builder.go

package builder

import "fmt"

const (
	defaultMaxTotal = 10
	defaultMaxIdle  = 9
	defaultMinIdle  = 1
)

// ResourcePoolConfig resource pool
type ResourcePoolConfig struct {
	name     string
	maxTotal int
	maxIdle  int
	minIdle  int
}

// ResourcePoolConfigBuilder 用于构建 ResourcePoolConfig
type ResourcePoolConfigBuilder struct {
	err      error
	name     string
	maxTotal int
	maxIdle  int
	minIdle  int
}

// SetName SetName
func (b *ResourcePoolConfigBuilder) SetName(name string) {
	if b.err != nil {
		return
	}
	if name == "" {
		b.err = fmt.Errorf("name can not be empty")
	}
	b.name = name
}

// SetMinIdle SetMinIdle
func (b *ResourcePoolConfigBuilder) SetMinIdle(minIdle int) {
	if b.err != nil {
		return
	}
	if minIdle < 0 {
		b.err = fmt.Errorf("max tatal cannot < 0, input: %d", minIdle)
	}
	b.minIdle = minIdle
}

// SetMaxIdle SetMaxIdle
func (b *ResourcePoolConfigBuilder) SetMaxIdle(maxIdle int) {
	if b.err != nil {
		return
	}
	if maxIdle < 0 {
		b.err = fmt.Errorf("max tatal cannot < 0, input: %d", maxIdle)
	}
	b.maxIdle = maxIdle
}

// SetMaxTotal SetMaxTotal
func (b *ResourcePoolConfigBuilder) SetMaxTotal(maxTotal int) {
	if b.err != nil {
		return
	}
	if maxTotal <= 0 {
		b.err = fmt.Errorf("max tatal cannot <= 0, input: %d", maxTotal)
	}
	b.maxTotal = maxTotal
}

// Build Build
func (b *ResourcePoolConfigBuilder) Build() (*ResourcePoolConfig, error) {
	if b.err != nil {
		return nil, b.err
	}

	if b.name == "" {
		return nil, fmt.Errorf("name can not be empty")
	}

	// 设置默认值
	if b.minIdle == 0 {
		b.minIdle = defaultMinIdle
	}

	if b.maxIdle == 0 {
		b.maxIdle = defaultMaxIdle
	}

	if b.maxTotal == 0 {
		b.maxTotal = defaultMaxTotal
	}

	if b.maxTotal < b.maxIdle {
		return nil, fmt.Errorf("max total(%d) cannot < max idle(%d)", b.maxTotal, b.maxIdle)
	}

	if b.minIdle > b.maxIdle {
		return nil, fmt.Errorf("max idle(%d) cannot < min idle(%d)", b.maxIdle, b.minIdle)
	}

	return &ResourcePoolConfig{
		name:     b.name,
		maxTotal: b.maxTotal,
		maxIdle:  b.maxIdle,
		minIdle:  b.minIdle,
	}, nil
}