org.graalvm.polyglot.proxy.ProxyHashMap Maven / Gradle / Ivy
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package org.graalvm.polyglot.proxy;
import org.graalvm.polyglot.Context;
import org.graalvm.polyglot.HostAccess.Builder;
import org.graalvm.polyglot.Value;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.NoSuchElementException;
/**
* Interface to be implemented to mimic guest language hash maps.
*
* @see Proxy
* @since 21.1
*/
public interface ProxyHashMap extends Proxy {
/**
* Returns the number of map entries.
*
* @since 21.1
*/
long getHashSize();
/**
* Returns {@code true} if the proxy object contains a mapping for the specified key, or else
* {@code false}. Every key which returns {@code true} for {@link #hasHashEntry(Value)} must be
* included in the {@link Value#isIterator() iterator} returned by
* {@link #getHashEntriesIterator()} to allow guest language to enumerate map entries.
*
* @see #getHashEntriesIterator()
* @since 21.1
*/
boolean hasHashEntry(Value key);
/**
* Returns the value for the specified key.
*
* @throws UnsupportedOperationException if the operation is unsupported
* @since 21.1
*/
Object getHashValue(Value key);
/**
* Associates the specified value with the specified key. If the mapping for the specified key
* does not {@link #hasHashEntry(Value) exist} then a new mapping is defined otherwise, an
* existing mapping is updated.
*
* @throws UnsupportedOperationException if the operation is unsupported
* @since 21.1
*/
void putHashEntry(Value key, Value value);
/**
* Removes the mapping for a given key. If the removal of existing mappings is not supported
* then an {@link UnsupportedOperationException} is thrown.
*
* @return {@code true} when the mapping was removed, {@code false} when the mapping didn't
* exist.
* @throws UnsupportedOperationException if the operation is unsupported
* @since 21.1
*/
default boolean removeHashEntry(@SuppressWarnings("unused") Value key) {
throw new UnsupportedOperationException("removeHashEntry() not supported.");
}
/**
* Returns the hash entries iterator. The returned object must be interpreted as an iterator
* using the semantics of {@link Context#asValue(Object)} otherwise an
* {@link IllegalStateException} is thrown. The iterator elements must be interpreted as two
* elements array using the semantics of {@link Context#asValue(Object)}.
*
* Examples for valid return values are:
*
* - {@link ProxyIterator}
*
- {@link Iterator}, requires {@link Builder#allowIteratorAccess(boolean) host iterable
* access}
*
- A guest language object representing an iterator
*
*
* Examples for valid iterator elements are:
*
* - {@link ProxyArray}
*
- {@link List}, requires {@link Builder#allowListAccess(boolean) host list access}
*
- {@code Object[2]}, requires {@link Builder#allowArrayAccess(boolean) host array access}
*
- {@link Entry}, requires {@link Builder#allowMapAccess(boolean) host map access}
*
- A guest language object representing an array
*
*
* @see ProxyIterator
* @since 21.1
*/
Object getHashEntriesIterator();
/**
* Creates a proxy hash map backed by a Java {@link Map}. The map keys are
* {@link Value#as(Class) as Object unboxed}. If the set values are host values then they will
* be {@link Value#asHostObject() unboxed}.
*
* @since 21.1
*/
static ProxyHashMap from(Map values) {
return new ProxyHashMapImpl(values);
}
}
final class ProxyHashMapImpl implements ProxyHashMap {
private final Map values;
ProxyHashMapImpl(Map values) {
this.values = values;
}
@Override
public long getHashSize() {
return values.size();
}
@Override
public boolean hasHashEntry(Value key) {
Object unboxedKey = unboxKey(key);
return values.containsKey(unboxedKey);
}
@Override
public Object getHashValue(Value key) {
Object unboxedKey = unboxKey(key);
return values.get(unboxedKey);
}
@Override
public void putHashEntry(Value key, Value value) {
Object unboxedKey = unboxKey(key);
values.put(unboxedKey, value.isHostObject() ? value.asHostObject() : value);
}
@Override
public boolean removeHashEntry(Value key) {
Object unboxedKey = unboxKey(key);
if (values.containsKey(unboxedKey)) {
values.remove(unboxedKey);
return true;
} else {
return false;
}
}
@Override
public Object getHashEntriesIterator() {
Iterator> entryIterator = values.entrySet().iterator();
return new ProxyIterator() {
@Override
public boolean hasNext() {
return entryIterator.hasNext();
}
@Override
public Object getNext() throws NoSuchElementException, UnsupportedOperationException {
return new ProxyEntryImpl(entryIterator.next());
}
};
}
private static Object unboxKey(Value key) {
return key.as(Object.class);
}
private class ProxyEntryImpl implements ProxyArray {
private Map.Entry mapEntry;
ProxyEntryImpl(Map.Entry mapEntry) {
this.mapEntry = mapEntry;
}
@Override
public Object get(long index) {
if (index == 0L) {
return mapEntry.getKey();
} else if (index == 1L) {
return mapEntry.getValue();
} else {
throw new ArrayIndexOutOfBoundsException();
}
}
@Override
public void set(long index, Value value) {
if (index == 0L) {
throw new UnsupportedOperationException();
} else if (index == 1L) {
ProxyHashMapImpl.this.values.put(mapEntry.getKey(), value.isHostObject() ? value.asHostObject() : value);
} else {
throw new ArrayIndexOutOfBoundsException();
}
}
@Override
public long getSize() {
return 2;
}
}
}