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/*
* Copyright 2015 Google Inc.
*
* 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.google.googlejavaformat.java;
import com.google.common.base.Verify;
import java.util.List;
import java.util.Optional;
/** Heuristics for classifying qualified names as types. */
public final class TypeNameClassifier {
private TypeNameClassifier() {}
/** A state machine for classifying qualified names. */
private enum TyParseState {
/** The start state. */
START(false) {
@Override
public TyParseState next(JavaCaseFormat n) {
switch (n) {
case UPPERCASE:
// if we see an UpperCamel later, assume this was a class
// e.g. com.google.FOO.Bar
return TyParseState.AMBIGUOUS;
case LOWER_CAMEL:
return TyParseState.REJECT;
case LOWERCASE:
// could be a package
return TyParseState.START;
case UPPER_CAMEL:
return TyParseState.TYPE;
}
throw new AssertionError();
}
},
/** The current prefix is a type. */
TYPE(true) {
@Override
public TyParseState next(JavaCaseFormat n) {
switch (n) {
case UPPERCASE:
case LOWER_CAMEL:
case LOWERCASE:
return TyParseState.FIRST_STATIC_MEMBER;
case UPPER_CAMEL:
return TyParseState.TYPE;
}
throw new AssertionError();
}
},
/** The current prefix is a type, followed by a single static member access. */
FIRST_STATIC_MEMBER(true) {
@Override
public TyParseState next(JavaCaseFormat n) {
return TyParseState.REJECT;
}
},
/** Anything not represented by one of the other states. */
REJECT(false) {
@Override
public TyParseState next(JavaCaseFormat n) {
return TyParseState.REJECT;
}
},
/** An ambiguous type prefix. */
AMBIGUOUS(false) {
@Override
public TyParseState next(JavaCaseFormat n) {
switch (n) {
case UPPERCASE:
return AMBIGUOUS;
case LOWER_CAMEL:
case LOWERCASE:
return TyParseState.REJECT;
case UPPER_CAMEL:
return TyParseState.TYPE;
}
throw new AssertionError();
}
};
private final boolean isSingleUnit;
TyParseState(boolean isSingleUnit) {
this.isSingleUnit = isSingleUnit;
}
public boolean isSingleUnit() {
return isSingleUnit;
}
/** Transition function. */
public abstract TyParseState next(JavaCaseFormat n);
}
/**
* Returns the end index (inclusive) of the longest prefix that matches the naming conventions of
* a type or static field access, or -1 if no such prefix was found.
*
* <p>Examples:
*
* <ul>
* <li>ClassName
* <li>ClassName.staticMemberName
* <li>com.google.ClassName.InnerClass.staticMemberName
* </ul>
*/
static Optional<Integer> typePrefixLength(List<String> nameParts) {
TyParseState state = TyParseState.START;
Optional<Integer> typeLength = Optional.empty();
for (int i = 0; i < nameParts.size(); i++) {
state = state.next(JavaCaseFormat.from(nameParts.get(i)));
if (state == TyParseState.REJECT) {
break;
}
if (state.isSingleUnit()) {
typeLength = Optional.of(i);
}
}
return typeLength;
}
/** Case formats used in Java identifiers. */
public enum JavaCaseFormat {
UPPERCASE,
LOWERCASE,
UPPER_CAMEL,
LOWER_CAMEL;
/** Classifies an identifier's case format. */
static JavaCaseFormat from(String name) {
Verify.verify(!name.isEmpty());
boolean firstUppercase = false;
boolean hasUppercase = false;
boolean hasLowercase = false;
boolean first = true;
for (int i = 0; i < name.length(); i++) {
char c = name.charAt(i);
if (!Character.isAlphabetic(c)) {
continue;
}
if (first) {
firstUppercase = Character.isUpperCase(c);
first = false;
}
hasUppercase |= Character.isUpperCase(c);
hasLowercase |= Character.isLowerCase(c);
}
if (firstUppercase) {
return (hasLowercase || name.length() == 1) ? UPPER_CAMEL : UPPERCASE;
} else {
return hasUppercase ? LOWER_CAMEL : LOWERCASE;
}
}
}
}
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