended for the purposes of search.</p>
* <p> Note that add like the removeField(s) methods only makes sense
* prior to adding a document to an index. These methods cannot
* be used to change the content of an existing index! In order to achieve this,
* a document has to be deleted from an index and a new changed version of that
* document has to be added.</p>
*/
public final void add(Field field) {
fields.add(field);
}
/**
* <p>Removes field with the specified name from the document.
* If multiple fields exist with this name, this method removes the first field that has been added.
* If there is no field with the specified name, the document remains unchanged.</p>
* <p> Note that the removeField(s) methods like the add method only make sense
* prior to adding a document to an index. These methods cannot
* be used to change the content of an existing index! In order to achieve this,
* a document has to be deleted from an index and a new changed version of that
* document has to be added.</p>
*/
public final void removeField(String name) {
Iterator it = fields.iterator();
while (it.hasNext()) {
Field field = (Field)it.next();
if (field.name().equals(name)) {
it.remove();
return;
}
}
}
/**
* <p>Removes all fields with the given name from the document.
* If there is no field with the specified name, the document remains unchanged.</p>
* <p> Note that the removeField(s) methods like the add method only make sense
* prior to adding a document to an index. These methods cannot
* be used to change the content of an existing index! In order to achieve this,
* a document has to be deleted from an index and a new changed version of that
* document has to be added.</p>
*/
public final void removeFields(String name) {
Iterator it = fields.iterator();
while (it.hasNext()) {
Field field = (Field)it.next();
if (field.name().equals(name)) {
it.remove();
}
}
}
/** Returns a field with the given name if any exist in this document, or
* null. If multiple fields exists with this name, this method returns the
* first value added.
*/
public final Field getField(String name) {
for (int i = 0; i < fields.size(); i++) {
Field field = (Field)fields.get(i);
if (field.name().equals(name))
return field;
}
return null;
}
/** Returns the string value of the field with the given name if any exist in
* this document, or null. If multiple fields exist with this name, this
* method returns the first value added.
*/
public final String get(String name) {
Field field = getField(name);
if (field != null)
return field.stringValue();
else
return null;
}
/** Returns an Enumeration of all the fields in a document. */
public final Enumeration fields() {
return ((Vector)fields).elements();
}
/**
* Returns an array of {@link Field}s with the given name.
* This method can return <code>null</code>.
*
* @param name the name of the field
* @return a <code>Field[]</code> array
*/
public final Field[] getFields(String name) {
List result = new ArrayList();
for (int i = 0; i < fields.size(); i++) {
Field field = (Field)fields.get(i);
if (field.name().equals(name)) {
result.add(field);
}
}
if (result.size() == 0)
return null;
return (Field[])result.toArray(new Field[result.size()]);
}
/**
* Returns an array of values of the field specified as the method parameter.
* This method can return <code>null</code>.
*
* @param name the name of the field
* @return a <code>String[]</code> of field values
*/
public final String[] getValues(String name) {
Field[] namedFields = getFields(name);
if (namedFields == null)
return null;
String[] values = new String[namedFields.length];
for (int i = 0; i < namedFields.length; i++) {
values[i] = namedFields[i].stringValue();
}
return values;
}
/** Prints the fields of a document for human consumption. */
public final String toString() {
StringBuffer buffer = new StringBuffer();
buffer.append("Document<");
for (int i = 0; i < fields.size(); i++) {
Field field = (Field)fields.get(i);
buffer.append(field.toString());
if (i != fields.size()-1)
buffer.append(" ");
}
buffer.append(">");
return buffer.toString();
}
}
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