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Kubernetes Service Discovery for Hazelcast Discovery SPI
/*
* Copyright (c) 2008-2019, Hazelcast, Inc. All Rights Reserved.
*
* 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.hazelcast.query.impl.getters;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.List;
/**
* Represents a query path for Json querying. Parsing of a query path
* is lazy. This cursor splits parts of an attribute path by "."s and
* "["s.
*/
public class JsonPathCursor {
private static final Charset UTF8_CHARSET = Charset.forName("UTF8");
private static final int DEFAULT_PATH_ELEMENT_COUNT = 5;
private List triples;
private String attributePath;
private String current;
private byte[] currentAsUtf8;
private int currentArrayIndex = -1;
private boolean isArray;
private boolean isAny;
private int cursor;
private JsonPathCursor(String originalPath, List triples) {
this.attributePath = originalPath;
this.triples = triples;
}
/**
* Creates a shallow copy of this object
*
* @param other
*/
JsonPathCursor(JsonPathCursor other) {
this.attributePath = other.attributePath;
this.triples = other.triples;
}
/**
* Creates a new cursor from given attribute path.
*
* @param attributePath
*/
public static JsonPathCursor createCursor(String attributePath) {
ArrayList triples = new ArrayList(DEFAULT_PATH_ELEMENT_COUNT);
int start = 0;
int end;
while (start < attributePath.length()) {
boolean isArray = false;
try {
while (attributePath.charAt(start) == '[' || attributePath.charAt(start) == '.') {
start++;
}
} catch (IndexOutOfBoundsException e) {
throw createIllegalArgumentException(attributePath);
}
end = start + 1;
while (end < attributePath.length()) {
char c = attributePath.charAt(end);
if ('.' == c || '[' == c) {
break;
} else if (']' == c) {
isArray = true;
break;
}
end++;
}
String part = attributePath.substring(start, end);
Triple triple = new Triple(part, part.getBytes(UTF8_CHARSET), isArray);
triples.add(triple);
start = end + 1;
}
return new JsonPathCursor(attributePath, triples);
}
private static IllegalArgumentException createIllegalArgumentException(String attributePath) {
return new IllegalArgumentException("Malformed query path " + attributePath);
}
public String getAttributePath() {
return attributePath;
}
/**
* Returns the next attribute path part. The returned string is either
* the name of the next attribute or the string representation of an
* array index. {@code null} indicates the end of input.
*
* @return either {@code null} or the next part of the attribute path
*/
public String getNext() {
next();
return current;
}
/**
* Returns the current attribute path part. The returned string is either
* the name of the current attribute or the string representation of an
* array index. {@code null} indicates the end of input.
*
* @return either {@code null} or the current part of the attribute path
*/
public String getCurrent() {
return current;
}
/**
* Returns byte array of UTF8 encoded {@link #getCurrent()}. This
* method caches the UTF8 encoded byte array, so it is more
* efficient to call repeteadly.
*
* The returned byte array must not be modified!
*
* @return
*/
@SuppressFBWarnings(value = "EI_EXPOSE_REP", justification = "Making a copy reverses the benefit of this method")
public byte[] getCurrentAsUTF8() {
return currentAsUtf8;
}
/**
* @return true if the current item is an array
*/
public boolean isArray() {
return isArray;
}
/**
* @return true if the current item is "any"
*/
public boolean isAny() {
return isAny;
}
/**
* Returns array index if the current item is array and not "any".
*
* @return -1 if the current item is "any" or non-array.
*/
public int getArrayIndex() {
return currentArrayIndex;
}
public void reset() {
current = null;
currentArrayIndex = -1;
isArray = false;
isAny = false;
cursor = 0;
}
public boolean hasNext() {
return cursor < triples.size();
}
private void next() {
if (cursor < triples.size()) {
Triple triple = triples.get(cursor);
current = triple.string;
currentAsUtf8 = triple.stringAsUtf8;
isArray = triple.isArray;
currentArrayIndex = -1;
isAny = false;
if (isArray) {
if ("any".equals(current)) {
isAny = true;
} else {
isAny = false;
currentArrayIndex = Integer.parseInt(current);
}
}
cursor++;
} else {
current = null;
currentAsUtf8 = null;
currentArrayIndex = -1;
isAny = false;
isArray = false;
}
}
private static final class Triple {
private final String string;
private final byte[] stringAsUtf8;
private final boolean isArray;
private Triple(String string, byte[] stringAsUtf8, boolean isArray) {
this.string = string;
this.stringAsUtf8 = stringAsUtf8;
this.isArray = isArray;
}
}
}