net.sourceforge.pmd.lang.java.symbols.SymbolResolver Maven / Gradle / Ivy
/*
* BSD-style license; for more info see http://pmd.sourceforge.net/license.html
*/
package net.sourceforge.pmd.lang.java.symbols;
import static net.sourceforge.pmd.util.CollectionUtil.listOf;
import java.util.List;
import org.apache.commons.lang3.ArrayUtils;
import org.checkerframework.checker.nullness.qual.NonNull;
import org.checkerframework.checker.nullness.qual.Nullable;
/**
* Resolves symbols from their global name. This abstracts over whether
* we're looking on a classpath, in a file tree, in a serialized index, etc.
*/
public interface SymbolResolver {
/**
* Resolves a class symbol from its canonical name. Periods ('.') will
* not be interpreted as nested-class separators, so this performs at
* most one classloader lookup. Note that external symbol resolvers
* do not need to implement lookup for primitive types, for local
* and anonymous classes, or for array classes. This is handled by
* the AST implementation or by the type system. Looking up such symbols
* is undefined behaviour.
*/
@Nullable
JClassSymbol resolveClassFromBinaryName(@NonNull String binaryName);
/**
* Resolves a class symbol from its canonical name. Periods ('.') may
* be interpreted as nested-class separators, so for n segments, this
* performs at most n classloader lookups.
*/
@Nullable
default JClassSymbol resolveClassFromCanonicalName(@NonNull String canonicalName) {
JClassSymbol symbol = resolveClassFromBinaryName(canonicalName);
if (symbol != null) {
return symbol;
}
int lastDotIdx = canonicalName.lastIndexOf('.');
if (lastDotIdx < 0) {
return null;
} else {
JClassSymbol outer = resolveClassFromCanonicalName(canonicalName.substring(0, lastDotIdx));
if (outer != null) {
String innerName = canonicalName.substring(lastDotIdx + 1);
return outer.getDeclaredClass(innerName);
}
}
return null;
}
/**
* Produce a symbol resolver that asks the given resolvers in order.
*
* @param first First resolver
* @param others Rest of the resolvers
*/
static SymbolResolver layer(SymbolResolver first, SymbolResolver... others) {
assert first != null : "Null first table";
assert others != null : "Null array";
assert !ArrayUtils.contains(others, null) : "Null component";
return new SymbolResolver() {
private final List stack = listOf(first, others);
@Override
public @Nullable JClassSymbol resolveClassFromBinaryName(@NonNull String binaryName) {
for (SymbolResolver resolver : stack) {
JClassSymbol sym = resolver.resolveClassFromBinaryName(binaryName);
if (sym != null) {
return sym;
}
}
return null;
}
};
}
}