ebean/src/main/java/io/ebeaninternal/server/query/SqlTreeNodeManyWhereJoin.java

package io.ebeaninternal.server.query;

import io.ebean.Version;
import io.ebean.bean.EntityBean;
import io.ebean.util.SplitName;
import io.ebeaninternal.api.SpiQuery;
import io.ebeaninternal.server.deploy.DbReadContext;
import io.ebeaninternal.server.deploy.DbSqlContext;
import io.ebeaninternal.server.deploy.TableJoin;
import io.ebeaninternal.server.type.ScalarType;

import java.util.List;

/**
 * Join to Many (or child of a many) to support where clause predicates on many properties.
 */
class SqlTreeNodeManyWhereJoin implements SqlTreeNode {

  private final String parentPrefix;

  private final String prefix;

  private final STreePropertyAssoc nodeBeanProp;

  /**
   * The many where join which is either INNER or OUTER.
   */
  private final SqlJoinType manyJoinType;

  SqlTreeNodeManyWhereJoin(String prefix, STreePropertyAssoc prop, SqlJoinType manyJoinType) {
    this.nodeBeanProp = prop;
    this.prefix = prefix;
    this.manyJoinType = manyJoinType;

    String[] split = SplitName.split(prefix);
    this.parentPrefix = split[0];
  }

  @Override
  public boolean isSingleProperty() {
    return false;
  }

  @Override
  public ScalarType<?> getSingleAttributeScalarType() {
    throw new IllegalStateException("No expected");
  }

  @Override
  public void addAsOfTableAlias(SpiQuery<?> query) {
    // do nothing here ...
  }

  @Override
  public void addSoftDeletePredicate(SpiQuery<?> query) {
    // do nothing here ...
  }

  @Override
  public boolean isAggregation() {
    return false;
  }

  @Override
  public void appendDistinctOn(DbSqlContext ctx, boolean subQuery) {
    // do nothing here ...
  }

  @Override
  public void appendGroupBy(DbSqlContext ctx, boolean subQuery) {
    // do nothing here
  }

  /**
   * Append to the FROM clause for this node.
   */
  @Override
  public void appendFrom(DbSqlContext ctx, SqlJoinType currentJoinType) {

    // always use the join type as per this many where join
    // (OUTER for disjunction and otherwise INNER)
    appendFromBaseTable(ctx, manyJoinType);
  }

  /**
   * Join to base table for this node. This includes a join to the
   * intersection table if this is a ManyToMany node.
   */
  private void appendFromBaseTable(DbSqlContext ctx, SqlJoinType joinType) {

    String alias = ctx.getTableAliasManyWhere(prefix);
    String parentAlias = ctx.getTableAliasManyWhere(parentPrefix);

    if (nodeBeanProp instanceof STreePropertyAssocOne) {
      nodeBeanProp.addJoin(joinType, parentAlias, alias, ctx);

    } else {
      STreePropertyAssocMany manyProp = (STreePropertyAssocMany) nodeBeanProp;
      if (!manyProp.hasJoinTable()) {
        manyProp.addJoin(joinType, parentAlias, alias, ctx);

      } else {
        String alias2 = alias + "z_";

        TableJoin manyToManyJoin = manyProp.getIntersectionTableJoin();
        manyToManyJoin.addJoin(joinType, parentAlias, alias2, ctx);
        manyProp.addJoin(joinType, alias2, alias, ctx);
      }
    }
  }

  @Override
  public void buildRawSqlSelectChain(List<String> selectChain) {
    // nothing to add
  }

  @Override
  public void appendSelect(DbSqlContext ctx, boolean subQuery) {
    // nothing to do here
  }

  @Override
  public void appendWhere(DbSqlContext ctx) {
    // nothing to do here
  }

  @Override
  public EntityBean load(DbReadContext ctx, EntityBean localBean, EntityBean parentBean) {
    // nothing to do here
    return null;
  }

  @Override
  public <T> Version<T> loadVersion(DbReadContext ctx) {
    // nothing to do here
    return null;
  }

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