// Copyright (C) 2013 The Android Open Source Project
//
// 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.gerrit.server.index;
import static com.google.common.base.Preconditions.checkState;
import com.google.common.base.Function;
import com.google.common.base.MoreObjects;
import com.google.common.base.Predicates;
import com.google.common.collect.FluentIterable;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.gerrit.server.index.FieldDef.FillArgs;
import com.google.gwtorm.server.OrmException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Optional;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/** Specific version of a secondary index schema. */
public class Schema<T> {
public static class Builder<T> {
private final List<FieldDef<T, ?>> fields = new ArrayList<>();
public Builder<T> add(Schema<T> schema) {
this.fields.addAll(schema.getFields().values());
return this;
}
@SafeVarargs
public final Builder<T> add(FieldDef<T, ?>... fields) {
this.fields.addAll(Arrays.asList(fields));
return this;
}
@SafeVarargs
public final Builder<T> remove(FieldDef<T, ?>... fields) {
this.fields.removeAll(Arrays.asList(fields));
return this;
}
public Schema<T> build() {
return new Schema<>(ImmutableList.copyOf(fields));
}
}
private static final Logger log = LoggerFactory.getLogger(Schema.class);
public static class Values<T> {
private final FieldDef<T, ?> field;
private final Iterable<?> values;
private Values(FieldDef<T, ?> field, Iterable<?> values) {
this.field = field;
this.values = values;
}
public FieldDef<T, ?> getField() {
return field;
}
public Iterable<?> getValues() {
return values;
}
}
private static <T> FieldDef<T, ?> checkSame(FieldDef<T, ?> f1, FieldDef<T, ?> f2) {
checkState(f1 == f2, "Mismatched %s fields: %s != %s", f1.getName(), f1, f2);
return f1;
}
private final ImmutableMap<String, FieldDef<T, ?>> fields;
private final ImmutableMap<String, FieldDef<T, ?>> storedFields;
private int version;
public Schema(Iterable<FieldDef<T, ?>> fields) {
this(0, fields);
}
public Schema(int version, Iterable<FieldDef<T, ?>> fields) {
this.version = version;
ImmutableMap.Builder<String, FieldDef<T, ?>> b = ImmutableMap.builder();
ImmutableMap.Builder<String, FieldDef<T, ?>> sb = ImmutableMap.builder();
for (FieldDef<T, ?> f : fields) {
b.put(f.getName(), f);
if (f.isStored()) {
sb.put(f.getName(), f);
}
}
this.fields = b.build();
this.storedFields = sb.build();
}
public final int getVersion() {
return version;
}
/**
* Get all fields in this schema.
*
* <p>This is primarily useful for iteration. Most callers should prefer one of the helper methods
* {@link #getField(FieldDef, FieldDef...)} or {@link #hasField(FieldDef)} to looking up fields by
* name
*
* @return all fields in this schema indexed by name.
*/
public final ImmutableMap<String, FieldDef<T, ?>> getFields() {
return fields;
}
/** @return all fields in this schema where {@link FieldDef#isStored()} is true. */
public final ImmutableMap<String, FieldDef<T, ?>> getStoredFields() {
return storedFields;
}
/**
* Look up fields in this schema.
*
* @param first the preferred field to look up.
* @param rest additional fields to look up.
* @return the first field in the schema matching {@code first} or {@code rest}, in order, or
* absent if no field matches.
*/
@SafeVarargs
public final Optional<FieldDef<T, ?>> getField(FieldDef<T, ?> first, FieldDef<T, ?>... rest) {
FieldDef<T, ?> field = fields.get(first.getName());
if (field != null) {
return Optional.of(checkSame(field, first));
}
for (FieldDef<T, ?> f : rest) {
field = fields.get(f.getName());
if (field != null) {
return Optional.of(checkSame(field, f));
}
}
return Optional.empty();
}
/**
* Check whether a field is present in this schema.
*
* @param field field to look up.
* @return whether the field is present.
*/
public final boolean hasField(FieldDef<T, ?> field) {
FieldDef<T, ?> f = fields.get(field.getName());
if (f == null) {
return false;
}
checkSame(f, field);
return true;
}
/**
* Build all fields in the schema from an input object.
*
* <p>Null values are omitted, as are fields which cause errors, which are logged.
*
* @param obj input object.
* @param fillArgs arguments for filling fields.
* @return all non-null field values from the object.
*/
public final Iterable<Values<T>> buildFields(final T obj, final FillArgs fillArgs) {
return FluentIterable.from(fields.values())
.transform(
new Function<FieldDef<T, ?>, Values<T>>() {
@Override
public Values<T> apply(FieldDef<T, ?> f) {
Object v;
try {
v = f.get(obj, fillArgs);
} catch (OrmException e) {
log.error(String.format("error getting field %s of %s", f.getName(), obj), e);
return null;
}
if (v == null) {
return null;
} else if (f.isRepeatable()) {
return new Values<>(f, (Iterable<?>) v);
} else {
return new Values<>(f, Collections.singleton(v));
}
}
})
.filter(Predicates.notNull());
}
@Override
public String toString() {
return MoreObjects.toStringHelper(this).addValue(fields.keySet()).toString();
}
public void setVersion(int version) {
this.version = version;
}
}