dk.ilios.spanner.model.InstrumentSpec.java Source code

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Here is the source code for dk.ilios.spanner.model.InstrumentSpec.java

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/*
 * Copyright (C) 2012 Google Inc.
 *
 * 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.
 *
 * Original author: gak@google.com (Gregory Kick)
 */

package dk.ilios.spanner.model;

import com.google.common.base.Objects;
import com.google.common.collect.ImmutableSortedMap;
import com.google.common.collect.Maps;

import java.util.Map;
import java.util.SortedMap;

import dk.ilios.spanner.json.ExcludeFromJson;
import dk.ilios.spanner.util.StringMapFunnel;
import dk.ilios.spanner.util.PersistentHashing;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;

/**
 * A specification by which the application of an instrument can be uniquely identified.
 */
public final class InstrumentSpec {

    @ExcludeFromJson
    private int id;
    private String className;
    private SortedMap<String, String> options;

    @ExcludeFromJson
    private int hash;

    private InstrumentSpec(Builder builder) {
        this.className = builder.className;
        this.options = Maps.newTreeMap(builder.options);
    }

    public String className() {
        return className;
    }

    public ImmutableSortedMap<String, String> options() {
        return ImmutableSortedMap.copyOf(options);
    }

    @Override
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        } else if (obj instanceof InstrumentSpec) {
            InstrumentSpec that = (InstrumentSpec) obj;
            return this.className.equals(that.className) && this.options.equals(that.options);
        } else {
            return false;
        }
    }

    private void initHash() {
        if (hash == 0) {
            this.hash = PersistentHashing.getPersistentHashFunction().newHasher().putUnencodedChars(className)
                    .putObject(options, StringMapFunnel.INSTANCE).hash().asInt();
        }
    }

    @Override
    public int hashCode() {
        initHash();
        return hash;
    }

    @Override
    public String toString() {
        return Objects.toStringHelper(this).add("className", className).add("options", options).toString();
    }

    public static final class Builder {
        private String className;
        private final SortedMap<String, String> options = Maps.newTreeMap();

        public Builder className(String className) {
            this.className = checkNotNull(className);
            return this;
        }

        public Builder instrumentClass(Class<?> insturmentClass) {
            return className(insturmentClass.getName());
        }

        public Builder addOption(String option, String value) {
            this.options.put(option, value);
            return this;
        }

        public Builder addAllOptions(Map<String, String> options) {
            this.options.putAll(options);
            return this;
        }

        public InstrumentSpec build() {
            checkState(className != null);
            return new InstrumentSpec(this);
        }
    }
}