Adding an initial API for the DomTree data structure.
Change-Id: I55da78c11f49c1e5843cfefbe0a5eed02c59498b
diff --git a/core/api/src/main/java/org/onosproject/store/service/DocumentPath.java b/core/api/src/main/java/org/onosproject/store/service/DocumentPath.java
new file mode 100644
index 0000000..1147c22
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/store/service/DocumentPath.java
@@ -0,0 +1,151 @@
+/*
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * 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 org.onosproject.store.service;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Lists;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * A path class for identifying nodes within the {@code DocumentTree}.
+ *
+ * Note: indexing is ONE based so the root is the 1st level, to retrieve the
+ * root one should query level 1.
+ */
+public class DocumentPath implements Comparable {
+
+ private final ArrayList<String> tokens = Lists.newArrayList();
+
+ /**
+ * Private utility constructor for internal generation of partial paths only.
+ *
+ * @param path
+ */
+ private DocumentPath(List<String> path) {
+ Preconditions.checkNotNull(path);
+ this.tokens.addAll(path);
+ }
+
+ /**
+ * Constructor to generate new {@DocumentPath}, new paths must contain at
+ * least one name and string names may NOT contain any '.'s. If one field
+ * is null that field will be ignored.
+ *
+ * @throws IllegalDocumentNameException if both parameters are null or the string
+ * name contains an illegal character ('.')
+ * @param nodeName the name of the last level of this path
+ * @param parentPath the path representing the parents leading up to this
+ * node, in the case of the root this should be null
+ */
+ public DocumentPath(String nodeName, DocumentPath parentPath) {
+ if (nodeName.contains(".")) {
+ throw new IllegalDocumentNameException(
+ "Periods are not allowed in names.");
+ }
+ if (parentPath != null) {
+ tokens.addAll(parentPath.path());
+ }
+ if (nodeName != null) {
+ tokens.add(nodeName);
+ }
+ if (tokens.isEmpty()) {
+ throw new IllegalDocumentNameException("A document path must contain at" +
+ "least one non-null" +
+ "element.");
+ }
+ }
+
+ /**
+ * Returns a path from the root to the parent of this node, if this node is
+ * the root this call returns null.
+ *
+ * @return a {@code DocumentPath} representing a path to this paths parent,
+ * null if this a root path
+ */
+ public DocumentPath parent() {
+ if (tokens.size() <= 1) {
+ return null;
+ }
+ return new DocumentPath(this.tokens.subList(0, tokens.size() - 1));
+ }
+
+ /**
+ * Returns the complete list of tokens representing this path in correct
+ * order.
+ *
+ * @return a list of strings representing this path
+ */
+ public List<String> path() {
+ return ImmutableList.copyOf(tokens);
+ }
+
+ @Override
+ public int hashCode() {
+ return Objects.hash(tokens);
+ }
+
+ @Override
+ public boolean equals(Object obj) {
+ if (obj instanceof DocumentPath) {
+ DocumentPath that = (DocumentPath) obj;
+ return this.tokens.equals(that.tokens);
+ }
+ return false;
+ }
+
+ @Override
+ public String toString() {
+ StringBuilder stringBuilder = new StringBuilder();
+ Iterator<String> iter = tokens.iterator();
+ while (iter.hasNext()) {
+ stringBuilder.append(iter.next());
+ if (iter.hasNext()) {
+ stringBuilder.append(".");
+ }
+ }
+ return stringBuilder.toString();
+ }
+
+ @Override
+ public int compareTo(Object o) {
+ if (o instanceof DocumentPath) {
+ DocumentPath that = (DocumentPath) o;
+ int shorterLength = this.tokens.size() > that.tokens.size() ?
+ that.tokens.size() : this.tokens.size();
+ for (int i = 0; i < shorterLength; i++) {
+ if (this.tokens.get(i).compareTo(that.tokens.get(i)) != 0) {
+ return this.tokens.get(i).compareTo(that.tokens.get(i));
+ }
+ }
+
+ if (this.tokens.size() > that.tokens.size()) {
+ return 1;
+ } else if (that.tokens.size() > this.tokens.size()) {
+ return -1;
+ } else {
+ return 0;
+ }
+ }
+ throw new IllegalArgumentException("Compare can only compare objects" +
+ "of the same type.");
+ }
+}