001: /*
002: * <copyright>
003: *
004: * Copyright 1997-2004 BBNT Solutions, LLC
005: * under sponsorship of the Defense Advanced Research Projects
006: * Agency (DARPA).
007: *
008: * You can redistribute this software and/or modify it under the
009: * terms of the Cougaar Open Source License as published on the
010: * Cougaar Open Source Website (www.cougaar.org).
011: *
012: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
013: * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
014: * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
015: * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
016: * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
017: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
018: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
019: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
020: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
021: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
022: * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
023: *
024: * </copyright>
025: */
026:
027: package org.cougaar.core.qos.metrics;
028:
029: import java.util.Observer;
030: import java.util.Properties;
031:
032: import org.cougaar.core.component.Service;
033:
034: /**
035: * This is the query interface to the metrics services. The two basic
036: * operations, query and unubscribe, have several optional paramters,
037: * which is wny each comes in four variants. The structure of paths
038: * is defined in the Metrics Services html documenation and won't be
039: * covered here.
040: */
041: public interface MetricsService extends Service {
042: /**
043: * Retrieves the current value at the given path. The path can
044: * include special context-dependent variables whose runtime value
045: * will be determined by the evaluator. For now the qos_tags are
046: * not used.
047: */
048: Metric getValue(String path, VariableEvaluator evaluator,
049: Properties qos_tags);
050:
051: /**
052: * Retrieves the current value at the given path. The path can
053: * include special context-dependent variables whose runtime value
054: * will be determined by the evaluator.
055: */
056: Metric getValue(String path, VariableEvaluator evaluator);
057:
058: /**
059: * Retrieves the current value at the given path. No
060: * context-dependent variable handling will be done. For now the
061: * qos_tags are not used.
062: */
063: Metric getValue(String path, Properties qos_tags);
064:
065: /**
066: * Retrieves the current value at the given path. No
067: * context-dependent variable handling will be done.
068: */
069: Metric getValue(String path);
070:
071: /**
072: * Subscribes the given observer to the given path. The usual
073: * Observer api will be used for callbacks. The path can include
074: * special context-dependent variables whose runtime value will be
075: * determined by the evaluator. Ordinarily a callback will be
076: * invoked whenever the value at the path changes. This can be
077: * restricted with the qualifier.
078: */
079: Object subscribeToValue(String path, Observer observer,
080: VariableEvaluator evaluator,
081: MetricNotificationQualifier qualifier);
082:
083: /**
084: * Subscribes the given observer to the given path. The usual
085: * Observer api will be used for callbacks. The path can include
086: * special context-dependent variables whose runtime value will be
087: * determined by the evaluator. No restrictions are imposed
088: * on the callbacks, which will be invoked whenever the value at
089: * the path changes.
090: */
091: Object subscribeToValue(String path, Observer observer,
092: VariableEvaluator evaluator);
093:
094: /**
095: * Subscribes the given observer to the given path. The usual
096: * Observer api will be used for callbacks. No context-dependent
097: * variable handling will be done. Ordinarily a callback will be
098: * invoked whenever the value at the path changes. This can be
099: * restricted with the qualifier.
100: */
101: Object subscribeToValue(String path, Observer observer,
102: MetricNotificationQualifier qualifier);
103:
104: /**
105: * Subscribes the given observer to the given path. The usual
106: * Observer api will be used for callbacks. No context-dependent
107: * variable handling will be done, and no restrictions are imposed
108: * on the callbacks, which will be invoked whenever the value at
109: * the path changes.
110: */
111: Object subscribeToValue(String path, Observer observer);
112:
113: /**
114: * End a previously established subscription. The handle is as
115: * returned by one of the subscribeToValue calls.
116: */
117: void unsubscribeToValue(Object subscription_handle);
118:
119: }
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