/*
* @(#)SQLInputImpl.java 1.4 04/05/05
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package javax.sql.rowset.serial;
import java.sql.*;
import javax.sql.*;
import java.io.*;
import java.math.*;
import java.util.Map;
/**
* 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.
* @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 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 = attributes;
// 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 {
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.
* <p>
* @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 {
String attrib = (String)getNextAttribute();
if (attrib == null) {
lastValueWasNull = true;
return null;
} else {
lastValueWasNull = false;
return attrib;
}
}
/**
* 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.
* <p>
* @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();
if (attrib == null) {
lastValueWasNull = true;
return false;
} else {
lastValueWasNull = false;
return 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.
* <p>
* @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();
if (attrib == null) {
lastValueWasNull = true;
return (byte)0;
} else {
lastValueWasNull = false;
return 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.
* <P>
* @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();
if (attrib == null) {
lastValueWasNull = true;
return (short)0;
} else {
lastValueWasNull = false;
return 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.
* <P>
* @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();
if (attrib == null) {
lastValueWasNull = true;
return (int)0;
} else {
lastValueWasNull = false;
return 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.
* <P>
* @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();
if (attrib == null) {
lastValueWasNull = true;
return (long)0;
} else {
lastValueWasNull = false;
return 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.
* <P>
* @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();
if (attrib == null) {
lastValueWasNull = true;
return (float)0;
} else {
lastValueWasNull = false;
return 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.
* <P>
* @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();
if (attrib == null) {
lastValueWasNull = true;
return (double)0;
} else {
lastValueWasNull = false;
return 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.
* <P>
* @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 {
java.math.BigDecimal attrib = (java.math.BigDecimal)getNextAttribute();
if (attrib == null) {
lastValueWasNull = true;
return null;
} else {
lastValueWasNull = false;
return attrib;
}
}
/**
* 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.
* <P>
* @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 {
byte[] attrib = (byte[])getNextAttribute();
if (attrib == null) {
lastValueWasNull = true;
return null;
} else {
lastValueWasNull = false;
return attrib;
}
}
/**
* 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.
* <P>
* @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 {
java.sql.Date attrib = (java.sql.Date)getNextAttribute();
if (attrib == null) {
lastValueWasNull = true;
return null;
} else {
lastValueWasNull = false;
return attrib;
}
}
/**
* 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 {
java.sql.Time attrib = (java.sql.Time)getNextAttribute();
if (attrib == null) {
lastValueWasNull = true;
return null;
} else {
lastValueWasNull = false;
return attrib;
}
}
/**
* 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 {
java.sql.Timestamp attrib = (java.sql.Timestamp)getNextAttribute();
if (attrib == null) {
lastValueWasNull = true;
return null;
} else {
lastValueWasNull = false;
return attrib;
}
}
/**
* 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 {
java.io.Reader attrib = (java.io.Reader)getNextAttribute();
if (attrib == null) {
lastValueWasNull = true;
return null;
} else {
lastValueWasNull = false;
return attrib;
}
}
/**
* 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 {
java.io.InputStream attrib = (java.io.InputStream)getNextAttribute();
if (attrib == null) {
lastValueWasNull = true;
return null;
} else {
lastValueWasNull = false;
return attrib;
}
}
/**
* 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 {
java.io.InputStream attrib = (java.io.InputStream)getNextAttribute();
if (attrib == null) {
lastValueWasNull = true;
return null;
} else {
lastValueWasNull = false;
return attrib;
}
}
//================================================================
// 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 = (Object)getNextAttribute();
if (attrib == null) {
lastValueWasNull = true;
return null;
} else {
lastValueWasNull = false;
if (attrib instanceof Struct) {
Struct s = (Struct)attrib;
// look up the class in the map
Class c = (Class)map.get(s.getSQLTypeName());
if (c != null) {
// create new instance of the class
SQLData obj = null;
try {
obj = (SQLData)c.newInstance();
} catch (java.lang.InstantiationException ex) {
throw new SQLException("Unable to instantiate: " +
ex.getMessage());
} catch (java.lang.IllegalAccessException ex) {
throw new SQLException("Unable to instantiate: " +
ex.getMessage());
}
// 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 (Object)obj;
}
}
return (Object)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 {
Ref attrib = (Ref)getNextAttribute();
if (attrib == null) {
lastValueWasNull = true;
return null;
} else {
lastValueWasNull = false;
return attrib;
}
}
/**
* 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
* to the UDT mapping as implemented by a <code>SQLData</code>
* implementation.
*
* @return a <code>Blob</code> object representing the SQL
* <code>BLOB</code> value at the head of this 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 Blob readBlob() throws SQLException {
Blob attrib = (Blob)getNextAttribute();
if (attrib == null) {
lastValueWasNull = true;
return null;
} else {
lastValueWasNull = false;
return attrib;
}
}
/**
* Retrieves the <code>CLOB</code> value at the head of this
* <code>SQLInputImpl</code> object as a <code>Clob</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
* to the UDT mapping as implemented by a <code>SQLData</code>
* implementation.
*
* @return a <code>Clob</code> object representing the SQL
* <code>CLOB</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 Clob readClob() throws SQLException {
Clob attrib = (Clob)getNextAttribute();
if (attrib == null) {
lastValueWasNull = true;
return null;
} else {
lastValueWasNull = false;
return attrib;
}
}
/**
* Reads an SQL <code>ARRAY</code> value from the stream and
* returns it as an <code>Array</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
* to the UDT mapping as implemented by a <code>SQLData</code>
* implementation.
*
* @return an <code>Array</code> object representing the SQL
* <code>ARRAY</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 Array readArray() throws SQLException {
Array attrib = (Array)getNextAttribute();
if (attrib == null) {
lastValueWasNull = true;
return null;
} else {
lastValueWasNull = false;
return attrib;
}
}
/**
* Ascertains whether the last value read from this
* <code>SQLInputImpl</code> object was <code>null</code>.
*
* @return <code>true</code> if the SQL value read most recently was
* <code>null</code>; otherwise, <code>false</code>; by default it
* will return false
* @throws SQLException if an error occurs determining the last value
* read was a <code>null</code> value or not;
*/
public boolean wasNull() throws SQLException {
return lastValueWasNull;
}
/**
* Reads an SQL <code>DATALINK</code> value from the stream and
* returns it as an <code>URL</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
* to the UDT mapping as implemented by a <code>SQLData</code>
* implementation.
*
* @return an <code>URL</code> object representing the SQL
* <code>DATALINK</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 java.net.URL readURL() throws SQLException {
throw new SQLException("Operation not supported");
}
}
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