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package com.sun.tools.javac.jvm;
import com.sun.tools.javac.code.Type;
import com.sun.tools.javac.code.Types;
import com.sun.tools.javac.code.Types.UniqueType;
import com.sun.tools.javac.util.List;
import com.sun.tools.javac.util.Name;
import com.sun.tools.javac.util.Pair;
import java.util.Objects;
import java.util.stream.Stream;
This interface models all javac entities that can be used to represent constant pool entries.
A pool constant entity must (i) be associated with a constant pool entry tag and have a function
which generates a key for the desired pool entry (so as to avoid duplicate entries when writing the
constant pool).
/**
* This interface models all javac entities that can be used to represent constant pool entries.
* A pool constant entity must (i) be associated with a constant pool entry tag and have a function
* which generates a key for the desired pool entry (so as to avoid duplicate entries when writing the
* constant pool).
*/
public interface PoolConstant {
The constant pool entry key.
/**
* The constant pool entry key.
*/
default Object poolKey(Types types) { return this; }
The constant pool entry tag.
/**
* The constant pool entry tag.
*/
int poolTag();
The root of pool constants that can be loaded (e.g. with ldc, or appear as static arguments to a bootstrap method. /**
* The root of pool constants that can be loaded (e.g. with {@code ldc}, or appear as static
* arguments to a bootstrap method.
*/
interface LoadableConstant extends PoolConstant {
Create a pool constant describing a given int value. /**
* Create a pool constant describing a given {@code int} value.
*/
static LoadableConstant Int(int i) {
return new BasicConstant(ClassFile.CONSTANT_Integer, i);
}
Create a pool constant describing a given float value. /**
* Create a pool constant describing a given {@code float} value.
*/
static LoadableConstant Float(float f) {
return new BasicConstant(ClassFile.CONSTANT_Float, f);
}
Create a pool constant describing a given long value. /**
* Create a pool constant describing a given {@code long} value.
*/
static LoadableConstant Long(long l) {
return new BasicConstant(ClassFile.CONSTANT_Long, l);
}
Create a pool constant describing a given double value. /**
* Create a pool constant describing a given {@code double} value.
*/
static LoadableConstant Double(double d) {
return new BasicConstant(ClassFile.CONSTANT_Double, d);
}
Create a pool constant describing a given String value. /**
* Create a pool constant describing a given {@code String} value.
*/
static LoadableConstant String(String s) {
return new BasicConstant(ClassFile.CONSTANT_String, s);
}
This class models a pool constant of given basic type, one of int, float, long, double or String. /**
* This class models a pool constant of given basic type, one of {@code int}, {@code float},
* {@code long}, {@code double} or {@code String}.
*/
class BasicConstant implements LoadableConstant {
int tag;
Object data;
private BasicConstant(int tag, Object data) {
this.tag = tag;
this.data = data;
}
@Override
public int poolTag() {
return tag;
}
@Override
public Object poolKey(Types types) {
return data;
}
}
}
This interface models a dynamic pool constant (either of kind InvokeDynamic or ConstantDynamic). In addition to the functionalities provided by the base interface, a dynamic pool constant must expose its dynamic type, bootstrap method and static argument list. Finally, a dynamic constant must have a way to compute a bootstrap method key - that is, a unique key for the bootstrap method entry it refers to, to avoid duplicates when writing the BootstrapMethods attribute. /**
* This interface models a dynamic pool constant (either of kind {@code InvokeDynamic} or
* {@code ConstantDynamic}). In addition to the functionalities provided by the base interface,
* a dynamic pool constant must expose its dynamic type, bootstrap method and static argument list.
* Finally, a dynamic constant must have a way to compute a bootstrap method key - that is,
* a unique key for the bootstrap method entry it refers to, to avoid duplicates when writing
* the {@code BootstrapMethods} attribute.
*/
interface Dynamic extends PoolConstant {
The dynamic constant's dynamic type.
/**
* The dynamic constant's dynamic type.
*/
PoolConstant dynamicType();
The dynamic constant's static argument list.
/**
* The dynamic constant's static argument list.
*/
LoadableConstant[] staticArgs();
The dynamic constant's bootstrap method.
/**
* The dynamic constant's bootstrap method.
*/
LoadableConstant bootstrapMethod();
default BsmKey bsmKey(Types types) {
return new BsmKey(types, bootstrapMethod(), staticArgs());
}
@Override
default Object poolKey(Types types) {
return new Pair<>(bsmKey(types), dynamicType().poolKey(types));
}
A class modelling a bootstrap method key.
/**
* A class modelling a bootstrap method key.
*/
class BsmKey {
The key's bootstrap method constant.
/**
* The key's bootstrap method constant.
*/
public final LoadableConstant bsm;
The key's static argument list.
/**
* The key's static argument list.
*/
public final LoadableConstant[] staticArgs;
private final Object bsmKey;
private final List<?> staticArgKeys;
private BsmKey(Types types, LoadableConstant bsm, LoadableConstant[] staticArgs) {
this.bsm = bsm;
this.bsmKey = bsm.poolKey(types);
this.staticArgs = staticArgs;
this.staticArgKeys = Stream.of(staticArgs)
.map(p -> p.poolKey(types))
.collect(List.collector());
}
@Override
public int hashCode() {
return bsmKey.hashCode() +
staticArgKeys.hashCode();
}
@Override
public boolean equals(Object obj) {
if (obj instanceof BsmKey) {
BsmKey other = (BsmKey)obj;
return Objects.equals(bsmKey, other.bsmKey) &&
Objects.equals(staticArgKeys, other.staticArgKeys);
} else {
return false;
}
}
}
}
A pool constant implememntation describing a name and type pool entry.
/**
* A pool constant implememntation describing a name and type pool entry.
*/
final class NameAndType implements PoolConstant {
final Name name;
final Type type;
NameAndType(Name name, Type type) {
this.name = name;
this.type = type;
}
@Override
public int poolTag() {
return ClassFile.CONSTANT_NameandType;
}
@Override
public Object poolKey(Types types) {
return new Pair<>(name, new UniqueType(type, types));
}
}
}