Document


1   package org.enhydra.snapper.api;
2   
3   /**
4   
5    */
6   
7   import java.util.Enumeration  ;
8   import java.util.Iterator  ;
9   import java.util.List  ;
10  import java.util.ArrayList  ;
11  import java.util.Vector  ;
12  
13  
14  /** Documents are the unit of indexing and search.
15   *
16   * A Document is a set of fields.  Each field has a name and a textual value.
17   * A field may be {@link Field#isStored() stored} with the document, in which
18   * case it is returned with search hits on the document.  Thus each document
19   * should typically contain one or more stored fields which uniquely identify
20   * it.
21   *
22   * <p>Note that fields which are <i>not</i> {@link Field#isStored() stored} are
23   * <i>not</i> available in documents retrieved from the index, e.g. with {@link
24   * Hits#doc(int)}, {@link Searcher#doc(int)} or {@link
25   * IndexReader#document(int)}.
26   */
27  
28  public interface Document {
29  
30  
31  
32  
33    /** Sets a boost factor for hits on any field of this document.  This value
34     * will be multiplied into the score of all hits on this document.
35     *
36     * <p>Values are multiplied into the value of {@link Field#getBoost()} of
37     * each field in this document.  Thus, this method in effect sets a default
38     * boost for the fields of this document.
39     *
40     * @see Field#setBoost(float)
41     */
42    public void setBoost(float boost);
43  
44    /** Returns the boost factor for hits on any field of this document.
45     *
46     * <p>The default value is 1.0.
47     *
48     * <p>Note: This value is not stored directly with the document in the index.
49     * Documents returned from {@link IndexReader#document(int)} and
50     * {@link Hits#doc(int)} may thus not have the same value present as when
51     * this document was indexed.
52     *
53     * @see #setBoost(float)
54     */
55    public float getBoost();
56  
57    /**
58     * <p>Adds a field to a document.  Several fields may be added with
59     * the same name.  In this case, if the fields are indexed, their text is
60     * treated as though appended for the purposes of search.</p>
61     * <p> Note that add like the removeField(s) methods only makes sense 
62     * prior to adding a document to an index. These methods cannot
63     * be used to change the content of an existing index! In order to achieve this,
64     * a document has to be deleted from an index and a new changed version of that
65     * document has to be added.</p>
66     */
67    public void add(Field field);
68    
69    /**
70     * <p>Removes field with the specified name from the document.
71     * If multiple fields exist with this name, this method removes the first field that has been added.
72     * If there is no field with the specified name, the document remains unchanged.</p>
73     * <p> Note that the removeField(s) methods like the add method only make sense 
74     * prior to adding a document to an index. These methods cannot
75     * be used to change the content of an existing index! In order to achieve this,
76     * a document has to be deleted from an index and a new changed version of that
77     * document has to be added.</p>
78     */
79    public void removeField(String   name); 
80    
81    /**
82     * <p>Removes all fields with the given name from the document.
83     * If there is no field with the specified name, the document remains unchanged.</p>
84     * <p> Note that the removeField(s) methods like the add method only make sense 
85     * prior to adding a document to an index. These methods cannot
86     * be used to change the content of an existing index! In order to achieve this,
87     * a document has to be deleted from an index and a new changed version of that
88     * document has to be added.</p>
89     */
90    public void removeFields(String   name);
91  
92    /** Returns a field with the given name if any exist in this document, or
93     * null.  If multiple fields exists with this name, this method returns the
94     * first value added.
95     */
96    public Field getField(String   name);
97  
98    /** Returns the string value of the field with the given name if any exist in
99     * this document, or null.  If multiple fields exist with this name, this
100    * method returns the first value added.
101    */
102   public  String   get(String   name);
103 
104   /** Returns an Enumeration of all the fields in a document. */
105   public  Enumeration   fields();
106   /**
107    * Returns an array of {@link Field}s with the given name.
108    * This method can return <code>null</code>.
109    *
110    * @param name the name of the field
111    * @return a <code>Field[]</code> array
112    */
113    public Field[] getFields(String   name);
114 
115   /**
116    * Returns an array of values of the field specified as the method parameter.
117    * This method can return <code>null</code>.
118    *
119    * @param name the name of the field
120    * @return a <code>String[]</code> of field values
121    */
122   public String  [] getValues(String   name);
123 
124   /** Prints the fields of a document for human consumption. */
125   public String   toString();
126 }
127 
128
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