com.yahoo.text.JSON Maven / Gradle / Ivy
// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.text;
import com.yahoo.slime.Slime;
import com.yahoo.slime.SlimeUtils;
import java.util.Map;
/**
* Static methods for working with JSON.
*
* @author bratseth
*/
public final class JSON {
/** No instances */
private JSON() {}
/**
* Outputs a map as a JSON 'object' string, provided that the map values
* are either
*
* - String
*
- Number
*
- Any object whose toString returns JSON
*
*/
public static String encode(Map map) {
StringBuilder b = new StringBuilder("{");
for (Map.Entry entry : map.entrySet()) {
b.append("\"").append(escape(entry.getKey())).append("\":");
if (entry.getValue() instanceof String)
b.append("\"").append(escape(entry.getValue().toString())).append("\"");
else // Number, or some other object which returns JSON
b.append(entry.getValue());
b.append(",");
}
if (b.length()>1)
b.setLength(b.length()-1); // remove last comma
b.append("}");
return b.toString();
}
/** Returns the given string as a properly json escaped string */
public static String escape(String s) {
StringBuilder b = null; // lazy create to optimize for "nothing to do" case
for (int i=0; i < s.length(); i = s.offsetByCodePoints(i, 1)) {
final int codepoint = s.codePointAt(i);
if (codepoint == '"') {
if (b == null)
b = new StringBuilder(s.substring(0, i));
b.append('\\');
}
if (b != null)
b.appendCodePoint(codepoint);
}
return b != null ? b.toString() : s;
}
/**
* Test whether two JSON strings are equal, e.g. the order of fields in an object is irrelevant.
*
* When comparing two numbers of the two JSON strings, the result is only guaranteed to be
* correct if (a) both are integers (without fraction and exponent) and each fits in a long, or
* (b) both are non-integers, fits in a double, and are syntactically identical. Examples
* of pairs that may not be equal: 1 and 1.0 (different types), 0.1 and 1e-1, 0.0 and 0.00.
*
* @throws RuntimeException on invalid JSON
*/
public static boolean equals(String left, String right) {
Slime leftSlime = SlimeUtils.jsonToSlimeOrThrow(left);
Slime rightSlime = SlimeUtils.jsonToSlimeOrThrow(right);
return leftSlime.equalTo(rightSlime);
}
public static String canonical(String jsonString) {
return SlimeUtils.jsonToSlimeOrThrow(jsonString).toString();
}
}