initial import

core/conf/properties.go

@@ -0,0 +1,109 @@
+package conf
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+	"sync"
+
+	"zero/core/iox"
+)
+
+// PropertyError represents a configuration error message.
+type PropertyError struct {
+	error
+	message string
+}
+
+// Properties interface provides the means to access configuration.
+type Properties interface {
+	GetString(key string) string
+	SetString(key, value string)
+	GetInt(key string) int
+	SetInt(key string, value int)
+	ToString() string
+}
+
+// Properties config is a key/value pair based configuration structure.
+type mapBasedProperties struct {
+	properties map[string]string
+	lock       sync.RWMutex
+}
+
+// Loads the properties into a properties configuration instance. May return the
+// configuration itself along with an error that indicates if there was a problem loading the configuration.
+func LoadProperties(filename string) (Properties, error) {
+	lines, err := iox.ReadTextLines(filename, iox.WithoutBlank(), iox.OmitWithPrefix("#"))
+	if err != nil {
+		return nil, nil
+	}
+
+	raw := make(map[string]string)
+	for i := range lines {
+		pair := strings.Split(lines[i], "=")
+		if len(pair) != 2 {
+			// invalid property format
+			return nil, &PropertyError{
+				message: fmt.Sprintf("invalid property format: %s", pair),
+			}
+		}
+
+		key := strings.TrimSpace(pair[0])
+		value := strings.TrimSpace(pair[1])
+		raw[key] = value
+	}
+
+	return &mapBasedProperties{
+		properties: raw,
+	}, nil
+}
+
+func (config *mapBasedProperties) GetString(key string) string {
+	config.lock.RLock()
+	ret := config.properties[key]
+	config.lock.RUnlock()
+
+	return ret
+}
+
+func (config *mapBasedProperties) SetString(key, value string) {
+	config.lock.Lock()
+	config.properties[key] = value
+	config.lock.Unlock()
+}
+
+func (config *mapBasedProperties) GetInt(key string) int {
+	config.lock.RLock()
+	// default 0
+	value, _ := strconv.Atoi(config.properties[key])
+	config.lock.RUnlock()
+
+	return value
+}
+
+func (config *mapBasedProperties) SetInt(key string, value int) {
+	config.lock.Lock()
+	config.properties[key] = strconv.Itoa(value)
+	config.lock.Unlock()
+}
+
+// Dumps the configuration internal map into a string.
+func (config *mapBasedProperties) ToString() string {
+	config.lock.RLock()
+	ret := fmt.Sprintf("%s", config.properties)
+	config.lock.RUnlock()
+
+	return ret
+}
+
+// Returns the error message.
+func (configError *PropertyError) Error() string {
+	return configError.message
+}
+
+// Builds a new properties configuration structure
+func NewProperties() Properties {
+	return &mapBasedProperties{
+		properties: make(map[string]string),
+	}
+}