1 files changed, 143 insertions, 0 deletions
diff --git a/packages/StatementService/src/com/android/statementservice/retriever/Relation.java b/packages/StatementService/src/com/android/statementservice/retriever/Relation.java
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+++ b/packages/StatementService/src/com/android/statementservice/retriever/Relation.java
@@ -0,0 +1,143 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * 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.android.statementservice.retriever;
+
+import android.annotation.NonNull;
+
+import java.util.regex.Pattern;
+
+/**
+ * An immutable value type representing a statement relation with "kind" and "detail".
+ *
+ * <p> The set of kinds is enumerated by the API: <ul> <li> <b>delegate_permission</b>: The detail
+ * field specifies which permission to delegate. A statement involving this relation does not
+ * constitute a requirement to do the delegation, just a permission to do so. </ul>
+ *
+ * <p> We may add other kinds in the future.
+ *
+ * <p> The detail field is a lowercase alphanumeric string with underscores and periods allowed
+ * (matching the regex [a-z0-9_.]+), but otherwise unstructured. It is also possible to specify '*'
+ * (the wildcard character) as the detail if the relation applies to any detail in the specified
+ * kind.
+ */
+public final class Relation {
+
+    private static final Pattern KIND_PATTERN = Pattern.compile("^[a-z0-9_.]+$");
+    private static final Pattern DETAIL_PATTERN = Pattern.compile("^([a-z0-9_.]+|[*])$");
+
+    private static final String MATCH_ALL_DETAILS = "*";
+
+    private final String mKind;
+    private final String mDetail;
+
+    private Relation(String kind, String detail) {
+        mKind = kind;
+        mDetail = detail;
+    }
+
+    /**
+     * Returns the relation's kind.
+     */
+    @NonNull
+    public String getKind() {
+        return mKind;
+    }
+
+    /**
+     * Returns the relation's detail.
+     */
+    @NonNull
+    public String getDetail() {
+        return mDetail;
+    }
+
+    /**
+     * Creates a new Relation object for the specified {@code kind} and {@code detail}.
+     *
+     * @throws AssociationServiceException if {@code kind} or {@code detail} is not well formatted.
+     */
+    public static Relation create(@NonNull String kind, @NonNull String detail)
+            throws AssociationServiceException {
+        if (!KIND_PATTERN.matcher(kind).matches() || !DETAIL_PATTERN.matcher(detail).matches()) {
+            throw new AssociationServiceException("Relation not well formatted.");
+        }
+        return new Relation(kind, detail);
+    }
+
+    /**
+     * Creates a new Relation object from its string representation.
+     *
+     * @throws AssociationServiceException if the relation is not well formatted.
+     */
+    public static Relation create(@NonNull String relation) throws AssociationServiceException {
+        String[] r = relation.split("/", 2);
+        if (r.length != 2) {
+            throw new AssociationServiceException("Relation not well formatted.");
+        }
+        return create(r[0], r[1]);
+    }
+
+    /**
+     * Returns true if {@code relation} has the same kind and detail. If {@code
+     * relation.getDetail()} is wildcard (*) then returns true if the kind is the same.
+     */
+    public boolean matches(Relation relation) {
+        return getKind().equals(relation.getKind()) && (getDetail().equals(MATCH_ALL_DETAILS)
+                || getDetail().equals(relation.getDetail()));
+    }
+
+    /**
+     * Returns a string representation of this relation.
+     */
+    @Override
+    public String toString() {
+        StringBuilder relation = new StringBuilder();
+        relation.append(getKind());
+        relation.append("/");
+        relation.append(getDetail());
+        return relation.toString();
+    }
+
+    // equals() and hashCode() are generated by Android Studio.
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+
+        Relation relation = (Relation) o;
+
+        if (mDetail != null ? !mDetail.equals(relation.mDetail) : relation.mDetail != null) {
+            return false;
+        }
+        if (mKind != null ? !mKind.equals(relation.mKind) : relation.mKind != null) {
+            return false;
+        }
+
+        return true;
+    }
+
+    @Override
+    public int hashCode() {
+        int result = mKind != null ? mKind.hashCode() : 0;
+        result = 31 * result + (mDetail != null ? mDetail.hashCode() : 0);
+        return result;
+    }
+}