Package net.sf.basedb.core.query
Class LogExpression
- java.lang.Object
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- net.sf.basedb.core.query.LogExpression
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- All Implemented Interfaces:
Expression
,QueryElement
public class LogExpression extends Object implements Expression
Take the n-based logarithm of an expression: log(n, e).The n-based logarithm is easily calculated as the natural logarithm of x divided natural logarithm of the base, ie. log(n, e) = ln(e) / ln(n)
- Version:
- 2.0
- Author:
- Nicklas
- See Also:
Expressions.log(double, Expression)
- Last modified
- $Date: 2012-09-14 09:28:35 +0200 (fr, 14 sep 2012) $
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Field Summary
Fields Modifier and Type Field Description private double
base
private Expression
e1
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Constructor Summary
Constructors Constructor Description LogExpression(double base, Expression e1)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description boolean
equals(Object other)
This expression is equal to another LogExpression if their child expressions and bases are equal.Collection<? extends QueryElement>
getChildren()
Get the children of this query element or null if it has no children.int
hashCode()
String
toQl(Query query, DbControl dc)
Create a query language string of the query element.String
toString()
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Field Detail
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base
private final double base
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e1
private final Expression e1
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Constructor Detail
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LogExpression
LogExpression(double base, Expression e1)
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Method Detail
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toQl
public String toQl(Query query, DbControl dc) throws BaseException
Description copied from interface:QueryElement
Create a query language string of the query element. Use theQuery.getQueryType()
method to find out which query language is wanted in case the element requires different syntax for different languages.- Specified by:
toQl
in interfaceQueryElement
- Parameters:
query
- The query that is about to be executeddc
- TheDbControl
object used to execute the query- Throws:
BaseException
- If there is any other error
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getChildren
public Collection<? extends QueryElement> getChildren()
Description copied from interface:QueryElement
Get the children of this query element or null if it has no children. For example theAddExpression
has two children, the expression beeing added.- Specified by:
getChildren
in interfaceQueryElement
- Returns:
- The expression
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equals
public boolean equals(Object other)
This expression is equal to another LogExpression if their child expressions and bases are equal.
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