ebean/src/main/java/com/avaje/ebeaninternal/server/deploy/TableJoin.java

package com.avaje.ebeaninternal.server.deploy;

import java.sql.SQLException;
import java.util.LinkedHashMap;

import com.avaje.ebean.bean.EntityBean;
import com.avaje.ebeaninternal.server.core.InternString;
import com.avaje.ebeaninternal.server.deploy.meta.DeployBeanProperty;
import com.avaje.ebeaninternal.server.deploy.meta.DeployTableJoin;
import com.avaje.ebeaninternal.server.deploy.meta.DeployTableJoinColumn;
import com.avaje.ebeaninternal.server.query.SplitName;
import com.avaje.ebeaninternal.server.query.SqlBeanLoad;

/**
 * Represents a join to another table.
 */
public final class TableJoin {

  public static final String LEFT_OUTER = "left outer join";

  public static final String JOIN = "join";

  /**
   * Flag set when the imported key maps to the primary key. This occurs for
   * intersection tables (ManyToMany).
   */
  private final boolean importedPrimaryKey;

  /**
   * The joined table.
   */
  private final String table;

  /**
   * The type of join. LEFT OUTER etc.
   */
  private final String type;

  /**
   * The persist cascade info.
   */
  private final BeanCascadeInfo cascadeInfo;

  private final InheritInfo inheritInfo;
    
  /**
   * Properties as an array.
   */
  private final BeanProperty[] properties;

  /**
   * Columns as an array.
   */
  private final TableJoinColumn[] columns;

  /**
   * Create a TableJoin.
   */
  public TableJoin(DeployTableJoin deploy, LinkedHashMap<String, BeanProperty> propMap) {

    this.importedPrimaryKey = deploy.isImportedPrimaryKey();
    this.table = InternString.intern(deploy.getTable());
    this.type = InternString.intern(deploy.getType());
    this.cascadeInfo = deploy.getCascadeInfo();
    this.inheritInfo = deploy.getInheritInfo();

    DeployTableJoinColumn[] deployCols = deploy.columns();
    this.columns = new TableJoinColumn[deployCols.length];
    for (int i = 0; i < deployCols.length; i++) {
      this.columns[i] = new TableJoinColumn(deployCols[i]);
    }

    DeployBeanProperty[] deployProps = deploy.properties();
    if (deployProps.length > 0 && propMap == null) {
      throw new NullPointerException("propMap is null?");
    }

    this.properties = new BeanProperty[deployProps.length];
    for (int i = 0; i < deployProps.length; i++) {
      BeanProperty prop = propMap.get(deployProps[i].getName());
      this.properties[i] = prop;
    }

  }

  public String toString() {
    StringBuilder sb = new StringBuilder(30);
    sb.append(type).append(" ").append(table).append(" ");
    for (int i = 0; i < columns.length; i++) {
      sb.append(columns[i]).append(" ");
    }
    return sb.toString();
  }

  public void appendSelect(DbSqlContext ctx, boolean subQuery) {
    for (int i = 0, x = properties.length; i < x; i++) {
      properties[i].appendSelect(ctx, subQuery);
    }
  }

  public void load(SqlBeanLoad sqlBeanLoad) throws SQLException {
    for (int i = 0, x = properties.length; i < x; i++) {
      properties[i].load(sqlBeanLoad);
    }
  }

  public Object readSet(DbReadContext ctx, EntityBean bean, Class<?> type) throws SQLException {
    for (int i = 0, x = properties.length; i < x; i++) {
      properties[i].readSet(ctx, bean, type);
    }
    return null;
  }

  /**
   * Return true if the imported foreign key maps to the primary key.
   */
  public boolean isImportedPrimaryKey() {
    return importedPrimaryKey;
  }

  /**
   * Return the persist info.
   */
  public BeanCascadeInfo getCascadeInfo() {
    return cascadeInfo;
  }

  /**
   * Return the join columns.
   */
  public TableJoinColumn[] columns() {
    return columns;
  }

  /**
   * For secondary table joins returns the properties mapped to that table.
   */
  public BeanProperty[] properties() {
    return properties;
  }

  /**
   * Return the joined table name.
   */
  public String getTable() {
    return table;
  }

  /**
   * Return the type of join. LEFT OUTER JOIN etc.
   */
  public String getType() {
    return type;
  }

  /**
   * Return true if this join is a left outer join.
   */
  public boolean isOuterJoin() {
    return type.equals(LEFT_OUTER);
  }

  public boolean addJoin(boolean forceOuterJoin, String prefix, DbSqlContext ctx) {

    String[] names = SplitName.split(prefix);
    String a1 = ctx.getTableAlias(names[0]);
    String a2 = ctx.getTableAlias(prefix);

    return addJoin(forceOuterJoin, a1, a2, ctx);
  }

  public boolean addJoin(boolean forceOuterJoin, String a1, String a2, DbSqlContext ctx) {

   	String inheritance = inheritInfo != null ? inheritInfo.getWhere() : null;

    ctx.addJoin(forceOuterJoin?LEFT_OUTER:type, table, columns(), a1, a2, inheritance);
        
    return forceOuterJoin || LEFT_OUTER.equals(type);
  }

  /**
   * Explicitly add a (non-outer) join.
   */
  public void addInnerJoin(String a1, String a2, DbSqlContext ctx) {
   	String inheritance = inheritInfo != null ? inheritInfo.getWhere() : null;
    ctx.addJoin(JOIN, table, columns(), a1, a2, inheritance);
  }
}