com.persist.JsonOps.scala Maven / Gradle / Ivy
/*
* Copyright 2012-2015 Persist Software
*
* http://www.persist.com
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.persist
import scala.collection.immutable.HashMap
import JsonParse._
import JsonUnparse._
/**
*
* Provides types and functions for working with Json types.
*
* Json is represented by immutable Scala types.
* Instead of having separate Json types, type aliases are
* defined for Json forms.
*
* Scala types used for Json are
*
* - Json Object. Immutable Map[String,Json]. Note that keys are not ordered. When converting to a string with Compact or Pretty keys are sorted.
* - Json Array. Immutable Seq[Json]
* - Json String. String
* - Json Boolean. Boolean
* - Json Number. Int, Long, BigDecimal (with .), Double (with e)
* - Json Null. Null
*
* Any of the Json types can be at the top level
* of a document (not just array and object).
*
* The Json parser supports some extensions that are useful for human edited
* Json input (such as configurations).
*
* - Comments. The characters // to end of line are discarded during parsing.
* - Scala-like raw strings. Start with ""{ and end with }"". Treated as normal strings after parsing.
* - No quotes on simple names. If an object component name starts with a letter and contains
* only letters and digits the " quotes are not required. After parsing names with and without
* quotes are not distinguished.
*
*/
object JsonOps {
/**
*
* A type alias for all Json forms.
* Json values should be restricted by convention
* to only those types used to represent Json.
*
*/
type Json = Any
/**
*
* The Json null value.
*
*/
val jnull = null.asInstanceOf[Json]
/**
*
* A type alias for of Json Objects.
*/
type JsonObject = Map[String, Json]
/**
*
* A constructor for JsonObject.
*
* @param pairs a sequence of name value pairs.
*
* @return the constructed Json Object.
*/
def JsonObject(pairs: (String, Json)*): JsonObject = new HashMap[String, Json]() ++ pairs
/**
*
* An empty JsonObject.
*/
val emptyJsonObject = JsonObject()
/**
*
* A type alias for Json Arrays.
*/
type JsonArray = Seq[Json]
/**
*
* A constructor for JsonArray.
*
* @param elements a sequence of array element values.
*
* @return the constructed Json Array.
*
*/
def JsonArray(elements: Json*): JsonArray = List() ++ elements
/**
*
* An empty JsonArray.
*
*/
val emptyJsonArray = JsonArray()
/**
* A Json parser.
*
* @param s a Json string.
* @return the Json tree resulting from parsing the string.
*/
def Json(s: String): Json = {
parse(s)
}
/**
* A Json unparser. It produces the most compact single line string form.
*
* @param j a Json tree.
* @param safe if false bad data types in tree will throw exceptions; if
* true no exceptions are thrown and error information is included
* in the output (default is false).
* @param sort if false, fields in maps are not sorted and
* performance is improved.
* @return the Json string for the tree.
*/
def Compact(j: Json, safe: Boolean = false, sort:Boolean = true): String = {
compact(j, safe, sort)
}
/**
* A Json unparser. It produces a multiple line form
* designed for human readability.
*
* @param j a Json tree.
* @param indent the number of characters to indent the entire output (default is 0).
* @param width the maximum number of character that should be on a line (default is 50).
* This is only a goal; in practice some may contain more characters.
* @param count The maximum number of array elements that should be placed on a single
* line (default is 6).
* @param safe if false bad data types in tree will throw exceptions; if
* true no exceptions are thrown and error information is included
* in the output (default is false).
* @return
*/
def Pretty(j: Json, indent: Int = 0, width: Int = 50, count: Int = 6, safe: Boolean = false): String = {
pretty(j, indent, width, count, safe)
}
/**
*
* Get a value within a nested Json value.
*
* @param a the input Json value.
* @param ilist a list of values that are either strings or integers
* - A string selects the value of a JsonObject name-value pair where
* the name equals the string.
* - An integer i selects the ith elements of a JsonArray.
*
* @return the selected value or null if not present.
*
*/
def jget(a: Json, ilist: Any*): Json = {
if (ilist.size == 0) {
a
} else {
val result = (a, ilist.head) match {
case (a1: JsonArray, i1: Int) => {
if (0 <= i1 && i1 < a1.size) {
a1(i1)
} else {
null
}
}
case (a1: scala.collection.Map[String, Json]@unchecked, i1: String) => {
a1.getOrElse(i1, null)
}
case _ => null
}
jget(result, ilist.tail: _*)
}
}
/**
*
* Tests if a nested Json value is present.
*
* @param a the input Json value.
* @param ilist a list of values that are either strings or integers
* - A string selects the value of a JsonObject name-value pair where
* the name equals the string.
* - An integer i selects the ith elements of a JsonArray.
*
* @return true if the selected field is present.
*
*/
def jhas(a: Json, ilist: Any*): Boolean = {
if (ilist.size == 0) {
true
} else {
(a, ilist.head) match {
case (a1: JsonArray, i1: Int) => {
if (0 <= i1 && i1 < a1.size) {
if (ilist.size == 1) {
true
} else {
jhas(a1(i1), ilist.tail: _*)
}
} else {
false
}
}
case (a1: JsonObject@unchecked, i1: String) => {
a1.get(i1) match {
case Some(v) => {
if (ilist.size == 1) {
true
} else {
jhas(v, ilist.tail: _*)
}
}
case None => false
}
}
case _ => false
}
}
}
/**
*
* Replace a value within a nested Json value.
*
* @param a the input Json value.
* @param ilist a list of values that are either strings or integers
* - A string selects the value of a JsonObject name-value pair where
* the name equals the string.
* - An integer i selects the ith elements of a JsonArray.
* @param v the new value.
*
* @return a copy of the input with the value replaced.
*
*/
def jput(a: Json, ilist: Any*)(v: Json): Json = {
if (ilist.size == 0) {
a
} else {
(a, ilist.head) match {
case (a1: JsonArray, i1: Int) => {
if (0 <= i1 && i1 < a1.size) {
val (a2, a3) = a1.splitAt(i1)
val v1 = if (ilist.size == 1) {
v
} else {
jput(a1(i1), ilist.tail: _*)(v)
}
(a2 :+ v) ++ (a3.tail)
} else {
a1
}
}
case (a1: JsonObject@unchecked, i1: String) => {
if (ilist.size == 1) {
a1 + (i1 -> v)
} else {
val a2 = if (a1.contains(i1)) a1(i1) else emptyJsonObject
a1 + (i1 -> jput(a2, ilist.tail: _*)(v))
}
}
case _ => a
}
}
}
/**
*
* Delete a value within a nested Json value.
*
* @param a the input Json value.
* @param ilist a list of values that are either strings or integers
* - A string selects the value of a JsonObject name-value pair where
* the name equals the string.
* - An integer i selects the ith elements of a JsonArray.
*
* @return a copy of the input with the value replaced.
*
*/
def jdelete(a: Json, ilist: Any*): Json = {
if (ilist.size == 0) {
a
} else {
(a, ilist.head) match {
case (a1: JsonArray, i1: Int) => {
if (0 <= i1 && i1 < a1.size) {
val (a2, a3) = a1.splitAt(i1)
if (ilist.size == 1) {
a2 ++ (a3.tail)
} else {
val v = jdelete(a1(i1), ilist.tail: _*)
(a2 :+ v) ++ (a3.tail)
}
} else {
a1
}
}
case (a1: JsonObject@unchecked, i1: String) => {
if (a1.contains(i1)) {
if (ilist.size == 1) {
a1 - i1
} else {
a1 + (i1 -> jdelete(a1(i1), ilist.tail: _*))
}
} else {
a1
}
}
case _ => a
}
}
}
/**
*
* Insert a value within a nested Json value.
*
* @param a the input Json value.
* @param ilist a list of values that are either strings or integers
* - A string selects the value of a JsonObject name-value pair where
* the name equals the string.
* - An integer i selects the ith elements of a JsonArray.
* @param v the new value
*
* @return a copy of the input with the value inserted. For JsonArrays the value is inserted before the
* specified value.
*
*/
def jinsert(a: Json, ilist: Any*)(v: Json): Json = {
if (ilist.size == 0) {
a
} else {
(a, ilist.head) match {
case (a1: JsonArray, i1: Int) => {
if (0 <= i1 && i1 <= a1.size) {
val (a2, a3) = a1.splitAt(i1)
val v1 = if (ilist.size == 1) {
v
} else {
jput(a1(i1), ilist.tail: _*)(v)
}
(a2 :+ v) ++ a3
} else {
a1
}
}
case (a1: JsonObject@unchecked, i1: String) => {
if (!a1.contains(i1)) {
if (ilist.size == 1) {
a1 + (i1 -> v)
} else {
a1 + (i1 -> jput(a1(i1), ilist.tail: _*)(v))
}
} else {
a1
}
}
case _ => a
}
}
}
/**
*
* Get the size of a Json value.
* - For a Json Object the number of name-value pairs.
* - For a Json Array the number of elements.
* - For anything else, 0.
*
*/
def jsize(j: Json): Int = {
j match {
case a1: JsonObject@unchecked => a1.size
case a1: JsonArray => a1.size
case x => 0
}
}
/**
*
* Get a string value within a nested Json value.
*
* @param ilist a list of values that are either strings or integers
* - A string selects the value of a JsonObject name-value pair where
* the name equals the string.
* - An integer i selects the ith elements of a JsonArray.
*
* @return the selected string value or "" if not present.
*
*/
def jgetString(a: Json, ilist: Any*): String = {
jget(a, ilist: _*) match {
case s: String => s
case x => ""
}
}
/**
*
* Get a boolean value within a nested Json value.
*
* @param ilist a list of values that are either strings or integers
* - A string selects the value of a JsonObject name-value pair where
* the name equals the string.
* - An integer i selects the ith elements of a JsonArray.
*
* @return the selected boolean value or false if not present.
*
*/
def jgetBoolean(a: Json, ilist: Any*): Boolean = {
jget(a, ilist: _*) match {
case b: Boolean => b
case x => false
}
}
/**
*
* Get an integer value within a nested Json value.
*
* @param ilist a list of values that are either strings or integers
* - A string selects the value of a JsonObject name-value pair where
* the name equals the string.
* - An integer i selects the ith elements of a JsonArray.
*
* @return the selected integer value or 0 if not present.
*
*/
def jgetInt(a: Json, ilist: Any*): Int = {
jget(a, ilist: _*) match {
case l: Long => {
val i = l.toInt
if (i == l) {
i
} else {
0
}
}
case i: Int => i
case x => 0
}
}
/**
*
* Get a long value within a nested Json value.
*
* @param ilist a list of values that are either strings or integers
* - A string selects the value of a JsonObject name-value pair where
* the name equals the string.
* - An integer i selects the ith elements of a JsonArray.
*
* @return the selected long value or 0 if not present.
*
*/
def jgetLong(a: Json, ilist: Any*): Long = {
jget(a, ilist: _*) match {
case l: Long => l
case i: Int => i
case x => 0
}
}
/**
*
* Get a big decimal value within a nested Json value.
*
* @param ilist a list of values that are either strings or integers
* - A string selects the value of a JsonObject name-value pair where
* the name equals the string.
* - An integer i selects the ith elements of a JsonArray.
*
* @return the selected big decimal value or 0.0 if not present.
*
*/
def jgetBigDecimal(a: Json, ilist: Any*): BigDecimal = {
jget(a, ilist: _*) match {
case b: BigDecimal => b
case d: Double => BigDecimal(d)
case l: Long => l
case i: Int => i
case x => 0
}
}
/**
*
* Get a double value within a nested Json value.
*
* @param ilist a list of values that are either strings or integers
* - A string selects the value of a JsonObject name-value pair where
* the name equals the string.
* - An integer i selects the ith elements of a JsonArray.
*
* @return the selected double value or 0.0 if not present.
*
*/
def jgetDouble(a: Json, ilist: Any*): Double = {
jget(a, ilist: _*) match {
case d: Double => d
case b: BigDecimal => b.toDouble
case l: Long => l
case i: Int => i
case x => 0
}
}
/**
*
* Get a JsonArray value within a nested Json value.
*
* @param ilist a list of values that are either strings or integers
* - A string selects the value of a JsonObject name-value pair where
* the name equals the string.
* - An integer i selects the ith elements of a JsonArray.
*
* @return the selected JsonArray value or an empty JsonArray if not present.
*
*/
def jgetArray(a: Json, ilist: Any*): JsonArray = {
jget(a, ilist: _*) match {
case s: JsonArray => s
case x => emptyJsonArray
}
}
/**
*
* Get a JsonObject value within a nested Json value.
*
* @param ilist a list of values that are either strings or integers
* - A string selects the value of a JsonObject name-value pair where
* the name equals the string.
* - An integer i selects the ith elements of a JsonArray.
*
* @return the selected JsonObject value or an empty JsonObject if not present.
*
*/
def jgetObject(a: Json, ilist: Any*): JsonObject = {
jget(a, ilist: _*) match {
case m: JsonObject@unchecked => m
case x => emptyJsonObject
}
}
/**
*
* An extractor for nested Json values.
*
* @param ilist a list of values that are either strings or integers
* - A string selects the value of a JsonObject name-value pair where
* the name equals the string.
* - An integer i selects the ith elements of a JsonArray.
*
* @example {{{
* val A = jfield("a")
* val B = jfield("b")
* val C = jfield("c")
* jval match {
* case a:A & b:B => foo(a,b)
* case c:C => bar(c)
* }
* }}}
*
*/
case class jfield(ilist: Any*) {
def unapply(m: Json) = {
val result = jget(m, ilist: _*)
if (result == null) {
None
} else {
Some(result)
}
}
}
/**
*
* An extractor composition operator.
*
* @example {{{
* val A = jfield("a")
* val B = jfield("b")
* val C = jfield("c")
* jval match {
* case a:A & b:B => foo(a,b)
* case c:C => bar(c)
* }
* }}}
*
*/
object & {
def unapply(a: Any) = Some(a, a)
}
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