SqlNullCheckedResultSet.java
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.dbutils.wrappers;
import java.io.InputStream;
import java.io.Reader;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.math.BigDecimal;
import java.net.URL;
import java.sql.Blob;
import java.sql.Clob;
import java.sql.Date;
import java.sql.Ref;
import java.sql.ResultSet;
import java.sql.Time;
import java.sql.Timestamp;
import java.util.HashMap;
import java.util.Map;
import org.apache.commons.dbutils.ProxyFactory;
/**
* Decorates a {@code ResultSet} with checks for a SQL NULL value on each
* {@code getXXX} method. If a column value obtained by a
* {@code getXXX} 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} 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 resultSet = stmt.executeQuery("SELECT col1, col2 FROM table1");
*
* // Wrap the result set for SQL NULL checking
* SqlNullCheckedResultSet wrapper = new SqlNullCheckedResultSet(resultSet);
* wrapper.setNullString("---N/A---"); // Set null string
* wrapper.setNullInt(-999); // Set null integer
* resultSet = ProxyFactory.instance().createResultSet(wrapper);
*
* while (resultSet.next()) {
* // If col1 is SQL NULL, value returned will be "---N/A---"
* String col1 = resultSet.getString("col1");
* // If col2 is SQL NULL, value returned will be -999
* int col2 = resultSet.getInt("col2");
* }
* resultSet.close();
* </pre>
* </blockquote>
* </p>
* <p>Unlike some other classes in DbUtils, this class is NOT thread-safe.</p>
*/
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> NULL_METHODS = new HashMap<>();
/**
* The {@code getNull} string prefix.
* @since 1.4
*/
private static final String GET_NULL_PREFIX = "getNull";
static {
final Method[] methods = SqlNullCheckedResultSet.class.getMethods();
for (final Method method : methods) {
final String methodName = method.getName();
if (methodName.startsWith(GET_NULL_PREFIX)) {
final String normalName = "get" + methodName.substring(GET_NULL_PREFIX.length());
NULL_METHODS.put(normalName, method);
}
}
}
/**
* The factory to create proxies with.
*/
private static final ProxyFactory factory = ProxyFactory.instance();
/**
* Wraps the {@code ResultSet} in an instance of this class. This is
* equivalent to:
* <pre>
* ProxyFactory.instance().createResultSet(new SqlNullCheckedResultSet(resultSet));
* </pre>
*
* @param resultSet The {@code ResultSet} to wrap.
* @return wrapped ResultSet
*/
public static ResultSet wrap(final ResultSet resultSet) {
return factory.createResultSet(new SqlNullCheckedResultSet(resultSet));
}
private InputStream nullAsciiStream;
private BigDecimal nullBigDecimal;
private InputStream nullBinaryStream;
private Blob nullBlob;
private boolean nullBoolean;
private byte nullByte;
private byte[] nullBytes;
private Reader nullCharacterStream;
private Clob nullClob;
private Date nullDate;
private double nullDouble;
private float nullFloat;
private int nullInt;
private long nullLong;
private Object nullObject;
private Ref nullRef;
private short nullShort;
private String nullString;
private Time nullTime;
private Timestamp nullTimestamp;
private URL nullURL;
/**
* The wrapped result.
*/
private final ResultSet resultSet;
/**
* Constructs a new instance of
* {@code SqlNullCheckedResultSet}
* to wrap the specified {@code ResultSet}.
* @param resultSet ResultSet to wrap
*/
public SqlNullCheckedResultSet(final ResultSet resultSet) {
this.resultSet = resultSet;
}
/**
* Returns the value when a SQL null is encountered as the result of
* invoking a {@code getAsciiStream} 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} 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} 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} 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} 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} 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} method.
*
* @return the value
*/
public byte[] getNullBytes() {
if (this.nullBytes == null) {
return null;
}
return this.nullBytes.clone();
}
/**
* Returns the value when a SQL null is encountered as the result of
* invoking a {@code getCharacterStream} 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} 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} 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} 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} 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} 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} 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} 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} 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} 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} 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} method.
*
* @return the value
*/
public Time getNullTime() {
return this.nullTime != null ? new Time(this.nullTime.getTime()) : null;
}
/**
* Returns the value when a SQL null is encountered as the result of
* invoking a {@code getTimestamp} method.
*
* @return the value
*/
public Timestamp getNullTimestamp() {
if (this.nullTimestamp == null) {
return null;
}
final Timestamp ts = new Timestamp(this.nullTimestamp.getTime());
ts.setNanos(this.nullTimestamp.getNanos());
return ts;
}
/**
* Returns the value when a SQL null is encountered as the result of
* invoking a {@code getURL} method.
*
* @return the value
*/
public URL getNullURL() {
return this.nullURL;
}
/**
* Intercepts calls to {@code get*} methods and calls the appropriate
* {@code getNull*} method if the {@code ResultSet} returned
* {@code null}.
*
* @see java.lang.reflect.InvocationHandler#invoke(Object, java.lang.reflect.Method, 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(final Object proxy, final Method method, final Object[] args)
throws Throwable {
final Object result = method.invoke(this.resultSet, args);
final Method nullMethod = NULL_METHODS.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.resultSet.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} method.
*
* @param nullAsciiStream the value
*/
public void setNullAsciiStream(final InputStream nullAsciiStream) {
this.nullAsciiStream = nullAsciiStream;
}
/**
* Sets the value to return when a SQL null is encountered as the result of
* invoking a {@code getBigDecimal} method.
*
* @param nullBigDecimal the value
*/
public void setNullBigDecimal(final BigDecimal nullBigDecimal) {
this.nullBigDecimal = nullBigDecimal;
}
/**
* Sets the value to return when a SQL null is encountered as the result of
* invoking a {@code getBinaryStream} method.
*
* @param nullBinaryStream the value
*/
public void setNullBinaryStream(final InputStream nullBinaryStream) {
this.nullBinaryStream = nullBinaryStream;
}
/**
* Sets the value to return when a SQL null is encountered as the result of
* invoking a {@code getBlob} method.
*
* @param nullBlob the value
*/
public void setNullBlob(final Blob nullBlob) {
this.nullBlob = nullBlob;
}
/**
* Sets the value to return when a SQL null is encountered as the result of
* invoking a {@code getBoolean} method.
*
* @param nullBoolean the value
*/
public void setNullBoolean(final boolean nullBoolean) {
this.nullBoolean = nullBoolean;
}
/**
* Sets the value to return when a SQL null is encountered as the result of
* invoking a {@code getByte} method.
*
* @param nullByte the value
*/
public void setNullByte(final byte nullByte) {
this.nullByte = nullByte;
}
/**
* Sets the value to return when a SQL null is encountered as the result of
* invoking a {@code getBytes} method.
*
* @param nullBytes the value
*/
public void setNullBytes(final byte[] nullBytes) {
if (nullBytes != null) {
this.nullBytes = nullBytes.clone();
} else {
this.nullBytes = null;
}
}
/**
* Sets the value to return when a SQL null is encountered as the result of
* invoking a {@code getCharacterStream} method.
*
* @param nullCharacterStream the value
*/
public void setNullCharacterStream(final Reader nullCharacterStream) {
this.nullCharacterStream = nullCharacterStream;
}
/**
* Sets the value to return when a SQL null is encountered as the result of
* invoking a {@code getClob} method.
*
* @param nullClob the value
*/
public void setNullClob(final Clob nullClob) {
this.nullClob = nullClob;
}
/**
* Sets the value to return when a SQL null is encountered as the result of
* invoking a {@code getDate} method.
*
* @param nullDate the value
*/
public void setNullDate(final 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} method.
*
* @param nullDouble the value
*/
public void setNullDouble(final double nullDouble) {
this.nullDouble = nullDouble;
}
/**
* Sets the value to return when a SQL null is encountered as the result of
* invoking a {@code getFloat} method.
*
* @param nullFloat the value
*/
public void setNullFloat(final float nullFloat) {
this.nullFloat = nullFloat;
}
/**
* Sets the value to return when a SQL null is encountered as the result of
* invoking a {@code getInt} method.
*
* @param nullInt the value
*/
public void setNullInt(final int nullInt) {
this.nullInt = nullInt;
}
/**
* Sets the value to return when a SQL null is encountered as the result of
* invoking a {@code getLong} method.
*
* @param nullLong the value
*/
public void setNullLong(final long nullLong) {
this.nullLong = nullLong;
}
/**
* Sets the value to return when a SQL null is encountered as the result of
* invoking a {@code getObject} method.
*
* @param nullObject the value
*/
public void setNullObject(final Object nullObject) {
this.nullObject = nullObject;
}
/**
* Sets the value to return when a SQL null is encountered as the result of
* invoking a {@code getRef} method.
*
* @param nullRef the value
*/
public void setNullRef(final Ref nullRef) {
this.nullRef = nullRef;
}
/**
* Sets the value to return when a SQL null is encountered as the result of
* invoking a {@code getShort} method.
*
* @param nullShort the value
*/
public void setNullShort(final short nullShort) {
this.nullShort = nullShort;
}
/**
* Sets the value to return when a SQL null is encountered as the result of
* invoking a {@code getString} method.
*
* @param nullString the value
*/
public void setNullString(final String nullString) {
this.nullString = nullString;
}
/**
* Sets the value to return when a SQL null is encountered as the result of
* invoking a {@code getTime} method.
*
* @param nullTime the value
*/
public void setNullTime(final Time nullTime) {
this.nullTime = nullTime != null ? new Time(nullTime.getTime()) : null;
}
/**
* Sets the value to return when a SQL null is encountered as the result of
* invoking a {@code getTimestamp} method.
*
* @param nullTimestamp the value
*/
public void setNullTimestamp(final Timestamp nullTimestamp) {
if (nullTimestamp != null) {
this.nullTimestamp = new Timestamp(nullTimestamp.getTime());
this.nullTimestamp.setNanos(nullTimestamp.getNanos());
} else {
this.nullTimestamp = null;
}
}
/**
* Sets the value to return when a SQL null is encountered as the result of
* invoking a {@code getURL} method.
*
* @param nullURL the value
*/
public void setNullURL(final URL nullURL) {
this.nullURL = nullURL;
}
}