diff options
Diffstat (limited to 'predicate-search-core/src/main/java/com/yahoo/document/predicate/Predicate.java')
-rw-r--r-- | predicate-search-core/src/main/java/com/yahoo/document/predicate/Predicate.java | 79 |
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 --- /dev/null +++ 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); + } + } + +} |