/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to you 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 org.apache.pivot.json;
import org.apache.pivot.beans.BeanAdapter;
import org.apache.pivot.collections.ArrayList;
import org.apache.pivot.collections.Dictionary;
import org.apache.pivot.collections.Sequence;
/**
* Contains utility methods for working with JSON or JSON-like data structures.
*/
public class JSON {
/**
* Returns the value at a given path.
*
* @param root
* The root object.
*
* @param path
* The path to the value as a JavaScript path.
*
* @return
* The value at the given path.
*
* @see #get(Object, Sequence)
*/
@SuppressWarnings("unchecked")
public static <T> T get(Object root, String path) {
return (T)get(root, parse(path));
}
/**
* Returns the value at a given path.
*
* @param root
* The root object.
*
* @param keys
* The path to the value as a sequence of keys.
*
* @return
* The value at the given path.
*/
@SuppressWarnings("unchecked")
public static <T> T get(Object root, Sequence<String> keys) {
if (keys == null) {
throw new IllegalArgumentException("keys is null.");
}
Object value = root;
for (int i = 0, n = keys.getLength(); i < n; i++) {
if (value == null) {
break;
}
String key = keys.get(i);
BeanAdapter beanAdapter = new BeanAdapter(value);
if (beanAdapter.containsKey(key)) {
value = beanAdapter.get(key);
} else if (value instanceof Sequence<?>) {
Sequence<Object> sequence = (Sequence<Object>)value;
value = sequence.get(Integer.parseInt(key));
} else if (value instanceof Dictionary<?, ?>) {
Dictionary<String, Object> dictionary = (Dictionary<String, Object>)value;
value = dictionary.get(key);
} else {
throw new IllegalArgumentException("Property \"" + key + "\" not found.");
}
}
return (T)value;
}
public static byte getByte(Object root, String path) {
Number value = get(root, path);
return value.byteValue();
}
public static short getShort(Object root, String path) {
Number value = get(root, path);
return value.shortValue();
}
public static int getInt(Object root, String path) {
Number value = get(root, path);
return value.intValue();
}
public static long getLong(Object root, String path) {
Number value = get(root, path);
return value.longValue();
}
public static float getFloat(Object root, String path) {
Number value = get(root, path);
return value.floatValue();
}
public static double getDouble(Object root, String path) {
Number value = get(root, path);
return value.doubleValue();
}
/**
* Sets the value at the given path.
*
* @param root
* @param path
* @param value
*
* @return
* The value previously associated with the path.
*/
@SuppressWarnings("unchecked")
public static <T> T put(Object root, String path, T value) {
if (root == null) {
throw new IllegalArgumentException("root is null.");
}
Sequence<String> keys = parse(path);
if (keys.getLength() == 0) {
throw new IllegalArgumentException("Path is empty.");
}
String key = keys.remove(keys.getLength() - 1, 1).get(0);
Object parent = get(root, keys);
if (parent == null) {
throw new IllegalArgumentException("Invalid path.");
}
BeanAdapter beanAdapter = new BeanAdapter(parent);
Object previousValue;
if (beanAdapter.containsKey(key)) {
previousValue = beanAdapter.put(key, value);
} else if (parent instanceof Sequence<?>) {
Sequence<Object> sequence = (Sequence<Object>)parent;
previousValue = sequence.update(Integer.parseInt(key), value);
} else if (parent instanceof Dictionary<?, ?>) {
Dictionary<String, Object> dictionary = (Dictionary<String, Object>)parent;
previousValue = dictionary.put(key, value);
} else {
throw new IllegalArgumentException("Property \"" + key + "\" not found.");
}
return (T)previousValue;
}
/**
* Removes the value at the given path.
*
* @param root
* @param path
*
* @return
* The value that was removed.
*/
@SuppressWarnings("unchecked")
public static <T> T remove(Object root, String path) {
if (root == null) {
throw new IllegalArgumentException("root is null.");
}
Sequence<String> keys = parse(path);
if (keys.getLength() == 0) {
throw new IllegalArgumentException("Path is empty.");
}
String key = keys.remove(keys.getLength() - 1, 1).get(0);
Object parent = get(root, keys);
if (parent == null) {
throw new IllegalArgumentException("Invalid path.");
}
Object previousValue;
if (parent instanceof Sequence<?>) {
Sequence<Object> sequence = (Sequence<Object>)parent;
previousValue = sequence.remove(Integer.parseInt(key), 1).get(0);
} else if (parent instanceof Dictionary<?, ?>) {
Dictionary<String, Object> dictionary = (Dictionary<String, Object>)parent;
previousValue = dictionary.remove(key);
} else {
throw new IllegalArgumentException("Property \"" + key + "\" not found.");
}
return (T)previousValue;
}
/**
* Tests the existence of a path in a given object.
*
* @param root
* @param path
*
* @return
* <tt>true</tt> if the path exists; <tt>false</tt>, otherwise.
*/
@SuppressWarnings("unchecked")
public static boolean containsKey(Object root, String path) {
if (root == null) {
throw new IllegalArgumentException("root is null.");
}
Sequence<String> keys = parse(path);
if (keys.getLength() == 0) {
throw new IllegalArgumentException("Path is empty.");
}
String key = keys.remove(keys.getLength() - 1, 1).get(0);
Object parent = get(root, keys);
boolean containsKey;
if (parent == null) {
containsKey = false;
} else {
BeanAdapter beanAdapter = new BeanAdapter(parent);
containsKey = beanAdapter.containsKey(key);
if (!containsKey) {
if (parent instanceof Sequence<?>) {
Sequence<Object> sequence = (Sequence<Object>)parent;
containsKey = (sequence.getLength() > Integer.parseInt(key));
} else if (parent instanceof Dictionary<?, ?>) {
Dictionary<String, Object> dictionary = (Dictionary<String, Object>)parent;
containsKey = dictionary.containsKey(key);
} else {
throw new IllegalArgumentException("Property \"" + key + "\" not found.");
}
}
}
return containsKey;
}
/**
* Parses a JSON path into a sequence of string keys.
*
* @param path
*/
public static Sequence<String> parse(String path) {
if (path == null) {
throw new IllegalArgumentException("path is null.");
}
ArrayList<String> keys = new ArrayList<String>();
int i = 0;
int n = path.length();
while (i < n) {
char c = path.charAt(i++);
StringBuilder identifierBuilder = new StringBuilder();
boolean bracketed = (c == '[');
if (bracketed
&& i < n) {
c = path.charAt(i++);
char quote = Character.UNASSIGNED;
boolean quoted = (c == '"'
|| c == '\'');
if (quoted
&& i < n) {
quote = c;
c = path.charAt(i++);
}
while (i <= n
&& bracketed) {
bracketed = quoted || (c != ']');
if (bracketed) {
if (c == quote) {
if (i < n) {
c = path.charAt(i++);
quoted = (c == quote);
}
}
if (quoted || c != ']') {
if (Character.isISOControl(c)) {
throw new IllegalArgumentException("Illegal identifier character.");
}
identifierBuilder.append(c);
if (i < n) {
c = path.charAt(i++);
}
}
}
}
if (quoted) {
throw new IllegalArgumentException("Unterminated quoted identifier.");
}
if (bracketed) {
throw new IllegalArgumentException("Unterminated bracketed identifier.");
}
if (i < n) {
c = path.charAt(i);
if (c == '.') {
i++;
}
}
} else {
while(i <= n
&& c != '.'
&& c != '[') {
if (!Character.isJavaIdentifierPart(c)) {
throw new IllegalArgumentException("Illegal identifier character.");
}
identifierBuilder.append(c);
if (i < n) {
c = path.charAt(i);
}
i++;
}
if (c == '[') {
i--;
}
}
if (c == '.'
&& i == n) {
throw new IllegalArgumentException("Path cannot end with a '.' character.");
}
if (identifierBuilder.length() == 0) {
throw new IllegalArgumentException("Missing identifier.");
}
keys.add(identifierBuilder.toString());
}
return keys;
}
}