index.java

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package org.garret.perst;

import java.util.Iterator;

/**
 * Interface of object index.
 * Index is used to provide fast access to the object by key. 
 * Object in the index are stored ordered by key value. 
 * It is possible to select object using exact value of the key or 
 * select set of objects which key belongs to the specified interval 
 * (each boundary can be specified or unspecified and can be inclusive or exclusive)
 * Key should be of scalar, String, java.util.Date or peristent object type.
 */
public interface Index extends GenericIndex { 
    /**
     * Put new object in the index. 
     * @param key object key
     * @param obj object associated with this key. Object can be not yet peristent, in this case
     * its forced to become persistent by assigning OID to it.
     * @return <code>true</code> if object is successfully inserted in the index, 
     * <code>false</code> if index was declared as unique and there is already object with such value
     * of the key in the index. 
     */
    public boolean       put(Key key, IPersistent obj);

    /**
     * Associate new value with the key. If there is already object with such key in the index, 
     * then it will be removed from the index and new value associated with this key.
     * @param key object key
     * @param obj object associated with this key. Object can be not yet peristent, in this case
     * its forced to become persistent by assigning OID to it.
     * @return object previously associated with this key, <code>null</code> if there was no such object
     */
    public IPersistent   set(Key key, IPersistent obj);

    /**
     * Remove object with specified key from the index
     * @param key value of the key of removed object
     * @param obj object removed from the index
     * @exception StorageError(StorageError.KEY_NOT_FOUND) exception if there is no such key in the index
     */
    public void          remove(Key key, IPersistent obj);

    /**
     * Remove key from the unique index.
     * @param key value of removed key
     * @return removed object
     * @exception StorageError(StorageError.KEY_NOT_FOUND) exception if there is no such key in the index,
     * or StorageError(StorageError.KEY_NOT_UNIQUE) if index is not unique.
     */
    public IPersistent   remove(Key key);


    /**
     * Put new object in the string index. 
     * @param key string key
     * @param obj object associated with this key. Object can be not yet peristent, in this case
     * its forced to become persistent by assigning OID to it.
     * @return <code>true</code> if object is successfully inserted in the index, 
     * <code>false</code> if index was declared as unique and there is already object with such value
     * of the key in the index. 
     */
    public boolean       put(String key, IPersistent obj);

    /**
     * Associate new value with string key. If there is already object with such key in the index, 
     * then it will be removed from the index and new value associated with this key.
     * @param key string key
     * @param obj object associated with this key. Object can be not yet peristent, in this case
     * its forced to become persistent by assigning OID to it.
     * @return object previously associated with this key, <code>null</code> if there was no such object
     */
    public IPersistent   set(String key, IPersistent obj);

    /**
     * Remove object with specified string key from the index
     * @param key value of the key of removed object
     * @param obj object removed from the index
     * @exception StorageError(StorageError.KEY_NOT_FOUND) exception if there is no such key in the index
     */
    public void          remove(String key, IPersistent obj);

    /**
     * Remove key from the unique string index.
     * @param key value of removed key
     * @return removed object
     * @exception StorageError(StorageError.KEY_NOT_FOUND) exception if there is no such key in the index,
     * or StorageError(StorageError.KEY_NOT_UNIQUE) if index is not unique.
     */
    public IPersistent   remove(String key);
}