/**
* Decorates a <code>ResultSet</code> with checks for a SQL NULL value on each <code>getXXX</code>
* method. If a column value obtained by a <code>getXXX</code> method is not SQL NULL, the column
* value is returned. If the column value is SQL null, an alternate value is returned. The alternate
* value defaults to the Java <code>null</code> value, which can be overridden for instances of the
* class.
*
* <p>Usage example:
*
* <blockquote>
*
* <pre>
* Connection conn = // somehow get a connection
* Statement stmt = conn.createStatement();
* ResultSet rs = stmt.executeQuery("SELECT col1, col2 FROM table1");
*
* // Wrap the result set for SQL NULL checking
* SqlNullCheckedResultSet wrapper = new SqlNullCheckedResultSet(rs);
* wrapper.setNullString("---N/A---"); // Set null string
* wrapper.setNullInt(-999); // Set null integer
* rs = ProxyFactory.instance().createResultSet(wrapper);
*
* while (rs.next()) {
* // If col1 is SQL NULL, value returned will be "---N/A---"
* String col1 = rs.getString("col1");
* // If col2 is SQL NULL, value returned will be -999
* int col2 = rs.getInt("col2");
* }
* rs.close();
* </pre>
*
* </blockquote>
*
* <p>Unlike some other classes in DbUtils, this class is NOT thread-safe.
*/
public class SqlNullCheckedResultSet implements InvocationHandler {
/**
* Maps normal method names (ie. "getBigDecimal") to the corresponding null Method object (ie.
* getNullBigDecimal).
*/
private static final Map<String, Method> nullMethods = new HashMap<String, Method>();
/**
* The {@code getNull} string prefix.
*
* @since 1.4
*/
private static final String GET_NULL_PREFIX = "getNull";
static {
Method[] methods = SqlNullCheckedResultSet.class.getMethods();
for (int i = 0; i < methods.length; i++) {
String methodName = methods[i].getName();
if (methodName.startsWith(GET_NULL_PREFIX)) {
String normalName = "get" + methodName.substring(GET_NULL_PREFIX.length());
nullMethods.put(normalName, methods[i]);
}
}
}
/** The factory to create proxies with. */
private static final ProxyFactory factory = ProxyFactory.instance();
/**
* Wraps the <code>ResultSet</code> in an instance of this class. This is equivalent to:
*
* <pre>
* ProxyFactory.instance().createResultSet(new SqlNullCheckedResultSet(rs));
* </pre>
*
* @param rs The <code>ResultSet</code> to wrap.
* @return wrapped ResultSet
*/
public static ResultSet wrap(ResultSet rs) {
return factory.createResultSet(new SqlNullCheckedResultSet(rs));
}
private InputStream nullAsciiStream = null;
private BigDecimal nullBigDecimal = null;
private InputStream nullBinaryStream = null;
private Blob nullBlob = null;
private boolean nullBoolean = false;
private byte nullByte = 0;
private byte[] nullBytes = null;
private Reader nullCharacterStream = null;
private Clob nullClob = null;
private Date nullDate = null;
private double nullDouble = 0.0;
private float nullFloat = 0.0f;
private int nullInt = 0;
private long nullLong = 0;
private Object nullObject = null;
private Ref nullRef = null;
private short nullShort = 0;
private String nullString = null;
private Time nullTime = null;
private Timestamp nullTimestamp = null;
private URL nullURL = null;
/** The wrapped result. */
private final ResultSet rs;
/**
* Constructs a new instance of <code>SqlNullCheckedResultSet</code> to wrap the specified <code>
* ResultSet</code>.
*
* @param rs ResultSet to wrap
*/
public SqlNullCheckedResultSet(ResultSet rs) {
super();
this.rs = rs;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>
* getAsciiStream</code> method.
*
* @return the value
*/
public InputStream getNullAsciiStream() {
return this.nullAsciiStream;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>
* getBigDecimal</code> method.
*
* @return the value
*/
public BigDecimal getNullBigDecimal() {
return this.nullBigDecimal;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>
* getBinaryStream</code> method.
*
* @return the value
*/
public InputStream getNullBinaryStream() {
return this.nullBinaryStream;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>getBlob
* </code> method.
*
* @return the value
*/
public Blob getNullBlob() {
return this.nullBlob;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>getBoolean
* </code> method.
*
* @return the value
*/
public boolean getNullBoolean() {
return this.nullBoolean;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>getByte
* </code> method.
*
* @return the value
*/
public byte getNullByte() {
return this.nullByte;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>getBytes
* </code> method.
*
* @return the value
*/
public byte[] getNullBytes() {
if (this.nullBytes == null) {
return null;
}
byte[] copy = new byte[this.nullBytes.length];
System.arraycopy(this.nullBytes, 0, copy, 0, this.nullBytes.length);
return copy;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>
* getCharacterStream</code> method.
*
* @return the value
*/
public Reader getNullCharacterStream() {
return this.nullCharacterStream;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>getClob
* </code> method.
*
* @return the value
*/
public Clob getNullClob() {
return this.nullClob;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>getDate
* </code> method.
*
* @return the value
*/
public Date getNullDate() {
return this.nullDate != null ? new Date(this.nullDate.getTime()) : null;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>getDouble
* </code> method.
*
* @return the value
*/
public double getNullDouble() {
return this.nullDouble;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>getFloat
* </code> method.
*
* @return the value
*/
public float getNullFloat() {
return this.nullFloat;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>getInt
* </code> method.
*
* @return the value
*/
public int getNullInt() {
return this.nullInt;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>getLong
* </code> method.
*
* @return the value
*/
public long getNullLong() {
return this.nullLong;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>getObject
* </code> method.
*
* @return the value
*/
public Object getNullObject() {
return this.nullObject;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>getRef
* </code> method.
*
* @return the value
*/
public Ref getNullRef() {
return this.nullRef;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>getShort
* </code> method.
*
* @return the value
*/
public short getNullShort() {
return this.nullShort;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>getString
* </code> method.
*
* @return the value
*/
public String getNullString() {
return this.nullString;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>getTime
* </code> method.
*
* @return the value
*/
public Time getNullTime() {
return this.nullTime;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>getTimestamp
* </code> method.
*
* @return the value
*/
public Timestamp getNullTimestamp() {
return this.nullTimestamp != null ? new Timestamp(this.nullTimestamp.getTime()) : null;
}
/**
* Returns the value when a SQL null is encountered as the result of invoking a <code>getURL
* </code> method.
*
* @return the value
*/
public URL getNullURL() {
return this.nullURL;
}
/**
* Intercepts calls to <code>get*</code> methods and calls the appropriate <code>getNull*</code>
* method if the <code>ResultSet</code> returned <code>null</code>.
*
* @see java.lang.reflect.InvocationHandler#invoke(java.lang.Object, java.lang.reflect.Method,
* java.lang.Object[])
* @param proxy Not used; all method calls go to the internal result set
* @param method The method to invoke on the result set
* @param args The arguments to pass to the result set
* @return null checked result
* @throws Throwable error
*/
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
Object result = method.invoke(this.rs, args);
Method nullMethod = nullMethods.get(method.getName());
// Check nullMethod != null first so that we don't call wasNull()
// before a true getter method was invoked on the ResultSet.
return (nullMethod != null && this.rs.wasNull())
? nullMethod.invoke(this, (Object[]) null)
: result;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getAsciiStream</code> method.
*
* @param nullAsciiStream the value
*/
public void setNullAsciiStream(InputStream nullAsciiStream) {
this.nullAsciiStream = nullAsciiStream;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getBigDecimal</code> method.
*
* @param nullBigDecimal the value
*/
public void setNullBigDecimal(BigDecimal nullBigDecimal) {
this.nullBigDecimal = nullBigDecimal;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getBinaryStream</code> method.
*
* @param nullBinaryStream the value
*/
public void setNullBinaryStream(InputStream nullBinaryStream) {
this.nullBinaryStream = nullBinaryStream;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getBlob</code> method.
*
* @param nullBlob the value
*/
public void setNullBlob(Blob nullBlob) {
this.nullBlob = nullBlob;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getBoolean</code> method.
*
* @param nullBoolean the value
*/
public void setNullBoolean(boolean nullBoolean) {
this.nullBoolean = nullBoolean;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getByte</code> method.
*
* @param nullByte the value
*/
public void setNullByte(byte nullByte) {
this.nullByte = nullByte;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getBytes</code> method.
*
* @param nullBytes the value
*/
public void setNullBytes(byte[] nullBytes) {
byte[] copy = new byte[nullBytes.length];
System.arraycopy(nullBytes, 0, copy, 0, nullBytes.length);
this.nullBytes = copy;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getCharacterStream</code> method.
*
* @param nullCharacterStream the value
*/
public void setNullCharacterStream(Reader nullCharacterStream) {
this.nullCharacterStream = nullCharacterStream;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getClob</code> method.
*
* @param nullClob the value
*/
public void setNullClob(Clob nullClob) {
this.nullClob = nullClob;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getDate</code> method.
*
* @param nullDate the value
*/
public void setNullDate(Date nullDate) {
this.nullDate = nullDate != null ? new Date(nullDate.getTime()) : null;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getDouble</code> method.
*
* @param nullDouble the value
*/
public void setNullDouble(double nullDouble) {
this.nullDouble = nullDouble;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getFloat</code> method.
*
* @param nullFloat the value
*/
public void setNullFloat(float nullFloat) {
this.nullFloat = nullFloat;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getInt</code> method.
*
* @param nullInt the value
*/
public void setNullInt(int nullInt) {
this.nullInt = nullInt;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getLong</code> method.
*
* @param nullLong the value
*/
public void setNullLong(long nullLong) {
this.nullLong = nullLong;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getObject</code> method.
*
* @param nullObject the value
*/
public void setNullObject(Object nullObject) {
this.nullObject = nullObject;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getRef</code> method.
*
* @param nullRef the value
*/
public void setNullRef(Ref nullRef) {
this.nullRef = nullRef;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getShort</code> method.
*
* @param nullShort the value
*/
public void setNullShort(short nullShort) {
this.nullShort = nullShort;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getString</code> method.
*
* @param nullString the value
*/
public void setNullString(String nullString) {
this.nullString = nullString;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getTime</code> method.
*
* @param nullTime the value
*/
public void setNullTime(Time nullTime) {
this.nullTime = nullTime;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getTimestamp</code> method.
*
* @param nullTimestamp the value
*/
public void setNullTimestamp(Timestamp nullTimestamp) {
this.nullTimestamp = nullTimestamp != null ? new Timestamp(nullTimestamp.getTime()) : null;
}
/**
* Sets the value to return when a SQL null is encountered as the result of invoking a <code>
* getURL</code> method.
*
* @param nullURL the value
*/
public void setNullURL(URL nullURL) {
this.nullURL = nullURL;
}
}
