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package org.apache.lucene.document;
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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import java.util.*; // for javadoc
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import org.apache.lucene.search.ScoreDoc; // for javadoc
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import org.apache.lucene.search.Searcher; // for javadoc
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import org.apache.lucene.index.IndexReader; // for javadoc
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/** Documents are the unit of indexing and search.
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* A Document is a set of fields. Each field has a name and a textual value.
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* A field may be {@link Fieldable#isStored() stored} with the document, in which
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* case it is returned with search hits on the document. Thus each document
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* should typically contain one or more stored fields which uniquely identify
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* <p>Note that fields which are <i>not</i> {@link Fieldable#isStored() stored} are
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* <i>not</i> available in documents retrieved from the index, e.g. with {@link
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* ScoreDoc#doc}, {@link Searcher#doc(int)} or {@link
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* IndexReader#document(int)}.
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public final class Document implements java.io.Serializable {
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List<Fieldable> fields = new ArrayList<Fieldable>();
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private float boost = 1.0f;
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/** Constructs a new document with no fields. */
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/** Sets a boost factor for hits on any field of this document. This value
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* will be multiplied into the score of all hits on this document.
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* <p>The default value is 1.0.
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* <p>Values are multiplied into the value of {@link Fieldable#getBoost()} of
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* each field in this document. Thus, this method in effect sets a default
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* boost for the fields of this document.
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* @see Fieldable#setBoost(float)
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public void setBoost(float boost) {
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/** Returns, at indexing time, the boost factor as set by {@link #setBoost(float)}.
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* <p>Note that once a document is indexed this value is no longer available
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* from the index. At search time, for retrieved documents, this method always
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* returns 1. This however does not mean that the boost value set at indexing
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* time was ignored - it was just combined with other indexing time factors and
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* stored elsewhere, for better indexing and search performance. (For more
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* information see the "norm(t,d)" part of the scoring formula in
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* {@link org.apache.lucene.search.Similarity Similarity}.)
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* @see #setBoost(float)
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public float getBoost() {
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* <p>Adds a field to a document. Several fields may be added with
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* the same name. In this case, if the fields are indexed, their text is
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* treated as though appended for the purposes of search.</p>
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* <p> Note that add like the removeField(s) methods only makes sense
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* prior to adding a document to an index. These methods cannot
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* be used to change the content of an existing index! In order to achieve this,
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* a document has to be deleted from an index and a new changed version of that
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* document has to be added.</p>
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public final void add(Fieldable field) {
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* <p>Removes field with the specified name from the document.
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* If multiple fields exist with this name, this method removes the first field that has been added.
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* If there is no field with the specified name, the document remains unchanged.</p>
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* <p> Note that the removeField(s) methods like the add method only make sense
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* prior to adding a document to an index. These methods cannot
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* be used to change the content of an existing index! In order to achieve this,
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* a document has to be deleted from an index and a new changed version of that
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* document has to be added.</p>
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public final void removeField(String name) {
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Iterator<Fieldable> it = fields.iterator();
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while (it.hasNext()) {
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Fieldable field = it.next();
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if (field.name().equals(name)) {
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* <p>Removes all fields with the given name from the document.
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* If there is no field with the specified name, the document remains unchanged.</p>
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* <p> Note that the removeField(s) methods like the add method only make sense
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* prior to adding a document to an index. These methods cannot
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* be used to change the content of an existing index! In order to achieve this,
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* a document has to be deleted from an index and a new changed version of that
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* document has to be added.</p>
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public final void removeFields(String name) {
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Iterator<Fieldable> it = fields.iterator();
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while (it.hasNext()) {
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Fieldable field = it.next();
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if (field.name().equals(name)) {
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/** Returns a field with the given name if any exist in this document, or
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* null. If multiple fields exists with this name, this method returns the
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* Do not use this method with lazy loaded fields or {@link NumericField}.
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* @deprecated use {@link #getFieldable} instead and cast depending on
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* @throws ClassCastException if you try to retrieve a numerical or
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public final Field getField(String name) {
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return (Field) getFieldable(name);
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/** Returns a field with the given name if any exist in this document, or
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* null. If multiple fields exists with this name, this method returns the
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public Fieldable getFieldable(String name) {
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for (Fieldable field : fields) {
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if (field.name().equals(name))
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/** Returns the string value of the field with the given name if any exist in
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* this document, or null. If multiple fields exist with this name, this
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* method returns the first value added. If only binary fields with this name
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* exist, returns null.
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* For {@link NumericField} it returns the string value of the number. If you want
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* the actual {@code NumericField} instance back, use {@link #getFieldable}.
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public final String get(String name) {
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for (Fieldable field : fields) {
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if (field.name().equals(name) && (!field.isBinary()))
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return field.stringValue();
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/** Returns a List of all the fields in a document.
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* <p>Note that fields which are <i>not</i> {@link Fieldable#isStored() stored} are
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* <i>not</i> available in documents retrieved from the
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* index, e.g. {@link Searcher#doc(int)} or {@link
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* IndexReader#document(int)}.
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public final List<Fieldable> getFields() {
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private final static Field[] NO_FIELDS = new Field[0];
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* Returns an array of {@link Field}s with the given name.
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* This method returns an empty array when there are no
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* matching fields. It never returns null.
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* Do not use this method with lazy loaded fields or {@link NumericField}.
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* @param name the name of the field
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* @return a <code>Field[]</code> array
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* @deprecated use {@link #getFieldable} instead and cast depending on
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* @throws ClassCastException if you try to retrieve a numerical or
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public final Field[] getFields(String name) {
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List<Field> result = new ArrayList<Field>();
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for (Fieldable field : fields) {
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if (field.name().equals(name)) {
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result.add((Field) field);
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if (result.size() == 0)
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return result.toArray(new Field[result.size()]);
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private final static Fieldable[] NO_FIELDABLES = new Fieldable[0];
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* Returns an array of {@link Fieldable}s with the given name.
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* This method returns an empty array when there are no
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* matching fields. It never returns null.
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* @param name the name of the field
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* @return a <code>Fieldable[]</code> array
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public Fieldable[] getFieldables(String name) {
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List<Fieldable> result = new ArrayList<Fieldable>();
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for (Fieldable field : fields) {
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if (field.name().equals(name)) {
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if (result.size() == 0)
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return NO_FIELDABLES;
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return result.toArray(new Fieldable[result.size()]);
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private final static String[] NO_STRINGS = new String[0];
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* Returns an array of values of the field specified as the method parameter.
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* This method returns an empty array when there are no
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* matching fields. It never returns null.
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* For {@link NumericField}s it returns the string value of the number. If you want
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* the actual {@code NumericField} instances back, use {@link #getFieldables}.
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* @param name the name of the field
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* @return a <code>String[]</code> of field values
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public final String[] getValues(String name) {
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List<String> result = new ArrayList<String>();
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for (Fieldable field : fields) {
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if (field.name().equals(name) && (!field.isBinary()))
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result.add(field.stringValue());
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if (result.size() == 0)
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return result.toArray(new String[result.size()]);
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private final static byte[][] NO_BYTES = new byte[0][];
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* Returns an array of byte arrays for of the fields that have the name specified
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* as the method parameter. This method returns an empty
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* array when there are no matching fields. It never
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* @param name the name of the field
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* @return a <code>byte[][]</code> of binary field values
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public final byte[][] getBinaryValues(String name) {
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List<byte[]> result = new ArrayList<byte[]>();
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for (Fieldable field : fields) {
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if (field.name().equals(name) && (field.isBinary()))
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result.add(field.getBinaryValue());
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if (result.size() == 0)
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return result.toArray(new byte[result.size()][]);
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* Returns an array of bytes for the first (or only) field that has the name
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* specified as the method parameter. This method will return <code>null</code>
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* if no binary fields with the specified name are available.
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* There may be non-binary fields with the same name.
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* @param name the name of the field.
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* @return a <code>byte[]</code> containing the binary field value or <code>null</code>
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public final byte[] getBinaryValue(String name) {
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for (Fieldable field : fields) {
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if (field.name().equals(name) && (field.isBinary()))
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return field.getBinaryValue();
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/** Prints the fields of a document for human consumption. */
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public final String toString() {
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StringBuilder buffer = new StringBuilder();
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buffer.append("Document<");
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for (int i = 0; i < fields.size(); i++) {
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Fieldable field = fields.get(i);
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buffer.append(field.toString());
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if (i != fields.size()-1)
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return buffer.toString();