com.querydsl.core.types.ExpressionUtils.createRootVariable()方法的使用及代码示例

x33g5p2x  于2022-01-19 转载在 其他  
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本文整理了Java中com.querydsl.core.types.ExpressionUtils.createRootVariable()方法的一些代码示例，展示了ExpressionUtils.createRootVariable()的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。ExpressionUtils.createRootVariable()方法的具体详情如下：
包路径：com.querydsl.core.types.ExpressionUtils
类名称：ExpressionUtils
方法名：createRootVariable

ExpressionUtils.createRootVariable介绍

[英]Create a new root variable based on the given path
[中]基于给定路径创建新的根变量

代码示例

代码示例来源：origin: querydsl/querydsl

@Override
public Expression<?> visit(Path<?> expr, Context context) {
  if (expr.getMetadata().getPathType() == PathType.COLLECTION_ANY) {
    Path<?> parent = (Path<?>) expr.getMetadata().getParent().accept(this, context);
    expr = ExpressionUtils.path(expr.getType(), PathMetadataFactory.forCollectionAny(parent));
    EntityPath<?> replacement = new EntityPathBase<Object>(expr.getType(),
        ExpressionUtils.createRootVariable(expr, replacedCounter++));
    context.add(expr, replacement);
    return replacement;
  } else if (expr.getMetadata().getParent() != null) {
    Context c = new Context();
    Path<?> parent = (Path<?>) expr.getMetadata().getParent().accept(this, c);
    if (c.replace) {
      context.add(c);
      return replaceParent(expr, parent);
    }
  }
  return expr;
}

代码示例来源：origin: com.querydsl/querydsl-jpa

@SuppressWarnings("unchecked")
@Override
public Expression<?> visit(Path<?> expr, @Nullable Void context) {
  expr = (Path<?>) super.visit(expr, null);
  PathMetadata pathMetadata = expr.getMetadata();
  if (pathMetadata.getPathType() == PathType.LISTVALUE
      || pathMetadata.getPathType() == PathType.LISTVALUE_CONSTANT) {
    Path<?> replacement = replacements.get(expr);
    if (replacement == null) {
      // join parent as path123 on index(path123) = ...
      Path parent = shorten(pathMetadata.getParent(), true);
      replacement = ExpressionUtils.path(expr.getType(),
          ExpressionUtils.createRootVariable(parent, replacements.size()));
      metadata.addJoin(JoinType.LEFTJOIN, ExpressionUtils.as(parent, replacement));
      metadata.addJoinCondition(ExpressionUtils.eq(
          (Expression) Expressions.operation(Integer.class, JPQLOps.INDEX, replacement),
          ExpressionUtils.toExpression(pathMetadata.getElement())));
      replacements.put(expr, replacement);
    }
    return replacement;
  } else {
    return super.visit(expr, context);
  }
}

代码示例来源：origin: com.querydsl/querydsl-jpa

@SuppressWarnings("unchecked")
@Override
public Expression<?> visit(Path<?> expr, @Nullable Void context) {
  expr = (Path<?>) super.visit(expr, null);
  PathMetadata pathMetadata = expr.getMetadata();
  if (pathMetadata.getPathType() == PathType.MAPVALUE
   || pathMetadata.getPathType() == PathType.MAPVALUE_CONSTANT) {
    Path<?> replacement = replacements.get(expr);
    if (replacement == null) {
      // join parent as path123 on key(path123) = ...
      Path parent = shorten(pathMetadata.getParent(), true);
      ParameterizedExpression parExpr = (ParameterizedExpression) pathMetadata.getParent();
      replacement = ExpressionUtils.path(parExpr.getParameter(1),
          ExpressionUtils.createRootVariable(parent, replacements.size()));
      metadata.addJoin(JoinType.LEFTJOIN, ExpressionUtils.as(parent, replacement));
      metadata.addJoinCondition(ExpressionUtils.eq(
          Expressions.operation(parExpr.getParameter(0), JPQLOps.KEY, replacement),
          ExpressionUtils.toExpression(pathMetadata.getElement())));
      replacements.put(expr, replacement);
    }
    return replacement;
  } else {
    return super.visit(expr, context);
  }
}

代码示例来源：origin: com.querydsl/querydsl-jpa

@SuppressWarnings("unchecked")
@Override
public Expression<?> visit(Operation<?> expr, @Nullable Void context) {
  if (expr.getOperator() == Ops.CONTAINS_KEY) {
    ParameterizedExpression map = (ParameterizedExpression<?>) expr.getArg(0);
    Expression key = expr.getArg(1);
    Path replacement = ExpressionUtils.path(map.getParameter(1),
        ExpressionUtils.createRootVariable((Path<?>) map, Math.abs(expr.hashCode())));
    metadata.addJoin(JoinType.LEFTJOIN, ExpressionUtils.as(map, replacement));
    metadata.addJoinCondition(ExpressionUtils.eq(
        Expressions.operation(map.getParameter(0), JPQLOps.KEY, replacement),
        key));
    return ExpressionUtils.isNotNull(replacement);
  } else if (expr.getOperator() == Ops.CONTAINS_VALUE) {
    ParameterizedExpression<?> map = (ParameterizedExpression<?>) expr.getArg(0);
    Expression<?> value = expr.getArg(1);
    return Expressions.predicate(JPQLOps.MEMBER_OF, value, map);
  } else {
    return super.visit(expr, context);
  }
}

代码示例来源：origin: com.querydsl/querydsl-jpa

@SuppressWarnings("unchecked")
@Override
protected Predicate exists(Context c, Predicate condition) {
  JPAQueryMixin<?> query = new JPAQueryMixin<Object>();
  query.setProjection(Expressions.ONE);
  for (int i = 0; i < c.paths.size(); i++) {
    Path<?> child = c.paths.get(i).getMetadata().getParent();
    EntityPath<Object> replacement = (EntityPath<Object>) c.replacements.get(i);
    if (c.paths.get(i).getType().isAnnotationPresent(Entity.class)) {
      query.addJoin(i == 0 ? JoinType.DEFAULT : JoinType.INNERJOIN, Expressions.as(
          Expressions.listPath((Class) c.paths.get(i).getType(), SimplePath.class,
              child.getMetadata()), replacement));
    } else {
      // join via parent
      Path<?> parent = child.getMetadata().getParent();
      EntityPathBase<Object> newParent = new EntityPathBase<Object>(parent.getType(),
          ExpressionUtils.createRootVariable(parent, Math.abs(condition.hashCode())));
      EntityPath<Object> newChild = new EntityPathBase<Object>(child.getType(),
          PathMetadataFactory.forProperty(newParent, child.getMetadata().getName()));
      query.from(newParent);
      query.addJoin(JoinType.INNERJOIN, Expressions.as(newChild, replacement));
      query.where(ExpressionUtils.eq(newParent, parent));
    }
  }
  c.clear();
  query.where(condition);
  return ExpressionUtils.predicate(Ops.EXISTS, asExpression(query.getMetadata()));
}

代码示例来源：origin: com.querydsl/querydsl-jpa

Path<T> newPath = ExpressionUtils.path(type, ExpressionUtils.createRootVariable(path));
leftJoin(path, newPath);
return newPath;
Path<T> oldPath = ExpressionUtils.path(path.getType(),
    new PathMetadata(parent, metadata.getElement(), metadata.getPathType()));
Path<T> newPath = ExpressionUtils.path(type, ExpressionUtils.createRootVariable(oldPath));
aliases.put(path, newPath);
leftJoin(oldPath, newPath);

代码示例来源：origin: com.querydsl/querydsl-jpa

/**
 * Shorten the parent path to a length of max 2 elements
 */
private Path<?> shorten(Path<?> path, boolean outer) {
  if (aliases.containsKey(path)) {
    return aliases.get(path);
  } else if (path.getMetadata().isRoot()) {
    return path;
  } else if (path.getMetadata().getParent().getMetadata().isRoot() && outer) {
    return path;
  } else {
    Class<?> type = JPAQueryMixin.getElementTypeOrType(path);
    Path<?> parent = shorten(path.getMetadata().getParent(), false);
    Path oldPath = ExpressionUtils.path(path.getType(),
        new PathMetadata(parent, path.getMetadata().getElement(), path.getMetadata().getPathType()));
    if (oldPath.getMetadata().getParent().getMetadata().isRoot() && outer) {
      return oldPath;
    } else {
      Path newPath = ExpressionUtils.path(type, ExpressionUtils.createRootVariable(oldPath));
      aliases.put(path, newPath);
      metadata.addJoin(JoinType.LEFTJOIN, ExpressionUtils.as(oldPath, newPath));
      return newPath;
    }
  }
}

代码示例来源：origin: com.querydsl/querydsl-jpa

/**
 * Shorten the parent path to a length of max 2 elements
 */
private Path<?> shorten(Path<?> path, boolean outer) {
  if (aliases.containsKey(path)) {
    return aliases.get(path);
  } else if (path.getMetadata().isRoot()) {
    return path;
  } else if (path.getMetadata().getParent().getMetadata().isRoot() && outer) {
    return path;
  } else {
    Class<?> type = JPAQueryMixin.getElementTypeOrType(path);
    Path<?> parent = shorten(path.getMetadata().getParent(), false);
    Path oldPath = ExpressionUtils.path(path.getType(),
        new PathMetadata(parent, path.getMetadata().getElement(), path.getMetadata().getPathType()));
    if (oldPath.getMetadata().getParent().getMetadata().isRoot() && outer) {
      return oldPath;
    } else {
      Path newPath = ExpressionUtils.path(type, ExpressionUtils.createRootVariable(oldPath));
      aliases.put(path, newPath);
      metadata.addJoin(JoinType.LEFTJOIN, ExpressionUtils.as(oldPath, newPath));
      return newPath;
    }
  }
}

代码示例来源：origin: com.querydsl/querydsl-core

@Override
public Expression<?> visit(Path<?> expr, Context context) {
  if (expr.getMetadata().getPathType() == PathType.COLLECTION_ANY) {
    Path<?> parent = (Path<?>) expr.getMetadata().getParent().accept(this, context);
    expr = ExpressionUtils.path(expr.getType(), PathMetadataFactory.forCollectionAny(parent));
    EntityPath<?> replacement = new EntityPathBase<Object>(expr.getType(),
        ExpressionUtils.createRootVariable(expr, replacedCounter++));
    context.add(expr, replacement);
    return replacement;
  } else if (expr.getMetadata().getParent() != null) {
    Context c = new Context();
    Path<?> parent = (Path<?>) expr.getMetadata().getParent().accept(this, c);
    if (c.replace) {
      context.add(c);
      return replaceParent(expr, parent);
    }
  }
  return expr;
}

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