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software.amazon.awssdk.services.neptune.jmespath.internal.JmesPathRuntime Maven / Gradle / Ivy
The AWS Java SDK for Neptune module holds the client classes that are used for
communicating with Neptune.
/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance with
* the License. A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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 software.amazon.awssdk.services.neptune.jmespath.internal;
import static java.util.stream.Collectors.toList;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.function.Function;
import software.amazon.awssdk.annotations.SdkInternalApi;
import software.amazon.awssdk.core.SdkField;
import software.amazon.awssdk.core.SdkPojo;
import software.amazon.awssdk.utils.ToString;
@SdkInternalApi
public final class JmesPathRuntime {
private JmesPathRuntime() {
}
/**
* An intermediate value for JMESPath expressions, encapsulating the different data types supported by JMESPath and
* the operations on that data.
*/
public static final class Value {
/**
* A null value.
*/
private static final Value NULL_VALUE = new Value(null);
/**
* The type associated with this value.
*/
private final Type type;
/**
* Whether this value is a "projection" value. Projection values are LIST values where certain operations are
* performed on each element of the list, instead of on the entire list.
*/
private final boolean isProjection;
/**
* The value if this is a {@link Type#POJO} (or null otherwise).
*/
private SdkPojo pojoValue;
/**
* The value if this is an {@link Type#INTEGER} (or null otherwise).
*/
private Integer integerValue;
/**
* The value if this is an {@link Type#STRING} (or null otherwise).
*/
private String stringValue;
/**
* The value if this is an {@link Type#LIST} (or null otherwise).
*/
private List listValue;
/**
* The value if this is an {@link Type#MAP} (or null otherwise).
*/
private Map mapValue;
/**
* The value if this is an {@link Type#BOOLEAN} (or null otherwise).
*/
private Boolean booleanValue;
/**
* Create a LIST value, specifying whether this is a projection. This is private and is usually invoked by
* {@link #newProjection(Collection)}.
*/
private Value(Collection value, boolean projection) {
this.type = Type.LIST;
this.listValue = new ArrayList<>(value);
this.isProjection = projection;
}
/**
* Create a MAP value, specifying whether this is a projection. This is private and is usually invoked by
* {@link #newProjection(Map)}.
*/
private Value(Map value, boolean projection) {
this.type = Type.MAP;
this.mapValue = new HashMap<>(value);
this.isProjection = projection;
}
/**
* Create a non-projection value, where the value type is determined reflectively.
*/
public Value(Object value) {
this.isProjection = false;
if (value == null) {
this.type = Type.NULL;
} else if (value instanceof SdkPojo) {
this.type = Type.POJO;
this.pojoValue = (SdkPojo) value;
} else if (value instanceof String) {
this.type = Type.STRING;
this.stringValue = (String) value;
} else if (value instanceof Integer) {
this.type = Type.INTEGER;
this.integerValue = (Integer) value;
} else if (value instanceof Collection) {
this.type = Type.LIST;
this.listValue = new ArrayList<>(((Collection) value));
} else if (value instanceof Map) {
this.type = Type.MAP;
this.mapValue = new HashMap<>((Map) value);
} else if (value instanceof Boolean) {
this.type = Type.BOOLEAN;
this.booleanValue = (Boolean) value;
} else {
throw new IllegalArgumentException("Unsupported value type: " + value.getClass());
}
}
/**
* Create a {@link Type#LIST} with a {@link #isProjection} of true.
*/
private static Value newProjection(Collection values) {
return new Value(values, true);
}
/**
* Create a {@link Type#MAP} with a {@link #isProjection} of true.
*/
private static Value newProjection(Map values) {
return new Value(values, true);
}
/**
* Retrieve the actual value that this represents (this will be the same value passed to the constructor).
*/
public Object value() {
switch (type) {
case NULL:
return null;
case POJO:
return pojoValue;
case INTEGER:
return integerValue;
case STRING:
return stringValue;
case BOOLEAN:
return booleanValue;
case LIST:
return listValue;
case MAP:
return mapValue;
default:
throw new IllegalStateException();
}
}
/**
* Retrieve the actual value that this represents, as a list of object.
*/
public List values() {
if (type == Type.NULL) {
return Collections.emptyList();
}
if (type == Type.LIST) {
return listValue;
}
return Collections.singletonList(value());
}
/**
* Retrieve the actual value that this represents, as a map of objects.
*/
private Map mapValues() {
if (type == Type.NULL) {
return Collections.emptyMap();
}
if (type == Type.MAP) {
return mapValue;
}
throw new IllegalStateException("Must be MAP type to get map values");
}
/**
* Retrieve the actual value that this represents, as a Boolean. Note that only null, boolean and string types
* are supported.
*/
public Boolean booleanValue() {
switch (type) {
case NULL:
return null;
case STRING:
return Boolean.parseBoolean(stringValue);
case BOOLEAN:
return booleanValue;
default:
throw new IllegalStateException(String.format("Cannot convert type %s to Boolean.", type));
}
}
/**
* Retrieve the actual value that this represents, as a String. Note that collection types are not supported.
*/
public String stringValue() {
switch (type) {
case NULL:
return null;
case INTEGER:
return integerValue.toString();
case STRING:
return stringValue;
case BOOLEAN:
return booleanValue.toString();
default:
throw new IllegalStateException(String.format("Cannot convert type %s to String.", type));
}
}
/**
* Retrieve the actual value that this represents, as a list of String. Note that if the contents of the list is
* not String, an exception is thrown. If the value has a different type, the code makes a best effort to return
* a single element list of String. See {@code stringValue}.
*/
public List stringValues() {
if (type == Type.NULL) {
return Collections.emptyList();
}
if (type == Type.LIST) {
List result = new ArrayList<>();
for (Object listEntry : listValue) {
Value entryAsValue = new Value(listEntry);
if (entryAsValue.type == Type.NULL) {
continue;
}
if (entryAsValue.type != Type.STRING) {
throw new IllegalStateException("Expected list elements to be of type String, but were "
+ entryAsValue.type);
}
result.add(entryAsValue.stringValue);
}
return result;
}
return Collections.singletonList(stringValue());
}
/**
* Retrieve the actual value that this represents, as a map of Strings. Note that if the contents of the map are
* not String, or if the value has a different type, an exception is thrown.
*/
public Map stringValuesMap() {
if (type == Type.NULL) {
return Collections.emptyMap();
}
if (type == Type.MAP) {
Map result = new HashMap<>();
mapValue.forEach((key, value) -> {
Value keyAsValue = new Value(key);
Value entryAsValue = new Value(value);
if (keyAsValue.type != Type.NULL) {
if (!isStringType(keyAsValue) || !isStringType(entryAsValue)) {
throw new IllegalStateException("Keys and values must be String type");
}
result.put(keyAsValue.stringValue, entryAsValue.stringValue);
}
});
return result;
}
throw new IllegalArgumentException("Not of type MAP");
}
private boolean isStringType(Value value) {
return value.type == Type.STRING;
}
/**
* Convert this value to a new constant value, discarding the current value.
*/
public Value constant(Value value) {
return value;
}
/**
* Convert this value to a new constant value, discarding the current value.
*/
public Value constant(Object constant) {
return new Value(constant);
}
/**
* Execute a wildcard expression on this value: https://jmespath.org/specification.html#wildcard-expressions
*/
public Value wildcard() {
if (type == Type.NULL) {
return NULL_VALUE;
}
if (type == Value.Type.LIST) {
return newProjection(listValue);
}
if (type == Type.MAP) {
return newProjection(mapValue);
}
if (type == Value.Type.POJO) {
return newProjection(pojoValue.sdkFields().stream().map(f -> f.getValueOrDefault(pojoValue))
.filter(Objects::nonNull).collect(toList()));
}
throw new IllegalArgumentException("Cannot use a wildcard expression on a " + type);
}
/**
* Execute a flattening expression on this value: https://jmespath.org/specification.html#flatten-operator
*/
public Value flatten() {
if (type == Type.NULL) {
return NULL_VALUE;
}
if (type != Type.LIST) {
throw new IllegalArgumentException("Cannot flatten a " + type);
}
List result = new ArrayList<>();
for (Object listEntry : listValue) {
Value listValue = new Value(listEntry);
if (listValue.type != Type.LIST) {
result.add(listEntry);
} else {
result.addAll(listValue.listValue);
}
}
return Value.newProjection(result);
}
/**
* Retrieve an identifier from this value: https://jmespath.org/specification.html#identifiers
*/
public Value field(String fieldName) {
if (isProjection) {
return project(v -> v.field(fieldName));
}
if (type == Type.NULL) {
return NULL_VALUE;
}
if (type == Type.POJO) {
return pojoValue.sdkFields().stream().filter(f -> f.memberName().equals(fieldName))
.map(f -> f.getValueOrDefault(pojoValue)).map(Value::new).findAny()
.orElseThrow(() -> new IllegalArgumentException("No such field: " + fieldName));
}
throw new IllegalArgumentException("Cannot get a field from a " + type);
}
/**
* Filter this value: https://jmespath.org/specification.html#filter-expressions
*/
public Value filter(Function predicate) {
if (isProjection) {
return project(f -> f.filter(predicate));
}
if (type == Type.NULL) {
return NULL_VALUE;
}
if (type == Type.LIST) {
List results = new ArrayList<>();
listValue.forEach(entry -> {
Value entryValue = new Value(entry);
Value predicateResult = predicate.apply(entryValue);
if (predicateResult.isTrue()) {
results.add(entry);
}
});
return new Value(results);
}
if (type == Type.MAP) {
Map results = new HashMap<>();
mapValue.forEach((key, entry) -> {
Value entryValue = new Value(entry);
Value predicateResult = predicate.apply(entryValue);
if (predicateResult.isTrue()) {
results.put(key, entry);
}
});
return new Value(results);
}
throw new IllegalArgumentException("Unsupported type for filter function: " + type);
}
/**
* Execute the length function, with this value as the first parameter:
* https://jmespath.org/specification.html#length
*/
public Value length() {
if (type == Type.NULL) {
return NULL_VALUE;
}
if (type == Type.STRING) {
return new Value(stringValue.length());
}
if (type == Type.POJO) {
return new Value(pojoValue.sdkFields().size());
}
if (type == Type.LIST) {
return new Value(Math.toIntExact(listValue.size()));
}
if (type == Type.MAP) {
return new Value(Math.toIntExact(mapValue.size()));
}
throw new IllegalArgumentException("Unsupported type for length function: " + type);
}
public Value keys() {
if (type == Type.NULL) {
return new Value(Collections.emptyList(), false);
}
if (type == Type.POJO) {
return new Value(pojoValue.sdkFields().stream().map(SdkField::memberName).collect(toList()));
}
if (type == Type.MAP) {
return new Value(mapValue.keySet());
}
throw new IllegalArgumentException("Unsupported type for keys function: " + type);
}
/**
* Execute the contains function, with this value as the first parameter:
* https://jmespath.org/specification.html#contains
*/
public Value contains(Value rhs) {
if (type == Type.NULL) {
return NULL_VALUE;
}
if (type == Type.STRING) {
if (rhs.type != Type.STRING) {
// Unclear from the spec whether we can check for a boolean in a string, for example...
return new Value(false);
}
return new Value(stringValue.contains(rhs.stringValue));
}
Object value = rhs.value();
if (type == Type.LIST) {
return new Value(listValue.stream().anyMatch(v -> Objects.equals(v, value)));
}
if (type == Type.MAP) {
return new Value(mapValue.containsValue(value));
}
throw new IllegalArgumentException("Unsupported type for contains function: " + type);
}
/**
* Compare this value to another value, using the specified comparison operator:
* https://jmespath.org/specification.html#comparison-operators
*/
public Value compare(String comparison, Value rhs) {
if (type != rhs.type) {
return new Value(false);
}
if (type == Type.INTEGER) {
switch (comparison) {
case "<":
return new Value(integerValue < rhs.integerValue);
case "<=":
return new Value(integerValue <= rhs.integerValue);
case ">":
return new Value(integerValue > rhs.integerValue);
case ">=":
return new Value(integerValue >= rhs.integerValue);
case "==":
return new Value(Objects.equals(integerValue, rhs.integerValue));
case "!=":
return new Value(!Objects.equals(integerValue, rhs.integerValue));
default:
throw new IllegalArgumentException("Unsupported comparison: " + comparison);
}
}
if (type == Type.NULL || type == Type.STRING || type == Type.BOOLEAN) {
switch (comparison) {
case "<":
case "<=":
case ">":
case ">=":
return NULL_VALUE; // Invalid comparison, spec says to treat as null.
case "==":
return new Value(Objects.equals(value(), rhs.value()));
case "!=":
return new Value(!Objects.equals(value(), rhs.value()));
default:
throw new IllegalArgumentException("Unsupported comparison: " + comparison);
}
}
throw new IllegalArgumentException("Unsupported type in comparison: " + type);
}
/**
* Perform a multi-select list expression on this value:
* https://jmespath.org/specification.html#multiselect-list
*/
@SafeVarargs
public final Value multiSelectList(Function... functions) {
if (isProjection) {
return project(v -> v.multiSelectList(functions));
}
if (type == Type.NULL) {
return NULL_VALUE;
}
List result = new ArrayList<>();
for (Function function : functions) {
result.add(function.apply(this).value());
}
return new Value(result);
}
/**
* Perform a multi-select hash expression on this value:
* https://jmespath.org/specification.html#multiselect-hash
*/
public final Value multiSelectHash(Map> selections) {
if (isProjection) {
return project(v -> v.multiSelectHash(selections));
}
if (type == Type.NULL) {
return NULL_VALUE;
}
if (type != Type.MAP) {
throw new IllegalArgumentException("Multi-select map operation is only supported for maps");
}
Map result = new HashMap<>();
for (Map.Entry> entry : selections.entrySet()) {
String key = entry.getKey();
Function function = entry.getValue();
Value selectedValue = function.apply(new Value(mapValue.get(key)));
result.put(key, selectedValue.value());
}
return new Value(result);
}
/**
* Perform an OR comparison between this value and another one:
* https://jmespath.org/specification.html#or-expressions
*/
public Value or(Value rhs) {
if (isTrue()) {
return this;
} else {
return rhs.isTrue() ? rhs : NULL_VALUE;
}
}
/**
* Perform an AND comparison between this value and another one:
* https://jmespath.org/specification.html#or-expressions
*/
public Value and(Value rhs) {
return isTrue() ? rhs : this;
}
/**
* Perform a NOT conversion on this value: https://jmespath.org/specification.html#not-expressions
*/
public Value not() {
return new Value(!isTrue());
}
/**
* Returns true is this value is "true-like" (or false otherwise):
* https://jmespath.org/specification.html#or-expressions
*/
private boolean isTrue() {
switch (type) {
case POJO:
return !pojoValue.sdkFields().isEmpty();
case LIST:
return !listValue.isEmpty();
case MAP:
return !mapValue.isEmpty();
case STRING:
return !stringValue.isEmpty();
case BOOLEAN:
return booleanValue;
default:
return false;
}
}
/**
* Project the provided function across all values in this list. Assumes this is a LIST or MAP and isProjection
* is true.
*/
private Value project(Function functionToApply) {
if (type == Type.LIST) {
return new Value(listValue.stream().map(Value::new).map(functionToApply).map(Value::value)
.filter(Objects::nonNull).collect(toList()), true);
}
if (type == Type.MAP) {
return new Value(mapValue.values().stream().map(Value::new).map(functionToApply).map(Value::value)
.filter(Objects::nonNull).collect(toList()), true);
}
throw new IllegalArgumentException("Can only project on List or Map types");
}
/**
* The JMESPath type of this value.
*/
private enum Type {
POJO,
LIST,
MAP,
BOOLEAN,
STRING,
INTEGER,
NULL
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
Value value = (Value) o;
return type == value.type && Objects.equals(value(), value.value());
}
@Override
public int hashCode() {
Object value = value();
int result = type.hashCode();
result = 31 * result + (value != null ? value.hashCode() : 0);
return result;
}
@Override
public String toString() {
return ToString.builder("Value").add("type", type).add("value", value()).build();
}
}
}
