1 files changed, 79 insertions, 0 deletions
diff --git a/predicate-search-core/src/main/java/com/yahoo/document/predicate/Predicate.java b/predicate-search-core/src/main/java/com/yahoo/document/predicate/Predicate.java
new file mode 100644
index 00000000000..2446d3e3524
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+++ b/predicate-search-core/src/main/java/com/yahoo/document/predicate/Predicate.java
@@ -0,0 +1,79 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.document.predicate;
+
+import com.yahoo.document.predicate.parser.PredicateLexer;
+import com.yahoo.document.predicate.parser.PredicateParser;
+import com.yahoo.text.Ascii;
+import org.antlr.runtime.ANTLRStringStream;
+import org.antlr.runtime.CommonTokenStream;
+import org.antlr.runtime.RecognitionException;
+
+import java.nio.charset.StandardCharsets;
+
+/**
+ * @author <a href="mailto:simon@yahoo-inc.com">Simon Thoresen Hult</a>
+ */
+public abstract class Predicate implements Cloneable {
+
+    private final static char QUOTE_CHAR = '\'';
+    private final static Ascii.Encoder ASCII_ENCODER = Ascii.newEncoder(StandardCharsets.UTF_8, QUOTE_CHAR);
+    private final static Ascii.Decoder ASCII_DECODER = Ascii.newDecoder(StandardCharsets.UTF_8);
+
+    @Override
+    public Predicate clone() throws CloneNotSupportedException {
+        return (Predicate)super.clone();
+    }
+
+    @Override
+    public final String toString() {
+        StringBuilder out = new StringBuilder();
+        appendTo(out);
+        return out.toString();
+    }
+
+    protected abstract void appendTo(StringBuilder out);
+
+    protected static void appendQuotedTo(String str, StringBuilder out) {
+        String encoded = asciiEncode(str);
+        if (requiresQuote(encoded)) {
+            out.append(QUOTE_CHAR).append(encoded).append(QUOTE_CHAR);
+        } else {
+            out.append(str);
+        }
+    }
+
+    private static boolean requiresQuote(String str) {
+        for (int i = 0, len = str.length(); i < len; i = str.offsetByCodePoints(i, 1)) {
+            int c = str.codePointAt(i);
+            if (c == Ascii.ESCAPE_CHAR || !Character.isLetterOrDigit(c)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    public static String asciiEncode(String str) {
+        return ASCII_ENCODER.encode(str);
+    }
+
+    public static String asciiDecode(String str) {
+        return ASCII_DECODER.decode(str);
+    }
+
+    public static Predicate fromBinary(byte[] buf) {
+        return BinaryFormat.decode(buf);
+    }
+
+    public static Predicate fromString(String str) {
+        ANTLRStringStream input = new ANTLRStringStream(str);
+        PredicateLexer lexer = new PredicateLexer(input);
+        CommonTokenStream tokens = new CommonTokenStream(lexer);
+        PredicateParser parser = new PredicateParser(tokens);
+        try {
+            return parser.predicate();
+        } catch (RecognitionException e) {
+            throw new IllegalArgumentException(e);
+        }
+    }
+
+}