Java tutorial
/* * Copyright 2015 herd contributors * * 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 org.finra.herd.dao.impl; import java.util.List; import javax.persistence.criteria.CriteriaBuilder; import javax.persistence.criteria.CriteriaQuery; import javax.persistence.criteria.Join; import javax.persistence.criteria.Order; import javax.persistence.criteria.Predicate; import javax.persistence.criteria.Root; import org.apache.commons.lang3.StringUtils; import org.springframework.stereotype.Repository; import org.finra.herd.dao.ExpectedPartitionValueDao; import org.finra.herd.model.api.xml.ExpectedPartitionValueKey; import org.finra.herd.model.api.xml.PartitionValueRange; import org.finra.herd.model.jpa.ExpectedPartitionValueEntity; import org.finra.herd.model.jpa.ExpectedPartitionValueEntity_; import org.finra.herd.model.jpa.PartitionKeyGroupEntity; import org.finra.herd.model.jpa.PartitionKeyGroupEntity_; @Repository public class ExpectedPartitionValueDaoImpl extends AbstractHerdDao implements ExpectedPartitionValueDao { @Override public ExpectedPartitionValueEntity getExpectedPartitionValue( ExpectedPartitionValueKey expectedPartitionValueKey, int offset) { // Create the criteria builder and the criteria. CriteriaBuilder builder = entityManager.getCriteriaBuilder(); CriteriaQuery<ExpectedPartitionValueEntity> criteria = builder .createQuery(ExpectedPartitionValueEntity.class); // The criteria root is the expected partition value. Root<ExpectedPartitionValueEntity> expectedPartitionValueEntity = criteria .from(ExpectedPartitionValueEntity.class); // Join to the other tables we can filter on. Join<ExpectedPartitionValueEntity, PartitionKeyGroupEntity> partitionKeyGroupEntity = expectedPartitionValueEntity .join(ExpectedPartitionValueEntity_.partitionKeyGroup); // Add a restriction to filter case insensitive groups that match the user specified group. Predicate whereRestriction = builder.equal( builder.upper(partitionKeyGroupEntity.get(PartitionKeyGroupEntity_.partitionKeyGroupName)), expectedPartitionValueKey.getPartitionKeyGroupName().toUpperCase()); // Depending on the offset, we might need to order the records in the query. Order orderByExpectedPartitionValue = null; // Add additional restrictions to handle expected partition value and an optional offset. if (offset == 0) { // Since there is no offset, we need to match the expected partition value exactly. whereRestriction = builder.and(whereRestriction, builder.equal(expectedPartitionValueEntity.get(ExpectedPartitionValueEntity_.partitionValue), expectedPartitionValueKey.getExpectedPartitionValue())); } else if (offset > 0) { // For a positive offset value, add a restriction to filter expected partition values that are >= the user specified expected partition value. whereRestriction = builder.and(whereRestriction, builder.greaterThanOrEqualTo( expectedPartitionValueEntity.get(ExpectedPartitionValueEntity_.partitionValue), expectedPartitionValueKey.getExpectedPartitionValue())); // Order by expected partition value in ascending order. orderByExpectedPartitionValue = builder .asc(expectedPartitionValueEntity.get(ExpectedPartitionValueEntity_.partitionValue)); } else { // For a negative offset value, add a restriction to filter expected partition values that are <= the user specified expected partition value. whereRestriction = builder.and(whereRestriction, builder.lessThanOrEqualTo( expectedPartitionValueEntity.get(ExpectedPartitionValueEntity_.partitionValue), expectedPartitionValueKey.getExpectedPartitionValue())); // Order by expected partition value in descending order. orderByExpectedPartitionValue = builder .desc(expectedPartitionValueEntity.get(ExpectedPartitionValueEntity_.partitionValue)); } // Add the clauses for the query and execute the query. if (offset == 0) { criteria.select(expectedPartitionValueEntity).where(whereRestriction); return executeSingleResultQuery(criteria, String.format( "Found more than one expected partition value with parameters {partitionKeyGroupName=\"%s\", expectedPartitionValue=\"%s\"}.", expectedPartitionValueKey.getPartitionKeyGroupName(), expectedPartitionValueKey.getExpectedPartitionValue())); } else { criteria.select(expectedPartitionValueEntity).where(whereRestriction) .orderBy(orderByExpectedPartitionValue); List<ExpectedPartitionValueEntity> resultList = entityManager.createQuery(criteria) .setFirstResult(Math.abs(offset)).setMaxResults(1).getResultList(); return resultList.size() > 0 ? resultList.get(0) : null; } } @Override public List<ExpectedPartitionValueEntity> getExpectedPartitionValuesByGroupAndRange( String partitionKeyGroupName, PartitionValueRange partitionValueRange) { // Create the criteria builder and the criteria. CriteriaBuilder builder = entityManager.getCriteriaBuilder(); CriteriaQuery<ExpectedPartitionValueEntity> criteria = builder .createQuery(ExpectedPartitionValueEntity.class); // The criteria root is the expected partition value. Root<ExpectedPartitionValueEntity> expectedPartitionValueEntity = criteria .from(ExpectedPartitionValueEntity.class); // Join to the other tables we can filter on. Join<ExpectedPartitionValueEntity, PartitionKeyGroupEntity> partitionKeyGroupEntity = expectedPartitionValueEntity .join(ExpectedPartitionValueEntity_.partitionKeyGroup); // Add a restriction to filter case insensitive groups that match the user specified group. Predicate whereRestriction = builder.equal( builder.upper(partitionKeyGroupEntity.get(PartitionKeyGroupEntity_.partitionKeyGroupName)), partitionKeyGroupName.toUpperCase()); // If we have a possible partition value range, we need to add additional restrictions. if (partitionValueRange != null) { // Add a restriction to filter values that are >= the user specified range start value. if (StringUtils.isNotBlank(partitionValueRange.getStartPartitionValue())) { whereRestriction = builder.and(whereRestriction, builder.greaterThanOrEqualTo( expectedPartitionValueEntity.get(ExpectedPartitionValueEntity_.partitionValue), partitionValueRange.getStartPartitionValue())); } // Add a restriction to filter values that are <= the user specified range end value. if (StringUtils.isNotBlank(partitionValueRange.getEndPartitionValue())) { whereRestriction = builder.and(whereRestriction, builder.lessThanOrEqualTo( expectedPartitionValueEntity.get(ExpectedPartitionValueEntity_.partitionValue), partitionValueRange.getEndPartitionValue())); } } // Order the results by partition value. Order orderByValue = builder .asc(expectedPartitionValueEntity.get(ExpectedPartitionValueEntity_.partitionValue)); // Add the clauses for the query. criteria.select(expectedPartitionValueEntity).where(whereRestriction).orderBy(orderByValue); // Execute the query and return the results. return entityManager.createQuery(criteria).getResultList(); } }