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Default provider for JSR 374:Java API for Processing JSON
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright (c) 2015-2017 Oracle and/or its affiliates. All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can
* obtain a copy of the License at
* https://oss.oracle.com/licenses/CDDL+GPL-1.1
* or LICENSE.txt. See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at LICENSE.txt.
*
* GPL Classpath Exception:
* Oracle designates this particular file as subject to the "Classpath"
* exception as provided by Oracle in the GPL Version 2 section of the License
* file that accompanied this code.
*
* Modifications:
* If applicable, add the following below the License Header, with the fields
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package org.glassfish.json;
import javax.json.JsonArray;
import javax.json.JsonException;
import javax.json.JsonObject;
import javax.json.JsonPointer;
import javax.json.JsonStructure;
import javax.json.JsonValue;
import java.io.Serializable;
import java.util.function.BiFunction;
/**
* This class is an immutable representation of a JSON Pointer as specified in
* RFC 6901.
*
* A JSON Pointer, when applied to a target {@link JsonValue},
* defines a reference location in the target.
* An empty JSON Pointer string defines a reference to the target itself.
* If the JSON Pointer string is non-empty, it must be a sequence
* of '/' prefixed tokens, and the target must either be a {@link JsonArray}
* or {@link JsonObject}. If the target is a {@code JsonArray}, the pointer
* defines a reference to an array element, and the last token specifies the index.
* If the target is a {@link JsonObject}, the pointer defines a reference to a
* name/value pair, and the last token specifies the name.
*
* The method {@link #getValue getValue()} returns the referenced value.
* The methods {@link #add add()}, {@link #replace replace()},
* and {@link #remove remove()} executes the operations specified in
* RFC 6902.
*
* @since 1.1
*/
public final class JsonPointerImpl implements JsonPointer, Serializable {
private static final long serialVersionUID = -8123110179640843141L;
private final String[] tokens;
private final String jsonPointer;
/**
* Constructs and initializes a JsonPointerImpl.
* @param jsonPointer the JSON Pointer string
* @throws NullPointerException if {@code jsonPointer} is {@code null}
* @throws JsonException if {@code jsonPointer} is not a valid JSON Pointer
*/
public JsonPointerImpl(String jsonPointer) {
this.jsonPointer = jsonPointer;
tokens = jsonPointer.split("/", -1); // keep the trailing blanks
if (! "".equals(tokens[0])) {
throw new JsonException(JsonMessages.POINTER_FORMAT_INVALID());
}
for (int i = 1; i < tokens.length; i++) {
String token = tokens[i];
StringBuilder reftoken = new StringBuilder();
for (int j = 0; j < token.length(); j++) {
char ch = token.charAt(j);
if (ch == '~' && j < token.length() - 1) {
char ch1 = token.charAt(j+1);
if (ch1 == '0') {
ch = '~'; j++;
} else if (ch1 == '1') {
ch = '/'; j++;
}
}
reftoken.append(ch);
}
tokens[i] = reftoken.toString();
}
}
/**
* Compares this {@code JsonPointer} with another object.
* @param obj the object to compare this {@code JsonPointer} against
* @return true if the given object is a {@code JsonPointer} with the same
* reference tokens as this one, false otherwise.
*/
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null || obj.getClass() != JsonPointerImpl.class)
return false;
return jsonPointer.equals(((JsonPointerImpl)obj).jsonPointer);
}
/**
* Returns the hash code value for this {@code JsonPointer} object.
* The hash code of this object is defined by the hash codes of it's reference tokens.
*
* @return the hash code value for this {@code JsonPointer} object
*/
@Override
public int hashCode() {
return jsonPointer.hashCode();
}
/**
* Returns {@code true} if there is a value at the referenced location in the specified {@code target}.
*
* @param target the target referenced by this {@code JsonPointer}
* @return {@code true} if this pointer points to a value in a specified {@code target}.
*/
@Override
public boolean containsValue(JsonStructure target) {
NodeReference[] refs = getReferences(target);
return refs[0].contains();
}
/**
* Returns the value at the referenced location in the specified {@code target}
*
* @param target the target referenced by this {@code JsonPointer}
* @return the referenced value in the target.
* @throws NullPointerException if {@code target} is null
* @throws JsonException if the referenced value does not exist
*/
@Override
public JsonValue getValue(JsonStructure target) {
NodeReference[] refs = getReferences(target);
return refs[0].get();
}
/**
* Adds or replaces a value at the referenced location in the specified
* {@code target} with the specified {@code value}.
*
* - If the reference is the target (empty JSON Pointer string),
* the specified {@code value}, which must be the same type as
* specified {@code target}, is returned.
* - If the reference is an array element, the specified {@code value} is inserted
* into the array, at the referenced index. The value currently at that location, and
* any subsequent values, are shifted to the right (adds one to the indices).
* Index starts with 0. If the reference is specified with a "-", or if the
* index is equal to the size of the array, the value is appended to the array.
* - If the reference is a name/value pair of a {@code JsonObject}, and the
* referenced value exists, the value is replaced by the specified {@code value}.
* If the value does not exist, a new name/value pair is added to the object.
*
*
* @param target the target referenced by this {@code JsonPointer}
* @param value the value to be added
* @return the transformed {@code target} after the value is added.
* @throws NullPointerException if {@code target} is {@code null}
* @throws JsonException if the reference is an array element and
* the index is out of range ({@code index < 0 || index > array size}),
* or if the pointer contains references to non-existing objects or arrays.
*/
@Override
public JsonStructure add(JsonStructure target, JsonValue value) {
return execute(NodeReference::add, target, value);
}
/**
* Replaces the value at the referenced location in the specified
* {@code target} with the specified {@code value}.
*
* @param target the target referenced by this {@code JsonPointer}
* @param value the value to be stored at the referenced location
* @return the transformed {@code target} after the value is replaced.
* @throws NullPointerException if {@code target} is {@code null}
* @throws JsonException if the referenced value does not exist,
* or if the reference is the target.
*/
@Override
public JsonStructure replace(JsonStructure target, JsonValue value) {
return execute(NodeReference::replace, target, value);
}
/**
* Removes the value at the reference location in the specified {@code target}
*
* @param target the target referenced by this {@code JsonPointer}
* @return the transformed {@code target} after the value is removed.
* @throws NullPointerException if {@code target} is {@code null}
* @throws JsonException if the referenced value does not exist,
* or if the reference is the target.
*/
@Override
public JsonStructure remove(JsonStructure target) {
return execute((r,v)->r.remove(), target, null);
}
/**
* Executes the operation
* @param op a {code BiFunction} used to specify the operation to execute on
* the leaf node of the Json Pointer
* @param target the target JsonStructure for this JsonPointer
* @param value the JsonValue for add and replace, can be null for getvalue and remove
*/
private JsonStructure execute(BiFunction op,
JsonStructure target, JsonValue value) {
NodeReference[] refs = getReferences(target);
JsonStructure result = op.apply(refs[0], value);
for (int i = 1; i < refs.length; i++) {
result = refs[i].replace(result);
}
return result;
}
/**
* Computes the {@code NodeReference}s for each node on the path of
* the JSON Pointer, in reverse order, starting from the leaf node
*/
private NodeReference[] getReferences(JsonStructure target) {
NodeReference[] references;
// First check if this is a reference to a JSON value tree
if (tokens.length == 1) {
references = new NodeReference[1];
references[0] = NodeReference.of(target);
return references;
}
references = new NodeReference[tokens.length-1];
JsonValue value = target;
int s = tokens.length;
for (int i = 1; i < s; i++) {
// Start with index 1, skipping the "" token
switch (value.getValueType()) {
case OBJECT:
JsonObject object = (JsonObject) value;
references[s-i-1] = NodeReference.of(object, tokens[i]);
if (i < s-1) {
value = object.get(tokens[i]);
if (value == null) {
// Except for the last name, the mapping must exist
throw new JsonException(JsonMessages.POINTER_MAPPING_MISSING(object, tokens[i]));
}
}
break;
case ARRAY:
int index = getIndex(tokens[i]);
JsonArray array = (JsonArray) value;
references[s-i-1] = NodeReference.of(array, index);
if (i < s-1 && index != -1) {
// The last array index in the path can have index value of -1
// ("-" in the JSON pointer)
value = array.get(index);
}
break;
default:
throw new JsonException(JsonMessages.POINTER_REFERENCE_INVALID(value.getValueType()));
}
}
return references;
}
/**
* Computes the array index
* @param token the input string token
* @return the array index. -1 if the token is "-"
* @throws JsonException if the string token is not in correct format
*/
static private int getIndex(String token) {
if (token == null || token.length() == 0) {
throw new JsonException(JsonMessages.POINTER_ARRAY_INDEX_ERR(token));
}
if (token.equals("-")) {
return -1;
}
if (token.equals("0")) {
return 0;
}
if (token.charAt(0) == '+' || token.charAt(0) == '-') {
throw new JsonException(JsonMessages.POINTER_ARRAY_INDEX_ERR(token));
}
try {
return Integer.parseInt(token);
} catch (NumberFormatException ex) {
throw new JsonException(JsonMessages.POINTER_ARRAY_INDEX_ILLEGAL(token), ex);
}
}
}
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