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 * Hibernate, Relational Persistence for Idiomatic Java
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package org.hibernate.dialect.function;

import java.util.List;

import org.hibernate.QueryException;
import org.hibernate.engine.spi.Mapping;
import org.hibernate.engine.spi.SessionFactoryImplementor;
import org.hibernate.type.Type;

Support for slightly more general templating than StandardSQLFunction, with an unlimited number of arguments.
Author:Gavin King
/** * Support for slightly more general templating than {@link StandardSQLFunction}, with an unlimited number of arguments. * * @author Gavin King */
public class VarArgsSQLFunction implements SQLFunction { private final String begin; private final String sep; private final String end; private final Type registeredType;
Constructs a VarArgsSQLFunction instance with a 'static' return type. An example of a 'static' return type would be something like an UPPER function which is always returning a SQL VARCHAR and thus a string type.
Params:
  • registeredType – The return type.
  • begin – The beginning of the function templating.
  • sep – The separator for each individual function argument.
  • end – The end of the function templating.
/** * Constructs a VarArgsSQLFunction instance with a 'static' return type. An example of a 'static' * return type would be something like an <tt>UPPER</tt> function which is always returning * a SQL VARCHAR and thus a string type. * * @param registeredType The return type. * @param begin The beginning of the function templating. * @param sep The separator for each individual function argument. * @param end The end of the function templating. */
public VarArgsSQLFunction(Type registeredType, String begin, String sep, String end) { this.registeredType = registeredType; this.begin = begin; this.sep = sep; this.end = end; }
Constructs a VarArgsSQLFunction instance with a 'dynamic' return type. For a dynamic return type, the type of the arguments are used to resolve the type. An example of a function with a 'dynamic' return would be MAX or MIN which return a double or an integer etc based on the types of the arguments.
Params:
  • begin – The beginning of the function templating.
  • sep – The separator for each individual function argument.
  • end – The end of the function templating.
See Also:
/** * Constructs a VarArgsSQLFunction instance with a 'dynamic' return type. For a dynamic return type, * the type of the arguments are used to resolve the type. An example of a function with a * 'dynamic' return would be <tt>MAX</tt> or <tt>MIN</tt> which return a double or an integer etc * based on the types of the arguments. * * @param begin The beginning of the function templating. * @param sep The separator for each individual function argument. * @param end The end of the function templating. * * @see #getReturnType Specifically, the 'firstArgumentType' argument is the 'dynamic' type. */
public VarArgsSQLFunction(String begin, String sep, String end) { this( null, begin, sep, end ); } @Override public boolean hasArguments() { return true; } @Override public boolean hasParenthesesIfNoArguments() { return true; } @Override public Type getReturnType(Type firstArgumentType, Mapping mapping) throws QueryException { return registeredType == null ? firstArgumentType : registeredType; } @Override public String render(Type firstArgumentType, List arguments, SessionFactoryImplementor factory) { final StringBuilder buf = new StringBuilder().append( begin ); for ( int i = 0; i < arguments.size(); i++ ) { buf.append( transformArgument( (String) arguments.get( i ) ) ); if ( i < arguments.size() - 1 ) { buf.append( sep ); } } return buf.append( end ).toString(); }
Called from render to allow applying a change or transformation to each individual argument.
Params:
  • argument – The argument being processed.
Returns:The transformed argument; may be the same, though should never be null.
/** * Called from {@link #render} to allow applying a change or transformation * to each individual argument. * * @param argument The argument being processed. * @return The transformed argument; may be the same, though should never be null. */
protected String transformArgument(String argument) { return argument; } }