Introduce Exec interface and implementers (#1)

Reviewed-on: #1

cache/cache.go

@@ -0,0 +1,47 @@
+package cache
+
+import (
+	"sync"
+
+	"git.gdulai.com/gdulai/simpleorm/schema"
+)
+
+type SchemaCache struct {
+	mu   sync.RWMutex
+	data map[string]*schema.Table
+}
+
+func NewSchemaCache(tables []*schema.Table) *SchemaCache {
+	cache := &SchemaCache{
+		data: make(map[string]*schema.Table),
+	}
+	for _, table := range tables {
+		cache.add(table)
+	}
+
+	return cache
+}
+
+func (o *SchemaCache) add(table *schema.Table) {
+	o.mu.Lock()
+	defer o.mu.Unlock()
+	o.data[table.Type.Name()] = table
+}
+
+func (o *SchemaCache) Get(typeName string) (*schema.Table, bool) {
+	o.mu.RLock()
+	defer o.mu.RUnlock()
+	table, ok := o.data[typeName]
+	return table, ok
+}
+
+func (o *SchemaCache) GetAll() []*schema.Table {
+	o.mu.RLock()
+	defer o.mu.RUnlock()
+	var result []*schema.Table
+
+	for _, v := range o.data {
+		result = append(result, v)
+	}
+	return result
+}