io.jooby.internal.apt.escape.LookupTranslator Maven / Gradle / Ivy
/*
* Jooby https://jooby.io
* Apache License Version 2.0 https://jooby.io/LICENSE.txt
* Copyright 2014 Edgar Espina
*/
package io.jooby.internal.apt.escape;
import java.io.IOException;
import java.io.Writer;
import java.util.BitSet;
import java.util.HashMap;
import java.util.Map;
/**
* Translates a value using a lookup table.
*
* @since 1.0
*/
class LookupTranslator extends CharSequenceTranslator {
/** The mapping to be used in translation. */
private final Map lookupMap;
/** The first character of each key in the lookupMap. */
private final BitSet prefixSet;
/** The length of the shortest key in the lookupMap. */
private final int shortest;
/** The length of the longest key in the lookupMap. */
private final int longest;
/**
* Constructs the lookup table to be used in translation
*
* Note that, as of Lang 3.1 (the origin of this code), the key to the lookup table is
* converted to a java.lang.String. This is because we need the key to support hashCode and
* equals(Object), allowing it to be the key for a HashMap. See LANG-882.
*
* @param lookupMap Map<CharSequence, CharSequence> table of translator mappings
*/
public LookupTranslator(final Map lookupMap) {
this.lookupMap = new HashMap<>();
this.prefixSet = new BitSet();
int currentShortest = Integer.MAX_VALUE;
int currentLongest = 0;
for (final Map.Entry pair : lookupMap.entrySet()) {
this.lookupMap.put(pair.getKey().toString(), pair.getValue().toString());
this.prefixSet.set(pair.getKey().charAt(0));
final int sz = pair.getKey().length();
if (sz < currentShortest) {
currentShortest = sz;
}
if (sz > currentLongest) {
currentLongest = sz;
}
}
this.shortest = currentShortest;
this.longest = currentLongest;
}
/** {@inheritDoc} */
@Override
public int translate(final CharSequence input, final int index, final Writer writer)
throws IOException {
// check if translation exists for the input at position index
if (prefixSet.get(input.charAt(index))) {
int max = longest;
if (index + longest > input.length()) {
max = input.length() - index;
}
// implement greedy algorithm by trying maximum match first
for (int i = max; i >= shortest; i--) {
final CharSequence subSeq = input.subSequence(index, index + i);
final String result = lookupMap.get(subSeq.toString());
if (result != null) {
writer.write(result);
return Character.codePointCount(subSeq, 0, subSeq.length());
}
}
}
return 0;
}
}