/*

 * Copyright (c) 2003, 2014, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package javax.sql.rowset.serial;

import java.sql.*;

import java.util.Arrays;

import java.util.Map;

import sun.reflect.misc.ReflectUtil;

/**

 * An input stream used for custom mapping user-defined types (UDTs).

 * An <code>SQLInputImpl</code> object is an input stream that contains a

 * stream of values that are the attributes of a UDT.

 * <p>

 * This class is used by the driver behind the scenes when the method

 * <code>getObject</code> is called on an SQL structured or distinct type

 * that has a custom mapping; a programmer never invokes

 * <code>SQLInputImpl</code> methods directly. They are provided here as a

 * convenience for those who write <code>RowSet</code> implementations.

 * <P>

 * The <code>SQLInputImpl</code> class provides a set of

 * reader methods analogous to the <code>ResultSet</code> getter

 * methods.  These methods make it possible to read the values in an

 * <code>SQLInputImpl</code> object.

 * <P>

 * The method <code>wasNull</code> is used to determine whether the

 * the last value read was SQL <code>NULL</code>.

 * <P>When the method <code>getObject</code> is called with an

 * object of a class implementing the interface <code>SQLData</code>,

 * the JDBC driver calls the method <code>SQLData.getSQLType</code>

 * to determine the SQL type of the UDT being custom mapped. The driver

 * creates an instance of <code>SQLInputImpl</code>, populating it with the

 * attributes of the UDT.  The driver then passes the input

 * stream to the method <code>SQLData.readSQL</code>, which in turn

 * calls the <code>SQLInputImpl</code> reader methods

 * to read the attributes from the input stream.

 * @since 1.5

 * @see java.sql.SQLData

 */

public class SQLInputImpl implements SQLInput {

    /**

     * <code>true</code> if the last value returned was <code>SQL NULL</code>;

     * <code>false</code> otherwise.

     */

    private boolean lastValueWasNull;

    /**

     * The current index into the array of SQL structured type attributes

     * that will be read from this <code>SQLInputImpl</code> object and

     * mapped to the fields of a class in the Java programming language.

     */

    private int idx;

    /**

     * The array of attributes to be read from this stream.  The order

     * of the attributes is the same as the order in which they were

     * listed in the SQL definition of the UDT.

     */

    private Object attrib[];

    /**

     * The type map to use when the method <code>readObject</code>

     * is invoked. This is a <code>java.util.Map</code> object in which

     * there may be zero or more entries.  Each entry consists of the

     * fully qualified name of a UDT (the value to be mapped) and the

     * <code>Class</code> object for a class that implements

     * <code>SQLData</code> (the Java class that defines how the UDT

     * will be mapped).

     */

    private Map<String,Class<?>> map;

    /**

     * Creates an <code>SQLInputImpl</code> object initialized with the

     * given array of attributes and the given type map. If any of the

     * attributes is a UDT whose name is in an entry in the type map,

     * the attribute will be mapped according to the corresponding

     * <code>SQLData</code> implementation.

     *

     * @param attributes an array of <code>Object</code> instances in which

     *        each element is an attribute of a UDT. The order of the

     *        attributes in the array is the same order in which

     *        the attributes were defined in the UDT definition.

     * @param map a <code>java.util.Map</code> object containing zero or more

     *        entries, with each entry consisting of 1) a <code>String</code>

     *        giving the fully

     *        qualified name of the UDT and 2) the <code>Class</code> object

     *        for the <code>SQLData</code> implementation that defines how

     *        the UDT is to be mapped

     * @throws SQLException if the <code>attributes</code> or the <code>map</code>

     *        is a <code>null</code> value

     */

    public SQLInputImpl(Object[] attributes, Map<String,Class<?>> map)

        throws SQLException

    {

        if ((attributes == null) || (map == null)) {

            throw new SQLException("Cannot instantiate a SQLInputImpl " +

            "object with null parameters");

        }

        // assign our local reference to the attribute stream

        attrib = Arrays.copyOf(attributes, attributes.length);

        // init the index point before the head of the stream

        idx = -1;

        // set the map

        this.map = map;

    }

    /**

     * Retrieves the next attribute in this <code>SQLInputImpl</code> object

     * as an <code>Object</code> in the Java programming language.

     *

     * @return the next value in the input stream

     *         as an <code>Object</code> in the Java programming language

     * @throws SQLException if the read position is located at an invalid

     *         position or if there are no further values in the stream

     */

    private Object getNextAttribute() throws SQLException {

        if (++idx >= attrib.length) {

            throw new SQLException("SQLInputImpl exception: Invalid read " +

                                   "position");

        } else {

            lastValueWasNull = attrib[idx] == null;

            return attrib[idx];

        }

    }

    //================================================================

    // Methods for reading attributes from the stream of SQL data.

    // These methods correspond to the column-accessor methods of

    // java.sql.ResultSet.

    //================================================================

    /**

     * Retrieves the next attribute in this <code>SQLInputImpl</code> object as

     * a <code>String</code> in the Java programming language.

     * <p>

     * This method does not perform type-safe checking to determine if the

     * returned type is the expected type; this responsibility is delegated

     * to the UDT mapping as defined by a <code>SQLData</code>

     * implementation.

     *

     * @return the next attribute in this <code>SQLInputImpl</code> object;

     *     if the value is <code>SQL NULL</code>, return <code>null</code>

     * @throws SQLException if the read position is located at an invalid

     *     position or if there are no further values in the stream.

     */

    public String readString() throws SQLException {

        return  (String)getNextAttribute();

    }

    /**

     * Retrieves the next attribute in this <code>SQLInputImpl</code> object as

     * a <code>boolean</code> in the Java programming language.

     * <p>

     * This method does not perform type-safe checking to determine if the

     * returned type is the expected type; this responsibility is delegated

     * to the UDT mapping as defined by a <code>SQLData</code>

     * implementation.

     *

     * @return the next attribute in this <code>SQLInputImpl</code> object;

     *     if the value is <code>SQL NULL</code>, return <code>null</code>

     * @throws SQLException if the read position is located at an invalid

     *     position or if there are no further values in the stream.

     */

    public boolean readBoolean() throws SQLException {

        Boolean attrib = (Boolean)getNextAttribute();

        return  (attrib == null) ? false : attrib.booleanValue();

    }

    /**

     * Retrieves the next attribute in this <code>SQLInputImpl</code> object as

     * a <code>byte</code> in the Java programming language.

     * <p>

     * This method does not perform type-safe checking to determine if the

     * returned type is the expected type; this responsibility is delegated

     * to the UDT mapping as defined by a <code>SQLData</code>

     * implementation.

     *

     * @return the next attribute in this <code>SQLInputImpl</code> object;

     *     if the value is <code>SQL NULL</code>, return <code>null</code>

     * @throws SQLException if the read position is located at an invalid

     *     position or if there are no further values in the stream

     */

    public byte readByte() throws SQLException {

        Byte attrib = (Byte)getNextAttribute();

        return  (attrib == null) ? 0 : attrib.byteValue();

    }

    /**

     * Retrieves the next attribute in this <code>SQLInputImpl</code> object

     * as a <code>short</code> in the Java programming language.

     * <P>

     * This method does not perform type-safe checking to determine if the

     * returned type is the expected type; this responsibility is delegated

     * to the UDT mapping as defined by a <code>SQLData</code> implementation.

     *

     * @return the next attribute in this <code>SQLInputImpl</code> object;

     *       if the value is <code>SQL NULL</code>, return <code>null</code>

     * @throws SQLException if the read position is located at an invalid

     *       position or if there are no more values in the stream

     */

    public short readShort() throws SQLException {

        Short attrib = (Short)getNextAttribute();

        return (attrib == null) ? 0 : attrib.shortValue();

    }

    /**

     * Retrieves the next attribute in this <code>SQLInputImpl</code> object

     * as an <code>int</code> in the Java programming language.

     * <P>

     * This method does not perform type-safe checking to determine if the

     * returned type is the expected type; this responsibility is delegated

     * to the UDT mapping as defined by a <code>SQLData</code> implementation.

     *

     * @return the next attribute in this <code>SQLInputImpl</code> object;

     *       if the value is <code>SQL NULL</code>, return <code>null</code>

     * @throws SQLException if the read position is located at an invalid

     *       position or if there are no more values in the stream

     */

    public int readInt() throws SQLException {

        Integer attrib = (Integer)getNextAttribute();

        return (attrib == null) ? 0 : attrib.intValue();

    }

    /**

     * Retrieves the next attribute in this <code>SQLInputImpl</code> object

     * as a <code>long</code> in the Java programming language.

     * <P>

     * This method does not perform type-safe checking to determine if the

     * returned type is the expected type; this responsibility is delegated

     * to the UDT mapping as defined by a <code>SQLData</code> implementation.

     *

     * @return the next attribute in this <code>SQLInputImpl</code> object;

     *       if the value is <code>SQL NULL</code>, return <code>null</code>

     * @throws SQLException if the read position is located at an invalid

     *       position or if there are no more values in the stream

     */

    public long readLong() throws SQLException {

        Long attrib = (Long)getNextAttribute();

        return (attrib == null) ? 0 : attrib.longValue();

    }

    /**

     * Retrieves the next attribute in this <code>SQLInputImpl</code> object

     * as a <code>float</code> in the Java programming language.

     * <P>

     * This method does not perform type-safe checking to determine if the

     * returned type is the expected type; this responsibility is delegated

     * to the UDT mapping as defined by a <code>SQLData</code> implementation.

     *

     * @return the next attribute in this <code>SQLInputImpl</code> object;

     *       if the value is <code>SQL NULL</code>, return <code>null</code>

     * @throws SQLException if the read position is located at an invalid

     *       position or if there are no more values in the stream

     */

    public float readFloat() throws SQLException {

        Float attrib = (Float)getNextAttribute();

        return (attrib == null) ? 0 : attrib.floatValue();

    }

    /**

     * Retrieves the next attribute in this <code>SQLInputImpl</code> object

     * as a <code>double</code> in the Java programming language.

     * <P>

     * This method does not perform type-safe checking to determine if the

     * returned type is the expected type; this responsibility is delegated

     * to the UDT mapping as defined by a <code>SQLData</code> implementation.

     *

     * @return the next attribute in this <code>SQLInputImpl</code> object;

     *       if the value is <code>SQL NULL</code>, return <code>null</code>

     * @throws SQLException if the read position is located at an invalid

     *       position or if there are no more values in the stream

     */

    public double readDouble() throws SQLException {

        Double attrib = (Double)getNextAttribute();

        return (attrib == null)  ? 0 :  attrib.doubleValue();

    }

    /**

     * Retrieves the next attribute in this <code>SQLInputImpl</code> object

     * as a <code>java.math.BigDecimal</code>.

     * <P>

     * This method does not perform type-safe checking to determine if the

     * returned type is the expected type; this responsibility is delegated

     * to the UDT mapping as defined by a <code>SQLData</code> implementation.

     *

     * @return the next attribute in this <code>SQLInputImpl</code> object;

     *       if the value is <code>SQL NULL</code>, return <code>null</code>

     * @throws SQLException if the read position is located at an invalid

     *       position or if there are no more values in the stream

     */

    public java.math.BigDecimal readBigDecimal() throws SQLException {

        return (java.math.BigDecimal)getNextAttribute();

    }

    /**

     * Retrieves the next attribute in this <code>SQLInputImpl</code> object

     * as an array of bytes.

     * <p>

     * This method does not perform type-safe checking to determine if the

     * returned type is the expected type; this responsibility is delegated

     * to the UDT mapping as defined by a <code>SQLData</code> implementation.

     *

     * @return the next attribute in this <code>SQLInputImpl</code> object;

     *       if the value is <code>SQL NULL</code>, return <code>null</code>

     * @throws SQLException if the read position is located at an invalid

     *       position or if there are no more values in the stream

     */

    public byte[] readBytes() throws SQLException {

        return (byte[])getNextAttribute();

    }

    /**

     * Retrieves the next attribute in this <code>SQLInputImpl</code> as

     * a <code>java.sql.Date</code> object.

     * <P>

     * This method does not perform type-safe checking to determine if the

     * returned type is the expected type; this responsibility is delegated

     * to the UDT mapping as defined by a <code>SQLData</code> implementation.

     *

     * @return the next attribute in this <code>SQLInputImpl</code> object;

     *       if the value is <code>SQL NULL</code>, return <code>null</code>

     * @throws SQLException if the read position is located at an invalid

     *       position or if there are no more values in the stream

     */

    public java.sql.Date readDate() throws SQLException {

        return (java.sql.Date)getNextAttribute();

    }

    /**

     * Retrieves the next attribute in this <code>SQLInputImpl</code> object as

     * a <code>java.sql.Time</code> object.

     * <P>

     * This method does not perform type-safe checking to determine if the

     * returned type is the expected type as this responsibility is delegated

     * to the UDT mapping as implemented by a <code>SQLData</code>

     * implementation.

     *

     * @return the attribute; if the value is <code>SQL NULL</code>, return

     * <code>null</code>

     * @throws SQLException if the read position is located at an invalid

     * position; or if there are no further values in the stream.

     */

    public java.sql.Time readTime() throws SQLException {

        return (java.sql.Time)getNextAttribute();

    }

    /**

     * Retrieves the next attribute in this <code>SQLInputImpl</code> object as

     * a <code>java.sql.Timestamp</code> object.

     *

     * @return the attribute; if the value is <code>SQL NULL</code>, return

     * <code>null</code>

     * @throws SQLException if the read position is located at an invalid

     * position; or if there are no further values in the stream.

     */

    public java.sql.Timestamp readTimestamp() throws SQLException {

        return (java.sql.Timestamp)getNextAttribute();

    }

    /**

     * Retrieves the next attribute in this <code>SQLInputImpl</code> object

     * as a stream of Unicode characters.

     * <P>

     * This method does not perform type-safe checking to determine if the

     * returned type is the expected type as this responsibility is delegated

     * to the UDT mapping as implemented by a <code>SQLData</code>

     * implementation.

     *

     * @return the attribute; if the value is <code>SQL NULL</code>, return <code>null</code>

     * @throws SQLException if the read position is located at an invalid

     * position; or if there are no further values in the stream.

     */

    public java.io.Reader readCharacterStream() throws SQLException {

        return (java.io.Reader)getNextAttribute();

    }

    /**

     * Returns the next attribute in this <code>SQLInputImpl</code> object

     * as a stream of ASCII characters.

     * <P>

     * This method does not perform type-safe checking to determine if the

     * returned type is the expected type as this responsibility is delegated

     * to the UDT mapping as implemented by a <code>SQLData</code>

     * implementation.

     *

     * @return the attribute; if the value is <code>SQL NULL</code>,

     * return <code>null</code>

     * @throws SQLException if the read position is located at an invalid

     * position; or if there are no further values in the stream.

     */

    public java.io.InputStream readAsciiStream() throws SQLException {

        return (java.io.InputStream)getNextAttribute();

    }

    /**

     * Returns the next attribute in this <code>SQLInputImpl</code> object

     * as a stream of uninterpreted bytes.

     * <P>

     * This method does not perform type-safe checking to determine if the

     * returned type is the expected type as this responsibility is delegated

     * to the UDT mapping as implemented by a <code>SQLData</code>

     * implementation.

     *

     * @return the attribute; if the value is <code>SQL NULL</code>, return

     * <code>null</code>

     * @throws SQLException if the read position is located at an invalid

     * position; or if there are no further values in the stream.

     */

    public java.io.InputStream readBinaryStream() throws SQLException {

        return (java.io.InputStream)getNextAttribute();

    }

    //================================================================

    // Methods for reading items of SQL user-defined types from the stream.

    //================================================================

    /**

     * Retrieves the value at the head of this <code>SQLInputImpl</code>

     * object as an <code>Object</code> in the Java programming language.  The

     * actual type of the object returned is determined by the default

     * mapping of SQL types to types in the Java programming language unless

     * there is a custom mapping, in which case the type of the object

     * returned is determined by this stream's type map.

     * <P>

     * The JDBC technology-enabled driver registers a type map with the stream

     * before passing the stream to the application.

     * <P>

     * When the datum at the head of the stream is an SQL <code>NULL</code>,

     * this method returns <code>null</code>.  If the datum is an SQL

     * structured or distinct type with a custom mapping, this method

     * determines the SQL type of the datum at the head of the stream,

     * constructs an object of the appropriate class, and calls the method

     * <code>SQLData.readSQL</code> on that object. The <code>readSQL</code>

     * method then calls the appropriate <code>SQLInputImpl.readXXX</code>

     * methods to retrieve the attribute values from the stream.

     *

     * @return the value at the head of the stream as an <code>Object</code>

     *         in the Java programming language; <code>null</code> if

     *         the value is SQL <code>NULL</code>

     * @throws SQLException if the read position is located at an invalid

     * position; or if there are no further values in the stream.

     */

    public Object readObject() throws SQLException {

        Object attrib = getNextAttribute();

        if (attrib instanceof Struct) {

            Struct s = (Struct)attrib;

            // look up the class in the map

            Class<?> c = map.get(s.getSQLTypeName());

            if (c != null) {

                // create new instance of the class

                SQLData obj = null;

                try {

                    ReflectUtil.checkPackageAccess(c);

                    @SuppressWarnings("deprecation")

                    Object tmp = c.newInstance();

                    obj = (SQLData)tmp;

                } catch (Exception ex) {

                    throw new SQLException("Unable to Instantiate: ", ex);

                }

                // get the attributes from the struct

                Object attribs[] = s.getAttributes(map);

                // create the SQLInput "stream"

                SQLInputImpl sqlInput = new SQLInputImpl(attribs, map);

                // read the values...

                obj.readSQL(sqlInput, s.getSQLTypeName());

                return obj;

            }

        }

        return attrib;

    }

    /**

     * Retrieves the value at the head of this <code>SQLInputImpl</code> object

     * as a <code>Ref</code> object in the Java programming language.

     *

     * @return a <code>Ref</code> object representing the SQL

     *         <code>REF</code> value at the head of the stream; if the value

     *         is <code>SQL NULL</code> return <code>null</code>

     * @throws SQLException if the read position is located at an invalid

     *         position; or if there are no further values in the stream.

     */

    public Ref readRef() throws SQLException {

        return (Ref)getNextAttribute();

    }

    /**

     * Retrieves the <code>BLOB</code> value at the head of this

     * <code>SQLInputImpl</code> object as a <code>Blob</code> object

     * in the Java programming language.

     * <P>

     * This method does not perform type-safe checking to determine if the

     * returned type is the expected type as this responsibility is delegated