javatools.database

Class ResultIterator<T>

java.lang.Object

javatools.datatypes.PeekIterator<T>

javatools.database.ResultIterator<T>

All Implemented Interfaces:

Closeable, AutoCloseable, Iterable<T>, Iterator<T>

public class ResultIterator<T>
extends PeekIterator<T>

Copyright 2016 Fabian M. Suchanek Licensed 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. This class wraps a ResultSet into an Iterator over a given Class. It requires a method that can wrap a row of a ResultSet into an object of the given class.
Example:

  // We need this class to define how to construct an Employer from a table row
  public static class EmployerWrapper implements ResultWrapper<Employer> {
  
     // Wraps the current row in a ResultSet into an Employer
     public Employer wrap(ResultSet r) {  
       return(new Employer(r.getString(1),r.getDouble(2)); 
     }
     
  }
  
  Database d=new OracleDatabase("scott","tiger");
  for(Employer e : d.query("SELECT * FROM employers WHERE salary>1000",
                           new EmployerConstructor())) {
     System.out.println(e);
  }
  

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	ResultIterator.ResultWrapper<T> Wraps the current row in a ResultSet into a T

Nested classes/interfaces inherited from class javatools.datatypes.PeekIterator

PeekIterator.ElementaryPeekIterator<T>, PeekIterator.SimplePeekIterator<T>

Field Summary

Fields

Modifier and Type	Field and Description
static ResultIterator.ResultWrapper<Boolean>	BooleanWrapper ResultWrapper for a single Boolean column
protected ResultIterator.ResultWrapper<T>	constructor Holds the constructor to be used for each row
static ResultIterator.ResultWrapper<Double[]>	DoublesWrapper ResultWrapper for several Doubles.
static ResultIterator.ResultWrapper<Double>	DoubleWrapper ResultWrapper for a single Double column.
static ResultIterator.ResultWrapper<Integer[]>	IntegersWrapper ResultWrapper for several Integers.
static ResultIterator.ResultWrapper<Integer>	IntegerWrapper ResultWrapper for a single Integer column
static ResultIterator.ResultWrapper<Long>	LongWrapper ResultWrapper for a single Long column.
protected ResultSet	resultSet Holds the resultSet
static ResultIterator.ResultWrapper<String[]>	StringsWrapper ResultWrapper for String columns
static ResultIterator.ResultWrapper<String>	StringWrapper ResultWrapper for a single String column

Fields inherited from class javatools.datatypes.PeekIterator

closed, EMPTY, fetchedNextValue, next

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ResultIterator() For subclasses
	ResultIterator(ResultSet s, ResultIterator.ResultWrapper<T> cons) Creates a ResultIterator for a ResultSet

Method Summary

Modifier and Type	Method and Description
void	close() Closes the resultset and the underlying statement
void	finalize() Closes the resultset
T	internalNext() Returns the next or NULL if no next element is available

Methods inherited from class javatools.datatypes.PeekIterator

asList, asList, asSet, asSet, asSet, emptyIterator, hasNext, internalSilentNext, iterator, list, list, main, next, nextOrNull, numElements, numElements, peek, remove, toString, toString, toString

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Iterator

forEachRemaining

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Detail

resultSet

protected ResultSet resultSet

Holds the resultSet

constructor

protected ResultIterator.ResultWrapper<T> constructor

Holds the constructor to be used for each row

BooleanWrapper

public static final ResultIterator.ResultWrapper<Boolean> BooleanWrapper

ResultWrapper for a single Boolean column

StringWrapper

public static final ResultIterator.ResultWrapper<String> StringWrapper

ResultWrapper for a single String column

StringsWrapper

public static final ResultIterator.ResultWrapper<String[]> StringsWrapper

ResultWrapper for String columns

LongWrapper

public static final ResultIterator.ResultWrapper<Long> LongWrapper

ResultWrapper for a single Long column. Returns NULL for NULL

DoubleWrapper

public static final ResultIterator.ResultWrapper<Double> DoubleWrapper

ResultWrapper for a single Double column. Returns NULL for NULL

DoublesWrapper

public static final ResultIterator.ResultWrapper<Double[]> DoublesWrapper

ResultWrapper for several Doubles. Returns NULL for NULL

IntegerWrapper

public static final ResultIterator.ResultWrapper<Integer> IntegerWrapper

ResultWrapper for a single Integer column

IntegersWrapper

public static final ResultIterator.ResultWrapper<Integer[]> IntegersWrapper

ResultWrapper for several Integers. Returns NULL for NULL

Constructor Detail

ResultIterator

public ResultIterator(ResultSet s,
                      ResultIterator.ResultWrapper<T> cons)

Creates a ResultIterator for a ResultSet

ResultIterator

protected ResultIterator()

For subclasses

Method Detail

internalNext

public T internalNext()
               throws Exception

Description copied from class: PeekIterator

Returns the next or NULL if no next element is available

Specified by:

internalNext in class PeekIterator<T>

Throws:

Exception

close

public void close()

Closes the resultset and the underlying statement

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class PeekIterator<T>

finalize

public void finalize()

Closes the resultset

Overrides:

finalize in class Object