本文整理了Java中com.querydsl.core.types.ExpressionUtils.extract()方法的一些代码示例，展示了ExpressionUtils.extract()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.extract()方法的具体详情如下：
包路径：com.querydsl.core.types.ExpressionUtils
类名称：ExpressionUtils
方法名：extract

ExpressionUtils.extract介绍

[英]Get the potentially wrapped expression
[中]获取潜在的包装表达式

代码示例

代码示例来源：origin: querydsl/querydsl

/**
 * Create a BooleanBuilder with the given initial value
 *
 * @param initial initial value
 */
public BooleanBuilder(Predicate initial) {
  predicate = (Predicate) ExpressionUtils.extract(initial);
}

代码示例来源：origin: querydsl/querydsl

/**
 * Create a new JTSGeometryExpression
 *
 * @param expr Expression of type Geometry
 * @return new JTSGeometryExpression
 */
public static <T extends Geometry> JTSGeometryExpression<T> asJTSGeometry(
    Expression<T> expr) {
  Expression<T> underlyingMixin = ExpressionUtils.extract(expr);
  return new JTSGeometryExpression<T>(underlyingMixin) {
    private static final long serialVersionUID = -6714044005570420009L;
    @Override
    public <R, C> R accept(Visitor<R, C> v, C context) {
      return this.mixin.accept(v, context);
    }
  };
}

代码示例来源：origin: querydsl/querydsl

@Override
public Object convert(final List<?> args) {
  final Object arg = args.get(index);
  if (arg instanceof Expression) {
    return ExpressionUtils.extract((Expression<?>) arg);
  } else {
    return arg;
  }
}

代码示例来源：origin: querydsl/querydsl

/**
 * Create the intersection of the given arguments
 *
 * @param left lhs of expression
 * @param right rhs of expression
 * @return left and right
 */
public static Predicate and(Predicate left, Predicate right) {
  left = (Predicate) extract(left);
  right = (Predicate) extract(right);
  if (left == null) {
    return right;
  } else if (right == null) {
    return left;
  } else {
    return predicate(Ops.AND, left, right);
  }
}

代码示例来源：origin: querydsl/querydsl

/**
 * Create a {@code left or right} expression
 *
 * @param left lhs of expression
 * @param right rhs of expression
 * @return left or right
 */
public static Predicate or(Predicate left, Predicate right) {
  left = (Predicate) extract(left);
  right = (Predicate) extract(right);
  if (left == null) {
    return right;
  } else if (right == null) {
    return left;
  } else {
    return predicate(Ops.OR, left, right);
  }
}

代码示例来源：origin: querydsl/querydsl

@Override
public void addHaving(Predicate e) {
  if (e == null) {
    return;
  }
  e = (Predicate) ExpressionUtils.extract(e);
  if (e != null) {
    // having elements can't be validated, since they can refer to projection elements
    // that are declared later
    having = and(having, e);
  }
}

代码示例来源：origin: querydsl/querydsl

private static Expression<?> asExpression(Object arg) {
  if (arg instanceof Expression) {
    return ExpressionUtils.extract((Expression<?>) arg);
  } else {
    return Expressions.constant(arg);
  }
}

代码示例来源：origin: querydsl/querydsl

/**
 * Create a {@code this && right} expression
 *
 * <p>Returns an intersection of this and the given expression</p>
 *
 * @param right right hand side of the union
 * @return {@code this &amp;&amp; right}
 */
public BooleanExpression and(@Nullable Predicate right) {
  right = (Predicate) ExpressionUtils.extract(right);
  if (right != null) {
    return Expressions.booleanOperation(Ops.AND, mixin, right);
  } else {
    return this;
  }
}

代码示例来源：origin: querydsl/querydsl

/**
 * Create a {@code this || right} expression
 *
 * <p>Returns a union of this and the given expression</p>
 *
 * @param right right hand side of the union
 * @return this || right
 */
public BooleanExpression or(@Nullable Predicate right) {
  right = (Predicate) ExpressionUtils.extract(right);
  if (right != null) {
    return Expressions.booleanOperation(Ops.OR, mixin, right);
  } else {
    return this;
  }
}

代码示例来源：origin: querydsl/querydsl

private static Expression<?> unwrap(Expression<?> expr) {
  expr = ExpressionUtils.extract(expr);
  if (expr instanceof Operation && ((Operation<?>) expr).getOperator() == Ops.ALIAS) {
    return ((Operation<?>) expr).getArg(0);
  }
  return expr;
}

代码示例来源：origin: querydsl/querydsl

public Query toQuery(Expression<?> expr, QueryMetadata metadata) {
  if (expr instanceof Operation<?>) {
    return toQuery((Operation<?>) expr, metadata);
  } else {
    return toQuery(ExpressionUtils.extract(expr), metadata);
  }
}

代码示例来源：origin: querydsl/querydsl

public Query toQuery(Expression<?> expr, QueryMetadata metadata) {
  if (expr instanceof Operation<?>) {
    return toQuery((Operation<?>) expr, metadata);
  } else {
    return toQuery(ExpressionUtils.extract(expr), metadata);
  }
}

代码示例来源：origin: querydsl/querydsl

public Query toQuery(Expression<?> expr, QueryMetadata metadata) {
  if (expr instanceof Operation<?>) {
    return toQuery((Operation<?>) expr, metadata);
  } else {
    return toQuery(ExpressionUtils.extract(expr), metadata);
  }
}

代码示例来源：origin: querydsl/querydsl

@Override
public void addWhere(Predicate e) {
  if (e == null) {
    return;
  }
  e = (Predicate) ExpressionUtils.extract(e);
  if (e != null) {
    validate(e);
    where = and(where, e);
  }
}

代码示例来源：origin: querydsl/querydsl

/**
 * Create a new GeometryExpression
 *
 * @param expr Expression of type Geometry
 * @return new GeometryExpression
 */
public static <T extends Geometry> GeometryExpression<T> asGeometry(Expression<T> expr) {
  Expression<T> underlyingMixin = ExpressionUtils.extract(expr);
  if (underlyingMixin instanceof PathImpl) {
    return new GeometryPath<T>((PathImpl<T>) underlyingMixin);
  } else if (underlyingMixin instanceof OperationImpl) {
    return new GeometryOperation<T>((OperationImpl<T>) underlyingMixin);
  } else {
    return new GeometryExpression<T>(underlyingMixin) {
      private static final long serialVersionUID = -6714044005570420009L;
      @Override
      public <R, C> R accept(Visitor<R, C> v, C context) {
        return this.mixin.accept(v, context);
      }
    };
  }
}

代码示例来源：origin: querydsl/querydsl

@Override
  protected Predicate convert(Predicate predicate, Role role) {
    predicate = (Predicate) ExpressionUtils.extract(predicate);
    if (predicate != null) {
      Context context = new Context();
      Predicate transformed = (Predicate) predicate.accept(collectionAnyVisitor, context);
      for (int i = 0; i < context.paths.size(); i++) {
        leftJoin(
          (Path) context.paths.get(i).getMetadata().getParent(),
          (Path) context.replacements.get(i));
        on(ANY);
      }
      return transformed;
    } else {
      return predicate;
    }
  }
}

代码示例来源：origin: querydsl/querydsl

/**
 * Create a new NumberExpression
 *
 * @param expr Expression of type Number
 * @return new NumberExpression
 */
public static <T extends Number & Comparable<?>> NumberExpression<T> asNumber(Expression<T> expr) {
  Expression<T> underlyingMixin = ExpressionUtils.extract(expr);
  if (underlyingMixin instanceof PathImpl) {
    return new NumberPath<T>((PathImpl<T>) underlyingMixin);
  } else if (underlyingMixin instanceof OperationImpl) {
    return new NumberOperation<T>((OperationImpl<T>) underlyingMixin);
  } else if (underlyingMixin instanceof TemplateExpressionImpl) {
    return new NumberTemplate<T>((TemplateExpressionImpl<T>) underlyingMixin);
  } else {
    return new NumberExpression<T>(underlyingMixin) {
      private static final long serialVersionUID = -8712299418891960222L;
      @Override
      public <R, C> R accept(Visitor<R, C> v, C context) {
        return this.mixin.accept(v, context);
      }
    };
  }
}

代码示例来源：origin: querydsl/querydsl

/**
 * Create a new BooleanExpression
 *
 * @param expr Expression of type Boolean
 * @return new BooleanExpression
 */
public static BooleanExpression asBoolean(Expression<Boolean> expr) {
  Expression<Boolean> underlyingMixin = ExpressionUtils.extract(expr);
  if (underlyingMixin instanceof PathImpl) {
    return new BooleanPath((PathImpl<Boolean>) underlyingMixin);
  } else if (underlyingMixin instanceof PredicateOperation) {
    return new BooleanOperation((PredicateOperation) underlyingMixin);
  } else if (underlyingMixin instanceof PredicateTemplate) {
    return new BooleanTemplate((PredicateTemplate) underlyingMixin);
  } else {
    return new BooleanExpression(underlyingMixin) {
      private static final long serialVersionUID = -8712299418891960222L;
      @Override
      public <R, C> R accept(Visitor<R, C> v, C context) {
        return this.mixin.accept(v, context);
      }
    };
  }
}

代码示例来源：origin: querydsl/querydsl

/**
 * Create a new EnumExpression
 *
 * @param expr Expression of type Enum
 * @return new EnumExpression
 */
public static <T extends Enum<T>> EnumExpression<T> asEnum(Expression<T> expr) {
  Expression<T> underlyingMixin = ExpressionUtils.extract(expr);
  if (underlyingMixin instanceof PathImpl) {
    return new EnumPath<T>((PathImpl<T>) underlyingMixin);
  } else if (underlyingMixin instanceof OperationImpl) {
    return new EnumOperation<T>((OperationImpl<T>) underlyingMixin);
  } else if (underlyingMixin instanceof TemplateExpressionImpl) {
    return new EnumTemplate<T>((TemplateExpressionImpl<T>) underlyingMixin);
  } else {
    return new EnumExpression<T>(underlyingMixin) {
      private static final long serialVersionUID = 949681836002045152L;
      @Override
      public <R, C> R accept(Visitor<R, C> v, C context) {
        return this.mixin.accept(v, context);
      }
    };
  }
}

代码示例来源：origin: querydsl/querydsl

@Test
public void and_empty() {
  BooleanBuilder builder = new BooleanBuilder();
  builder.and(new BooleanBuilder());
  assertNull(ExpressionUtils.extract(builder));
}