serialarray.java

Mobile 应用程序使用 Java Micro Edition (Java ME) 平台

/*
 * @(#)SerialArray.java	1.9 04/05/29
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package javax.sql.rowset.serial;

import java.sql.*;
import java.io.*;
import java.util.Map;
import java.net.URL;


/**
 * A serialized version of an <code>Array</code>
 * object, which is the mapping in the Java programming language of an SQL 
 * <code>ARRAY</code> value.
 * <P>
 * The <code>SerialArray</code> class provides a constructor for creating
 * a <code>SerialArray</code> instance from an <code>Array</code> object,
 * methods for getting the base type and the SQL name for the base type, and
 * methods for copying all or part of a <code>SerialArray</code> object.
 * <P>
 * Note: In order for this class to function correctly, a connection to the
 * data source 
 * must be available in order for the SQL <code>Array</code> object to be 
 * materialized (have all of its elements brought to the client server)
 * if necessary. At this time, logical pointers to the data in the data source,
 * such as locators, are not currently supported. 
 */
public class SerialArray implements Array, Serializable, Cloneable {

	/**
	 * A serialized array in which each element is an <code>Object</code>
	 * in the Java programming language that represents an element
	 * in the SQL <code>ARRAY</code> value. 
	 * @serial
	 */
    private Object[] elements;

	/**
	 * The SQL type of the elements in this <code>SerialArray</code> object.  The
	 * type is expressed as one of the constants from the class 
	 * <code>java.sql.Types</code>.
	 * @serial
	 */
    private int baseType;

	/**
	 * The type name used by the DBMS for the elements in the SQL <code>ARRAY</code>
	 * value that this <code>SerialArray</code> object represents. 
	 * @serial
	 */
    private String baseTypeName;

	/**
	 * The number of elements in this <code>SerialArray</code> object, which
	 * is also the number of elements in the SQL <code>ARRAY</code> value
	 * that this <code>SerialArray</code> object represents.
	 * @serial
	 */
    private int len;
    
    /**
     * Constructs a new <code>SerialArray</code> object from the given
     * <code>Array</code> object, using the given type map for the custom
     * mapping of each element when the elements are SQL UDTs.
     * <P>
     * This method does custom mapping if the array elements are a UDT
     * and the given type map has an entry for that UDT.
     * Custom mapping is recursive, 
     * meaning that if, for instance, an element of an SQL structured type
     * is an SQL structured type that itself has an element that is an SQL
     * structured type, each structured type that has a custom mapping will be
     * mapped according to the given type map.
     * <P>
     * The new <code>SerialArray</code>
     * object contains the same elements as the <code>Array</code> object 
     * from which it is built, except when the base type is the SQL type
     * <code>STRUCT</code>, <code>ARRAY</code>, <code>BLOB</code>, 
     * <code>CLOB</code>, <code>DATALINK</code> or <code>JAVA_OBJECT</code>.  
     * In this case, each element in the new 
     * <code>SerialArray</code> object is the appropriate serialized form,
     * that is, a <code>SerialStruct</code>, <code>SerialArray</code>,
     * <code>SerialBlob</code>, <code>SerialClob</code>, 
     * <code>SerialDatalink</code>, or <code>SerialJavaObject</code> object.
     * <P> 
     * Note: (1) The <code>Array</code> object from which a <code>SerialArray</code>
     * object is created must have materialized the SQL <code>ARRAY</code> value's
     * data on the client before it is passed to the constructor.  Otherwise,
     * the new <code>SerialArray</code> object will contain no data.
     * <p>
     * Note: (2) If the <code>Array</code> contains <code>java.sql.Types.JAVA_OBJECT</code>
     * types, the <code>SerialJavaObject</code> constructor is called where checks
     * are made to ensure this object is serializable. 
     * <p>
     * Note: (3) The <code>Array</code> object supplied to this constructor cannot
     * return <code>null</code> for any <code>Array.getArray()</code> methods. 
     * <code>SerialArray</code> cannot serialize null array values.
     * 
     *
     * @param array the <code>Array</code> object to be serialized
     * @param map a <code>java.util.Map</code> object in which
     *        each entry consists of 1) a <code>String</code> object
     *        giving the fully qualified name of a UDT (an SQL structured type or
     *        distinct type) and 2) the
     *        <code>Class</code> object for the <code>SQLData</code> implementation
     *        that defines how the UDT is to be mapped. The <i>map</i> 
     *        parameter does not have any effect for <code>Blob</code>, 
     *        <code>Clob</code>, <code>DATALINK</code>, or 
     *        <code>JAVA_OBJECT</code> types.
     * @throws SerialException if an error occurs serializing the 
     *        <code>Array</code> object
     * @throws SQLException if a database access error occurs or if the 
     *        <i>array</i> or the <i>map</i> values are <code>null</code>
     */
     public SerialArray(Array array, Map<String,Class<?>> map) 
         throws SerialException, SQLException 
     {
         
        if ((array == null) || (map == null)) {
            throw new SQLException("Cannot instantiate a SerialArray " +
            "object with null parameters");
        }   
                 
        if ((elements = (Object[])array.getArray()) == null) {
             throw new SQLException("Invalid Array object. Calls to Array.getArray() " +
                 "return null value which cannot be serialized");
         }

	elements = (Object[])array.getArray(map);
        baseType = array.getBaseType();
        baseTypeName = array.getBaseTypeName();
        len = elements.length;

        switch (baseType) {
            case java.sql.Types.STRUCT: 
                for (int i = 0; i < len; i++) {
                    elements[i] = new SerialStruct((Struct)elements[i], map);
                }
            break;
        
            case java.sql.Types.ARRAY:
                for (int i = 0; i < len; i++) {
                    elements[i] = new SerialArray((Array)elements[i], map);
                }
            break;
        
            case java.sql.Types.BLOB: 
            for (int i = 0; i < len; i++) {
                elements[i] = new SerialBlob((Blob)elements[i]);                
            }
            break;
       
            case java.sql.Types.CLOB: 
                for (int i = 0; i < len; i++) {
                    elements[i] = new SerialClob((Clob)elements[i]);
                }
            break;

            case java.sql.Types.DATALINK:
                for (int i = 0; i < len; i++) {
                    elements[i] = new SerialDatalink((URL)elements[i]);
                }
            break;
            
            case java.sql.Types.JAVA_OBJECT:
                for (int i = 0; i < len; i++) {
    		elements[i] = new SerialJavaObject((Object)elements[i]);
            }
        default:
            ;
        }
  }
     
    /**
     * This method frees the <code>Array</code> object and releases the resources that 
     * it holds. The object is invalid once the <code>free</code>
     * method is called.
     *<p>
     * After <code>free</code> has been called, any attempt to invoke a
     * method other than <code>free</code> will result in a <code>SQLException</code> 
     * being thrown.  If <code>free</code> is called multiple times, the subsequent
     * calls to <code>free</code> are treated as a no-op.
     *<p>
     * 
     * @throws SQLException if an error occurs releasing
     * the Array's resources
     * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
     * this method
     * @since 1.6
     */
    public void free() throws SQLException {
         throw new SQLFeatureNotSupportedException("Feature not supported");
    }   
     
    /**
     * Constructs a new <code>SerialArray</code> object from the given
     * <code>Array</code> object.
     * <P>
     * This constructor does not do custom mapping.  If the base type of the array
     * is an SQL structured type and custom mapping is desired, the constructor
     * <code>SerialArray(Array array, Map map)</code> should be used.
     * <P>
     * The new <code>SerialArray</code>
     * object contains the same elements as the <code>Array</code> object 
     * from which it is built, except when the base type is the SQL type
     * <code>BLOB</code>, 
     * <code>CLOB</code>, <code>DATALINK</code> or <code>JAVA_OBJECT</code>.  
     * In this case, each element in the new 
     * <code>SerialArray</code> object is the appropriate serialized form,
     * that is, a <code>SerialBlob</code>, <code>SerialClob</code>,
     * <code>SerialDatalink</code>, or <code>SerialJavaObject</code> object.
     * <P> 
     * Note: (1) The <code>Array</code> object from which a <code>SerialArray</code>
     * object is created must have materialized the SQL <code>ARRAY</code> value's
     * data on the client before it is passed to the constructor.  Otherwise,
     * the new <code>SerialArray</code> object will contain no data.
     * <p>
     * Note: (2) The <code>Array</code> object supplied to this constructor cannot
     * return <code>null</code> for any <code>Array.getArray()</code> methods. 
     * <code>SerialArray</code> cannot serialize <code>null</code> array values.
     *
     * @param array the <code>Array</code> object to be serialized
     * @throws SerialException if an error occurs serializing the 
     *     <code>Array</code> object
     * @throws SQLException if a database access error occurs or the 
     *     <i>array</i> parameter is <code>null</code>.         
     */
     public SerialArray(Array array) throws SerialException, SQLException {
         if (array == null) {
             throw new SQLException("Cannot instantiate a SerialArray " +
                 "object with a null Array object");
         }                             
         
         if ((elements = (Object[])array.getArray()) == null) {
             throw new SQLException("Invalid Array object. Calls to Array.getArray() " +
                 "return null value which cannot be serialized");
         }
         
         //elements = (Object[])array.getArray();
         baseType = array.getBaseType();
         baseTypeName = array.getBaseTypeName();
         len = elements.length;

        switch (baseType) {

        case java.sql.Types.BLOB: 
            for (int i = 0; i < len; i++) {
                elements[i] = new SerialBlob((Blob)elements[i]);
            }
            break;
            
        case java.sql.Types.CLOB: 
            for (int i = 0; i < len; i++) {
                elements[i] = new SerialClob((Clob)elements[i]);
            }