/* Copyright (c) 2015 James Ahlborn 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. */ package com.healthmarketscience.sqlbuilder.custom.postgresql; import java.io.IOException; import com.healthmarketscience.common.util.AppendableExt; import com.healthmarketscience.sqlbuilder.Converter; import com.healthmarketscience.sqlbuilder.NumberValueObject; import com.healthmarketscience.sqlbuilder.SelectQuery; import com.healthmarketscience.sqlbuilder.SqlObject; import com.healthmarketscience.sqlbuilder.ValidationContext; import com.healthmarketscience.sqlbuilder.ValidationException; import com.healthmarketscience.sqlbuilder.Verifiable; import com.healthmarketscience.sqlbuilder.custom.CustomSyntax; import com.healthmarketscience.sqlbuilder.custom.HookType; /** * Appends a PostgreSQL limit clause like {@code " LIMIT <limit>"} for use in * {@link SelectQuery}s. * * @see SelectQuery#addCustomization(CustomSyntax) * * @author James Ahlborn */ public class PgLimitClause extends CustomSyntax implements Verifiable<PgLimitClause> { private SqlObject _value; public PgLimitClause(Object value) { _value = Converter.toValueSqlObject(value); } @Override public void apply(SelectQuery query) { query.addCustomization(SelectQuery.Hook.FOR_UPDATE, HookType.BEFORE, this); } @Override public void appendTo(AppendableExt app) throws IOException { app.append(" LIMIT "); app.append(_value); } @Override protected void collectSchemaObjects(ValidationContext vContext) { vContext.addVerifiable(this); collectSchemaObjects(_value, vContext); } @Override public final PgLimitClause validate() throws ValidationException { doValidate(); return this; } @Override public void validate(ValidationContext vContext) throws ValidationException { if(_value == null) { throw new ValidationException("Limit clause is missing row count"); } validateValue(_value, "Limit"); } static void validateValue(SqlObject valueObj, String type) { if(!(valueObj instanceof NumberValueObject)) { // nothing we can do, custom value return; } if(!((NumberValueObject)valueObj).isIntegralInRange(0, Long.MAX_VALUE)) { throw new ValidationException( type + " value must be positive integer, given: " + valueObj); } } }