Introducing Antlr4 for cpsPath parsing

-created new module for cpPathParser
-added antlr rule for cpsPathWithSingleLeafCondition
-added antlr rule for cpsPathWithDescendant (and with leaf conditions)
-added antlr rule for ancestor axis
-added unit test (copied from existing CpsPathQuerySpec)
-udpated cps-ri to use new cpPathQuery from parser module
-'imported' lexer rules from publix xPath grammar
-Re-used existing CpsPathException but conversion happens in cps-ri to prevent additional dependency in cps-path-parser module

Issue-ID: CPS-376

Change-Id: I2c5df98969402cbf69f6573c52705879450ce606
Signed-off-by: ToineSiebelink <toine.siebelink@est.tech>

3 files changed, 225 insertions, 0 deletions

diff --git a/cps-path-parser/src/main/java/org/onap/cps/cpspath/parser/CpsPathBuilder.java b/cps-path-parser/src/main/java/org/onap/cps/cpspath/parser/CpsPathBuilder.java
new file mode 100644
index 000000000..83e076d53
--- /dev/null
+++ b/cps-path-parser/src/main/java/org/onap/cps/cpspath/parser/CpsPathBuilder.java
@@ -0,0 +1,107 @@
+package org.onap.cps.cpspath.parser;
+/*
+ *  ============LICENSE_START=======================================================
+ *  Copyright (C) 2021 Nordix Foundation
+ *  ================================================================================
+ *  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.
+ *
+ *  SPDX-License-Identifier: Apache-2.0
+ *  ============LICENSE_END=========================================================
+ */
+
+import java.util.HashMap;
+import java.util.Map;
+import org.onap.cps.cpspath.parser.antlr4.CpsPathBaseListener;
+import org.onap.cps.cpspath.parser.antlr4.CpsPathParser.AncestorAxisContext;
+import org.onap.cps.cpspath.parser.antlr4.CpsPathParser.CpsPathWithDescendantAndLeafConditionsContext;
+import org.onap.cps.cpspath.parser.antlr4.CpsPathParser.CpsPathWithDescendantContext;
+import org.onap.cps.cpspath.parser.antlr4.CpsPathParser.CpsPathWithSingleLeafConditionContext;
+import org.onap.cps.cpspath.parser.antlr4.CpsPathParser.LeafConditionContext;
+import org.onap.cps.cpspath.parser.antlr4.CpsPathParser.MultipleValueConditionsContext;
+import org.onap.cps.cpspath.parser.antlr4.CpsPathParser.PrefixContext;
+import org.onap.cps.cpspath.parser.antlr4.CpsPathParser.SingleValueConditionContext;
+
+public class CpsPathBuilder extends CpsPathBaseListener {
+
+    final CpsPathQuery cpsPathQuery = new CpsPathQuery();
+
+    final Map<String, Object> leavesData = new HashMap<>();
+
+    @Override
+    public void exitPrefix(final PrefixContext ctx) {
+        cpsPathQuery.setXpathPrefix(ctx.getText());
+    }
+
+    @Override
+    public void exitLeafCondition(final LeafConditionContext ctx) {
+        Object comparisonValue = null;
+        if (ctx.IntegerLiteral() != null) {
+            comparisonValue = Integer.valueOf(ctx.IntegerLiteral().getText());
+        }
+        if (ctx.StringLiteral() != null) {
+            comparisonValue = stripFirstAndLastCharacter(ctx.StringLiteral().getText());
+        } else if (comparisonValue == null) {
+            throw new IllegalStateException("Unsupported comparison value encountered in expression" + ctx.getText());
+        }
+        leavesData.put(ctx.leafName().getText(), comparisonValue);
+    }
+
+    @Override
+    public void enterSingleValueCondition(final SingleValueConditionContext ctx) {
+        leavesData.clear();
+    }
+
+    @Override
+    public void enterMultipleValueConditions(final MultipleValueConditionsContext ctx) {
+        leavesData.clear();
+    }
+
+    @Override
+    public void exitSingleValueCondition(final SingleValueConditionContext ctx) {
+        final String leafName = ctx.leafCondition().leafName().getText();
+        cpsPathQuery.setLeafName(leafName);
+        cpsPathQuery.setLeafValue(leavesData.get(leafName));
+    }
+
+    @Override
+    public void exitCpsPathWithSingleLeafCondition(final CpsPathWithSingleLeafConditionContext ctx) {
+        cpsPathQuery.setCpsPathQueryType(CpsPathQueryType.XPATH_LEAF_VALUE);
+    }
+
+    @Override
+    public void exitCpsPathWithDescendant(final CpsPathWithDescendantContext ctx) {
+        cpsPathQuery.setCpsPathQueryType(CpsPathQueryType.XPATH_HAS_DESCENDANT_ANYWHERE);
+        cpsPathQuery.setDescendantName(cpsPathQuery.getXpathPrefix().substring(1));
+    }
+
+    @Override
+    public void exitCpsPathWithDescendantAndLeafConditions(
+        final CpsPathWithDescendantAndLeafConditionsContext ctx) {
+        cpsPathQuery.setCpsPathQueryType(CpsPathQueryType.XPATH_HAS_DESCENDANT_WITH_LEAF_VALUES);
+        cpsPathQuery.setDescendantName(cpsPathQuery.getXpathPrefix().substring(1));
+        cpsPathQuery.setLeavesData(leavesData);
+    }
+
+    @Override
+    public void exitAncestorAxis(final AncestorAxisContext ctx) {
+        cpsPathQuery.setAncestorSchemaNodeIdentifier(ctx.ancestorPath().getText());
+    }
+
+    CpsPathQuery build() {
+        return cpsPathQuery;
+    }
+
+    private static String stripFirstAndLastCharacter(final String wrappedString) {
+        return wrappedString.substring(1, wrappedString.length() - 1);
+    }
+
+}
diff --git a/cps-path-parser/src/main/java/org/onap/cps/cpspath/parser/CpsPathQuery.java b/cps-path-parser/src/main/java/org/onap/cps/cpspath/parser/CpsPathQuery.java
new file mode 100644
index 000000000..32fe0cbb7
--- /dev/null
+++ b/cps-path-parser/src/main/java/org/onap/cps/cpspath/parser/CpsPathQuery.java
@@ -0,0 +1,79 @@
+/*
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2021 Nordix Foundation
+ *  ================================================================================
+ *  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.
+ *
+ *  SPDX-License-Identifier: Apache-2.0
+ *  ============LICENSE_END=========================================================
+ */
+
+package org.onap.cps.cpspath.parser;
+
+
+import java.util.Map;
+import lombok.AccessLevel;
+import lombok.Getter;
+import lombok.Setter;
+import org.antlr.v4.runtime.BaseErrorListener;
+import org.antlr.v4.runtime.CharStreams;
+import org.antlr.v4.runtime.CommonTokenStream;
+import org.antlr.v4.runtime.RecognitionException;
+import org.antlr.v4.runtime.Recognizer;
+import org.onap.cps.cpspath.parser.antlr4.CpsPathLexer;
+import org.onap.cps.cpspath.parser.antlr4.CpsPathParser;
+
+@Getter
+@Setter(AccessLevel.PACKAGE)
+public class CpsPathQuery {
+
+    private CpsPathQueryType cpsPathQueryType;
+    private String xpathPrefix;
+    private String leafName;
+    private Object leafValue;
+    private String descendantName;
+    private Map<String, Object> leavesData;
+    private String ancestorSchemaNodeIdentifier = "";
+
+    /**
+     * Returns a cps path query.
+     *
+     * @param cpsPathSource cps path
+     * @return a CpsPathQuery object.
+     */
+    public static CpsPathQuery createFrom(final String cpsPathSource) {
+        final var inputStream = CharStreams.fromString(cpsPathSource);
+        final var cpsPathLexer = new CpsPathLexer(inputStream);
+        final var cpsPathParser = new CpsPathParser(new CommonTokenStream(cpsPathLexer));
+        cpsPathParser.addErrorListener(new BaseErrorListener() {
+            @Override
+            public void syntaxError(final Recognizer<?, ?> recognizer, final Object offendingSymbol, final int line,
+                                    final int charPositionInLine, final String msg, final RecognitionException e) {
+                throw new IllegalStateException("failed to parse at line " + line + " due to " + msg, e);
+            }
+        });
+        final var cpsPathBuilder = new CpsPathBuilder();
+        cpsPathParser.addParseListener(cpsPathBuilder);
+        cpsPathParser.cpsPath();
+        return cpsPathBuilder.build();
+    }
+
+    /**
+     * Has ancestor axis been populated.
+     *
+     * @return boolean value.
+     */
+    public boolean hasAncestorAxis() {
+        return !(ancestorSchemaNodeIdentifier.isEmpty());
+    }
+
+}
diff --git a/cps-path-parser/src/main/java/org/onap/cps/cpspath/parser/CpsPathQueryType.java b/cps-path-parser/src/main/java/org/onap/cps/cpspath/parser/CpsPathQueryType.java
new file mode 100644
index 000000000..bc6b9f092
--- /dev/null
+++ b/cps-path-parser/src/main/java/org/onap/cps/cpspath/parser/CpsPathQueryType.java
@@ -0,0 +1,39 @@
+/*
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2021 Nordix Foundation
+ *  Modifications Copyright (C) 2020-2021 Bell Canada.
+ *  ================================================================================
+ *  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.
+ *
+ *  SPDX-License-Identifier: Apache-2.0
+ *  ============LICENSE_END=========================================================
+ */
+
+package org.onap.cps.cpspath.parser;
+
+/**
+ * The enum Cps path query type.
+ */
+public enum CpsPathQueryType {
+    /**
+     * Xpath descendant anywhere type e.g. //nodeName .
+     */
+    XPATH_HAS_DESCENDANT_ANYWHERE,
+    /**
+     * Xpath descendant anywhere type e.g. //nodeName[@leafName="value"] .
+     */
+    XPATH_HAS_DESCENDANT_WITH_LEAF_VALUES,
+    /**
+     * Xpath leaf value cps path query type e.g. /cps-path[@leaf1="leafValue" and @leaf2=123] .
+     */
+    XPATH_LEAF_VALUE
+}