org.hibernate.dialect.function.PositionSubstringFunction.java Source code

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Here is the source code for org.hibernate.dialect.function.PositionSubstringFunction.java

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/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
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.StandardBasicTypes;
import org.hibernate.type.Type;

/**
 * Emulation of <tt>locate()</tt> on PostgreSQL
 *
 * @author Gavin King
 */
public class PositionSubstringFunction implements SQLFunction {
    @Override
    public boolean hasArguments() {
        return true;
    }

    @Override
    public boolean hasParenthesesIfNoArguments() {
        return true;
    }

    @Override
    public Type getReturnType(Type firstArgumentType, Mapping mapping) throws QueryException {
        return StandardBasicTypes.INTEGER;
    }

    @Override
    public String render(Type firstArgumentType, List args, SessionFactoryImplementor factory)
            throws QueryException {
        final boolean threeArgs = args.size() > 2;
        final Object pattern = args.get(0);
        final Object string = args.get(1);
        final Object start = threeArgs ? args.get(2) : null;

        final StringBuilder buf = new StringBuilder();
        if (threeArgs) {
            buf.append('(');
        }
        buf.append("position(").append(pattern).append(" in ");
        if (threeArgs) {
            buf.append("substring(");
        }
        buf.append(string);
        if (threeArgs) {
            buf.append(", ").append(start).append(')');
        }
        buf.append(')');
        if (threeArgs) {
            buf.append('+').append(start).append("-1)");
        }
        return buf.toString();
    }

}